|ADHIKARI, PRATIMA - Mississippi State University|
|LEE, C - Genebiotech Company, Ltd|
|Cox, Nelson - Nac|
|KIM, WOO - University Of Georgia|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2018
Publication Date: 9/27/2018
Citation: Adhikari, P., Lee, C.H., Cosby, D.E., Cox Jr, N.A., Kim, W.K. 2018. Effect of probiotics on fecal excretion, colonization of internal organs and immune gene expression in the ileum of laying hens challenged with Salmonella Enteritidis. Poultry Science. 97(1):2525-2533. https://doi.org/10.3382/ps/pey443.
Interpretive Summary: Control of Salmonella colonization of layers continues to be an issue in the industry. With the regulations preventing the use of antimicrobials in the poultry industry, new methods are required to reduce the levels of Salmonella in laying hens. This study evaluated the effects of probiotic supplementation on the colonization of White Leghorn layers with Salmonella and the immunological responses of the chickens to the supplementation or through colonization with Salmonella. Important regulation of immune genes was observed after supplementation by probiotics.
Technical Abstract: A study was conducted to evaluate the supplementation of probiotics on Salmonella colonization in the ceca and various internal organs as well as immune response in laying hens challenged with Salmonella Enteritidis. Thirty-two White Leghorns were housed individually in wire laying cages under 16L:8D lighting schedule. Hens were challenged individually with nalidixic acid resistant Salmonella Enteritidis (SENAR) after which time they were grouped into four treatments: T1 = SENAR unchallenged control, T2 = SENAR challenged control, T3= SENAR challenged+0.05% probiotics (Lactobacillus Plantarum), and T4 = SENAR challenged+0.1% probiotics. All hens, including T1 were euthanized and sampled for the liver with gall bladder (L/GB), ovary, spleen and ceca on 7-days post-infection (dpi). Fecal screening was performed on individual hens at both 3 and 6 days post infection (dpi). No difference was detected between the treatments in cecal SENAR enumeration, and the mean log 10 cfu/gm of SENAR in the ceca was 3.7 for all three treatments. The prevalence of SENAR was lowest for ovary in all treatments and was highest in the spleen. However, there were no significant differences between the treatments in the internal organs. There was no significant difference in the fecal shedding among the treatments on either 3 or 6 dpi, with incidence of positive feces higher at 3 dpi compared to 6 dpi (100 vs. 70 - 80%). RNA was extracted from the ileum and subjected to real-time quantitative (RT-PCR) for measurement of both pro- and anti-inflammatory cytokines such as interleukin (IL)- 1ß, 6, 10, interferon gamma (IFN-') and toll-like receptor (TLR)- 4. SENAR challenge resulted in significant upregulation (P < 0.05) of cytokines tested. Highest level of probiotics resulted in a significant decrease in IFN-' and elevation of IL-10 gene expression in the ileum of chickens. For the remaining cytokines tested, the supplementation of probiotics resulted in either higher or similar expression to that of SENAR challenge. This study reveals that there was important regulation of immune genes by probiotics supplementation.