Download C-FAR Swine Odor and Manure Management Nutrition

C-FAR Swine Odor and Manure Management
Nutrition
Principle Investigator: Gary Apgar, Southern Illinois University
Summary
This research was carried out to investigate three areas: (1) phytase addition to diets
containing wheat middlings, (2) removal of inorganic phosphorus from swine finishing diets,
and (3) dietary nitrogen and sulfur reduction on odor-causing components of swine manure.
Phytase addition to diets containing wheat middlings resulted in increased calcium,
phosphorus, dry matter digestibility estimates and performance equal to diets containing
inorganic phosphorus. Removing inorganic phosphorus reduced average daily gain and
average daily feed intake but adding phytase restored pig performance. Reduction of
nitrogen and sulfur in swine finishing diets did not affect pig performance but did alter the
concentration of manure components implicated in odor.
Introduction
The C-FAR Strategic Research Initiative on Swine Odor and Waste Management has
funded 3 projects with Dr. Gary Apgar at SIU-Carbondale: phytase addition to diets
containing wheat middlings; removal of inorganic phosphorus from finish diets; impacts of
dietary nitrogen and sulfur reduction on odor.
1. Phytase addition to wheat middling diets
Grow-finish pigs were fed 3-phase diets containing wheat middlings (phase 1, 4%
WM; phase 2, 9%; phase 3, 10%) with inorganic phosphorus or 500 FTU/kg phytase added
to diets with no inorganic phosphorus supplementation. Diets contained chromic oxide, and
indirect apparent digestibility coefficients for dry matter, calcium, and phosphorus were
estimated.
Growth parameters did not differ among dietary treatments overall. Phase-2 dry
matter digestibilities were equal across treatments. But during phase-3 pigs fed phytase had
improved dry matter digestibilities over controls (81.7 vs76.4%). Phase-3 apparent
digestibility coefficients for calcium was higher (38.3% vs. 20.5%, P<0.001) for pigs fed
phytase. Phase-2 and -3 apparent digestibility coefficients for phosphorus were higher
(49.1% vs. 32.2% and 54.4 % vs. 29.5%, respectively, P<0.05) for pigs fed diets containing
phytase.
By adding phytase to diets containing wheat middlings, apparent digestibility coefficient
estimates for calcium, phosphorus, and dry matter digestibility increased. Performance
results were equal to those on diets containing inorganic phosphorus.
2. Dietary P removal with and without added phytase for grow-finish pigs
Crossbred pigs (117.5 + 3.1 lb) were used to evaluate effects of removing inorganic P
from diets with or without added phytase during two 28-d phases (early and late):
Treatment 1. Control (early--0.49% total P, .19% available P.; late--0.43% total
phosphorus, 0.15% available phosphorus).
Treatment 2. As 1 but without inorganic phosphorus (early--0.36% total P, 0.07%
available phosphorus; late--0.33% total phosphorus, 0.06% available phosphorus).
Treatment 3. As 2 + 500 FTU/kg phytase.
Pigs’ average daily gain (ADG), average daily feed intake (ADFI), and feed
efficiency (G:F) were measured every 2 weeks. Pigs were scanned for 10th rib backfat
thickness and longissimus area and values adjusted to covariance-common body weight (229
lb). One male and one female pig per pen were slaughtered, and fourth metacarpal bone
collected and ashed. During early and late phases pigs fed the treatment 2 diet had lower
ADG and ADFI (760 vs. 831 and 2,275 vs. 2,399 grams, P< 0.05) than pigs fed treatment 3
diets. Backfat thickness and longissimus area did not differ among treatments. Fourth
metacarpal dry and ash weights were greater for treatment 3 (P<0.05) than for treatment 2.
Bone-ash percentage did not differ between treatments 2 and 3 but pigs fed treatment 1 diet
had greater bone-ash percentage (P<0.05) than did those fed diets lacking inorganic
phosphorus (Treatments 2 and 3).
Removing inorganic phosphorus reduced ADG and ADFI but adding phytase restored
pig performance and bone ash.
3. Effect of elevated and reduced dietary nitrogen and sulfur concentrations on odorcausing components of manure of finish pigs
Ninety-five crossbred finishing pigs (180 lb) were used to evaluate effects of elevated
or reduced dietary nitrogen (N) and sulfur (S) on pig performance and odor components of
pig manure. Growth measurements were made every 7 days. Corn-soybean meal diets
containing chromic oxide were fed during 2 phases (175-220 lb, 220-240 lb bodyweight).
