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Feed Additives Pages 319 – 325 (Chapter 6) Why use them? • Cause a desired response/benefit – – – – – – – – – – – Alter metabolism affect growth change pH manipulate microflora improve digestion increase yield Reduce acidosis Improve immune response Increase palatability Reduce fecal odor Reduce joint pain Major Classes • Growth Promotion and Feed Efficiency – Antibiotics • Medicinal Uses – Coccidiostats, worming agents • Others – – – – – – – Buffers and Neutralizers Antioxidants Preservatives Binders Direct Fed Microbials Coloring Agents Flavorings • Hormonelike products – Feed Additives – Implants Examples • Antibiotics: disease prevention • Coccidiostats: control parasites • Xanthophyll: makes egg yolks yellow – Cantaxanthin • Hormones (hormone like): increases growth • Yeast, Fungi, Direct fed microbials • Buffers: HCO3 etc.. Prevent rumen acidosis • Antioxidants: prevents feed from getting rancid • Pellet Binders: keeps feed in pellet form • Flavoring Agents: makes feed taste better • Surfactants: lipid digestion, increase milk production, yield • Anionic salts: acidify diet to increase Ca absorption FEED ADDITIVES • Use of feed additives is strictly regulated in the developed countries, and many others, to ensure: – Human food safety – Animal safety – Additive efficacy – Minimal environmental impact • Dramatic increase in globalization of marketing of animal products has led to more uniformity in regulations among countries. – Animal products must comply with the laws of the countries to which they are being sold. FEED ADDITIVES • AAFCO (Association of American Feed Control Officials) provides the U.S. mechanism for developing and implementing uniform & equitable laws, regulations, standards, and enforcement policies. – Regulating manufacture, distribution, and sale of safe and effective animal feeds. • AAFCO defines a feed additive as… – "an ingredient or combination of ingredients added to the basic feed mix …to fulfill a specific need." – " …usually used in micro quantities and requires careful handling and mixing" FEED ADDITIVES • Animal products are routinely tested to ensure that feed additives are being used correctly. – Use of feed additives has been beneficial to livestock producers under our modern methods of production. • Feed additives have been used extensively in the U.S. and many other countries since the discovery & commercial production of antibiotics and sulfa drugs in the late 1940s. • Development of intense production systems made possible because of additives that could control disease/parasites. • The European Union recently banned feeding of antibiotics to animals meant for human consumption. Growth Promotion and Feed Efficiency • Antibiotics – Substance produced by a living organism that has bacteriostatic or bactericidal properties. – Fed to reduce incidence of subclinical levels of infections in the GI or respiratory tracts. – Increase rate of gain and feed efficiency. • Chemotherapeutic Agents – Inorganic or organic compound that inhibits the growth of target organisms (not produced by living organism). ADDITIVES CLASSED AS DRUGS • In the U.S., use & regulation of additives classed as drugs is controlled by the Center for Veterinary Medicine, within the FDA. – To determine that drugs & medicated feed are properly labeled for intended use and that animal feeds and food derived from animals are safe to eat. – What is the human risk? • Federal law states no animal drug can be used in feed until adequate research submitted to the FDA proves the drug is both safe and effective. – In developing a new drug for use with animals, manufacturers must go through extensive testing. ADDITIVES CLASSED AS DRUGS Antibiotics • Antibiotics are compounds produced by microorganisms. – inhibit growth/metabolism of some (not all) other microorganisms. – In some instances, they may be toxic to warmblooded animals. – Most antibiotic names end in -cin or -mycin. • All antibiotics used commercially for growth promotion are produced by fermentation processes using fungi or bacteria. Growth Promotion & Feed Efficiency: Antibiotics • Antibiotics are effective at improving production when fed at low levels to young, growing animals. Growth Promotion & Feed Efficiency: Antibiotics • Feed Efficiency Improvement: – Growth is nearly always increased, particularly with animals exposed to adverse environmental