Progress 10/01/99 to 09/30/05
Outputs
An important challenge for commercial swine production is to produce hogs in a cost-effective manner under conditions of increasing public and regulatory pressure to eliminate risks to consumer health and unnecessary excretion of nutrients into the environment. From a swine nutrition standpoint, critical issues include: 1) formulation of diets to optimize production efficiency while avoiding unnecessary nutrient supplementation and, 2) reducing dependency on use of antibacterial feed additives for growth promotion and health maintenance in young growing pigs. Regarding the first item, the potential exists for improved reproductive performance in sows by supplementing elevated levels of the essential vitamin folic acid. Potentially, different chemical forms of this vitamin could be more biologically active in swine. Using a long-term sow study, we researched the biological and economic impact of supplementing breeding sow diets with potential sources of folic acid
including a low-cost synthetic form of the vitamin and two more expensive chemically reduced forms. Our results demonstrated that supplementing folic acid (2 mg per kg of feed) in sow diets increased circulating levels of folic acid in sows and in nursing piglets. Supplementing the chemically reduced forms of the vitamin tended to elevate circulation of reduced folates in sows and pigs. However, there was no litter size or milk production advantage with the more expensive sources of folic acid as compared to the synthetic (oxidized) form. The key significance of this work was to demonstrate that the oxidized form of supplemental folic acid is just as biologically effective as reduced forms and is more cost effective. In another series of experiments in the project, we assessed a variety of feed additives as potential alternatives to traditional antibiotic feed additives for weanling and young growing pigs. The potential replacement supplements studied in this series of experiments
included a yeast cell wall extract, a bacillus pro-biotic product, a poly-aspartate bio-polymer, organic and inorganic forms of supplemental copper and spray-dried plasma protein. The combined results of these experiments demonstrated the following: i) Yeast cell wall extract product, poly-aspartate bio-polymer product and bacillus pro-biotic product are not effective as feed additives when compared to the growth responses seen with traditional antibiotic addition to weanling pig diets; ii) Elevated (100 to 200 mg per kg feed) dietary copper in antibiotic-free diets can improve weanling pig performance and lower levels of the organic form of copper can elicit growth response with lower copper excretion into the manure; and iii) Addition of spray-dried plasma protein to antibiotic free diets for weanling pigs improves growth performance and this response is more pronounced if sanitation in the pig housing facility is less than ideal.
Impacts
There is increasing pressure on the commercial swine industry to produce pork cost-effectively while reducing nutrient excretion into the environment and reducing the quantity of antibacterial feed additives used in swine feeds. Our research results have demonstrated that the oxidized form of supplemental folic acid is the most cost-effective source to provide breeding sows while maintaining good reproductive performance. Avoiding use of the more expensive reduced forms of folic acid for vitamin supplementation can conservatively save from 2 to 4 dollars per ton in sow feed costs. On a national herd basis of 6 million sows, this could equate to 12 to 24 million dollars in annual feed cost savings. The research in this project on reducing antibiotic use in pig diets has demonstrated that certain potential replacement products are not effective and therefore cannot be justified from a cost standpoint. However, the work has also demonstrated that use of antibiotic feed
additives is not essential to cost-effective feeding of young pigs. Moderate supplementation with dietary copper, particularly in organic form, can promote young pig growth performance with minimal copper excretion. Strategic supplementation of spray-dried plasma protein and improved sanitation can also yield acceptable production without antibiotic use. These practices will reduce regulatory pressure and enhance consumer confidence in the quality of pork products.
Publications
- Harper, A.F. 2000. Managing swine feeding to minimize manure nutrients. In: Proceedings from the Managing Nutrients and Pathogens from Animal Agriculture Conference; Natural Resource, Agriculture, and Engineering Service Publ.130, pages 196 to 208. Cooperative Extension, 152 Riley-Robb Hall, Ithaca, NY.
- Harper, A.F., R.D. Coffey, G.R. Hollis, D.C. Mahan, and J.S. Radcliffe. 2002. Swine diets. Pork Industry Handbook Fact Sheet No. 23. Purdue University Coop. Extension Service, West Lafayette, Indiana.
- Harper, A.F., and M.J. Estienne. 2004. Can we raise pigs without antibiotics in feed? Proceedings of the Thirty-Seventh Annual Virginia Pork Industry Conference, pp.15-22.
