Progress 04/15/00 to 09/30/05
Outputs
Research studies have been conducted to quantitate the impact of weaning system on growth performance and on the immune system of early-weaned pigs reared in two different weaning systems. Rearing weanling pigs under segregated nursery conditions improved growth performance and altered the immune status of the pig. This research led to studies to evaluate weaning age and direct fed microbials as means of altering immune status and animal growth performance. Effects of weaning pigs at 14 or 21 days of age on growth performance, behavior, and immune function were evaluated during the nursery and early growing periods in a wean-to-finish facility. Pigs weaned at 14 d of age grew slower than pigs weaned at 21 d of age during the nursery phase of production and were less immunogically developed as evidenced by increased mortality. However, pigs weaned at a younger age grew faster than pigs weaned at an older age for the overall growing/finishing period and surpassed the
older pigs in weight. This study demonstrates that weaning pigs at an early age results in a less immunologically-developed pig compared to pigs weaned later, and this may contribute to the benefits of early-weaning with respect to an overall improvement in gain, efficiency of gain and days to a common weight. However, management strategies should be further explored to optimize these benefits without the detrimental effects on health, as observed during the nursery period in pigs weaned at an earlier age in this study. A study to evaluate the effects of two direct-fed microbials (Lactobacillus brevis and a Bacillus culture) on growth, gastrointestinal microflora, and immune system characteristics of weanling pigs compared to antibiotic supplementation has been completed. Both supplementation with Lactobacillus brevis and antibiotic resulted in improved average daily gain, feed intake, and body weight at the end of the trial compared to pigs fed a control diet. In addition,
Lactobacillus brevis supplementation altered the gastrointestinal microbial population. The combination of Lactobacillus brevis and Bacillus seemed to result in beneficial immune responses characteristic of decreased inflammation similar to antibiotic supplementation. These studies indicate that direct-fed microbial supplementation improves growth performance of pigs during the nursery period, and results in potentially beneficial alterations in gastrointestinal microflora, morphology, monocyte/macrophage activity, and immune cell populations.
Impacts
Pigs produced in conventional intensively managed swine production systems are routinely weaned as early as 19 to 21 days of age in on-site or off-site segregated early weaning systems. Our data suggest that rearing weanling pigs in an off-site facility can improve growth performance and that performance during the nursery period may be dependent on the immune status of the pig. Additional studies demonstrated that weaning age and direct fed microbials also enhanced performance and altered immune status. A better understanding of the impact of rearing system on immune function is essential to understanding the growth performance enhancement associated with off-site production systems and direct-fed microbials. There has been increasing pressure on the livestock industry to decrease or discontinue the use of antibiotics in animal agriculture because of the risk of increasing the incidence of antibiotic-resistant bacteria. Development of effective direct-fed microbials
may hold promise as an alternative to growth promoting additions of antibiotics added to swine diets.
Publications
- Brown, D. C., Dirain, M. S., Davis, M. E., Maxwell, C. V., Johnson, Z. B. and Rehberger, T.. 2005. Comparison of direct-fed microbials and antibiotic supplementation on gastrointestinal morphology of weanling pigs. J. Anim. Sci. 83(Suppl. 2):76.
- Davis, M. E., Dirain, M. S., Brown, D. C., Maxwell, C. V., Johnson, Z. B., and Rehberger, T. 2005. Comparison of direct-fed microbials and antibiotic supplementation on gastrointestinal microflora and immune characteristics of weanling pigs. J. Anim. Sci. 83(Suppl. 2):77.
- Davis, M. E., Sears, S. C., Apple, J. K., Maxwell, C. V., and Johnson, Z. B. 2006. Effect of weaning age and commingling after the nursery phase of pigs in a wean-to-finish facility on growth, and humoral and behavioral indicators of well-being. J. Anim. Sci. 84:743-756.