conditions. – Feed intake usually decreases in ruminants. – Varies by animal species. – Antibiotic-fed animals are less apt to go off feed. – Can control a wide variety of diseases. – As a rule, reduce the incidence or severity of several types of diarrhea Growth Promotion & Feed Efficiency: Antibiotics • Some are approved at low levels of continuous use for reducing the incidence of… – Enterotoxemia (overeating disease) in lambs. – Liver abscesses in fattening cattle. – Diarrhea in young mammals deprived of colostrum. • In poultry, some claims include… – Reduction in respiratory disease. – Nonspecific enteritis (blue comb) & infectious sinusitis. – Improved egg production and hatchability. Growth Promotion & Feed Efficiency: Antibiotics • Two antibiotics for use in cattle, monensin and lasalocid, are unusual in that they give a good response in both growing and mature animals. – Approval was first received for use as coccidiostats with poultry. – Both of these antibiotics are quite toxic to horses. Growth Promotion & Feed Efficiency: Antibiotics • Obtaining approval for new feed additive drugs has become more difficult in recent years. – More investigative effort & expense are involved. – Few recent approvals. • Very few antibiotic additives are approved for horses, rabbits, sheep, goats, ducks, pheasants & quail. – NONE for geese, dogs, cats, exotics. • The primary reason is the cost of obtaining approval in relation to potential sales volumes. Growth Promotion & Feed Efficiency: Antibiotics • In poultry: very typical to see more than one included. • Most can be used for layers, except high levels of chlortetracycline and erythromycin. • Manufacturer approval must be obtained for using different combinations of antibiotics. – Or combinations of antibiotics & other controlled drugs. • Far more drug combinations have been approved for chickens & turkeys than all other animals combined. – It is illegal to feed antibiotics at different levels or in different combinations from those previously approved. Growth Promotion & Feed Efficiency: Chemotherapeutic Agents • Arsenicals are all synthetic compounds (chemotherapeutic agent) & include a number of drugs used in turkey, chicken, and swine rations. – Control of parasites. – Some stimulate growth in the same manner as antibiotics. – The effect can be additive to antibiotic stimulation. • Several arsenicals have claims of improved growth production as well as improved feed efficiency for chickens, turkeys, or swine. – And control of Blackhead in poultry & diarrhea in swine. Growth Promotion & Feed Efficiency: Chemotherapeutic Agents • Arsenicals have the disadvantage that they may accumulate in body tissues, particularly the liver. – At the levels fed, they are not considered toxic. – All have a minimum 5-day withdrawal period before animals are to be slaughtered for human food. – Large public concern: “arsenic in my food” Medicinal Uses of Additives • Prevention or treatment – Coccidiostats (poultry) – Histostats • Histomoniasis (Blackhead) – protozoan disease affecting turkeys and some other poultry. Affects the liver and cecum. – G.I = enteritis, diarrhea, dysentery – Anthelmintic (worming) agents Medicinal Uses: Coccidiostats • Coccidia are microscopic parasites. – Coccidiostats include a wide variety of compounds, ranging from a number of synthetic drugs to antibiotics. • Coccidiosis outbreaks are very large concern in confinement poultry operations. – Evidence suggests coccidiosis is becoming a greater problem with sheep & cattle in close confinement. Medicinal Uses: Nitrofurans • Synthetic antibiotic • The nitrofurans are antibacterial compounds and are effective against a relatively large number of microbial diseases. – Continued use of nitrofurans has not yet developed bacterial resistance, as is the case for some antibiotics. Medicinal Uses: Sulfas • Reduction in use – Problems with tissue residues • Most of problems alleviated by sulfas can be managed with other additives. Hormone-Like Additives • Hormones are substances produced by the endocrine organs to activate other organs. Synthesized compounds that produce the same responses as natural hormones can be used to: – Promote milk production – Promote animal growth • Fed as an additive or implanted Hormone-Like Additives • Melengestrol acetate (MGA) is the only hormone-like production improver remaining on the approved list. – Extensively used with beef