- Zhao, J. 2005. Impact of dietary proteins on growth performance, intestinal morphology, and mRNA abundance in weanling pigs. Ph.D. Dissertation; Virginia Polytechnic Institute and State University, Blacksburg, Virginia.
|
Progress 10/01/03 to 09/30/04
Outputs
Our previous research demonstrated that inclusion of spray-dried plasma protein (SDPP) in unmedicated diets for early-weaned pigs improves post-weaning growth. This has relevance because future regulations may prohibit the use of medicated feed additives in swine feeds. The objective of this experiment was to determine the effects of supplemental SDPP and a marine-based hydrolyzed protein source (MBHP) in unmedicated weanling pig diets on nitrogen balance and digestibility. At weaning, pigs (n = 48, 5.4 kg body weight, 17 days of age) were placed in metabolism cages with two pigs per cage. There were three dietary treatments (8 cages/treatment): a corn-soy-whey control diet or similar diets containing 6 percent SDPP or 6 percent MBHP. Diets were formulated to be equivalent in energy and essential amino acids. A 7-day adjustment period was followed by two 5-day collection periods, during which total feces, urine, and feed refusals were collected. Pigs were fed their
respective diets in two equal portions at 12-h intervals to give daily intake of approximately 3 percent of body weight. Dry matter content of feed and fecal samples was determined by oven drying. Nitrogen concentration of feces, feed and urine was determined by the Kjeldahl method. Analytical data were used to calculate dry matter and protein digestibility and nitrogen balance. Supplementation of 6 percent SDPP or 6 percent MBHP had no impact on protein digestibility, retention, or biological value in the diet. Percent absorbed nitrogen ranged from 88.51 to 89.34 percent, and was not different among treatments (P = 0.55). Similarly, percent nitrogen retention ranged from 69.08 to 72.01, and was not different among treatments (P = 0.39). The calculated percent biological value and dry matter digestibility were 80.92 and 91.51; 77.62 and 92.01; 78.03 and 91.28 for the control, SDPP and MBHP treatments, respectively, with no difference among treatments (P = 0.22 to 0.39). In summary,
inclusion of SDPP or MBHP in the diet of weanling piglets did not alter digestibility, nitrogen balance or biological value of protein. Situations in which supplementation of these products improves performance in unmedicated pig feeds appear unrelated to effects on nitrogen digestibility or nitrogen balance.
Impacts
Inclusion of feed grade spray-dried plasma protein (SDPP) in unmedicated diets for weanling pigs improves feed intake and growth performance. However, this improvement is unrelated to alterations in digestibility of crude protein in the diet. Under conditions in which medicated feed additives are not allowed or are discontinued in weanling pig diets, SDPP offers one alternative for enhanced growth and health in early weaned pigs. The most strategic period of use for SDPP would be in the intitial post-weaning diet phase.
Publications
- Zhao, J., A.F. Harper, K.E. Webb, Jr., and M.E. Estienne. 2004. Spray dried plasma in the initial post-weaning diet improves pig performance during phase I with no effects in subsequent diet phases. J. Anim. Sci. (p. 7 meeting abstracts, Southern Section ASAS meetings, Tulsa, Oklahoma, February 14-18, 2004).
- Zhao, J., A.F. Harper, K.E. Webb, Jr., and M.E. Estienne. 2004. Effect of specialty protein supplements on nitrogen balance and digestibility in weanling pigs. J. Anim. Sci. 82 (Suppl. 1, abstr.):456.
|
Progress 10/01/02 to 09/30/03
Outputs
Elevated levels of copper and zinc are frequently used in young pig diets to improve growth performance. However, elevated dietary mineral levels result in excess mineral excretion in pig manure. Potentially this could cause elevated soil copper levels on land receiving applications of swine manure. Lower inclusion rates result in lower excretion rates. We used 210 crossbred weanling pigs 18 to 27 days of age in a growth experiment to determine response to elevated dietary copper from an organic copper complex (BioPlex copper, Alltech Inc., Nicholasville, KY) or traditional copper sulfate. Pigs were assigned from groups based on weight, ancestry and sex to five dietary treatments including: a diet with no added copper beyond that provided in the trace mineral premix (control), a diet with 100 ppm added copper from BioPlex copper (BP-100), a diet with 200 ppm added copper from BioPlex (BP-200), a diet with 100 ppm added copper from copper sulfate (CS-100), and a diet
with 200 ppm added copper from copper sulfate (CS-200). Each of the nine replications consisted of two pens assigned to the control diet and one pen assigned to each elevated copper treatment. Four pigs were housed in each pen except for one replication with three pigs per pen. Diet complexity and nutrient density were adjusted in three phases over the 5-week trial. Feed and water were available ad libitum. During week one post-weaning, pigs fed elevated dietary copper grew faster and more efficiently than those fed the control diet (P less than 0.04). During week one daily weight gain was 167, 208, 189, 172, and 219 grams and gain-to-feed ratio was 0.58, 0.67, 0.60, 0.62, and 0.70 for the control, BP-100, BP-200, CS-100, and CS-200 treatments, respectively. There was a copper source by dietary level interaction (P less than 0.04) during week one in which the greater copper response for daily gain and gain-to-feed with the BP source was at the 100 ppm dietary level but the greater
response with the CS source was at the 200 ppm copper level. By the end of the 5-week trial, there were no significant responses (P greater than 0.08) to elevated dietary copper. Mean daily gain for the total 5-week period was 454, 484, 468, 463, and 460 grams and gain-to-feed was 0.59, 0.61, 0.60, 0.61, and 0.58 for the control, BP-100, BP-200, CS-100, and CS-200 treatments, respectively. Elevating dietary copper was effective in promoting growth in pigs during the first week after weaning and a lower level (100 ppm) was more effective from the BP copper source than from the CS source. However, for the overall 5-week trial, performance was similar across treatment groups.