- Halbrook, E. A., Maxwell, C. V., Davis, M. E., Brown, D. C., Johnson, Z. B., and Rehberger, T.. 2005. Effect of milk supplementation, with a direct-fed microbial during lactation on subsequent nursery performance. J. Anim. Sci. 83(Suppl. 2):76.
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Progress 01/01/04 to 12/30/04
Outputs
There has been increasing pressure on the livestock industry to decrease or discontinue the use of antibiotics in animal agriculture because of the risk of increasing the incidence of antibiotic-resistant bacteria. Direct-fed microbials may hold promise as an alternative to growth promoting additions of antibiotics added to swine diets. We have recently completed a study to evaluate the effects of two direct-fed microbials (Lactobacillus brevis and a Bacillus culture) on growth, gastrointestinal microflora, and immune system characteristics of weanling pigs compared to antibiotic supplementation. Both supplementation with Lactobacillus brevis and antibiotic resulted in improved average daily gain, feed intake, and body weight at the end of the trial compared to pigs fed a control diet. In addition, Lactobacillus brevis supplementation altered the gastrointestinal microbial population. Different bacterial populations were present in pigs provided Lactobacillus brevis
that were absent in pigs not administered 1E1, and similarly, populations were present in pigs not provided Lactobacillus brevis that were absent in pigs exposed to Lactobacillus brevis. Furthermore, the combination of Lactobacillus brevis and Bacillus seems to result in beneficial immune responses characteristic of decreased inflammation similar to antibiotic supplementation. This study indicates that direct-fed microbial supplementation improves the growth performance of pigs during the nursery period, and results in potentially beneficial alterations in gastrointestinal microflora, morphology, monocyte/macrophage activity, and immune cell populations.
Impacts
The need for alternatives to antibiotic supplementation has prompted scientists to explore additional methods to improve pig growth and health The administration of direct-fed microbials such as lactobacilli and Bacillus strains, may be a more direct approach to alter the intestinal microflora and decrease populations of bacteria having a negative impact on pig performance than antibiotic supplementation. Directly altering the microbial colonization of the intestinal tract could be a means to improve swine growth and efficiency, by reducing the level of specific pathogens while establishing a more beneficial microbial population. This could decrease or eliminate the reliance of the industry on growth-promoting levels of antibiotics.
Publications
- Davis, M. E., Brown, D. C., Maxwell, C. V., Johnson, Z. B., Kegley, E. B., and Dvorak, R. A. 2004. Effect of phosphorylated mannans and pharmacological additions of zinc oxide on growth and immunocompetence of weanling pigs. J. Anim. Sci. 82:581-587.
- Davis, M. E., Maxwell, C. V., Erf, G. F., Brown, D. C., and Wistuba, T. J. 2004. Dietary supplementation with phosphorylated mannans improves growth response and modulates immune function of weanling pigs. J. Anim. Sci. 82:1882-1891.
- Dirain, M. S., Davis, M. E., Brown, D. C., Maxwell, C. V., Johnson, Z. B., and Rehberger, T. 2004. Comparison of the effect of direct-fed microbials and antibiotic supplementation on the growth response of weanling pigs. J. Anim. Sci. 82(Suppl. 1):139.
- Davis, M. E., Maxwell, C. V., Apple, J. K., Johnson, Z. B., and Arthur, S. C. 2004. Effect of weaning age and commingling after the nursery phase on growth performance of pigs in a wean-to- finish facility. J. Anim. Sci. 82(Suppl. 2):72.
- Davis, M. E., Maxwell, C. V., Apple, J. K., Johnson, Z. B., Arthur, S. C., and Brown, D. C. 2004. Effect of weaning age and commingling after the nursery phase on immune characteristics of pigs in a wean-to-finish facility. J. Anim. Sci. 82(Suppl. 2):72.
- Davis, M. E., Apple, J. K., Maxwell, C. V., Arthur, S. C., Johnson, Z. B., Dirain, M. S. 2004. Effect of Weaning Age and Commingling After the Nursery Phase on Growth Performance, Immunity, and Behavioral Indicators of Welfare. Arkansas Animal Science Department Report. Arkansas Agri. Exper. Sta. Research Series 522:160-165.
