Submitted to: Veterinary Immunology International Symposium
Publication Type: Proceedings
Publication Acceptance Date: 5/8/2007
Publication Date: 8/15/2007
Citation: Solano Aguilar, G., Shea-Donohue, T., Madden, K., Dawson, H.D., Jones, Y., Restrepo, M.P., Beshah, E., Urban Jr, J.F. 2007. Feeding probiotic bacteria to swine enhances immunity to Ascaris Suum. Veterinary Immunology International Symposium. p.110. Interpretive Summary:
Technical Abstract: Probiotic bacterial species are included in the diet to promote health. Probiotics purportedly protect the intestine against pathogenic microorganisms and can reduce inflammation; however, quantitative measurement of probiotic growth and related effects on intestinal function are often lacking. Ascaris suum commonly infects pigs and induces a Th2-derived response in the intestine that is associated with expulsion of the fourth-stage larvae (L4) from the jejunum. The physiological aspect of expulsion represents a “weep and sweep” response, characterized by smooth muscle hyper-contractility and increased luminal fluid associated with reduced sodium-linked glucose absorption. We investigated the effect of feeding Bifidobacterium lactis subspecies animalis (Bb12) on the immune and intestinal function of young pigs subsequently infected with A. suum. Pregnant sows were orally inoculated with a daily dose of Bb12 (3.5 x 1010 cfu) or a placebo during the last trimester of pregnancy, and to their offspring from birth until weaning. Six weeks after weaning, piglets were inoculated with A. suum and the jejunal mucosae was stripped and mounted in Ussing chambers to determine changes in permeability and glucose absorption at 21 days after infection. Pig jejunum, mesenteric lymph nodes, and proximal colon were collected and assayed for gene expression by real time PCR. Bb12 was quantitatively detected using a single copy tuf gene and found at the highest concentration in the colon of probiotic-treated piglets. Probiotic treatment did not affect intestinal permeability, but significantly attenuated the reduction in glucose absorption and the hyper-secretory response to histamine induced by A. suum infection suggesting a selective effect of the probiotic on nutrient absorption and mast cell responses against parasite infection. Probiotic treatment of A. suum-infected pigs significantly increased mRNA expression of genes associated with enhanced protection against parasitic infection, including IL-25, RETNLB, and SOCS3, and did not interfere with normal expulsion of L4 from the jejunum. The results show that probiotic bacteria can selectively enhance local immunity to A. suum without affecting nutrient absorption. This experimental system could be used to evaluate the effect of feeding Bb12 and other probiotics on responses to different infectious agents to reduce antibiotic use. It also models the effect of feeding probiotics to mothers and their newborn children on reduced expression of allergic disease in humans.