Impacts
When therapeutic levels of dietary copper are used for growth enhancement in young pigs, lower inclusion rates are needed if the copper source is an organic copper complex as used in this study. Lower copper inclusion rate results in reduced copper excretion and consequently, less potential for copper build-up in agricultural soils receiving applications of swine manure.
Publications
- Harper, A.F., J.W. Knight, E. Kokue, and J.L. Usry. 2003. Plasma reduced folates, reproductive performance, and conceptus development in sows in response to supplementation with oxidized and reduced sources of folic acid. J. Anim. Sci. 81:735-744.
- Harper, A.F., W.A. Selby, C.M. Wood, M.J. Estienne, J.P. Fontenot, and L.A. Kuehn. 2003. Growth performance in weanling pigs fed diets with elevated copper levels from two copper sources. J. Anim. Sci. 81(abstr., in press).
- Harper, A.F., J.B. Meldrum, J. Zhao, and M.J. Estienne. 2003. Sample collection depth and physical separation by screening affect aflatoxin concentration in contaminated corn. J. Anim. Sci. 81 (suppl. 1, abstr.): 56.
|
Progress 10/01/01 to 09/30/02
Outputs
Regulatory agencies and consumer groups continue to raise concerns about the routine use of growth promoting (sub-therapeutic) antimicrobial products in swine diets. Concerns center on the potential for development of resistant microbes and drug residues in meat products. Use of antimicrobial feed additives is especially common and efficacious in weanling and starter pigs. A growth experiment was conducted to assess the efficacy of a pro-biotic product (Bacillus licheniformis and subtilis) as a potential replacement for growth promoting antimicrobial products in weanling pigs (n=112, ave. initial weight 7.3 kg). Treatments were arranged in a 2x2 factorial design and included: 1) a control diet with no supplemental growth promoter; 2) a diet containing carbodox antibiotic at 55 ppm; 3) a diet containing the Bacillus probiotic at 0.1 percent; and 4) a diet containing both additives in combination. Diet complexity and nutrient density were adjusted in three phases over
the 5-week trial to meet or exceed National Research Council (1998) recommendations for starter pigs. Throughout the experiment overall pig health was good and there were no dietary treatment effects (P more than 0.15) on fecal firmness as measured by fecal firmness scores. For the overall 5-week period, average daily gain was 483 gm, 521 gm, 458 gm and 503 gm, and feed-to-gain ratio was 1.62, 1.57, 1.66 and 1.58 for the control, carbodox, probiotic and carbodox plus probiotic diets, respectively. The overall main effect of carbodox addition was an 8.9 percent increase in daily pig weight gain and a 3.6 percent improvement in feed efficiency (P less than 0.01). There was a moderate reduction (-4 percent, P less than 0.05) in growth rate with probiotic supplementation. Under the conditions of this experiment the antimicrobial additive was effective as a growth promoter for weanling pigs, but the probiotic was not.
Impacts
Swine producers need reliable information regarding potential replacement products for antimicrobial feed additives . Our data demonstrate that so-called bacterial probiotic products do not elicit growth promoting effects similar to those seen with antibiotic feed additves. Through utilization of this information, swine producers will avoid unecessary use of ineffective feed additive products and unecessary increases in feed costs.
Publications
- Harper, A.F., and M.J. Estienne. 2002. Efficacy of three potential alternatives to antimicrobial feed additves for weanling pigs. Prof. Animal Scientist 18:(in press).
- Harper, A.F., R.D. Coffey, G.R. Hollis, D.C. Mahan, and J.S. Radcliffe. 2002. Swine diets. Pork Industry Handbook Fact Sheet 23. Purdue Univ. Cooperative Extension Service, West Lafayette, Indiana.