- Maxwell, C. V., Davis, M. E., Brown, D. C., Dvorak, R. A., Musser, R. and Johnson, Z. B. 2004. Efficacy of NuPro in Nursery Diets. Arkansas Animal Science Department Report. Arkansas Agri. Exper. Sta. Research Series 522:166-169.
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Progress 01/01/03 to 12/31/03
Outputs
We have recently completed a study to provide documentation concerning the impact of weaning age in a wean-to-finish facility on well-being and growth performance. Pigs were weaned at 14 or 21 days of age. Effects of weaning age on growth performance, behavior, and immune function were evaluated during the nursery period and early growing period. Pigs were fed to market weight to evaluate any carryover effect of weaning age on days to market and efficiency. Pigs weaned at 14 d of age grew slower than pigs weaned at 21 d of age during the nursery phase of production and were less immunogically developed as evidenced by increased mortality. In addition, younger pigs spent less time lying recumbent on the day of weaning and more time standing or walking during the overall nursery phase, suggesting that younger pigs were less apt to settle into their new environment than older pigs. However, pigs weaned at a younger age grew faster than pigs weaned at an older age for the
overall growing/finishing period and surpassed the older pigs in weight. Improved weight gain in pigs weaned at 14 days of age decreased the overall days to market by 4 days. Feed efficiency was also improved by 6 % during the nursery period and 5% during the growing finishing period in pigs weaned at 14 days of age compared to those weaned at 21 days. This study demonstrates that weaning pigs at an early age results in a less immunologically developed pig compared to pigs weaned later, and this may contribute to the benefits of early-weaning with respect to an overall improvement in gain, efficiency of gain and days to a common weight. However, management strategies should be further explored to optimize these benefits without the detrimental effects on health, as observed during the nursery period in pigs weaned at an earlier age in this study.
Impacts
Improved efficiency associated with early-weaning provided a reduced feed cost of $1.66/pig while reduced days to market would reduce facility cost by $0.32/ pig. If these cost savings could be applied to the approximately 100 million pigs produced in the U. S., this would amount to a reduced cost of over $198 million annually in the U. S. alone. In addition, weaning at an earlier age should improve efficiency in the sow herd by increasing pigs/sow/year. However, management strategies need to be further explored to optimize these benefits without the detrimental effects on health during the nursery phase of production.
Publications
- Singh, S., et al. 2003. Effect of a b-glucan product on performance and immune function of weanling pigs. J. Anim. Sci. 81(Suppl. 2):64.
- Maxwell, C. V., et al. 2003. Efficacy of mannan oligosaccharide supplementation through late gestation and lactation on sow and litter performance. J. Anim. Sci. 81 (Suppl. 2):69.
- Davis, M. E., et al. 2003. Influence of Lactobacillus brevis 1E-1 on the gastrointestinal microflora, gut morphology, and pig performance pre- and post-weaning. 9th International Symp. On Digestive Physiology in Pigs, Banff, AL, Canada. Vol 2:265-267.
