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Principles of Animal Nutrition Objectives: An understanding of basic nutrition concepts and terminology Relationship between nutrition and animal function Sources of information Examples of nutrition application Outline Classification of nutrients and nutrient analysis Feed classification and composition Digestibility: measurement and variability Energy requirement and feed energy utilization Water as a nutrient and water quality Carbohydrates Lipids Protein: monogastric animals and ruminants Minerals: macro and micro Vitamins: fat and water soluble 1 References: Basic Animal Nutrition and Feeding. Pond, Church and Pond, John Wiley, Fourth Edition 1995. Applied Animal Nutrition; Feeds and Feeding. Cheeke, Collier MacMillan, 2nd Ed, 1999. Nutrient Requirements of Domestic Animals. National Academy of Sciences, National Research Council (NAS-NRC), Washington, D.C. Description graduate veterinarian requirement: Veterinary Nutrition Education Program AVMA (www.acvn.org) On-line Glossaries: Definitions of English terms in Animal Science and Agriculture USA: http://www.epa.gov/agriculture/ag101/glossary.html Canada: http://www.aps.uoguelph.ca/~gking/Ag_2350/glossary.htm 2 What to learn from Nutrition Lectures? How feeds are classified Differences in composition How types of feeds differ Digestibility concepts and influencing factors Energy partition in the animal and feed energy GE to NE Energy requirement estimation Carbohydrates as energy and gut microbe modifiers Lipids as energy and fatty acid sources Monogastric animal protein nutrition, essential amino acids, protein quality Ruminant protein utilization, rumen microbial protein, bypass protein, Cornell fractions 3 Under what circumstances may macro and micro mineral deficiencies occur, general signs of deficiencies, appropriate supplements Be familiar with fat and water soluble vitamins Basic nutrition vocabulary and understanding of nutrition principles Laboratories outcomes (not offered at CAU) Be familiar with feedstuffs and simple methods of ration formulation Sensitivity to the possibility of inadequate nutrition or toxicity of diet constituents in all clinical cases Understand general ration characteristics, digestibility / availability, nutrient requirements and approaches to determining requirements Some familiarity with feed processing and equipment 4 NUTRIENT: Any chemical element or compound in the diet that supports life processes, such as reproduction, growth, lactation, draft power, and maintenance. Classes of nutrients: 1. Water 2. Proteins and amino acids 3. Carbohydrates 4. Lipids 5. Vitamins 6. Inorganic elements (minerals) *Note energy is not considered a nutrient – it is derived from nutrients: lipids, carbohydrates and protein 5 6 Specialty terms: Functional foods or nutraceuticals: These are foods that have non-nutrient effects that contribute to health Pre- and pro-biotics: Prebiotics are nutrients that specifically allow growth of beneficial microbial populations in the gut Probiotics: are microbial communities/strains included in feed (inoculation) to colonize the gut and improve gut health of the host ***************************************************** Energy: Not a nutrient in itself but fuel (ATP) provided by lipid, carbohydrate, and carbon skeleton of amino acids after removal of N. Essential Nutrient: Required in diet because it can not be synthesized by the body in sufficient amounts to satisfy metabolic needs. 7 Nutrition is an Interdisciplinary Science It involves the following science disciplines: Digestive physiology Biochemistry Analytical chemistry Endocrinology and Metabolism Microbiology Pathology Nutritional Genomics and Genetics Animal behaviour and management Environmental studies Animal Nutrition also incorporates economic considerations 8 Nutrition: Purpose of Nutrition is to provide Nourishment It is the science (or study) of daily diet and health 1. Nutrient requirements of animals 2. Content of nutrients in food or feed 3. The balancing (mixing in specific amounts)of a mixture of feed ingredients to meet the animal’s nutrient requirement at lowest cost 4. Through computer models predict from feed nutrient content the actual animal performance that one can expect from an animal fed a certain diet 9 The Application of Nutrition in Feeding Animals (How to approach feeding management in steps): 1. Q: What is the nutrient requirement of class of animal for specific productive or physiological function (look this up in tables)? Note that these are minimum requirements for typically healthy animals under ideal conditions (thus not very practical) They do not take into consideration stress, disease or parasite conditions of the animal Feed formulation must also be sensitive to environmental considerations (low N and P in urine and feces) 10 Requirement vs allowance Requirement is the minimum; allowance is a practical approach allowing a safety margin 2. Q: What is the nutrient content of feed ingredients? Preferably from chemical analysis, Near Infrared Spectroscopy (NIR) or else from tables and data bases; 11 and a.Consider availability of nutrients (digestibility) b.Consider anti-nutritional factors c. Consider antagonism between nutrients and other factors (feed matrix) 3. Formulate and balance a ration using the feed ingredients available on a least cost basis with set limits (parameters) Computer models Limits to production Animal health 12 Sequence of Events in Nutrient Deficiency The discovery of most of the nutrients as essential dietary constituents has been accomplished largely with farm and laboratory animals. Regardless of the nutrient deficiency the same sequence of events prevails: 13 Nutrient deficiency ↓ Biochemical defect ↓ Functional defect ↓ Microscopic anatomical defect ↓ Macroscopic anatomical defect ↓ Morbidity (illness) ↓ Mortality (death) 14 Nutrition Affects Health Status of Animals Beef Cattle: Rumen Acidosis – amount and form of carbohydrates Rumen Impaction – high fiber, low energy and low protein roughage Low Fertility, Calving Difficulty – over-fat cows Dairy Cattle: Ketosis – body condition, feed intake, liver metabolism (similar to pregnancy toxemia in sheep) Fatty Liver Syndrome – body condition and feed intake Low Milk Fat Syndrome – amount and type of carbohydrate, low rumen pH 15 Milk Fever – calcium, acid base balance Left Abomasal Displacement – body condition, exercise Llamas: Diarrhea – amount and frequency of eating Constipation – amount and quality of forage in young llamas Swine: Poor Milk Production – excess body condition Lameness – body condition, mineral and vitamin D nutrition Obesity in Sows – feed energy density, feeding system 16 Horses: Malnutrition- starvation Laminitis – carbohydrate overload Contracted tendons – minerals, rate of growth Reasons for Continued Nutritional Study 1. Genetic improvement of animals 2. Increased artificial rearing 3. Environmental concerns and Green House Gas emissions 4. Changing genetics of crops-feeds 5. Reduced use of multiple protein sources; primarily reliance on a few feedstuffs 6. Early weaning in swine 7. New feedstuffs 8. Changes in agronomic practices 9. Narrow profit margins 17 Reasons for Chemical Analysis of Feeds and Feed Ingredients Ration formulation: - Analyze feed samples for on farm use - To develop feed data bases on feed composition - Regional and company data bases To provide analyses for use in estimating available energy use of feedstuffs (TDN, Net Energy etc.) To provide information to solve a production problem that may be feed related To place a market value on a feed To verify a commercial guarantee For use in a feed quality competition (forage quality) 18 Feed Sampling for Analysis: Sampling technique is the most important cause of variation in nutrient values Method is important to avoid error Show slides here Forage Hay: Penn State core sampler - 10-12 bales Silage: grab samples - 4 to 6 250 ml samples composited and mixed Feed in bags Core samples from 5 bags Bulk feed in a bin 10 samples from different areas - Mix on a flat surface on paper 19 - Store in a tightly closed container - Refrigerate if necessary Nutrient Groups We know which the nutrients are, but how do we measure these chemically? Chemical analysis using the Proximate Principles ‘Weende System’ Water Crude Protein (CP; assumes 16% nitrogen in crude protein) 100 ÷ 16 = 6.25 therefore N % x 6.25 = CP % Crude Non Protein N (NPN) and true protein [Melamine is a NPN] Ether extract (fat) 20 Ash Crude fibre (older method) Nitrogen Free Extract (non-fibre carbohydrate or starch) In flow diagram next page: Ash is further analyzed for minerals by atomic absorption spectrophotometry. Fiber is measured as Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF). 21 Flow diagram Proximate Analysis 22 FIBRE IN FEEDS 1. Old Measure: Crude Fibre (CF) Indigestible by monogastric animals 2. Van Soest Fibre or Plant Cell Wall method (for forages) slide a.Neutral Detergent Fibre (NDF) includes Cellulose (beta glucose linkage) Lignin (phenolics) Hemicellulose (xylose, arabinose, ribose) b. Acid Detergent Fibre (ADF) includes Cellulose Lignin c. Acid Detergent Lignin (ADL) 23 Example Dairy Feeding: ADF 19-21% of DM NDF 30-32% of DM (early lactation 28%) NDF digestible, slowly degradable More gradual organic acid production Increased saliva flow higher HCO3- secretion buffering Reduced risk of rumen acidosis 24 Other Typical Feed Analyses silage pH (3.8 – 5.0) and butyric acid bomb calorimetry for gross energy (GE) amino acid analysis NIR: near infrared, estimates protein, energy and fibre using equations feed microscopy, identify ingredients and contaminants 25 WATER CONTENT OF FEEDS 1. Reported as “As Is” OR “As Fed” OR “Air-Dry” 2. Standardized to 90% DM, is also termed Hay Equivalent (HE) as most hay has around 90% DM 3. Standardized to Dry Matter (DM) Basis (0% moisture or 100% DM) 2 and 3 are done to standardize comparisons of feed ingredients and price Remember: More water or moisture in a feed dilutes the nutrient content or density. Less water concentrates the nutrient content or density. 