- Cooper, H.J., A.F. Harper, and M.J. Estienne. 2002. An assessment of a direct fed microbial feed additive (probiotic) for weanling pigs when fed alone and in combination with carbodox antibiotic. J. Anim. Sci. 80(Suppl. 2):8.
|
Progress 10/01/00 to 09/30/01
Outputs
The concern for development of resistant bacterial populations and drug residues in meat products has led to a call for reduction or elimination of use of antimicrobial feed additives in livestock feeds. Feeding elevated supplemental levels of copper (175 - 250 ppm) has been shown to enhance performance of weanling pigs in much the same manner as feeding supplemental antibiotics. When feeding high levels of copper, excessive amounts of copper are excreted which could be damaging to the environment. A weanling pig experiment was conducted to determine if an organic copper complex was more efficacious at promoting growth in pigs when supplemented at lower levels than the traditional source, copper sulfate. A total of 120 crossbred pigs 16 to 23 days of age were used. The pigs were allotted to 4 dietary treatments with six replicate pens of 4 pigs each per treatment. Treatments included a control diet with only 11 ppm supplemental copper, a diet containing 50 ppm copper
from the organic copper source, a diet containing 200 ppm copper from the organic copper source and a diet containing 200 ppm copper from copper sulfate. Pigs were allowed feed and water ad libitum and were weighed weekly for 5 weeks. Pigs fed 200 ppm copper from the organic source grew 9.3 percent faster and had 12.3 percent higher daily feed intake than pigs fed the control diet. Growth rates for pigs fed 50 ppm copper from the organic source and 200 ppm copper from copper sulfate were intermediate and not statistically different from the control. The low level of copper supplementation from the organic source (50 ppm) produced performance similar to the high level (200 ppm) from copper sulfate but copper excretion was reduced by over 60 percent with the lower level. A second experiment investigated if a hulless variety of barley would have greater nutritional digestibility for swine than traditional hulled barley. Ninety-six crossbred grower pigs (initial average weight 38 kg) were
used in a 6-week growth and digestibility trial. Diet treatments included a control corn-soy based diet, a diet based on hulless barley, a diet based on hulled barley, a diet based on hulled barley with added fat to compensate for reduced dietary energy, and a diet based on soft winter wheat. During the final week of the trial fecal samples were collected and digestibility values were determined using the indirect method with chromic oxide as an indigestible dietary marker. Growth performance was statistically similar across all dietary treatments. However, pigs fed diets based on hulled barley without supplemental fat had lower digestibility (and higher excretion) of phosphorus, protein, energy and total dry matter than those fed the hulless barley diet, the wheat based diet or the control corn-soy diet.
Impacts
Supplementing the diet of weanling pigs with elevated levels of copper has the potential to reduce the need for use of antimicrobial feed additives. However, it appears that commercially available organic copper complexes may be fed at slightly lower levels than traditional copper sulfate with similar performance results and less copper excretion into the environment. The lower fiber content of hulless barley appears to result in higher digestibility and nutritional value for pigs relative to traditional hulled barley. Consequently less nutrient and dry matter excretion into the environment can be expected when using hulless barley as a primary feed ingredient as compared to hulled varieties.
Publications
- Harper, A.F., C.M. Wood, V.E. Hofler, R.J. Schiele, R.C. Sims, E.J. Walter, and, M.J. Estienne. 2001. Assessment of an organic copper complex and copper sulfate as growth promoters for weanling pigs. J. Animal Science 79(Suppl. 2): 16.
- Fenton, A.N., J.S. Radcliffe, A.F. Harper, and M.J. Estienne. 2001. Feeding value of hulless and hulled barley in grower pig diets. J. Animal Science 79(Suppl. 1): 108.
