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United States Department of Agriculture

Agricultural Research Service

Research Project: HANDLING AND TRANSPORT STRESS INTERACTIONS WITH PATHOGEN BIOLOGY IN SWINE AND CATTLE Title: Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids; Part I. Effects on growth performance, microbial populations and immune status

Authors
item Walsh, Maria -
item Rostagno, Marcos
item Gardiner, Gillian -
item Sutton, Alan -
item Richert, Brian -
item Radcliffe, John -

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 2011
Publication Date: August 20, 2012
Citation: Walsh, M.C., Rostagno, M.H., Gardiner, G.E., Sutton, A., Richert, B.T., Radcliffe, J.S. 2012. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids; Part I. Effects on growth performance, microbial populations and immune status. Journal of Animal Science. 90:261-271.

Interpretive Summary: The objective of this study was to evaluate the effects of water-delivered direct-fed microbials (a mix of beneficial or probiotic bacterial strains) or organic acids on immune status, Salmonella infection and shedding, and intestinal microbial populations following a Salmonella challenge in weanling pigs. Pigs were challenged with Salmonella 6 days post commencement of water treatments. Treatments were as follows; 1) control diet; 2) control diet + DFM in drinking water; 3) control diet + an organic acid based blend in drinking water, and 4) control diet + 55 ppm of the antibiotic carbadox (positive control). Serum samples were taken on days 6, 8, 10, and 14 to determine the concentration of immune mediators. Fecal samples were taken on days 0, 5, 7, and 11 for detection of Salmonella shedding and enumeration of selected bacteria. Five pigs per treatment were harvested on days 6, 8, 10, and 14. Intestinal wall and contents, and lymph nodes were taken for Salmonella detection. Scrapings of the wall of each portion of the small intestine were taken for measurement of the concentration of immune response mediators. Water delivery of microbials attenuated a decline in average daily gain on day 2 to 6 post-challenge compared to the negative control. In-feed antibiotic and water-delivered microbials tended to reduce Salmonella presence in the small intestine contents, while large intestine carriage of Salmonella was only reduced by in-feed antibiotic on day 8 post-challenge. Serum mediators of immune response tended to increase up to day 4 post-challenge. Water acidification resulted in higher concentrations of immune response mediators in the small intestine than all other treatments, but only tended to increase concentrations of these mediators compared to in-feed antibiotic on day 8 post-challenge. In conclusion, water delivery of microbials following a Salmonella challenge appeared to attenuate the adverse effects of the infection on weanling pig growth performance. Also, microbials administration via drinking water was shown to be as capable as in-feed antibiotic to reduce the presence of Salmonella in the small intestine. Together, these findings suggest that administering microbials via drinking water offers an alterative approach to in-feed antibiotics in the treatment of Salmonella infection in weanling pigs.

Technical Abstract: Pigs (n=88) weaned at 19 ± 2 d of age were used in a 14 d study to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on immune status, Salmonella infection and shedding, and intestinal microbial populations following a Salmonella Typhimurium challenge. Pigs were challenged with Salmonella 6 d post commencement of water treatments. Treatments were as follows; 1) control diet; 2) control diet + DFM in drinking water; 3) control diet + an organic acid based blend in drinking water, and 4) control diet + 55 ppm antibiotic carbadox (positive control). Serum samples were taken on d 6, 8, 10, and 14 for determination of TNF-alpha concentration. Fecal samples were taken on d 0, 5, 7, and 11 for detection of Salmonella shedding and enumeration of total Enterobacteriaceae. Five pigs per treatment were harvested on d 6, 8, 10, and 14. Intestinal and cecal tissue and contents, and mesenteric lymph nodes (MLN) were taken for Salmonella detection. Duodenal, jejunal and ileal mucosal scrapings were taken for measurement of mucosal TNFa concentration. Water delivery of DFMs attenuated a decline in ADG on d 2 to 6 post-challenge compared to the negative control (P < 0.05). In-feed antibiotic and water-delivered DFM treatments tended to reduce (P = 0.09) Salmonella presence in ileal contents, while cecal carriage of Salmonella was only reduced by in-feed antibiotics on d 8 post-challenge (P < 0.001). Serum TNF-alpha tended to increase (P = 0.08) up to d 4 post-challenge. Water acidification resulted in higher duodenal concentrations of TNF-alpha (P < 0.05) than all other treatments and tended to increase jejunal TNF-alpha concentrations (P < 0.10) compared to in-feed antibiotic on d 8 post-challenge. In conclusion, water delivery of DFMs following a Salmonella enterica var Typhimurium challenge appeared to attenuate the adverse effects of the infection on weanling pig growth performance. Also, DFM administration via drinking water was shown to be as capable as in-feed antibiotic to reduce the presence of Salmonella in the ileum. Together, these findings suggest that administering DFM via drinking water may offer an alterative approach to in-feed antibiotics in the treatment of Salmonella infection in weanling pigs.

Last Modified: 10/31/2014
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