26 EXAMPLE : Dog food as fed = 35% DM (65% water) and 3% CP Convert CP% to a dry 100% DM basis = 3% CP X (100 % DM / 35 % DM) = 8.57% or 3% CP / (35 % DM / 100 % DM) = 8.57% Hay and Hay Equivalent: 10% CP on a 87% DM basis = 10 x 90/87 = 10.34% CP as HE (90% DM) (drier feed thus increasing nutrient density) 27 LAB - FEED CLASSIFICATION CONCENTRATES High in energy, low in fibre content high energy - (and can be high protein) Cereal grains: barley, corn, oats, wheat Grain milling by-products: wheat bran, rice bran Food processing by-products; molasses, distillers and brewers byproducts Roots and tubers; turnips, potatoes, cassava PROTEIN SUPPLEMENTS Contain more than 20% protein Oilseed meals; canola meal, soybean meal, cottonseed meal, linseed meal Grain legumes; peas, lentils, beans, lupins Animal proteins; fishmeal, meat and bone meal, feather meal nitrogen/protein for ruminants Non protein nitrogen; urea, ammonium phosphate Rumen bypass protein; dehydrated alfalfa, corn gluten meal 28 Roughages Bulky material with high fibre content and low nutrient density. Protein and mineral content varies widely Pasture Silage (see next page) Hay Straw Roughages can be legume of non-legume Legume is a N fixator and has higher protein content – clover, alfalfa (lucerne) Non-legume – grass silage, barley silage, corn silage, grass hays (bluegrass, timothy). 29 FEED ADDITIVES Mineral supplements, limestone, salt Vitamin supplements Amino acids Drugs; antibiotics, ionophores Preservatives; antioxidants, mold inhibitors Buffers; sodium bicarbonate Flavors; anise, fenugreek, licorice Pellet binders; lignosulfonate, bentonite Silage process: (slide) 30 High quality silage low butyrate, high lactate and low pH PHASES: I: Oxygen 12-24h II: Acetic acid 24-72h III: low pH low acetic high lactate 3-4d IV: Preserved with lactate V: feed out with oxygen infiltration spoilage and mold formation 31 GENERAL RATION CHARACTERISTICS SWINE: Cereal grains 7O-80% OiI meals (soy or canola meal) Mineral-vitamin supplements Synthetic amino acids DAIRY COWS: Forages (hay-silage) 40-95% Cereal grains Oil meals and byproduct feeds Proteins not degraded in the rumen ie. blood meal, various heated proteins Mineral-vitamin supplements Buffers (sodium-bicarbonate) 32 Lecture Digestibility: The proportion of the feed not excreted in the feces, and which is therefore assumed to be absorbed (it is implied that nutrients which disappeared from the gut were absorbed in a useful form, but this was not measured! Methods of Determining Digestibility Measurement Total collection Indicator methods Estimation Chemical analysis ie. ADF, or more complete analysis Enzyme laboratory methods 33 Artificial rumen (in vitro) Rumen nylon bag (in sacco) Mobile nylon bag; moves through part or all of the intestine in surgically altered animals (pigs) Total Collection Method Animals are fed a single feed or a diet of known composition for a number of days and during the latter part of the period all feces are collected; After 10-14 days for monogastrics, 2030 d for ruminants. Must know amount and composition of feed consumed and amount and composition of feces voided. Then calculate: 34 Apparent Digestibility, % Nutrient intake - Nutrient in feces x 100 Nutrient intake True Digestibility, % Correct for endogenous excretion Nutrient intake - (Nutrient in feces - endogenous nutrient) x 100 Nutrient intake True digestibility is used mainly for protein and fat. Can also be used for minerals. Index or indicator method An indicator substance is mixed with the diet or given by bolus: Bolus characteristics: 35 Not absorbed (No effect on the animal) Not altered in the gut Excreted uniformly in the feces Readily measured Example: Chromium Sesquioxide (Cr203) green color 36 FACTORS AFFECTING DIGESTIBILITY Animal Factors Type of Digestive Tract Low digestibility of plant cell walls (fiber) by monogastrics Age of animal Level of feed intake Health status Feed Factors Feed composition (type of plant, stage of maturity, amount and type of fibre) Processing of feed, fine particle size, part of plant Additives, enzymes Associative or Matrix effects (one feed changing the digestibility of others) 37 Effect of Environment Temperature: low temperature, faster rate of passage, lower digestibility (ruminants) ******************************************************** *********************************************** OTHER METHODS USED TO EVALUATE FEEDS AND DETERMINE NUTRIENT REQUIREMENTS Used in combination, may overlap 1. Dose-Response Trials Growth (dietary amino acid level) Biochemical or functional defect (Thiamin or Vitamin A) Nutrient balance (protein, trace minerals) 2. Factorial Method (energy, protein) Maintenance 38 Growth Production (milk, wool, activity) 3. Digestion Trials Measures availability of nutrients in feeds Whole digestive tract or part of the tract in surgically altered animals, rumen fistula, or duodenal canula 4. Clinical-metabolic evaluation Biochemical, function, microscopicmacroscopic defects 5. Use of statistical analysis 39 EXAMPLE OF DIGESTIBILITY BY TOTAL COLLECTION • Steer 300 kg live weight. • 14 day adjustment period on experimental ration • 5 day fecal collection • 5 day feed intake, DM; 6 kg/day x 5 days = 30 kg • 5 day fecal collection; Total wet feces = 40 kg DM % in feces = 30% Total dry feces = 30% of 40 kg = 12 kg • Dry matter digestibility = 30kg DM intake - 12 kg DM in feces x 100 = 60% DM Dig. 30kg • Crude protein digestibility = 15% CP in feed DM 17% CP in fecal DM CP digestibility = (30 kg x 15%) - (12 kg x 17%) X 100 = 55.6% 30KG X 15% • Digestibility of other nutrients Gross energy; DE, kcal/kg Ether extract ADF, NDF Starch or nitrogen free extract 40 ENERGY Required by all animals for: Maintenance, growth, physiological functions of living tissue Thermoregulation Locomotion Measurement: Calorie “Quantitatively, energy is the most important element of diet.” Source: CHO, Lipids (fats) (protein) - Animal will eat to satisfy its energy requirement - Determines the daily intake of feed - Thus determines the overall intake of all nutrients - Nutrients musts be balanced to the energy intake 41 BIOENERGETICS - Energy sources, utilization and metabolism All animal functions and biochemical processes require a source of energy ENERGY TERMINOLOGY Calorie (CAL) = energy to raise 1 g water from 14.5 to 15.5 C Kcal = 1000 calories Mcal = 1000 kcal (also called a therm) Joule (J) = 4.184 cal BTU = 252 cal (not used in animal nutrition) Calorie system: North American feed industry, US research Joule system: UK Feed industry and research and Canadian research publications. 42 GROSS ENERGY Heat released from complete oxidation of a feed can be measured in an oxygen bomb calorimeter Nutrient Kcal /g Carbohydrate mean 4.20 Protein mean 5.65 Fat mean 9.30 Ash (minerals) 0 Water 0 Glucose 3.78 Glycine 2.04 Lysine 4.84 Ethyl alcohol 7.11 Methane 13.3 Acetic acid 3.49 Propionic acid 4.96 Butyric acid 5.95 43 Gross energy is influenced mainly by water, fat and ash content of a feed and to a lesser extent by the type of carbohydrate, fat and protein 44 Gross Energy of Feed (GE) (Heat of Combustion) Fecal Energy (FE) 1. Undigested feed 2. Enteric microbes & their products 3. Excretions into the GI tract 4. Cellular debris from the GI tract Apparent Digestible Energy (DE) Urinary Energy (UE) Gaseous Products of Digestion (primarily methane) Metabolizable Energy (ME) Heat Increment (heat of nutrient metabolism) Heat of Fermentation (from the rumen, cecum, large intestine) Net Energy (NE) Maintenance Energy 1. Basal Metabolism 2. Voluntary Activity 3. Thermal Regulation 4. Product Formation 5. Waste Formation and Excretion Productive or Recovered Energy 1. Tissue Energy (muscle, fat) 2. Lactation (milk) 3. Conceptus 4. Wool, Hair 5. Work Heat Production 45 Digestible Energy (DE) DE = Gross Energy – Fecal Energy DE/GE = 80% for pigs and poultry DE/GE = 70-80% for ruminants fed concentrates DE/GE = 50-60 % for ruminants fed roughages Metabolizable Energy (ME) Takes into account additional losses arising from the absorption and metabolism of the feed, such as energy loss in urine and energy lost in gaseous products of digestion. ME = DE – (UE + GPD) ME is usually in the range of 82 % of DE in ruminants and 92 % in pigs GPD - Gaseous Products of Digestion: Results from fermentation in the digestive tract. The gases produced contain energy and thus result in energy loss. 46 Methane, Hydrogen and Hydrogen Sulfide Non-ruminants: <1 % Ruminants 5 – 15 % (significant) Efficiency of ME use: ME use for maintenance, 65 % in ruminants ME use for lactation, 65 % in ruminants ME use for growth and fattening, 45 % in ruminants, 70 % in nonruminants 47 Net Energy Net energy refers to the part of the feed that is completely useful to the animal to maintain itself or to produce growth, milk, eggs, etc. NE = ME – Heat Increment HI - Heat Increment Increase in Heat Production Following Eating When the Animal is in a ThermoNeutral Environment. Work of Digestion = 5% Heat of Fermentation = 15 % Nutrient Metabolism = 80 % Factors Affecting Heat Increment Digestibility of ration high then lower HI 48 Makeup of Ration Forages have higher HI than concentrates (more heat of fermentation and C2) Level of Feeding How the Feed is Utilized (In ruminants the C2:C3 ratio, with C3 more efficient metabolism) Amino Acid Balance (40%) Nutrient Deficiency Frequency of Feeding Higher frequency, lower HI Injury or infection (30-40%) Genetics 49 NE - MAINTENANCE NE - PRODUCTION BASAL METABOLISM GROWTH HEAT TO KEEP BODY WARM FAT DEPOSITION VOLUNTARY ACTIVITY ASSOCIATED WITH MAINTENANCE REPRODUCTIVE PRODUCTS MILK WORK 50 Maximum Level of Energy Intake For growth in most species = twice maintenance For work in most species = twice maintenance For lactation = two to four times maintenance (dairy cows can take in 4x maint.) Estimate of Feed intake kg DM/d: Look up in NRC tables Rough guide – express as % of Body Weight (BW) Maintenance ~1.8 - 2.0 % BW Peak lactation ~ 3.5-3.8% BW Growth ~ 2.8-3.0 % BW 51 Determination of Net Energy Requirements and Feed Values Feed values can be determined by measuring or estimating the various components of energy partition. The difference between gross energy and the components gives an estimate of NE. Requirements can be estimated from energy stored in products (gain or milk) when a known amount of feed is consumed. Stored energy (gain) can be obtained from slaughter trials and carcass analysis or various estimates of carcass composition: Specific gravity Ultrasound Isotope dilution techniques Combinations of methods can be used for both feed values and requirements. 