Effects of a triple-strain Bacillus-based probiotic on cecal and ovarian colonization of Salmonella Enteritidis in commercial pullets.

A commercial triple-strain Bacillus-based probiotic (GALLIPRO® Fit) was evaluated for its ability to reduce cecal and ovarian colonization by Salmonella enteritidis (SE) in commercial layer pullets. A total of 250 day-old W-36 pullets were assigned to two dietary treatments on top of a standard diet: a non-supplemented control (CON) and a probiotic-supplemented (GALLIPRO® Fit) group (500 g/MT of feed; 1.6 × 106 CFU/g of finished feed; PRO). At 16 weeks of age, birds were orally challenged with 3.9 × 10⁸ CFU of a nalidixic acid-resistant SE strain. Cecal contents and ovaries were collected at 6, 10, 14, and 17 days post-infection (dpi) from 24 pullets per treatment group (n=192) for SE enumeration and prevalence assessment. Cecal SE counts were significantly reduced by 1.22 log₁₀ CFU/g in probiotic-fed birds compared to controls at 10 dpi (4.22 vs 5.44 log10 CFU/g; P = 0.0154), while no significant differences were observed at other time points. No differences in SE prevalence were detected in ceca or ovaries between treatments. These findings indicate that dietary supplementation with a multi-strain Bacillus-based probiotic may contribute to transient reductions in intestinal Salmonella Enteritidis load in layer pullets following a challenge, although effects on systemic invasion were not observed.