heifers – Suppress estrus which results in more efficient and more rapid gain. Hormone-Like Implants Pages 322-323 • Although not feed additives, several products are available for use as subcutaneous implants. – Hexestrol, (outside the U.S.) – Ralgro™: Anabolic agent, improves feed efficiency. – Synovex™: a combination of estrogen & progesterone. – Rapid Gain™: a combination of testosterone & estrogen – Steer-oid™: a combination of progesterone and estradiol. • A high percentage of growing- finishing cattle and sheep are treated with one or more of these implants. Hormone-Like Additives • In ruminants, natural or synthetic hormones produce a response that results from increased nitrogen retention accompanied by an increased intake of feed. – Increased growth rate; Improvement in feed efficiency. – Reduced deposition of body fat, which may, at times, result in a lower carcass grade for animals fed to the same weight as nontreated animals. Hormone-Like Additives: -agonists • Molecules that structurally resemble epinephrine – Caffeine, ephedrine, aspirin • Easily made in the lab • Muscle: – Increase in muscle synthesis – Decrease in muscle breakdown • Fat – Decrease in lipogenesis – Increase in lipolysis • Ractopamine (Paylean) • May impact behavior: Aggression Antioxidants • Used to prevent rancidity of unsaturated fatty acids • Inclusion rates up to 0.25 Lb per ton feed. • BHA/BHT (Butylated hydroxyanisole or toluene) • Ethyoxiquin • Vitamin E • Rosemary Preservatives • Used to prevent feed deterioration (mold/bacteria inhibitors) – Increase shelf life – Vitamin C – Calcium sorbate – Citric acid – Phosphoric acid – Propylene glycol (toxic to cats) – Sodium propionate – Sodium metabisulfate Buffers and Neutralizers – Buffers & Neutralizers • Lessen the decrease in pH caused by VFA production • Valuable for use in high concentrate diets to ruminants but not high forage diets • Examples – Sodium bicarbonate (most effective and most common; AKA: baking soda) – Potassium bicarbonate – Calcium carbonate – Magnesium oxide – Magnesium carbonate DFMs and Yeast www.microbialcompendium.com – Include cultures of live organisms, or ingredients (or both) that stimulate microflora in the gut to favor healthy environments. – Bacteria, Enzymes, Mold, Oligosaccharides, Yeast – Lactobacillus, streptococcus, fungi, aspergillus, bacillus – Probiotics • Scientifically inconsistent • Consist of microbial cultures – Can stimulate cultural growth • Reasons for use – – – – Increase/balance beneficial bacteria Reduce toxic byproducts of digestion Support rate of gain and feed efficiency Alleviate/minimize stress • Various times for use – When do you use them? • Most common with horses, young animals Microorganisms found to be appropriate for use in animal feeds • • • • • • • • • • • • • • • • • Aspergillus niger • • Aspergillus oryzae • Bacillus coagulans • Bacillus lentus • • Bacillus licheniformis • Bacillus pumilus • Bacillus subtilis • • Bacteroides amylophilus • Bacteroides capillosus • Bacteroides ruminocola • • Bacteroides suis • Bifidobacterium adolescentis • • Bifidobacterium animalis • Bifidobacterium bifidum • Bifidobacterium infantis • Bifidobacterium longum • Bifidobacterium thermophilum• • Lactobacillus acidophilus • Lactobacillus brevis • Lactobacillus buchneri (cattle only) • Lactobacillus bulgaricus • Lactobacillus casei • Lactobacillus cellobiosus Lactobacillus curvatus • Lactobacillus delbruekii • Lactobacillus farciminis (swine only) • Lactobacillus fermentum • Lactobacillus helveticus • Lactobacillus lactis Lactobacillus plantarum • Lactobacillus reuterii • Leuconostoc mesenteroides Pediococcus acidilacticii • Pediococcus cerevisiae (damnosus) • Pediococcus pentosaceus Propionibacterium acidpropionici • (cattle only) • Propionibacterium freudenreichii • Propionibacterium shermanii • Saccharomyces cerevisiae • • • • *Enterococcus cremoris *Enterococcus diacetylactis *Enterococcus faecium *Enterococcus intermedius *Enterococcus lactis *Enterococcus thermophilus Yeast Aspergillus niger Leuconostoc mesenteroides Pediococcus acidilacticii Pediococcus cerevisiae (damnosus) Pediococcus pentosaceus Propionibacterium acidpropionici (cattle only) Propionibacterium freudenreichii Propionibacterium shermanii Saccharomyces cerevisiae *Enterococcus cremoris *Enterococcus diacetylactis *Enterococcus faecium *Enterococcus intermedius *Enterococcus lactis *Enterococcus thermophilus Yeast