Location: Livestock Behavior ResearchTitle: Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport Author
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2012
Publication Date: 8/15/2012
Citation: Walsh, M.C., Rostagno, M.H., Gardiner, G.E., Sutton, A.L., Richert, B.T., Radcliffe, J.S. 2012. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport. Journal of Animal Science. 90:2599-2608. Interpretive Summary: The objective of this study was to evaluate the effects of water-delivered probiotics (beneficial bacteria) or organic acids on intestinal morphology and nutrient absorption in weanling pigs following a Salmonella infection. Pigs were weaned at 19 days of age and assigned to one of the following treatments, which were administered for 14 days: 1) control diet; 2) control diet + probiotic in drinking water; 3) control diet + organic acid in drinking water; and 4) control diet + antibiotic. Pigs were challenged with Salmonella Typhimurium 6 days post commencement of treatments. Pigs were harvested prior to Salmonella challenge and on days 2, 4, and 8 post-challenge. Tissue samples from different portions of the small intestine were collected. Salmonella infection resulted in decreased phosphorus and glucose intestinal transport, and increased glutamine uptake. Water delivery of either probiotic or organic acids was unable to beneficially affect intestinal morphology. In conclusion, none of the additives markedly affected intestinal absorptive and secretory functions in the face of a Salmonella challenge.
Technical Abstract: The objective of this study was to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs following deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to one of the following treatments, which were administered for 14 d: 1) control diet; 2) control diet + DFM (Enterococcus faecium, Bacillus subtilis and Bacillus licheniformis) in drinking water at 109 cfu/L for each strain of bacteria; 3) control diet + organic acid-based blend (predominantly propionic, acetic, and benzoic acid) in drinking water at 2.58 mL/L; and 4) control diet + 55 mg/kg carbadox. Pigs were challenged with 1010 cfu Salmonella enterica var Typhimurium 6 d post commencement of treatments. Pigs (n = 22/d) were harvested prior to Salmonella challenge and on d 2, 4, and 8 post-challenge. Duodenal, jejunal, and ileal mucosal tissues were sampled for measurement of villus height and crypt depth. Jejunal tissue was sampled for determination of active nutrient absorption in modified Ussing chambers. Duodenal villus height was greater in pigs fed in-feed antibiotic prior to infection (P < 0.05). Jejunal crypts were deeper in DFM and acid treated pigs on d 4 post-infection compared to all other treatments (P < 0.05). Salmonella infection resulted in a linear decrease in phosphorus (P < 0.001) and glucose (P < 0.05) active transport and an increase (P < 0.001) in glutamine uptake immediately postchallenge. Basal short-circuit current (Isc) was reduced by Salmonella infection; however, water-delivered DFM or organic acid treatments had greater basal Isc on d 2 post-challenge than pigs fed carbadox. Carbachol induced chloride ion secretion was greatest in negative control pigs prior to infection (P < 0.01) and DFM treated pigs (P < 0.05) after infection. In conclusion, both the DFM and acidification treatments induced increases in basal active ion movement and jejunal crypt depth, which could be interpreted as responses consistent with increased Salmonella pathology; however, none of the additives markedly affected intestinal absorptive and secretary function in response to Salmonella challenge.