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Progress 01/01/02 to 12/31/02
Outputs
Research studies have been conducted to quantitate the impact of weaning system on growth performance and on the immune system of early weaned pigs reared in two different weaning systems. Crossbred pigs (N=88) were weaned at 19 plus or minus 2 d of age, allotted to either the offsite or onsite facility based on initial BW (5.94 plus or minus .07 kg onsite; 5.87 plus or minus .07 kg offsite). Pigs in each group were divided into 4 weight groups and pigs in each weight group were allotted into equal subgroups (2 or 3 pigs/pen) and stratified based on sex and litter. All pigs received common diets and were managed similarly. On d 1, 3, 11, and 24 postweaning, one animal from each weight block was randomly slaughtered (n=4 per facility) and blood was collected for differential cell counts, lymphocyte blastogenesis assay, and cytokine profiles. Polymononuclear cells and intraepithelial lymphocytes (IEL) were isolated for single and double stain analysis using flow
cytometry techniques. Bile was collected for quantification of immunoglobin A (IgA). During phase1, ADG (P<0.01) and ADFI (P<0.01) were greater and pigs reared in offsite facilities were heavier at 24 d postweaning (P< 0.05) than pigs reared onsite (17.38 plus or minus .35 kg vs. 15.85 plus or minus .35 kg, respectively). Lymphocytes isolated from pigs from both facilities had a higher (P<0.01) mitogen stimulation index on d 1 postweaning compared to d 3, 11 and 24 postweaning. Production of IgA and the percentage of eosophils from pigs at both locations were higher (P<0.05) at 24 d postweaning compared to other days sampled. Pigs reared onsite had higher (P<0.05) interleukin 4 (IL-4) production on d 1 postweaning compared to pigs reared off-site at d 1, 11, and 24 postweaning while pigs at the offsite facility had higher IL-4 production on d three postweaning; there were no differences (P>0.10) in interleukin-2. The percentage of neutrophils increased (P<0.05) in pigs reared at the
offsite facility from d 1 through 3 postweaning followed by an increase (P<0.05) in lymphocytes on d 11. Systemic T lymphocyte populations were greater (P<0.01) on d 24 postweaning, the number of CD4+ cells was higher (P<0.05) on d 1 postweaning and double positive cells (CD4+CD8+) were lower (P<0.10) on d 3 postweaning in pigs from both facilities compared to the other days sampled. Onsite pigs had a higher (P<0.10) population of CD4+ IEL at d 1 postweaning compared to offsite pigs on d 1, 3, 11 and 24 postweaning. After d 1 postweaning the population of CD4+ IEL decreased (P<0.05) in on-site pigs and the population of CD8+ IEL from the off-site pigs increased (P<0.05). The population CD8+ IEL then decreased (P<0.05) on d 24 postweaning for off-site pigs. The population of CD8+ IEL was higher (P<0.05) for the offsite pigs on d 3 and 11 postweaning than onsite pigs on d 3 postweaning. Offsite pigs had a higher (P<0.05) population of IEL positive for the gamma/delta T cell receptor
(TCR1) on d 1 postweaning compared to onsite pigs on d 1, 11 and 24 postweaning and offsite pigs on d 3 and 11 postweaning. Double positive and CD8+CD4- IEL were lower (P<0.05) on d 1 and 3 postweaning than d 11 and 24 postweaning.
Impacts
Pigs produced in conventional intensively managed swine production systems are routinely weaned as early as 19 to 21 days of age in onsite or offsite segregated early weaning systems. Our data suggest that rearing weanling pigs in an offsite facility can improve growth performance and that performance during the nursery period may be dependent on the immune status of the pig. Differing nursery environments also alters systemic and enteric T cell subpopulations which may indicate that the pigs T cell repertoire develops in response to the level of exposure to disease. A better understanding of the impact of rearing system on immune function is essential to understanding the growth performance enhancement associated with offsite production systems.
Publications
- Davis, M. E., Maxwell, C. V., Brown, D. C., De Rodas, B. Z., Johnson, Z. B., Kegley, E. B., Hellwig, D. H., and Dvorak,R. A. 2002. Effect of dietary mannan oligosaccharides and (or) pharmacological additions of copper sulfate on growth performance and immunocompetence of weanling and growing/finishing pigs. J. Anim. Sci. 80:2887-2894.
- Davis, M. E., Maxwell, C. V., Brown, D. C., and Wistuba, T. J. 2002. Growth performance and immune parameters of weanling pigs fed mannan oligosaccharides. J. Anim. Sci. 80(Suppl. 1):40.
