Effect of probiotics on fecal excretion, colonization in internal organs and immune gene expression in the ileum of laying hens challenged with Salmonella Enteritidis

ABSTRACT A study was conducted to evaluate the supplementation of probiotics on Salmonellacolonization in the ceca and various internal organs as well as immune response in laying hens challenged with Salmonella entericaserovar Enteritidis (SE). Thirty-two 46-wk-old White Leghorns (W-36) were housed individually in wired laying cages under 16L:8D lighting schedule. Hens were challenged individually with nalidixic acid resistant SalmonellaEnteritidis (SENAR) after which time they were grouped into four treatments: T1 = SENARunchallenged control, T2 = SENARchallenged control, T3 = SENARchallenged + 0.05% probiotics (Lactobacillus plantarum), and T4 = SENARchallenged + 0.1% probiotics. All hens, including T1, were euthanized and sampled for the liver with gall bladder (L/GB), ileum, ovary, spleen, and ceca on 7-days post-infection (dpi). Fecal screening was performed on individual hens at both 3 and 6 dpi. No difference was detected between the treatments in cecal SENARenumeration, and the mean log 10 cfu/gm of SENARin the ceca was 3.7 for all three treatments. The prevalence of SENARwas lowest for ovary in all treatments and was highest in the spleen. However, there were no significant differences among 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% to 80%). SENARchallenge resulted in significant upregulation (P