Effect of Newly Characterized Probiotic Lactobacilli on Weight Gain, Immunomodulation and Gut Microbiota of Campylobacter jejuni Challenged Broiler Chicken

The aim of the present study was to determine the competitive exclusion of Campylobacter jejuni in poultry gut by three potential probiotic lactobacilli strains. A total of 135 birds of one day age were randomly divided into nine groups. The groups of prevention model received respective strains from day 1-35 and treatment model received lactobacilli from day 15-35 (after challenging with C. jejuni). These groups were given lactobacilli (similar to 10(8) CFUs) while challenged with C. jejuni on day 14 by oral gavage (10(6) CFUs/bird). There were three control groups including A, B and I. Negative control (A) did not receive any treatment, C. jejuni was given to group B and group I was given Enrofloxacin formulation. Cloacal swabs were collected from birds of each group before and after challenge while the ceca were collected from birds after slaughtering (on day 35) for enumeration of aerobic bacteria, coliform, C. jejuni, lactobacilli and Bifidobacterium on selective agar plates. Effect of lactobacilli on weight gain and New Castle Disease vaccine (NDV) titer were also evaluated. Probiotic strain Lactobacillus gallinarum PL 53 considerably decreased log(10) values of aerobic plate count (3.19 +/- 0.66), coliform count (2.83 +/- 0.22) and C. jejuni (3.98 +/- 0.77) in poultry. The probiotics also enhanced Lactobacillus and Bifidobacterium spp counts (similar to 2-3 log increase). Treatment group C had maximum weight gain (1994 +/- 188.32g) and geometric mean titer (274.4) on day 28. The results of in-vivo experiments concluded that probiotic administration may be effective for targeted mitigation of C. jejuni in broiler birds. (C)2019 PVJ. All rights reserved