Lysine concentration was equalized across dietary treatments and amino acid concentrations
were balanced to support adequate growth. Dietary nitrogen was reduced during both
phases by approximately 1.5 percentage units. Dietary sulfur content was altered by removal
of trace mineral–sulfate sources, and trace minerals were fortified using low-sulfur chelate
formulations. Random fecal samples were collected once during phase-1, twice during
phase-2, from each pen. Fecal samples from collection 1 occurred after pigs had been on
phase-1 diet 7 days; samples for collections 2 and 3 were from pigs that had been on phase-2
diets for 7 and 14 days, respectively. Frozen fecal samples were subsampled, placed in
diluent, and analyzed by mass spectrometry for concentrations of known odorous compounds
Pig performance did not differ across treatments during either phase. After pigs had
been consuming phase-1 diet for 7 days, there was a N × S interaction for odor components
of manure (P < 0.039); hexanoic acid concentration decreased at lower sulfur content in highnitrogen diets but increased at lower nitrogen concentration (P<0.075), and 3-methylindole
tended to respond in the same manner (P<0.075).
After pigs had been consuming phase-2 diets for 7 days there was an N × S
interaction for odor components of manure (P<0.036), following the same pattern as above
for 4-methylphenol, and a tendency for this interaction to affect phenylacetic acid output
(P<.092).
After 14 days on the phase-2 diet, phenol concentration was increased in waste from
pigs fed low-nitrogen diets (P<0.013) and there was a N × S interaction for odor components
of manure (P<0.029), with phenol increasing with reduced sulfur content at elevated nitrogen
levels but decreasing with reduced sulfur at lower nitrogen levels. Indole concentration
tended to be lower in waste from pigs fed elevated nitrogen diets (P<0.10) as compared with
low nitrogen diets. Propanoic acid tended to be affected by dietary sulfur (P<0.092), with
reduced-sulfur diets having greater concentrations than diets containing elevated levels of
sulfur. 3-phenylpropanoic acid tended to reflect N × S interaction for odor components of
manure (P<0.10), with 3-phenylpropanoic acid increasing when sulfur was reduced in highnitrogen diets; decreasing when sulfur was reduced in low-nitrogen diets. These compounds
are responsible for the odor associated with swine waste. By quantifying these substances,
we are able to objectively evaluate the effects of nutritional strategies to reduce odor.
Reduction of nitrogen and sulfur in swine finishing diets did not affect pig
performance but did alter concentrations of manure components implicated in odor. Odorcausing constituents of swine waste were most affected by interaction between dietary
nitrogen and sulfur concentrations. The overall effectiveness of their ability to reduce odor
cannot be assessed, as these compounds were not hierarchically ranked with respect to odor
intensity.
Conclusions
1.
Adding 500 FTU/kg phytase to diets containing wheat middings and no
supplemental inorganic P resulted in performance equal to that with diets
containing inorganic phosphorus.
2.
Removing inorganic P from grow-finish pig diets reduced ADG and ADFI, but
adding 500 FTU/kg phytase maintained pig performance.
3.
Pig performance was not affected when diets with reduced nitrogen and sulfur
were fed, provided amino acid level and balance is adequate, but concentrations
of manure components implicated in swine odor were altered.
Abstracts from SRI funding
Apgar, G.A., K.E. Griswold, B. Jacobson and J. Salazar. 2002. Effect of elevated and
reduced N and S concentration upon growth and concentration of odor causing components
of waste of finishing pigs. J. Anim. Sci. 80(Suppl 1):395.
Apgar, G., C. Peter, T. Guthrie, K. Griswold and D. Baker. 2001. Phosphorus removal
with and without phytase in finishing pigs. J. Anim. Sci 79(Suppl. 1):396.
Bekiares, N., and G. Apgar. 2000. The effects of phytase supplementation to growingfinishing diets containing wheat middlings. J. Anim. Sci. 78(Suppl. 1):170.
Publications
Apgar, G.A., K.E. Griswold, K.L. Jones, J.S. Radcliffe, T.A. Guthrie and R.D. Arthur.
2003. Dietary phosphorus removal with and without microbial phytase addition for growing
finishing pigs. Professional Animal Scientist 19:312-316.
Apgar, G. A., X. Qiu, K. E. Griswold and F. Sun. 2002. The effects of phytase
supplementation to growing-finishing diets containing wheat middlings. China Animal
Husbandry & Veterinary Medicine. 29(6):16-19.
Invited presentations
Apgar, G.A. and K.E. Griswold. 2003. Feeding strategies for reducing N & P excretion from
livestock manure. Invited presentation, Livestock Manure Management Conference,
March 11, 2003.
Apgar, G.A. 2001. Nutrient output reduction. Invited presentation, Swine Manure and Odor
Management Field Day. August 29, 2001.