52 Other energy systems: Physiological Fuel Values (PFV) (or Atwater or 4-9-4 or ME) A form of ME where gas loss is ignored (used in dogs, pigs and people) Nutrient Protein NFE (CHO) Fat GE (kcal/g) 5.65 4.15 9.4 Urine 1.25 ----- Dig Factor 92 4.0 98 4.0 95 9.0 Measured as kcal/g Example: Bread, 100g of DM: 12.2 g CP, 2.3 g fat, 66 g of NFE (12.2 x 4) + (2.3 x 9) + (66 x 4) = 334 kcal ME 53 For pet foods • Modified Atwater factors for processed diets ▫ Carbohydrate: 3.5 kcal/g ▫ Protein: 3.5 kcal/g ▫ Fat: 8.5 kcal/g 54 55 56 57 Calculating Maintenance Energy Requirement Basal Metabolic Rate (BMR) or Basal Energy Requirement (BER) 70 X BW kg 0.75 (ME kcal/day) Fasting (in monogastric animals) At rest Thermoneutral Brain, liver, heart and kidneys make up about 5 % of body weight, but account for 60 % of basal oxygen consumption. Muscle makes up about 40 % of body weight, and accounts for 25 % of basal O2 consumption in monogastrics. In ruminants, Resting (fed and not fasting) Metabolic Rate is used (RMR): 77 X BW kg 0.75 (ME kcal/day) Voluntary activity Body temperature regulation 58 Waste formation and excretion Maintenance Estimate Is BMR X 1.2 to 1.8 depending on activity _____________________________________ Canine (dog)daily energy requirements (ACVN) In Kcal ME/kg BW Resting Energy Requirement (RER) = 70 x Wkg0.75 or 30(BW) + 70 (between 2 and 45 kg) Maintenance (0.8 to 1.6 x RER): Healthy, neutered adult Intact adult Obese prone Weight loss Geriatric 1.6 x RER 1.8 x RER 1.4 x RER 1.0 x RER 1.1 x RER Work: Light 2 x RER Moderate 3 x RER Maximum 4-8 x RER 59 Growth: Under 4 months 3 x RER 4 months to adult 2 x RER Lactation: 4 – 8 x RER or free choice feeding Feline (cat) daily energy requirement Same basis as for dogs Resting Energy Requirement (RER) = 70 x Wkg0.75 or 30(BW) + 70 (between 2 and 45 kg) Average, neutered healthy adult Intact adult Active adult Obese prone Critical care Geriatric Lactation Growing kittens 1.2 x RER 1.4 x RER 1.6 x RER 0.8 x RER 1.0 x RER 1.1 x RER 2-6 x RER 2.5 x RER 60 Caloric Restriction and Longevity Caloric restriction of 10-30% below ad libitum extends life span and health span, including brain and behavioural function. First reported by McCay, 1935. J of Nutrition, 10: 63 This has been found with many species: dogs, rodents, fish, nematodes, spiders, flies, protozoa, primates including humans Many theories: Reduced growth rate Reduced body adipose tissue Lower metabolic rate Reduced plasma glucose-insulin fluctuation?? Less oxidative cell damage from hydroxyl radicals, peroxides, etc. (mitochondrial membrane) Protection from acute stressors or the general protective action hypothesis 61 2007Reduced incidence of various diseases Improved disposition to resist disease Aging at a slower rate Protection against neurotoxic insult and reduced age-related neuronal loss Increased cellular stress resistance and adaptive cellular stress response Cyto-protective proteins, growth factors, antioxidant enzymes Exercise – caloric restriction interaction? Phytochemicals? Effect can be induced with alternating fasting and feeding periods with normal calorie intake, which suggests that induction of protective mechanisms may be important 62 CARBOHYDRATES IN NUTRITION Carbohydrate is a translation of the French term “Hydrate de Carbone” -They contain H and O in the proportion found in water They are the primary product of photosynthesis in plants There is no specific individual carbohydrate requirement for animals but some carbohydrate is needed for metabolic functions Dietary carbohydrate type and amount are related to health 63 FUNCTIONS OF CARBOHYDRATES Energy Source Structural component of other compounds -non essential amino acids -lipids (glycerol synthesis) Anti - ketogenic (prevents breakdown of fat and generation of ketones) Protein sparing effect Bulk (fiber) Palatability (or influence food preference) Sweetness Structure, water holding capacity in processed foods and feeds Pre-biotic 64 CLASSIFICATION Monosaccharides ( 5 and 6 carbon) Disaccharides Trisaccharides Polysaccharides Pentosans Hexosans Mixed Polysaccharides CARBOHYDRATES Large amounts in plants Starch (70% of cereal grain) Cellulose (up to 40% of forages) Hemicellulose Pectin - Small amounts in animals Glycogen Glucose Chitin 65 HOMOPOLYSACCHARIDE: CHO contains only ONE TYPE of saccharide unit 1. STARCH: slides basic unit: alpha-D-glucose principal starch form in CEREALS (seed energy storage) two (2) forms of starch exist: AMYLOSE and AMYLOPECTIN a. AMYLOSE: alpha 1,4 linkage only – straight chain 15 – 30 % of total starch in most plants soluble in water molecular wt: 10,000 – 100, 000 (glucose = 180) exists in alpha-helical coil: retains IODINE – blue color degraded by both and β – Amylase high amylose grains - lower glycemic index 66 b. AMYLOPECTIN: alpha 1,4 linkage with alpha 1,6 linkage at branch points 70 – 85% of total starch NOT soluble in water Molecular wt: > 1,000,000 Limited coil – cannot retain iodine red purple color Lots of side chains = 19 – 20 glucose unit Degraded by - Amylase only 2. GLYCOGEN: animal starch Basic unit: alpha – D – glucose Exists in small amount in LIVER and MUSCLE Similar to AMYLOPECTIN in structure Except HIGHLY BRANCHED – with shorter side chains Water soluble NO helical coil red color with iodine 67 3. CELLULOSE: Basic unit: β D – glucose With beta 1,4 linkage in straight chain Highly stable and crystalline: no animal enzyme can digest it Microbial CELLULASE can degrade it COTTON is one of the purest form Most abundant CHO in nature 4. INULIN: Basic unit: FRUCTOSE High molecular weight, soluble in water Found in roots and stems Used extensively in metabolic studies 68 HETEROPOLYSACCHARIDE: CHO contain more than one (2 – 6) types of sugars 1. HEMICELLULOSE NOT ½ of a CELLULOSE It is plant glue - sticky β - 1,4 linked XYLOSE (a pentose) branched complex mixture of glucose, mannose, arabinose and galactose principal component of plant CELL WALL mammalian enzymes CANNOT degrade this, however, microbial enzymes do 2. PECTIN mainly POLYMERS of alpha 1,4 linked glucose but also contain D-galacturonic acid. Thus, no animal enzyme can break it However, readily available to ruminant microbes Found primarily in the space between CELL WALLS Soluble in water 69 Non-CARBOHYDRATE LIGNIN: Polymers of PHENYL PROPANE derivatives Encases the cellulose and hemicellulose As plant matures it becomes “woody”: lignification Reduces digestibility of cellulose and hemicellulose NO animal or anaerobic microbial enzyme can break it SOME fungi and aerobic microbes can digest it 70 Major Components of Lignocellulosic Biomass (Department of Energy USA) Example of composition of wood 71 DIGESTIBILITY OF CARBOHYDRATES STARCH All species 80-100% Cell Walls Are in the Neutral Detergent Fiber (NDF) fraction: hemicellulose, cellulose and lignin Digestibility: Ruminants 50-90% Horse 35-50% Poultry 25-35% Pig 5-30% Dog 10-30% Human 25-40% 72 Nutritional Classification of Starch Non ruminant system Based on release of glucose from an in vitro assay using a pepsin-carbohydrase enzyme cocktail Rapidly available glucose (RAG) Rapidly available starch (RAS) 20 min test Slowly digestible starch (SDS) 120 min test Resistant starch (may have similar effects as fibre) Physically inaccessible (whole grain) Resistant granules Retrograde starch (Amylose), B type granules Glycemic Index: Rise in blood glucose after a test food is consumed High White Bread 100 Glucose 140 Instant Rice 124 French Fries 107 Sucrose 83 Low Skim Milk 46 Oatmeal 87 Pasta 40-70 Apple 34-76 73 DIGESTION IN RUMINANTS Reticulum: Receives feed from esophagus Pass feed to rumen and omasum Reticular groove reflex (suckling reflex) to shunt liquids directly to abomasum (calf) Eructation and rumination Rumen: Bulk of fermentation: bacteria, protozoa, fungi Digestion via microbial enzymes Some mineral absorption Volatile fatty acid absorption (extensive) VFA’s are major end products of fermentation and provide a major source of energy to ruminants Omasum: Regulates flow to lower gut: filter Water absorption Some mineral absorption (Mg) 74 Abomasum: Analogous to gastric stomach in nonruminants Digestive secretions (host) Digestion of Carbohydrates by Ruminants A. Ruminant’s saliva is different from the nonruminants. Saliva in the COW, SHEEP, and GOAT does not contain AMYLASE Output of saliva in ruminants is very high. It contains a lot of buffers Without it, rumen pH would drop markedly B. In the rumen conditions are ideal for bacterial and protozoal growth: Fairly constant pH (pH 6) Anaerobic conditions Constant temperature Constant supply of nutrients Continuous removal of products of microbial digestion 75 C. Microbial enzymes break glycosidic bonds of fiber and starch Bacterial cellulase and hemicellulase are capable of breaking the beta 1,4 bonds between CHO of cellulose and hemicelluloses Bacterial amylases also break starch into maltose. Protozoa engulf starch and digest starch inside their bodies. D. Glucose is present in the rumen only transiently Glucose is promptly used by microbes and through their glycolytic pathway converted into pyruvate. Pyruvate is further converted into endproducts called volatile fatty acids. These include ACETIC, PROPIONIC, BUTYRIC and other longer chain FATTY ACIDS. This process is called FERMENTATION. The VFAs are released from the microbes (as end-products) and are then available for absorption and utilization by various tissues. 