|
Progress 10/01/99 to 09/30/00
Outputs
Regulatory agencies and the general public continue to pressure the livestock feeding industry to reduce the use of subtherapeutic antimicrobial feed additives in livestock feeds. The principal concerns associated with this practice are increased risk for development of resistant microbes and the potential for antimicrobial drug residues in meat products. Two experiments were conducted to assess if certain non-antibacterial agents could serve as alternatives to traditional antimicrobial feed additives for weanling pigs and if these agents provided similar growth promotion effects as seen with traditional feed additives. In the first experiment, 80 crossbred weanling pigs were used to determine the effects of a mannan-oligosaccharide product as a feed additive alone and in combination with the antibiotic carbadox. A two by two factorial arrangement of treatments was used with 4 pigs per pen and 5 replicate pens per dietary treatment. Dietary treatments included a
control diet with no growth promoter, a diet supplemented with mannan-oligosaccharide (.3% during week 1 and .2% during weeks 2 through 5), a diet supplemented with 55 ppm carbadox, and a diet supplemented with the two feed additives in combination. There were no interactive effects of feeding the two supplements in combination. The main effect of supplementing carbadox was a significant 8% increase in feed consumption and a concomitant 9% increase in growth rate. However, there was no effect on performance due to supplementation with the mannan-oligosaccharide product. In the second experiment a commercially available polyaspartate biopolymer (PAB) was assessed as a potential growth promoter using 96 weanling pigs. Dietary treatments included an unsupplemented control diet, a diet with 100 ppm PAB, a diet with 200 ppm PAB, and a diet with 400 ppm PAB. Over the five-week experiment there were no effects of PAB supplemetation at any level on performance of weanling pigs. In these
experiments, neither potential alternative to traditional antimicrobial feed additives for weanling pigs produced any measurable effect on growth rate, feed consumption or feed conversion efficiency. In experiment 1, carbadox, a widely used antimicrobial feed additive for nursery pigs, produced measurable responses in growth performance.
Impacts
As regulatory agencies and the consumer public require a reduction in the use of growth promoting antimicrobial feed additives for pigs, it will be important to determine if proposed alternative growth promoters are effective and economically justified for use. The results of these experiments indicate that mannan-oligosaccharide and a polyaspartate biopolymer as alternatives to antimicrobial growth promoters have limited potential for positive effects. Therefore these agents are not likely to yield economic returns when selected as weanling pig growth promoters in commercial swine production.
Publications
- Harper, A. F. and M. J. Estienne. 2000. Effects of a polyaspartate biopolymer (PAB) on growth performance of weanling pigs. J. Animal Science 78(Suppl. 1):240.
- Harper, A. F. and M. J. Estienne. 2000. Efficacy of carbadox antibiotic and a mannan-oligosaccharide source as growth promoters for weanling pigs. J. Animal Science Southern Sectional Meeting Abstracts, January 29 - February 2, 2000, Lexington, Kentucky.
|
Progress 10/01/98 to 09/30/99
Outputs
Increased regulatory pressure and public concern over resistant microbes may force reduced use of antibacterial growth promoters in livestock and poultry feeding. It has been proposed that mannan-oligosaccharides may improve enteric health of young pigs and serve as a non-antimicrobial growth promoter. An experiment was conducted in 1999 to assess the performance of weanling pigs (n=80, 24 d of age) fed diets supplemented with or without the antibiotic carbadox or a commercially available source of mannan-oligosaccharides (Alltech, Inc., Nicholasville, KY). A 2x2 factorial arrangement was used with 4 pigs per pen and 5 pens per treatment. Dietary treatments were: (1) a control diet with no growth promoter, (2) a diet containing the mannan-oligosaccharide source (.3% during wk 1, .2% wk 2-5), (3) a diet containing carbadox (55 ppm), and (4) a diet containing both growth promoting agents. Diet nutrient density was adjusted in 3 phases over the 5-wk trial and feed and
water were available ad libitum. No interactive effects (P>.1) of feeding the two additives in combination were observed and there were no main effects of mannan-oligosaccharide addition at any point during the trial (P>.1). By wk 3 and for the overall trial, carbadox inclusion resulted in significant improvements in growth rate (P<.05) due primarily to enhanced feed consumption (P<.05). Daily gain and daily feed intake means over the total trial for treatments 1 through 4 were 445 and 771 g, 449 and 771 g, 490 and 839 g, and 490 and 826 g, respectively. Stool consistency scores recorded weekly for each pen did not reveal any diarrhea problems and there were no treatment effects (P>.1) on stool consistency. Under the conditions this experiment, weanling pigs supplemented with carbadox grew 9% faster than those not fed the antibiotic. However, a cost assessment indicated that the control pigs exhibited the lowest cumulative feed cost per unit of growth. Calculated feed costs per kg of
growth were .43, .44, .45 and .45 dollars for treatments 1 through 4 respectively.
Impacts
The data indicate that the antibiotic feed additive carbadox continues to be an effective growth promoter for weanling pigs. Under these experimental condition, mannan-oligosaccharides do not appear to be as effective as traditional antibiotics.
Publications
- Harper, A. F. and Estienne, M. J. 1999. Efficacy of carbadox antibiotic and a mannan-oligosaccharide source as growth promoters for weanling pigs. J. Anim. Sci. (Abstr., In Press).
|
|