- Brown, D. C., Maxwell, C. V., Davis, M. E., and Singh, S. 2002. Effect of segregated early weaning on growth performance and immune parameters of pigs. J. Anim. Sci. 80(Suppl. 1):197.
- Brown, D. C., Maxwell, C. V., Davis, M. E., Erf, G. F., and Singh, S. 2002 Effects of segregated early weaning on systemic and enteric T lymphocyte subpopulations in pigs. J. Anim. Sci. 80(Suppl.1):30.
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Progress 01/01/01 to 12/31/01
Outputs
Studies have been initiated to determine the impact of weaning on gut immune function in early-weaned pigs and to evaluate the potential for immunostimulates to enhance performance and immune function. A study involving 120 early-weaned pigs to monitor the impact of feeding different levels (0.00, 0.05, and 0.10 %) of a glucan product from Sacchromyces cervisae on growth performance and immune function in the young early-weaned pig has been completed. Serum samples were collected to ascertain acute phase protein levels at various intervals following weaning. During the overall study, ADG was higher for pigs fed the glucan product compared to pigs fed the control diet (0.38 and 0.34 kg). During the combined phase 1 and 2 periods, pigs fed the glucan product had higher G:F (0.76 and 0.78 for 0.05 % and 0.10 % supplementation, respectively) compared to pigs fed the control diet (0.72). At the termination of the study, pigs fed 0.05 % and 0.10 % of the glucan product
were, respectively, 0.98 and 0.99 kg heavier than pigs fed the control diet. On day 14 post-weaning, pigs fed the control diet had higher levels of ceruloplasmin when compared to pigs fed glucan supplemented diets. On day 28 post weaning, pigs fed the control diet had lower haptoglobin levels as compared to pigs fed glucan supplemented diets. The study indicates that beta-glucan can be fed to nursery pigs to improve weight gain and may impact the immune system. A second study involving 88 early-weaned pigs was conducted to study the impact of early-weaning (conventional versus segregated early-weaning) on performance and gut immune function of young pigs. During phase 1, pigs reared in the off-site facility had greater ADG and ADFI and were heavier at 24 d post-weaning than pigs reared on-site (17.38 kg vs. 15.85 kg, respectively). Lymphocytes isolated from pigs from both facilities had a higher mitogen stimulation index on d 1 post-weaning compared to d 3, 11 and 24 post-weaning.
Production of IgA and the percentage of eosophils from pigs at both locations were higher at 24 d post-weaning compared to other days sampled. Pigs reared on-site had higher interleukin-4 (IL-4) production on d 1 post-weaning compared to pigs reared off-site at d 1, 11, and 24 post-weaning while pigs at the off-site facility had higher IL-4 production on d three post-weaning; however, there were no differences in interleukin-2. The percentage of neutrophils increased in pigs reared in the off-site facility from d 1 through 3 post-weaning followed by an increase in lymphocytes on d 11. Data suggest that rearing weanling pigs in an off-site facility can improve growth performance and that performance during the nursery period may be dependent on the immune status of the pig.
Impacts
Pigs produced in conventional intensively managed swine production systems are routinely weaned as early as 19 to 21 days of age and as early as 10 to 14 days of age in off-site segregated early weaning systems. Typically, early-weaned pigs produced in Arkansas are commingled at weaning and reared in off-site nursery units before being transported to the corn belt for finishing. The stress of early-weaning and commingling pigs prior to the nursery phase of production and of long distance hauling to finishing presents a challenge for the swine industry. It has become common practice to add growth promoters such as antibiotics and pharmacological levels of copper to overcome the negative performance and health problems associated with these stressful production practices. These studies represent the initial steps necessary for the development of alternative means of producing and maintaining high health pigs which should minimize the need for antibiotics or
pharmacological levels of minerals.
Publications
- Jaen, J. F., Maxwell, C. V., Johnson, Z. B., Brown, D. C., Singh, S., Davis, M. E., Touchett, K. J., Coalson, J. A., and Musser, R. E.. 2001. Potential for egg protein as a protein source for phase 1 nursery diets. J. Anim. Sci. 79(Suppl. 1):107.