76 RUMINANT DIGESTIVE PROCESSES: 1. Feed enters the foregut and it may either be fermented by microbes or bypass the foregut altogether 2. Hence, digesta entering the abomasum included undigested feed and microbial cell mass 3. The proportions of these two components are extremely variable. Highly soluble feeds are extensively digested by microbes. Less soluble feed constituents largely bypass microbial degradation 4. Heat treated feed or feed treated with formaldehyde or coated with oil, so that high quality feed can escape the microbes in the rumen and thus can be break down in the abomasum and SI. 5. Ruminants absorb very little glucose 77 RUMEN FERMENTATION VS CECUM FERMENTATION: What is the difference?? Major absorption site is at SMALL INTESTINE Rumen is located before, and cecum is located after the small intestine FACTORS DETERMINING AMOUNTS & PROPORTIONS OF RUMEN VFA 1. Level of feed intake 2. Frequency of feeding 3. Proportions of starch and fibre 4. Size of forage particles small particle size (finely ground) increases C3 5. Presence of rumen modifiers in the diet (lonophores) increased C3 78 Alteration of ROUGHAGE : CONCENTRATE RATIO: o Increased roughage intake results in high acetic acid level high milk fat high methane production higher rumen pH (lower acidity; 6.1 – 6) o Increased concentrate intake results in: High propionic acid level High body fat Lower rumen pH (higher acidity; 5.5 – 5.8) Alteration of the PHYSICAL FORM of the diet: o Grinding and pelleting generally increase reactions which produce more Propionic acid (more rapid fermentation) and lower pH 79 Classification of Carbohydrate Fractions in Feed for Cattle Cornell - Penn State System Fraction CHO type Rate of rumen utilization, % /h A Soluble sugars 150-350 B1 Starch, pectin, beta-glucans 10-50 B2 Fermentable cell wall (NDF) 2-10 C Unavailable cell wall 0 80 CLASSIFICATION OF THE LIPIDS Simple lipids Fatty acids: C2 to C24, saturated and unsaturated Monoglycerides: monoacylglycerol Diglycerides: diacylglcerol Triglycerides: triacylglycerol Cholesterol: cholesterol esters Bile acids: cholic acid, taurocholic acid, glycocholic acid, etc. Vitamin A: vitamin A esters Waxes: esters of alcohols other than glycerol Prostaglandins: hormones, essential fatty acids Compound lipids: derivatives of phospatidic acid Phosphatidylcholine (lecithin) Phosphatidylethanolamine Phosphatidylserine Phosphatidylinositol Sphingolipids Other Lipids Glycolipids, Liproproteins, Androgens, Estrogens Chylomicrons, HDLs, LDLs, VLDLs 81 CLASSIFICATION OF LIPIDS Lipid = All Ether Extractable material 1. SIMPLE LIPIDS -Esters of FA and Alcohols (mainly Glycerol) FATS OILS (SOLID AT (LIQUID AT ROOM TEMP) ROOM TEMP) ESTERS OF FA AND OTHER ALCOHOLS: WAXES 2. COMPOUND LIPIDS - Esters of FA and Glycerol containing 2 FA residues and another chemical grouping (eg. Choline linked through phosphoric ACID: Lecithin) 3. DERIVED LIPIDS -Substances derived by hydrolysis EG. FA ALCOHOLS (EG. GLYCEROL) STEROLS AND CHOLESTEROL 82 THE ROLE OF LIPIDS IN NUTRITION Source of dietary energy 2.25 x carbohydrate Low heat increment - Minimize heat stress Source of essential fatty acids Linoleic C18:2 and Linolenic C18:3 Source of omega-3 fatty acids Carrier of fat soluble vitamins A, D, E, K Cell structure and metabolic role Feed/Food flavor (palatability) Dust control, food/feed consistency, Physical characteristics Minimizes wear on feed handling equipment 83 LIPID CONTENT OF COMMON FEEDSTUFFS Feed Lipid % of DM Linoleic % of Lipid Alfalfa hay Barley silage Brome grass hay 2.7 3.0 2.2 16 ------- Barley grain Corn grain Oat grain Wheat grain Wheat bran 1.9 3.8 4.5 1.6 6.0 42 56 33 40 55 Canola seed 40 65 Canola meal 3.5 ------ Soybeans 18 45 Soybean meal 1.0 40 Meat meal 9.0 2 Fish meal 9.0 2 Milk, whole 30 3 Lard 98 11 84 FUNCTIONS OF BODY FAT 1. Energy Reserve 2. Insulation 3. Protection and Cushioning 4. Cell Membranes 5. Steroid Hormones 6. Bile Acids 85 Essential Fatty Acids (EFA) Animals and people cannot synthesize EFAs, so these must be provided in the diet EFAs are precursors for C20 compounds (eicosanoids) prostaglandins, thromboxane’s and leukotrienes intracellular messengers only (not transported in blood) Most common mono-unsaturated FA in animals are: oleic (18:1c∆9) and palmitoleic (16:1c∆9). (∆ delta, counted from COOH) In animals and humans microsomes contain four Fatty Acid Desaturase enzymes, which can introduce desaturation at (Carbon) C4, C5, C6 or C9 (only up to C9). Linoleic acid 18:2c∆9,12 or linolenic acid 18:3c∆9,12,15 cannot be synthesized as they require desaturation beyond C9. These must be provided in diet: Thus are Essential Fatty Acids 86 Omega 6 (n-6) (means the first double bond is 6C from the terminal CH3): Linoleic acid (C18:2) Gamma Linolenic acid (C18:3) = GLA Arachidonic acid (C20:4) Omega 3 (n-3) (means the first double bond is 3C from the terminal CH3): Alpha Linolenic acid (C18:3) Plants ALA Eicosapentaenoic acid (C20:5) EPA Fish Docosahexanoic acid (C22:6) DHA Fish EPA and DHA melting point = -54°C! Omega-6 Omega-3 Gamma-linolenic (GLA) Alpha-linolenic ALA ↓ ↓ ↓ ↓ Arachidonic acid ↓ PGE2 EPA ↓ DHA ↓ PGE3 Anti-inflammatory Inflammatory 87 EFA: Need as 1% of calories WHO/FAO: n-6 : n-3 PUFA ratio from 4:1 to 10:1 Deficiency omega-6: Reduced growth, reproduction Skin lesions, dermatitis, impaired wound healing Edema, subcutaneous hemorrhage Reduced Inflammatory response Mechanisms of action for omega 3 FAs: Anti-arrhythmic Anti-thrombotic Anti-atherosclerotic Anti-inflammatory Improved endothelial function (vasomotor function/dilation) Lowers blood pressure Lowers triglyceride level Aspirin: • "non-steroidal anti-inflammatory drugs" (NSAIDs) (aspirin, ibuprofen, acetaminophen) • inhibit the synthesis of prostaglandins from arachidonic acid 88 Some important fatty acids of refined vegetable oils in Canada (w/w %) Fatty Acid 16:0 18:0 18:1 18:2 18:3 20:1 22:1 Flax Canola Soybean Corn Peanut 6 3 17 16 56* 4 2 55 26 10* 2 Tr 9 5 45 37 3* Tr Tr 11 2 27 59 1 Tr Tr 11 3 46 29 1 Tr Tr Sun- Olive Palm flower 7 14 42 5 2 4 19 64 38 66 16 9 Tr Tr Tr Tr * α-linolenic acid (omega 3) Fish oil, flax, canola/rapeseed, walnuts, soy sources of α-linolenic acid 89 Canola oil positive factors: High in C18:1 and LA (omega 6) : ALA (omega 3) = 2 : 1 Health Canada Diet Target ω 6 : ω 3 = from 4:1 to 10:1 US: 2.5 : 1 as ideal; 250 mg/d (2011) Common: 20:1 90 Essential fatty acids for cats and dogs Essential fatty acid (g) LA ALA AA EPA + DHA Essential fatty acid (g) LA ALA AA EPA + DHA Growing puppies allowance (per kg BW0.75) 0.8 0.05 0.022 0.036 Adult dogs recommended allowance (per kg BW0.75) Bitches late gestation and peak lactation allowance (per kg BW0.75) 0.36 0.014 1.6 0.10 0.03 0.06 Kittens allowance (per kg BW0.75) 0.29 0.01 0.01 0.05 Adult cats allowance (per kg BW0.75) Queens late gestation and peak lactation allowance (per kg BW0.75) 0.3 0.011 0.011 0.0044 0.14 0.0015 0.0025 Source: Nutrient Requirements of Dogs and Cats. 2006. National Research Council (U.S.) 91 92 Fatty acids are not a source of energy to microbes. There is minimal degradation of long-chain fatty acids in the rumen. No absorption of long chain fatty acids from the rumen Active hydrogenation of unsaturated fatty acids Microbial synthesis of long-chain fatty acids in the rumen (15g/kg nonfat org matter fermented) More fat leaves the rumen than consumed by the animal Lipids leaving the rumen: 80 to 90% free fatty acids attached to feed particles and microbes ~10% microbial phospholipids leave the rumen Small quantity of undigested fats in feed residue 93 Diagram of the molecular structure of different fatty acids Saturated fat saturated carbon atoms (each with 2 hydrogens) joined by a single bond Cis-unsaturated fatty acid Trans-unsaturated fatty acid unsaturated carbon atoms (each with unsaturated carbon atoms (each with 1 hydrogen) joined by a double 1 hydrogen) joined by a double bond. Cis configuration. bond. Trans configuration. Oleic acid (C18:1 cis 9) Elaidic acid (C18:1 trans 9) Oleic acid is a cis unsaturated fatty acid that comprises Elaidic acid is a trans unsaturated fatty acid often found 55-80% of olive oil. in hydrogenated vegetable oils. These fatty acids are geometric isomers (chemically identical except for the arrangement of the double bond). Trans fat not usually present in food unless use of hydrogenation process of PUFA oils high trans fat content. Small amounts of trans fats found in ruminant produced food (rumen microbial hydrogenation) 94 Conjugated Linoleic Acid (CLA) Present in ruminant fat, and produced in rumen fermentation by microbial saturation of UFA Linoleic acid (cis-9, cis-12 C18:2) hydrogenated to several trans forms including CLA (cis-9, trans-11 C18:2) POSITIVE HEALTH EFFECTS OF CLA o Anti-carcinogenic o Anti-atherogenic o Anti-obesity (nutrient partitioning) o Enhanced immune system o Prevents or delays diabetes Milk fat contains 3.5 to 7 mg CLA/g fat 95 CLA content in some foods Food CLA isomers mg/g fat Beef 4.3 Pork 0.6 Chicken 0.9 Milk 5.5 Colby cheese 6.1 Corn oil 0.2 cis 9, trans 11 % 85 82 84 92 92 39 Increasing CLA isomers in foods produced by ruminants: Grass pasturing Feeding unsaturated vegetable oils: fish oil, flax oil, canola oil. Can increase CLA content from typical 3-4 mg CLA/g fatty acids to 5-25 mg in milk. 96 Feeding unsaturated oils with high concentrate diet (low rumen pH) trans-10, cis 12 CLA isomer inhibits milk fat synthesis low milk fat Effects of Fats on Rumen Fermentation Upper limit is around 7-8% fat in diet. Typical is about 3% fat in diet ingredients and then one can add up to 3% from a fat source. Lipid-coated feed particles: interferes with attachment of microbes and enzymes to feed Cytotoxic to rumen microbes (cell membranes): FA associate with cell membranes masking cell membrane receptors and enzyme secretion Become incorporated in cell membranes and changing fluidity (electrolyte transport) 97 PUFA may change redox conditions in cells, oxidation stress - PUFA oils are more inhibitory than saturated fats - Feeding whole oil seeds with high PUFA content less inhibitory Consequences: Reduced feed intake Reduced fiber digestion! Reduced milk fat Increase propionate/acetate ratio Fatty acids can be used to defaunate the rumen (protozoa very sensitive) 98 OXIDATIVE RANCIDITY Auto-catalytic reaction in unsaturated fatty acids with generation of oxygen radicals and potentially leading to spontaneous combustion Accelerated by pro-oxidants o - Heat o - U.V. Light o - Moisture o –Transition Metals eg Cu,Fe, Mn Anti-oxidants o -Vitamin E o -Ethoxyquin o -Butyl Hydroxy Anisole (BHA) 99 Cholesterol: Many important steroids are derived from cholesterol in animals, including: HORMONES including androgens, estrogens, progestins, glucocorticoids, and mineralocorticoids BILE ACIDS which are detergent molecules secreted in bile from the gallbladder that assist in the absorption of dietary lipids in the intestine Animal products are a source of cholesterol- important in human nutrition Normally not considered in animal nutrition as the diets are mostly made up of plant ingredients 100 WATER Sources (3): Drinking water Water in feed Metabolic water Functions of water: Solvent, GIT extra- and intra-cellular and for excreta Chemical reactions – Synthesis of urea, protein hydrolysis Lubricant and solvent for lubricants Temperature regulation Physical protection, cushions organs and nerve tissue Average daily water requirements Class of livestock Dairy cow Beef cow Beef steer Feeder pig Ewe Laying hen L/day 160 55 35 7-10 2-7 0.25 101 Water content of feeds: Corn Barley Oats Hay Silage Beets Potatoes % water 12 11 9 10 (8-15) 70 (45-75) 87 75 Metabolic water formed from: Carbohydrate 60% Protein 40% Fat 100% (1 g water per 1 g fat) Factors affecting water requirement: DM intake. Water intake is 3x DM intake Composition of feed. Increased by salts and minerals Physiological state: lactation, pregnancy Ambient temperature and relative humidity (RH) Temperature of drinking water Frequency