Effects of a triple-strain <i>Bacillus</i>-based probiotic on cecal and ovarian colonization of <i>Salmonella Enteritidis</i> in commercial pullets.
Supplementing layer pullet diets with a Bacillus-based probiotic may lead to a temporary reduction in Salmonella Enteritidis levels in the gut, but it does not appear to affect systemic infection rates.
Where it sits
this study against the rest of the melanotan i (mt-i) corpusSummary and findings
A commercial triple-strain Bacillus-based probiotic was evaluated for its effects on cecal and ovarian colonization by Salmonella Enteritidis in commercial layer pullets. A total of 250 day-old W-36 pullets were assigned to either a control or probiotic-supplemented diet. At 10 days post-infection, cecal SE counts were significantly reduced by 1.22 log₁₀ CFU/g in probiotic-fed birds compared to controls.
Abstract
A commercial triple-strain <i>Bacillus</i>-based probiotic (GALLIPRO® Fit) was evaluated for its ability to reduce cecal and ovarian colonization by <i>Salmonella enteritidis</i> (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 × 10<sup>6</sup> 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 log<sub>10</sub> 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 <i>Bacillus</i>-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.
Background
This study addresses the potential of a Bacillus-based probiotic to mitigate Salmonella enteritidis colonization in poultry, a significant concern for food safety. Prior research has indicated probiotics may influence gut microbiota and pathogen resistance, but evidence on their effectiveness against Salmonella in commercial settings remains limited. This study is relevant as it explores a specific probiotic formulation and its impact on a common pathogen in poultry.
Methods
The study utilized a total of 250 day-old W-36 pullets, divided into two groups: a control group without supplementation and a probiotic-supplemented group receiving 500 g/MT of feed containing 1.6 × 10⁶ CFU/g. Birds were orally challenged with 3.9 × 10⁸ CFU of a nalidixic acid-resistant SE strain at 16 weeks of age. Cecal contents and ovaries were collected from 24 pullets per treatment group at 6, 10, 14, and 17 days post-infection for SE enumeration and prevalence assessment.
Results
At 10 days post-infection, cecal SE counts were significantly reduced by 1.22 log₁₀ CFU/g in probiotic-fed birds compared to controls (4.22 vs 5.44 log₁₀ CFU/g; P = 0.0154). No significant differences were observed at other time points, and SE prevalence in ceca or ovaries did not differ between treatments.
Interpretation
While the study demonstrated a statistically significant reduction in cecal SE counts at 10 dpi, the clinical significance of a 1.22 log₁₀ reduction may be limited, especially given that no differences in prevalence were found. This transient effect raises questions about the long-term efficacy of the probiotic in preventing Salmonella colonization. The study's limitations, including the lack of observed systemic invasion and the focus on a single time point for significant findings, suggest caution in interpreting the results for practical applications.
Key findings
- Cecal SE counts reduced by 1.22 log₁₀ CFU/g in probiotic-fed birds at 10 dpi, P = 0.0154.
- Cecal SE counts at 10 dpi: 4.22 log₁₀ CFU/g (PRO) vs 5.44 log₁₀ CFU/g (CON).
- No significant differences in SE prevalence in ceca or ovaries between treatments.
Limitations
- No significant differences in SE prevalence in ceca or ovaries.
- Transient reduction in SE counts may not indicate long-term efficacy.
- Single time point for significant findings limits broader conclusions.