Submitted to: Pig Veterinary Society International Congress Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 27, 2004
Publication Date: June 27, 2004
Citation: Solano Aguilar, G., Ledbetter, T., Dawson, H.D., Andrews, K., Harvey, R.B., Schoene, N., Urban Jr, J.F. 2004. The effect of probiotic bacteria on the immune system of weaned pigs monitored by Real time PCR. Proceedings 18th International Pig Veterinary Society Meeting, Hamburg, Germany, October 2004. p. 380. Technical Abstract: Public interest in the development and consumption of functional foods (foods that promote health beyond providing basic nutrition) is growing because of an appreciation of the role of nutrition in health. Rigorous scientific testing of claims for functional foods that contain probiotic bacteria promote health and prevent disease is needed. We have developed a pig model to test the effect of probiotics on immune function. Eight, 12-week-old pigs were divided into two groups with four pigs fed daily a capsule containing 10 billion colony forming units (cfu) freeze-dried Lactobacillus rhamnosus GG (LGG) (CAG Functional Foods, Inc) for 26 consecutive days and four other pigs left as non-treated controls. Blood and fecal samples were collected throughout the experiment at days 4, 7, 12, 18 and 25 after initiation of dietary treatment. At the end of the experiment (day 26), pigs were euthanized and tissues from lymph nodes (tracheobronchial, mesenteric, ileocecal) and intestinal sections (ileum, cecum, proximal and distal colon) were collected for 1) cell surface immune phenotypic analysis using flow cytometry; 2) DNA isolation and identification of LGG strain in tissues and fecal samples by Taqman real-time PCR; 3) mRNA gene expression of immune markers (cytokines) by real-time PCR. The results showed that there was no significant change in the immune phenotype of lymphoid cells isolated from peripheral blood, lymph nodes and intestinal mucosa in pigs treated with LGG compared to non-treated pigs. Real time PCR analysis of immune markers indicated that there was an upregulation in the gene expression of immune markers associated with the early innate immune response. These changes reflect an enhanced Th1-type response, similar to what has been reported for humans treated with LGG. It also validates our model for human studies that address questions of immune system development, function and response to infection. In addition, the application of real-time PCR technology can be exploited for quick identification of probiotic bacteria from tissue or fecal specimens.