of watering. Most species require at least 3/day or DM intake is reduced 102 Water quality Good water: Clear and colorless Low total solids No disease organisms, pesticides No undesirable flavour or odor No objectionable gases Quality considerations TDS = Total dissolved solids, mg/L Hardness: Soft water = <60 mg/L Ca + Mg Very hard = >800 mg/L Ca + Mg Maximum for livestock = 1000 mg/L Salinity: (salts, mainly NaCl) estimated from conductivity (EC) and may be expressed as TDS mg/L 103 TDS <1000 EC <1.5 Excellent for all types of livestock 1000 3000 1.5- Satisfactory for all livestock but 5 may slightly reduce productivity, mild diarrhea, especially poultry 3000 - 5-8 Acceptable except poultry. Will 5000 cause temporary diarrhea and may be refused at first 5000 - 8Usually safe for beef cattle, 7000 11 sheep, swine and horses 7000 – 11- Not suitable for young, pregnant 10,000 16 or lactating animals >10,000 >16 Not recommended under any conditions 104 Livestock water quality guidelines Parameter Calcium Nitrate + nitrite Nitrite alone Sulfate TDS mg/L (maxima) = PPM 1000 100 10 1000 3000 (2000 for aquatics) Aluminum Cadmium Copper 5 .02 1 (cattle) 0.5 (sheep) 5 (swine and poultry) 2 .1 .003 .5 .05 50 Fluoride Lead Mercury Molybdenum Selenium Zinc 105 Common water quality problems Sulfate >1000 mg/L Source: Calcium sulfate rock (gypsum) Effects: Reduces availability of Ca, Zn, Fe, Mn, Mo, Cu Action: Improve water quality and/or provide additional trace minerals, especially Cu Nitrite > 10 mg/L OR nitrate + nitrite >100 mg/L Source: Fertilizer or animal waste Effect: Formation of methemoglobin (brown blood), reduced vitamin A utilization and absorption Action: Prevent contamination Iron > 2 mg/L Not a nutritional problem. Causes scale formation in pipes; may form slimy bacterial films, poor taste. Can chlorinate and filter to remove iron Fecal contamination: Coliform count should not exceed 10 CFU/ml. Cryptosporidium, enterotoxigenic E. Coli, Salmonella, Leptospira, protozoa, round worms 106 Biochemical Oxygen Demand (BOD): Organic content of water - Chemical measure for estimating the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at a certain temperature over a specific time period. BOD of 3-5 mg O2/L water is maximum for aquatic life. Poor taste at 1-3 mg O2/L water Blue-Green Algae (cyanobacteria): Unpalatable and may contain toxins Suggested water treatments: Problem Solution Coliform count Chlorinate water Water hardness Install softener High nitrates or other Ion exchange or RO minerals system Iron Filtration High water pH Acidification High turbidity Coagulation 107 Vulnerability of water supplies 1. Surface water 2. Cisterns 3. Natural springs 4. Shallow hand-dug or sandpoint wells (<50 ft) 5. Artesian wells 6. Drilled wells 7. Public water supplies Small Animals Water requirement for dogs and cats is linked to energy consumption (water : calorie ratio). Water (ml per day) : ME (kcal per day) = 1:1 Dog example: 10 kg adult dog Maintenance requirement is 132 x BW0.75 = 742 kcal ME Water : energy ratio is 1:1 Water requirement = 742 ml 108 Of that 742 ml about 74-119 ml is generated from metabolic water. Required water intake from water and feed then is ca. 642 ml per day. Cats: Same ratio, but it is recommended to double the volume to allow for lifestage, environment, work activities. For both cats and dogs the recommendation is to allow animals to self regulate as opposed to working with required intake of water. 109 Protein Nutrition 1. Introduction, general, classes of proteins, amino acids 2. Non-ruminant protein nutrition a. Quality: i. Protein digestibility: ileal vs. fecal Amino acid digestibility: ileal vs. fecal Amino acid balance, biological value Assay for protein quality b. Requirement: i. Maintenance ii. Production 3. Ruminant protein nutrition a. Versus non-ruminant b. Microbial fermentation: microbial protein synthesis from non-protein nitrogen (NPN) energy interaction quality of microbial protein c. Feed protein: Solubility of N Degradable protein Bypass protein 110 Protein: 1.Primary function: Source of amino acids for body protein or source of Nitrogen for ruminants 2.Secondary function: Source of energy during: - consumption of excess protein - consumption of poor quality protein Lower efficiency of energy utilization (only 70-75 % vs carbohydrate 95%) due to energy cost required for clearance of NH2 Urea cycle and uric acid production require energy Protein nutrition is complex: chemistry (23 amino acids) more metabolic pathways essential vs. non-essential amino acids different digestion coefficients between amino acids 111 relative proportions of amino acids in feed matter optimal relative proportions of amino acids change with physiological state (growth, lactation, pregnancy, disease) very limited storage of amino acids Protein turn-over g / day: Protein intake represents only 1/3 of total protein synthesis Human: intake gut secretion fecal loss absorbed 100 g/d 70 g/d 170 g/d 10 g/d 160 g/d Protein turn-over: Protein synthesis / day Protein intake / day Amino acids re-used daily 300 g 100 g 200 g 112 Protein: highest concentration in muscle (apart from water) important in tissue growth animals have limited ability to synthesize protein: from amino acids only, and not from NH2 of all nutrients protein deficiency or imbalance between amino acids has the most pronounced negative effect on carcass quality Conclusion: Protein is an essential component in the diet. 113 Forms of proteins: 1. Fibrous: collagen, elastins, keratins 2. Globular: albumins, globulins, glutelins, histones, prolamines, protamines 3. Conjugated: nucleoproteins, mucoproteins, glycoproteins, lipoproteins, hemoproteins, metalloproteins 4. Derived: poorly defined, product of degradation Amino acids: Primarily used in the L- form, with a few exceptions Some OH analogs may substitute such as methionine hydroxy analog. Done for economic reasons. 114 Use of D and L amino acids by nonruminants: Amino acid MET (hionine) PHE (nylalanine) PRO (line) LEU (cine) VAL (ine) TRY (ptophan) ISO (leucine) HIS (tidine) LYS (ine) THRE (eonine) ARG (inine) D form relative to L = = = < slightly ½ limited limited limited 0 (negative effect) 0 0 115 Classification of amino acids: Essential (EAA; 10) Non-essential Arg (inine) Ala (nine) His (tidine) Asp (artic acid)** Iso (leucine) Cys (teine) Leu (cine) Gly (cine)** Lys (ine)* Ser (ine) Met (hionine)* Tyr (osine) Phe (nylalanine) Pro (line)** Thre (onine)* Glu (tamic acid)** Try (ptophan) Val (ine) * Not present in adequate quantity in grains ** Essential in some cases or may have nonnutritional effect (functional food) Cats (carnivore): Taurine is an EAA (present in meat) Specific amino acid relationships: Methionine: Requirement only met by Met Cysteine: Requirement met by Cys or Met 116 Phenylalanine: only met by Phe Tyrosine: met by Tyr or Phe Gly and Ser: interchanged Protein analysis: Normally Crude Protein (CP) Uses the Kjeldahl procedure and is a measure of total N in sample. o Non-protein nitrogen (NPN) is also converted to N and measured as N Use Kjeldahl factor to determine protein based on N being constant in feeds at 16 % of total protein (100/16 = 6.25) The factor can differ between some foods (milk = 6.38; feed = 6.25) Amino acid analyses is used mainly in research and by feed companies for quality control. Expensive and not used in routine ration formulation. 117 Monogastric protein nutrition Protein quality measurements: Digestibility: Apparent: True: P intake - P output P intake P intake - (P output - MFP) P intake MFP = Metabolic Fecal Protein = MFN x 6.25 MFN = Metabolic Fecal Nitrogen MFN is determined by: 1. Feeding a protein free diet and measure N in feces. 2. Feed different levels of protein in diets, measure N in feces, and extrapolate N back to a 0% protein diet. Does not work in poultry because urine contaminates the feces 118 Digestibility of protein is affected by a wide range of factors: 1. Heat damage of protein (enzymatic browning or Maillard reaction: formation of aminosugar complexes (Lys)). 2. Level of feed intake. 3. In forages age of plant at harvest (% fiber). 4. Anti-nutritive factors: - Trypsin inhibitor in raw soybean - Gossypol interferes with Lys - Lectins interfere with amylase - Tannins are complexing agents Which method of measuring digestibility is more reliable to estimate true nutrient absorption? Use composition of the feces or of the digesta at the ileal-caecal junction (Ileal vs. fecal method)? Consider interference by fermentation and metabolism in the caecum and large intestine: NH3 is generated, absorbed into the blood stream and excreted in urine 119 Remember that digestibility measures disappearance of N or protein (N x 6.25) from the G.I. Tract and not absorption) Example: Sorghum protein for pigs Apparent digestibility % True digestibility % Ileal 60.4 69.0 Fecal 71.1 78.4 Does CP digestibility reflect digestibility of all amino acids in the crude protein? No Use ileal or fecal method for estimating digestibility of amino acids? Ileal method. True digestibility AA (%) Ileal Lysine 73.4 Methionine 77.6 Phenylalanine 71.5 Valine 72.6 Fecal 77.8 76.5 81.1 80.2 120 Example of fecal vs. ileal measurement Comparison of ileal and fecal digestibilities of raw and heated soybean meal (SBM) (heat treatment inactivates the trypsin inhibitor in soybeans) Lys Met Cys Thr Tryp Raw Fecal Ileal 71.9 44.2 61.0 46.7 77.7 35.2 65.2 32.2 75.4 24.8 Heated Fecal Ileal 87.3 84.9 82.5 83.0 87.0 74.1 83.0 71.5 86.8 72.3 Are amino acid digestibilities constant for each feed or do they change with different feeds used in a feed formulation (matrix effect of ingredients)? Not constant due to matrix effects. 121 122 Protein quality - Amino acid balance in feed = concentration of amino acids in feed in relation to physiological needs: growth, lactation, pregnancy, eggs, wool Close match high quality protein Poor match low quality protein Identify limiting amino acid(s) in poor quality protein. 1st, 2nd, 3rd Poor amino balance growth response to the addition of limiting AA. Ie. Zein (corn protein) - poor quality - growth –ve 123 Growth in rats fed zein, or zein supplemented with tryptophan or with tryptophan and lysine Osborne and Mendel 1914 Lys 1st limiting; tryp 2nd limiting 1. Aim at ideal balance. 2. Fast growth ---- lean tissue amino acid composition is the requirement. 