- D. R. Smith, Moore, P. A., Jr., Maxwell, C. V., and Daniel, T. C. 2001. Effects of dietary phytase and aluminum chloride manure amendments on phosphorus in swine manure. J. Anim. Sci. 79(Suppl. 1):252.
- Davis, M. E., Maxwerll, C. V.l, de Rodas, B. Z., Brown, D. C., Johnson, Z. B., and Dvorak, R. A. 2001. Efficacy of mannan oligosaccharide (Bio-Mos) addition with two levels of cooper sulfate in the diets of growing-finishing pigs. J. Anim. Sci. 79(Suppl. 1):472.
- Maxwell, C. V., Brown, D. C., Davis, M. E., Johnson, Z. B., and Fakler, T. M.. 2001. Effect of copper source on performance of weanling pigs. J. Anim. Sci. 79(Suppl. 2):77.
- Davis, M. E., Brown, D. C., Maxwell, C. V., Johnson, Z. B., and Dvorak, R. A. 2001. Efficacy of mannan oligosaccharide (Bio-Mos) as a complete or partial replacement for zinc oxide in the diets of weanling pigs. J. Anim. Sci. 79(Suppl.2):78.
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Progress 01/01/00 to 12/31/00
Outputs
Studies have been initiated to determine the impact of weaning on gut immune function in early-weaned pigs and to evaluate the potential for immunostimulates to enhance performance and immune function. A study involving 120 early-weaned pigs is underway to monitor the impact of feeding different levels (0.00, 0.50, and 0.10 %) of a glucan product from Sacchromyces cervisae on growth performance and immune function in the young early-weaned pig. At seven days postweaning, the proliferative response of peripheral blood mononuclear cells to various mitogens such as Concanavalin A, Pokeweed Mitogen, and Phytohemagglutinin will be determined. In addition, the cytokine profile (IL-2, 4, 10, and IFN-gamma) of T lymphocytes will also be compared. Serum samples will be collected to ascertain acute phase protein levels at various intervals following weaning. The techniques for conducting these assays have already been standardized in our laboratory. A second study involving 172
early-weaned pigs will be conducted to study the impact of early weaning (conventional versus segregated early weaning) on gut immune function of young pigs. Intraepthelial lymphocytes from the duodenum and jejunum will be isolated at different times post-weaning and studied for their diversity and cytokine profile. Immunohistochemical studies to determine the diversity and distribution will also be conducted on the tissue samples obtained from gastrointestinal tract. In addition, the impact of weaning and weaning system on changes in gut microbiota will be evaluated. These studies are designed to evaluate alternatives to standard weaning practices in the swine industry involving antibiotics and high inclusion levels of copper and zinc.
Impacts
The swine industry is implementing early weaning for efficient and economical pig production. The obvious consequence of this early weaning is the abrupt change in diet from sow's milk to solid feed and a change in the environment. There is reduced feed intake during the first week and associated adverse changes in the animal's gut anatomy and physiology. The intestinal microflora are also adversely impacted during weaning resulting in higher numbers of potentially pathogenic acid-intolerant coliforms and decline of favorable lactobacilli. In addition, since the piglets are young, their immune system might not be totally equipped to deal with such pathogenic challenges. Pigs reared in isolation have been shown to have reduced immunological stress resulting in improved growth and efficiency of feed utilization. This suggests that reduced performance observed in our lab in a conventional nursery may be associated with the immunological stress associated with production
under these conditions. Our working hypothesis is that the mucosal immune system in the gut of early-weaned pigs reared under a conventional system is at an elevated level of stimulation compared to that of segregated early-weaned pigs. These studies are designed to evaluate alternatives to standard weaning practices in the swine industry and to develop a preliminary assessment of the immune status of early-weaned pigs growing under the different environments.
Publications
- No publications reported this period
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