ABSTRACT
A total of 192 Hy-Line Brown 40-week-old Salmonella-free layers were randomly assigned to 4 dietary treatments in a 5-wk experiment to test the efficacy of probiotics on egg production and quality, excreta and intestinal microbiota of laying birds challenged with Salmonella gallinarum. Dietary treatment comprised of (1) NC: ; basal diet, negative control, (2) PC: ; basal diet + oral S. gallinarum administration, positive control, (3) T1: ; basal diet + 0.1% Bacillus subtilis RX7 1 × 10(9) cfu/g + S. gallinarum administration and (4) T2: ; basal diet + 0.1% Bacillus methylotrophicus C14 1 × 10(9) cfu/g + S. gallinarum administration. All birds (n = 144) except NC were orally challenged with 1 ml suspension of 10(8) cfu/mL S. gallinarum KVCC BA 0700722 once at d 28 after the initiation of experiment. The egg production improved in post Salmonella-challenged birds whereas egg equality was improved during pre-challenge in probiotic supplemented birds compared to NC and PC. The Salmonella counts in the excreta were lower (P < 0.05) in T1 and T2 than PC at the end of the experiment whereas the Lactobacillus counts in the excreta were higher (P < 0.05) in T1 compared with NC. The Escherichia coli counts in excreta were numerically lower in T1 and T2 than PC. In the small and large intestine, there was slight increase in Lactobacillus counts in T2 compared with PC. The Salmonella counts in small and large intestine tended to be lower in T1 and T2 as compared with PC. However, Salmonella counts in challenged birds not supplemented with probiotics were significantly higher than non-challenged birds.
