Study links Bacillus licheniformis to gains in post-peak layers

A newly published paper in Animals suggests that Bacillus licheniformis supplementation may help stabilize performance in hens after peak lay, a period when production efficiency often starts to slip. In a 31-day feeding trial, 720 laying hens at 43 weeks of age received either a basal diet or feed supplemented with B. licheniformis at three inclusion levels. The middle dose, 5 × 10^9 CFU/kg, delivered the most consistent results, improving laying rate and feed-to-egg ratio while also boosting antioxidant markers and intestinal morphology. (mdpi.com)

That focus on the post-peak period is important. The authors frame this production stage as one marked by declining ovarian function, impaired intestinal barrier integrity, and rising oxidative stress, all of which can weigh on output and flock resilience. Earlier research has already linked B. licheniformis with better laying performance, gut integrity, and immune or antioxidant responses in layers, but much of that work has centered on peak-phase hens, heat stress models, or different strains and formulations. (mdpi.com)

In the new study, hens received B. licheniformis at 2.5 × 10^9, 5 × 10^9, or 1 × 10^10 CFU/kg for 31 days. According to the paper, the 5 × 10^9 CFU/kg group increased laying rate by 1.44 percentage points, from 78.96% to 80.40%, and reduced feed-to-egg ratio by 2.4%. It also lowered serum malondialdehyde by 35.8% and increased glutathione peroxidase by 33.2% and superoxide dismutase by 56.0%, suggesting improved systemic antioxidant capacity. The same group showed higher jejunal and ileal villus height and villus-to-crypt ratio, markers commonly used as indicators of absorptive surface and gut integrity. (mdpi.com)

The microbiota findings were more nuanced. The researchers reported a higher relative abundance of Clostridia_UCG-014 and norank_o_RF39, alongside a lower abundance of Megasphaera, in supplemented birds at the most effective dose. However, cecal volatile fatty acid concentrations did not differ significantly among groups, which suggests that any production benefit may be tied more to barrier function, redox balance, or selective microbial shifts than to broad changes in fermentation output. That’s consistent with prior laying-hen work showing B. licheniformis can alter cecal microbial composition, reduce Proteobacteria or potential pathogens, and improve tight-junction or villus-related measures. (mdpi.com)

Industry and regulatory context also matters here. A 2021 EFSA opinion on the Bacillus licheniformis DSM 28710 product B-Act concluded that the additive has the potential to be efficacious in laying hens at 1.6 × 10^9 CFU/kg complete feed, while also finding it presumptively safe for target animals, consumers, and the environment under the Qualified Presumption of Safety framework. That doesn’t validate every strain or every claim in the new paper, but it does show that B. licheniformis is already part of the regulatory and commercial conversation around layer nutrition. (efsa.onlinelibrary.wiley.com)

Why it matters: For veterinarians, poultry nutritionists, and technical service teams, the study reinforces a practical theme: probiotic value in layers may be greatest when matched to a specific production challenge. In this case, the challenge is the post-peak drop in efficiency, where oxidative stress, mucosal wear, and microbiome instability can compound one another. If these findings hold up in longer and larger commercial trials, B. licheniformis could be positioned less as a general “performance enhancer” and more as a targeted nutritional support tool for aging flocks, especially where feed efficiency and persistency of lay are under pressure. (mdpi.com)

There are still limits to keep in mind. The trial ran only 31 days, and the best response came from one dose rather than a simple dose-response curve. The paper also reports microbiota associations, not proof of mechanism. And because probiotic effects are often strain-specific, veterinary teams should be cautious about generalizing these results across all B. licheniformis products. Earlier studies in layers have shown positive signals, but they’ve also varied by strain, age, management conditions, and outcome measured. (mdpi.com)

What to watch: The next step is whether commercial follow-up studies test persistence of effect beyond one month, evaluate egg quality and shell outcomes more fully, and compare this dose range with already marketed B. licheniformis products under field conditions. If that happens, veterinary professionals will get a clearer sense of where this probiotic fits in post-peak flock health programs. (mdpi.com)