3. Ideal protein concept 124 125 Measuring protein quality 1. Ideal protein = ideal AA pattern concept Liebig’s “Law of Minimums" Undersupply of one single essential amino acid will inhibit the use of those in adequate supply 126 Ideal protein: Established ideal pattern (balance) of digestible essential amino acids for lean meat deposition (protein accretion), when supplied with sufficient nitrogen for the synthesis of non-essential amino acids. No excess, no deficiency and as little conversion of amino acids for energy is desirable. N excretion is minimized. The assumption is that the pattern of amino acids required does not change relative to the amount of lean tissue deposition, but the absolute amount of amino acids or ideal protein required does. The level of individual amino acid required is expressed on a ratio basis to lysine, which serves as the reference amino acid. Lysine is 1st or 2nd limiting amino acid. Simple chemical analysis in feeds. Lysine is used primarily for protein accretion. A lot of information on lysine requirements is available. Synthetic lysine is cheap 127 Ideal Protein: Is a perfect balance of amino acids that will cover the requirement of the animals Lysine is always set at 100% - all other amino acids are set as a % of lysine Allows for the calculation of the requirement of all amino acids if the lysine requirement is known 2. Biological assays Protein Efficiency Ratio PER (dates back to 1919): Feed efficiency measured on a protein level basis 10% CP in ration, 28d period Reference protein is casein Measure g gain/g protein consumed Rats or chicks 128 Quality is measured in terms of growth only, not lactation or pregancy. More applicable to children. Used in human nutrition and is a simple and cheap testing method. The test is highly standardized by WHO. Standard reference casein available for PER tests. 129 Nitrogen Balance True Biological Value: NI – (FN - MFN) – (UN - EUN) NI – (FN – MFN) x 100 Measures N retained as a % of N absorbed Classic test Biological value of proteins for growing and adult rats Protein Egg albumin Beef muscle Meat meal Casein Peanut meal Wheat gluten Growing 97 76 72-79 69 54 40 Adult 94 69 51 46 65 Many other tests including: Available lysine (color reaction) to test for Maillard reaction products In vitro protein digestion 130 Feed Protein for Ruminants: Quantity: The quantity of protein to be fed depends on the protein requirement of the ruminant and on the quality of the protein in the feed. Quality of Protein for Ruminants: Digestibility: Traditional method which has limitations as discussed. Digestibility of protein in forages is lower than that of grains and protein supplements. Forage protein digestibility depends on: - Forage species - Forage maturity - Weathering - Heating (Maillard reaction) 131 Modern protein classification based on: 1. Solubility in rumen: Totally and fast degraded to NH3 True protein and NPN Determined in buffer 2. Undigestible N (bound protein): ADF-bound; perform N assay on ADF 3. Degradability in rumen: Protein to varying degree is broken down to NH3. The rate of breakdown depends on physical characteristics of the protein, and on physical conditions in the rumen (dilution rate). Measured by protein disappearance from porous nylon bags hung in the rumen of fistulated ruminants. 4. Bypass protein (escape/undegradable): The protein is not broken down in the rumen and arrives in the abomasum intact. Measured by nylon bag technique. Useful to target limiting amino acids to the S.I., and also to increase total protein available to high producing ruminants. 132 3. RUMINANT PROTEIN NUTRITION Three objectives 1. OPTIMIZE MICROBIAL PROTEIN OUTPUT 2. OPTIMIZE BYPASS PROTEIN / FEED PROTEIN TO MEET NEEDS OF THE ANIMAL 3. MINIMIZE LOSS OF NH3 (COST AND ENVIRONMENT) 3.1 MICROBIAL PROTEIN: 3.1.1 QUALITY REL UNAFFECTED BY DIET BV = 80% (BACTERIA + PROTOZOA) TRUE DIGESTIBILITY: PROTOZOA 88% BACTERIA 66% PROTOZOA ON ROUGHAGE DIET 20% NUCLEIC ACIDS INFERIOR TO HIGH QUALITY ANIMAL PROTEIN SUPERIOR TO GRAIN PROTEIN EQUAL TO SOYBEAN MEAL OR CANOLA MEAL OR ALFALFA NB SOYBEAN MEAL = SBM CANOLA MEAL = CM RAPESEED MEAL = RSM 133 3.1.2 QUANTITY OF PROTEIN SYNTHESIS IN RUMEN by microbes 1. INHERENT METABOLIC LIMITATIONS IN BACTERIA AND PROTOZOA 2. PHYSICAL LIMITATIONS: SIZE OR CAPACITY OF RUMEN; FLOW OF DIGESTA 3. ENERGY SUPPLY FOR PROTEIN SYNTHESIS; OTHER NUTRIENTS 134 135 136 FACTORS AFFECTING THE AMOUNT OF MICROBIAL PROTEIN SYNTHESIS 1. RUMEN NH3 CONCENTRATION MAX RATE and EFFICIENCY OF MICROBIAL PROTEIN SYNTHESIS IS AT 5 MG NH3 /100 ml RUMEN FLUID > 5 MG / 100 ML NH3 TO BLOOD LIVER UREA LOSS < 5 MG / 100 ML N LACK 2. RUMEN pH pH high NH3 DIFFUSION pH low NH4 + SLOW DIFFUSION 137 138 3. DIETARY ENERGY LEVEL (need energy to drive microbial growth) % TDN MICROBIAL PROTEIN Produced g/KG DM > 75% 51.2 65-75% 38.4 < 65% 26.0 UPPER LIMIT OF NON PROTEIN NITROGEN UTILIZATION WHEN SUPPLEMENTING UREA (FERMENTATION POTENTIAL) % PROTEIN IN RATION % TDN (DM) BEFORE NPN IS ADDED 60-65 65-70 70-75 75-80 MAX CP AT WHICH NPN IS USED 8% 10 10.5 10.9 11.2 10 % 10.8 11.3 11.7 12.0 139 This example suggests that 3.2 % crude protein can be added in the form of urea when the starting CP is 8% and at 75-80 % TDN. If more is added, the NH3 from urea will be lost in urine as it cannot be used by microbes UREA FEEDING RULES: Urea contains 45% N, thus 1% urea contains 45/100 X 1 X 6.25 = 2.81 % crude protein. LIMIT 1% OF GRAIN MIX; 0.5% TOTAL DIET UREA IS NOT PALATABLE, MIX IN FEED MIX WITH MOLASSES 140 4. RATE OF FERMENTATION OF CARBOHYDRATE SYNCHRONIZE PATTERNS OF NH3 AND ENERGY SUPPLY MOLASSES: TOO FAST STRAW: TOO SLOW CEREAL STARCH ACCEPTABLE 141 CEREAL STARCH: IS ACCEPTABLE 142 5. OTHER NUTRIENTS? SULPHUR S : N = 1 : (10 - 12) FOR DE NOVO SYNTHESIS OF S AA. 6. RUMEN DILUTION RATE RATE OF FLOW OF DIGESTA OUT OF RUMEN % / HOUR SLOW RESIDENCE TIME OF BACTERIA IN RUMEN MAINTENANCE ENERGY ENERGY FOR GROWTH 143 BACTERIA MASS / ATP MAX (THEORETICAL) 20 EFFICIENCY OF BACTERIA GROWTH MAINTENANCE 15 YIELD 10 5 0 2 4 6 10 8 DILUTION RATE (% / h) DIL. RATE MAINTENANCE EXPENSE ENERGY FOR BACTERIA GROWTH OF BACTERIA BACTERIAL PROTEIN AVAILABLE TO HOST 144 Review again Modern protein classification for ruminants is based on: 1. Solubility in rumen: Totally and fast degraded to NH3 True protein and NPN Determined in buffer in lab 2. Undigestible N (bound protein): ADF-bound; perform N assay on ADF 3. Degradability in rumen: Protein to varying degree is broken down to NH3. The rate of breakdown depends on physical characteristics of the protein, and on physical conditions in the rumen (dilution rate). Measured by protein disappearance from porous nylon bags hung in the rumen of fistulated ruminants. 4. Bypass protein (escape/undegradable): The protein is not broken down in the rumen and arrives in the abomasum intact. Measured by nylon bag technique. Useful to target limiting amino acids to the S.I., and also to increase total protein available to high producing ruminants. 145 Application example – Cornell System Protein fractions in feed: A NPN that is soluble and available in the rumen B1 buffer soluble protein which is precipitated by tungstic acid. This fraction is made up of soluble and degradable true protein which is degraded in the rumen at a rate of 100350% per hour. B2 This is the buffer insoluble protein that is in the cell contents rather than in the cell wall. It is degraded at an intermediate rate of 5 to 15% per hour. B3 This is slowly degradable cell wall protein that may be increased in heat 146 processed feeds. The rate of degradation of this fraction is less than 1% per hour. C This is cell wall protein and N which is not fermented by rumen bacteria and is not available post-ruminally. It consist of N mainly associated with lignin, tannins and Maillard reaction products. 147 148 Factors affecting protein degradability Solubility in the rumen Retention time in the rumen Tertiary structure on the protein Feed processing and storage (heat damage etc.) Treatments to increase escape potential Heat treatment of the feed Formaldehyde treatment Tannin treatment Encapsulation in a rumen inert polymer 149 PROTEIN REQUIREMENT GRAMS OF CP / DAY = CRUDE SHOULD BE IN GRAMS OF DIGESTABLE AA / DAY = LACK DATA! A LARGE TURNOVER OF PROTEIN / DAY: PROTEIN INTAKE REPRESENTS ONLY 1/3 OF TOTAL PROTEIN SYNTHESIS. INTAKE 100 g / day GUT SECRETION 70 g / day 170 g 10 g fecal loss 160 g absorbed TURNOVER 300 g synth daily 100 g intake 200 g re-used AA 150 B. PROTEIN – ENERGY INTERACTIONS DEFICIENCY OF ENERGY WITH NORMAL PROTEIN INTAKE: LIMITS USE OF PROTEIN – AA converted to meet energy requirement; stunts growth, reduced muscle mass but lean animal GROWTH METABOLIC LIMIT E LIMITS GROWTH CP ENERGY % CP CP LIMITS GROWTH 151 AMINO ACID IMBALANCE WITH ADEQUATE ENERGY INTAKE limits use of protein for muscle DEAMINATION AND USE OF AA FOR ENERGY NOT USED FOR PROTEIN, BUT FOR FAT TISSUE SYNTHESIS, GROWTH with REDUCED MUSCLE MASS AND FAT DEPOSITION 152 C. PROTEIN OR AA DEFICIENCY NO PARTICULAR SIGNS: POOR GROWTH POOR PERFORMANCE MORE EXTREME: ANEMIA LOW BLOOD PROTEIN EDEMA REPRODUCTION KWASHIORKOR MARASMUS = = PROTEIN MAN ENERGY MAN 153 PROTEIN REQUIREMENT REQUIREMENT: MINIMUM AMOUNT OF A NUTRIENT NEEDED FOR A SPECIFIC FUNCTION ALLOWANCE: AMOUNT PROVIDED IN DIET TO SATISFY REQUIREMENT + MAY CONTAIN A SAFETY MARGIN REQUIREMENT EMPIRICAL THEORETICAL (TESTS) FACTORIAL OR PARTITION APPROACH LITERATURE VALUES OFTEN A COMBINATION of both 154 MINERALS INTRODUCTION: 26 of 90 elements are essential Major or macro (measured in %): S, Ca, P, K, Na, Cl, Mg, Fe Minor or trace (measured in ppm or ppb): I2, Cu, Zn, Mn, Co, Ni, Mo, Se, Cr, F, Sn, Si, V, As Essential: Required to maintain life Modern definition of essential: Consistently impaired function Supplementation prevents or cures >1 Investigator >1 Species Major advances in mineral nutrition research as a result of new analytical equipment. Atomic absorption spectrophotometer is the work horse. New experimental conditions: ultraclean lab equipment and animal housing filtered air synthetic diets 1969: ration with 5 ppb Se showed Se deficiency 155 Dependence of biological function on tissue concentration or intake of a nutrient Each element has its own specific curve Different tissues or enzymes will also have different curves i.e. some enzymes in different tissues have different sensitivities depending on essential nature of enzyme function For each element there is a range of safe and adequate exposures in which homeostasis is maintained Every element is potentially toxic In practice marginal areas difficult to define (subclinical) leading to marginally reduced animal performance on a large scale ------ high $ impact Clinical deficiency is only