Submitted to: Journal of Animal Science Supplement
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/11/2011
Publication Date: 6/1/2011
Citation: Weedman, S., Rostagno, M.H., Patterson, J., Yoon, I., Fitzner, G., Eicher, S.D. 2011. Yeast culture supplement during nursing and transport affects immunity and intestinal microbial ecology of weanling pigs. Journal of Animal Science Supplement. 89(6):1908-1921. Interpretive Summary: Weaning and transport stress can have a negative impact on the piglet's immune system and intestinal microbiota. Yeast products and extracts are believed to possibly alter responses that are suppressed by weaning or transport stress. In this study, growth and feed efficiency were not affected by the yeast treatment. However, yeast treatment resulted in a quicker immune response following weaning as shown by greater numbers of neutrophils (the cells that are the first defenders). Transport increased the percentage of cells that present antigen by day 14, but no yeast effect was found. The E. coli (a microbe that can become a pathogen with opportunity) was lower in the yeast-fed and transported pigs than in the control or yeast without transport pigs. Antigen recognition molecules also were only affected by time. On day 4, more transported piglets fed yeast were positive for Salmonella (a common food borne pathogen) in the mesenteric lymph nodes (lymph nodes adjacent to the intestine) compared than non-transported controls. All mesenteric lymph node samples became positive by day 7 sampling indicating an earlier clearance by the yeast and transported group than by the other treatments while numbers in the intestine remained similar among the treatments. In summary, transport altered immune responses further than did weaning alone and yeast treatment modulated the kinetics of some responses that may prevent or reduce the severity of an infection. These results can be used by producers and yeast companies as a basis for the benefit of developing a delivery method of supplementation of yeast products before weaning.
Technical Abstract: Weaning and transport stress can have a negative impact on the piglet's immune system and intestinal microbiota. The objective of this study was to determine the influence of a yeast product on innate immunity and microbial ecology of the gastrointestinal tract following stress of weaning and transport. In a 2 x 2 factorial arrangement of yeast (Y; XPC, Diamond V Mills) and transport (T), 108 pigs (n = 24 per treatment and 12 baseline pigs) were assigned to Y delivered orally in milk to provide 0.1g/kg of BW or control (C) receiving milk only supplements from d 4 to 21 (weaning). At weaning, YT and CT pigs were transported for 6 h and C and Y pigs were moved directly to nursery housing. Pigs were then supplemented with 0.2% XPC or a grain blank in feed for 2 wk. On d 1 pre- and d 1, 4, 7, and 14 post-transport, blood was collected for leukocyte analysis, and mesenteric lymph node (MLN), jejunal and ileal tissue, and jejunal, ileal, and cecal contents were collected for intestinal receptor expression, enumeration of Escherichia coli, coliforms and Lactobacillus, detection of Salmonella, and microbial profiling. Fecal swabs were obtained pre- and post-transport. Average daily gain, ADFI , and G:F were not different among the treatments. All control pigs had greater (P = 0.055) hematocrit percentages than did all yeast treated pigs on d 4. Neutrophil counts (P = 0.03) were greater for YT pigs than the other 3 treatments and increased over the study (P = 0.01). Lymphocyte counts were greater for Y pigs than YT pigs on d 4, but C pigs had greater counts than Y pigs on d 14 (treatment by day effect, P < 0.01). Monocyte counts also had a treatment by day effect (P = 0.05) such that C pigs had greater counts than Y pigs on d 1, but by d 4 the counts of the C pigs were less than the other 3 treatments. Monocyte percentages (P = 0.008) were greater for YT than for Y and C pigs. Neutrophil to lymphocyte ratio had a treatment by day interaction (P = 0.002) such that Y pigs had a greater ratio than YT and CT pigs on d 1 and than YT and C pigs on d 14. Fluorescence for CD14 (P = 0.004) and CD18 (P = 0.001) increased over time. Toll-like receptors 2 and 4 expression in jejunal tissue and mesenteric lymph nodes was affected by d. Jejunal E. coli counts for CT pigs were greater on d 1 than for Y piglets and YT piglets had lesser counts than did Y and C piglets on d 4 (treatment by d effect P < 0.05). Transport altered immune responses further than did weaning alone and yeast treatment modulated the kinetics of some responses.