tip of the iceberg and easily corrected 156 Single element can influence several metabolic processes. Example Cu 1. Cytochrome oxidase involved in ATP trapping - affects all energy dependent processes - affects a wide range of processes - differences between tissues in terms of effects and priority Lesion: nervous tissue specific effect Lesion elsewhere non-specific 2. Tyrosinase converts tyrosine to melanin (pigmentation) Tyrosinase requires Cu as a catalyst Cu deficiency: First sign = depigmentation 3. Lysyl oxidase connective tissue synthesis Tropoelastin elastin Cu deficiency connective tissue disorders, and cardiovascular disorders Functions fail at different times and therefore symptoms may indicate severity of deficiency or toxicity 157 Separate graphs: Depletion phase in terms of pools and elements Length of depletion phase can be variable depending on complicating factors such as chelators, stress, disease 158 Depletion rate is a function of: Reserve pool Rate of mobilization Requirement Length depletion phase can be variable depending on complicating factors 159 Homeostatic control: WHY??? Large variation of levels of minerals in feeds; even within plant species Factors responsible: Genus, species or strain of plant Type of soil Rate of plant growth Climatic or seasonal conditions Irrigation Stage of maturity Soil management (fertilizer, pH) Herbicides Environmental (acid rain, smelters, traffic pollution) Harvesting of plants (leave loss; soil contamination, equipment contamination) 50 fold differences in concentration common 10 fold differences in concentration within species common Degree and method of homeostasis vary Rejection of excess is as important as absorption and retention: Earth’s crust Mn 15X in conc than Zn Forages Mn about same conc as Zn Body Mn about 1% of Zn conc 160 Homeostatic control routes: 1. % absorbed 2. Excretion via urine 3. Tissue deposition in harmless and /or mobilizable forms 4. Secretion into milk 5. Endogenous excretion via feces (bile) Minor routes: exhalation, sloughing of cells skin, hair, wool, perspiration Mineral requirement: Affected by: Type, composition of product (physiological function) Type of animal, species, breed, sex, age Level and chemical form in diet Amount and nature of feed consumed Acidic; basic; chelating agents such as phytate, oxalates Non-dietary environment Stress affects homeostatic ability 161 162 Calcium and Phosphorus nutrition: inter-related both have to be in adequate amounts Ca:P ratio important dependence on vitamin D Bone: 25% ash (fresh) 45% water 10% fat 20% protein Bone (dry and fat-free basis): ash 55% protein 45% Ca:P = 2:1 also contains Mg, Na, Sn, Pb, F, S, carbonate and citrate Bone types: 1. Soft: readily mobilized, amorphous 2. Long: harder, static, crystalline Bone is characterized by active metabolism and constant turnover. 163 Ca and P exchange occurs across bone - blood. Deposition of salts depends on: concentrations of Ca and P solubility constant Ksp hormonal effects (calcitonin and PTH) weight stress leads to remodeling and strengthening Abnormal bone conditions: Rickets Occurs in growing animals only inadequate calcification of growing bone occurs with low concentrations of Ca or P in feed occurs with low absorption efficiency of Ca or P Vitamin D deficiency or phytate or abnormal Ca:P ratio Symptoms of rickets: reduced ash content of bones rubbery bones and beaks enlarged joints bending of ribs bent legs, arched backs, lameness, bone fracture Rickets can be corrected with Ca, P and vitamin D in early stage. 164 Osteomalacia as rickets, but occurs in mature animals sub-normal intake of Ca and P or reduced absorption high parathyroid hormone concentration in blood bone demineralization associated with pregnancy or lactation bone fracture (pelvic at calving) higher incidence in dairy cows Osteoporosis reduced absolute amount of bone, but with normal composition high incidence in middle-aged females: long term sub-normal Ca intake increased bone resorption estrogen provides “protective” effect Nutritional secondary hyperthyroidism also referred to as big head disease in horses low Ca and high P in diet >> Ca deficiency and interference of Ca absorption by high P content low blood Ca >>> high PTH>>> bone mobilization >>> normal to low normal Ca, but very high P in blood connective tissue invades demineralized bone resulting in deformity 165 occurs when horses are fed grain rations without supplements Function in soft tissues: Ca: Blood clotting Enzyme function: lipase, ATPase Nerve function: nerve/muscle action potential Insulin release beta-cells pancreas P: Energy metabolism Acid-base balance Deficiency: Ca: Tetany (milk fever in dairy cows) Increased blood clotting time Reduced insulin release (could lead to ketosis) Skeletal P: Reduced fertility!!!!!!!!!!!!!!! Reduced feed intake, pica Skeletal 166 Toxicities: Ca: Excess mineralization (osteopetrosis) - in soft and vascular tissues - arthritis (ie high Ca diet breeding bulls results in poor breeding performance) P: Laxative Bone resorption (big head) Kidney stones Ca and P Absorption: site and pH Ca: duodenum, pH 6.5 favours increased Ca absorption P: ileum, pH 7-7.5 favours increased P absorption Diet acidity: Increased acidity of diet favours increased Ca absorption (dairy cows to prevent milk fever) Ca:P ratio: High Ca in diet CaP salt precipitation in ileum High P diet CaP salt precipitation in duodenum 167 Chemical form of Ca and P and availability: Inorganic form is better available Organic form is often chelated and poorly available Common chelating agents: Phytate: chelates P, Ca and various trace metals and amino acids 50-80% of P in grain is in the phytate form and only 0-30% available to monogastric animals Phytate also widely present in other plant sources Rumen microbes produce phytase, and this phytate P is fully available to ruminants. Use of feed biotechnology to reduce phytate impact: 1. Produce phytase enzyme and supplement to diets for pigs and poultry. 2. Produce transgenic grains and canola incorporating a microbial phytase gene. - Increases availability of phytate P - Reduces the need for P supplementation in rations 168 – Overall less P excretion in manure and less impact on environment Oxalic acid: Chelates a wide range of minerals, but especially Ca Oxalic acid + Ca Ca oxalate precipitates Can lead to formation of calculi (kidney stones) Oxalate commonly high in beet tops, rhubarb, spinach, swiss chard, chocolate Oxalate can be high in forages Reported instances of oxalate-induced abnormal skeletal development in foals, where oxalates bound the equivalent of 0.8 % of dietary Ca. Ration ingredients: High fat diets formation of Ca soaps Diet mineral interactions: Fe, Al, Hg, Be, Sn can all interfere with P absorption Note: Ca and P absorption is critically dependent on vitamin D 169 Magnesium: Function: Component of bones and teeth Catalyst of many enzymes, including cholinesterase (nerve transmission) and ATPase (energy metabolism) Component of chlorophyll in plants Location of Mg in body: 60% in skeleton 40% throughout Second highest cation concentration in intracellular fluid Absorption of Mg: Both diffusion and active transport Slower than that of Ca Affected by: - NH4+ - K+ - Na, Ca, P, SO4, phytate, oxalate 170 High K+ (over 2%) 1. High DCAB (450 vs 250 meq/kg) causes alkalosis reduced Ca and Mg absorption milk fever and grass tetany 2. In ruminant Mg mainly absorbed through rumen wall (active through Na-linked carrier. High K+ reduces transmembrane potential of epithelial cells and thus Mg absorption. Mg deficiency: Hypomagnesemia Anorexia Grass tetany – grass staggers – hypomagnesemic tetany (reduced cholinesterase activity) Vasodilation Malformation teeth Requirement: 0.3 % of Dry Matter Use Mg sulfate or Mg oxide to supplement 171 Na, K, Cl: Osmotic pressure Acid-base balance Nervous function Nutrient transport Water metabolism Enzyme function HCl production stomach Na deficiency: Pica (depraved appetite), reduced appetite, reduced growth. Na is low in plants and Na supplementation ( as NaCl) of animals is always required Feed NaCl (white salt): increase appetite and palatability K deficiency: K is high in forages and low in grains and concentrates. 172 Normally K intake is adequate, when a substantial amount of forage is fed. Dairy cattle with high milk yield (high K loss in milk) and that are fed more grain and less forage to meet the energy requirement for milk production can become deficient in K. Requirement is 0.8 % There is some evidence to suggest that feeding of a high K diet (1.5%) during a limited period may be beneficial when animals are stressed and have reduced feed intake. Heat stress Shipping stress Ration change Lactation Electrolyte balance in feed: - anion-cation balance - alkaline alkalinity - affects acid-base balance, performance, and utilization of amino acids 173 - measured as (Na+ + K+ - Cl-) ~ 25 milliequivalents / 100 g feed - optimal growth around 25 milliequivalents, as less energy is expended on acid-base balance and thus more is available for growth (see graph) Sulfur: Required especially for ruminants to allow S amino acid synthesis in rumen. Recommended S : N = 1 : (10-12) Also required for thiamine and biotin vitamins In Western Canada we are mostly concerned about high S intakes. High S in ruminants - with Mo, formation of thiomolybdate and decoppering effect; CuS. - sulphate and thiosulfate inhibit the uptake of selenate - retention of both calcium and phosphorus is reduced by the addition of sulphate to diets 174 - interference with ruminal thiamine synthesis, resulting in primary thiamine deficiency or secondary thiamine deficiency (thiamine anti-metabolite formed in rumen). In both cases abnormal glucose metabolism in brain cerebro-cortical necrosis, also known as polioencephalomalacia (PEM) - Clinical Features of S Induced PEM: - Signs appear between the 3rd and 8th week of exposure - Initially affected animals exhibit transient attacks of mild excitation, loss of appetite and restlessness - some affected animals may recover spontaneously - growth of these individuals is stunted - Progression of clinical signs reflects development of necrotic lesions in the cerebral cortex - aimless wandering - head pressing - hyperexcitability - rigidity - opisthotonos 175 - in severely affected animals the signs reflect severe necrotic lesions in the cerebral cortex - recumbency - violent convulsions - coma and death - Pathological Features of S Induced PEM - Extensive necrotic lesions in the cerebral cortex - Polioencephalomalcia (softening of the gray matter of the brain) - Cerebrocortical necrosis - Note that a diet with high content of simple carbohydrates can also induce PEM (through thiamine anti-metabolite formed in rumen). Iron: Fe present in small amounts (4-5 g in humans): - 70% is in hemoglobin - gut mucosal cells, liver, spleen and marrow are storage sites 176 - present in plasma as transferrin - component of oxidation-reduction enzymes Storage of Fe in proteins: 1. Ferritin = protein with 20% Fe content and soluble 2. Hemosiderin = protein with 35% Fe content and insoluble Fe absorption: Active absorption: First step in lumen: Fe3+ Fe2+ Diet Fe3+ (ferric) must be reduced to Fe2+ (ferrous) before it can be absorbed into mucosal cells. 177 Vitamin C is a useful reducing agent. Note that ferrous iron is again oxidized to ferric iron in the mucosal cell. The enzyme ceruloplasmin is an important oxidation enzyme for this reaction. 178 Ceruloplasmin requires Cu for enzymatic activity, and this explains why anemia can be symptom of Cu deficiency. Efficiency of Fe absorption: - Fe status of animal and feedback inhibition at gut level - Low pH increased absorption - Vitamin C - Chelating agents: - his, lys increase absorption - lactoferrin in human milk is positive - phytates can reduce Fe absorption - High P, Zn, Mn, Cu, Cd can reduce absorption Range of homeostasis: 5-60% absorption efficiency Normal: 20 % (on which requirement is based) 179 Fe deficiency: - Anemia - microcytic (reduced cell size) - hypochromic (reduced hemoglobin) Symptoms of Fe deficiency: - Reduced activity (lethargy) - Palor (paleness) - Shortness of breath Among farm animals baby pigs are most susceptible to Fe deficiency. Baby pigs: 1. Low body reserves at birth 2. High growth rate (1 to 18 kg in 6 weeks) high Fe requirement for increased blood volume. 3. Sow’s milk contains little Fe. 4. Low feed intake. Inject 100-200 mg iron dextran at birth. Rooting behaviour of piglets on dirt floor or in the wild would allow adequate iron intake. 180 Farmers used to throw grass sod in pen for this purpose. White veal production (EU): Feed calves milk replacer with low Fe low myoglobin in muscle. Major animal welfare concerns. Practiced mainly in France and Italy, with some in Quebec for French market. 181 Iodine: Component of thyroid hormones T3 and T4 Three forms of thyroid iodine deficiency: 1. Simple primary deficiency 2. Competitive inhibition of iodide uptake in thyroid gland (i.e. by thiocyanate) 3. Non-competitive inhibition through reduced organification of iodide into thyroid hormone (i.e. goitrin, oxazolidinethione (OZT)) 1. Iodine content in feeds is low throughout the world except in coastal areas. Therefore to prevent primary deficiency iodine must always be supplemented to animals and humans (iodized salt – red salt for animal supplements). 2. Presence of goitrogens is variable and feedstuff dependent. Glucosinolates are a class of goitrogens that release thiocyanates (competitive inhibition). Goitrin is a non-competitive class of 182 goitrogens 3. Rapeseed is high in glucosinolates and therefore the meal was not very suitable for animal feeding. Canola is a much improved low glucosinolate rapeseed variety, and is very suitable for feeding. 4. Goitrogens are found in a wide range of plants (natural pesticide), including the cruciferae family with cabbage, cauliflower, brussels sprouts, mustard, horse radish, broccoli. Iodine deficiency signs: - Goiter - Low BMR, increased fat - Reduced fertility - High mortality at birth (fetus with goiter) - Myxedema - Alopecia Iodine requirement (normal conditions): 0.2 to 0.3 ppm 183 0.5 ppm for dairy cattle (iodine is secreted into milk at a high rate) The feeding rate must be increased (2-3 times) when goitrogens are present in order to compensate for competition. Iodine supplements: Salts: KI, KIO3 Ethylenediaminedihydroiodide (EDDI; “organic” iodine) is also available. It is used for the prevention of foot rot, but this application is of questionable value. The dosage of EDDI as iodine is very high and raises concern about iodine toxicity in animals and humans. Normal intake of a dairy cow is between 5 and 15 mg/d. Milk iodine normal range is 50-300 g/L. EDDI feeding results in intake of 200 mg/d and milk iodine levels up to 2000 g/L. 184 Human iodine requirement: children 50 g/d Adults 120 g/d High iodine-milk consumption results in iodine intakes in children (0.5-1L/d) in excess of 10x requirement toxicity concerns based on milk intake alone. Also consider iodized table salt, and salt in condiments, chips etc. Dairy farm families are at greater risk than the regular consumer, because they do not have the benefit of the pooling effect (mixing of high with low iodine milk) in case the on-farm milk is high in iodine. Iodine toxicity symptoms: - Increased salivation and lacrimation (symptoms are similar to those from IBR (infectious bovine rhinitis)) - Reduced fertility - Reduced productivity - Immuno-suppression 185 Manganese Mn: Required for: - Enzyme function; oxidative phosporylation, pyruvate carboxylase. - Chondroitin sulfate formation (cartilage) - Steroid synthesis from cholesterol Deficiency signs: 1. Leg-bone: - Newborn calves-lambs: weak or stillborn, with twisted or knuckled over pasterns - Lameness, short bowed legs - Perosis or slipped tendon in poultry (common symptom) 2. Reproduction: - delayed or silent estrus - reduced conception rates – embryonic death – reduced libido – reduced spermatogenesis Requirement: Is higher for reproduction in general and in poultry. 186 Range of 20-40 ppm, and 55 ppm in poultry Supplement with MnSO4, MnCO3, MnO ZINC Component of many enzymes including RNA and DNA polymerases, carbonic anhydrase, alkaline phosphatase, LDH Absorption: Primary interference by divalent cations Cu, Ca, Mg Phytate Deficiency: Reduced growth - anorexia Hyperkeratinization of epithelium: parakeratosis Infertility in males Impaired wound healing Requirement:40-50 ppm; ZnO, ZnS04 187 COBALT Discovered by E. Underwood around 1935 Most commonly deficient in ruminants: 1. Rumen microbes + cobalt vitamin B12 cyanocobalamine 2. Required for propionate metabolism in TCA cycle: Impaired gluconeogenesis Deficiency results in WASTING DISEASE Feed is available but animal starves to death Requirement: 0.1 ppm CoO, CoS04, CoCI2, CoC03 Blue Salt: Co + Iodine + NaCI Bullets Range Mix Fertilizer 188 COPPER Very important in the prairies Often deficient in cattle exposed to variable mineral intake: Breeding and pregnant most at risk COPPER DEFICIENCY SIGNS: 1. Anaemia a. Iron transport – ceruloplasmin b. Indirect Fe deficiency c. RBC synthesis 2. Achromotricia (depigmentation) Melanin synthesis tyrosinase - Cu dependent 3. Neonatal ataxia Swayback (Lambs) Reduced cytochrome oxidase 4. Falling Disease (Sudden Death) Bone deformities, reduced elastin and collagen synthesis Lysyl oxidase is Cu dependent 189 5. Scouring or diarrhea 6. Defective keratinization ABSORPTION: Upper small intestine Plasma: RBC =1:1 80% of Cu in plasma in ceruloplasmin Excretion: Increased with Mo, Sulfur, Cd, Zn Cu Status Measurement: 1. Feed analysis 2. Liver Cu 3. Plasma ceruloplasmin 4. Plasma Cu Copper Deficiency in the Prairies: 1. Simple Primary Deficiency: Low Cu in Feeds < 5 mg/kg 190 Depends on soil type, management, etc. Throughout western Canada 2. Secondary Deficiency: Most important cause of Cu deficiency Associated with high S and/or Mo intake Cu and SULFATES: Source of S is ground water: Greater than 800 ppm is bad Mean sulphate in Sask. is 1800 ppm Deep wells always suspect Shallow wells less Surface water acceptable ??? MOLYBDENUM: Mo levels in feeds depend on Mo in soil: focus on Eastern Sask. and Manitoba 191 With NORMAL S intake: Cu: Mo = 1: (2-3) Manageable Cu: Mo = 1:1 Difficult With HIGH S intake: The combination of Mo and S is problematic Formation of thiomolybdates (TM) under reducing conditions in the rumen: 1. TM chelation of Cu prevents absorption 2. Thiomolybdates decopper animal RECOMMENDATIONS: Cu requirement is 5-10 mg/kg For most of the prairies with moderate S (1800 ppm) and moderate Mo (1-2 ppm): 25 mg Cu/kg DM 192 Pregnant animals up to 55 ppm With elevated Mo and Moderate S: Undefined but probably 55 ppm Use of Cu injectables? Decoppering effect? SUPPLEMENTATION: Salts: copper sulfate Trace mineral mixes: force feed, free choice, salt blocks Injectables: Cu glycinate; Cu calcium EDTA Other: Drinking water supplement, wires, degradable glass COPPER TOXICITY: Sheep are very sensitive to Cu: Common cattle grain feed supplements with 25 ppm Cu KILL sheep! 193 Cattle tolerance: 100 ppm Pig tolerance: 450 ppm Breed and species differences exist Symptoms of Cu chronic toxicity: Gradual build-up of Cu in liver up to 1000 ppm Acute release of Cu into blood Haemolytic crisis, renal and hepatic failure, death ACUTE TOXICITY: In sheep death within 24-72 hours Nausea, salivation, abdominal pain, convulsions, paralysis, collapse Gastroenteritis, necrotic hepatitis, splenic and renal congestion Treatment of mild Cu toxicity at early stages: 194 Feed S and Mo to decopper ruminant animal Infuse thiomolybdate in monogastric animal SELENIUM Component of glutathione peroxidase present in a variety of tissues. Detoxifies peroxide radicals: peroxide, superoxides Prevents peroxidation damage to lipid membranes Protects unsaturated FA, including EFA Vitamin E relationship Se absorption: Better for the organic forms: Selenomethionine Selenocysteine 195 Salts: Sodium Selenite Sodium Selenate Excretion: Lungs, urine, feces SELENIUM DEFICIENCY: 1. Nutritional muscular dystrophy white muscle disease (lambs and calves) 2. Hepatosis dietetica - mulberry heart disease (pigs) 3. Exudative diathesis - subcutaneous haemorrhages (chicks) 4. Infertility - retained placenta Conditions: Low in soil, northern areas Unavailable: Low pH, Fe complexing Requirement: 0.25 - 0.50 ppm 196 Environment: PUFA and Vit E content of diet influence requirement Supplement: As Se salts in concentrate or free choice injectables Focus on maternal nutrition to ensure adequate mineral status neonate Se TOXICITY 10-15 fold safety range between requirement and toxicity 10-20 ppm for 8 weeks causes subacute toxicity in cattle Se accumulator plants, e.g., milk vetch (loco weed) 1. Blind staggers / Alkali disease horses Sloughing of hoofs lameness - deformation 2. Reduced fertility 197 3. Loss of long hair (horses) Se S in disulphide bonds proteins PREVENTION: 1. High inorganic sulphate intakes 2. High dietary protein levels 3. Arsenic supplements 198