A Bacillus Subtilis probiotic improves broiler performance and footpad condition

Footpad dermatitis (FPD) is considered an animal welfare issue. Wet and sticky litter are major causes of FPD (Taira et al., 2014). Our previous study showed that a well selected probiotic strain Bacillus subtilis 29784 can improve broiler performance by modulating intestinal microbiota and intestinal inflammatory status (Ghane et al., 2017; Jacquier et al., 2016). We hypothesize that the previous demonstrated benefits of B. subtilis 29784 on gut health will improve litter quality and may decrease FPD. In the present study, we evaluated B. subtilis 29784 for its effects on performance, litter quality, occurrence and severity of FPD of broiler.

The experiment was carried out at the Center for Expertise and Research in Nutrition (Adisseo, Commentry, France) and was conducted according to the European Union Guidelines of Animal Care and legislation governing the ethical treatment of animals. Three hundred and twenty day old male chicks Ross PM3 were randomly distributed into 2 treatments with 8 pen replicates of 20 birds per replicate (density: 13.3 birds/m²). All birds were housed in the same environmentally controlled house, with a wood shaving litter, and fed on corn-soybean meal based diets. The two treatments were: 1) Control, and 2) Control + B. subtilis 29784 (1 x 10⁸ CFU/kg of feed, from 0 to the end of experiment). The experiment was conducted until 35 days and broilers were euthanised with inhaled carbon dioxide gas. At 35 days, performance parameters (weight gain, feed intake and feed conversion ratio) were measured. Litter quality and FPD were scored, following the Welfare Quality® (2009) method, on all birds. Mortality was assessed daily. Data were analysed using ANOVA, and Tukey’s test for significance.

At 35 days, mortality rate was not influenced by dietary treatments and was 4% on average. Probiotic supplementation improved WG by +4.8% (P = 0.01) and FCR by -2.9% (P = 0.003). 60% of pens in the Control group had highly degraded litter (Score 4), whereas this condition was absent in the pens of the probiotic group (P = 0.031). The probiotic addition significantly improved FPD scores, with 21% decrease of pens scored as “4, highly necrotic” (P = 0.008) and 11% decrease of pens with combined scores “3+4, highly and visibly necrotic” (P = 0.014). As expected, the improvement of litter score resulted in a decrease of FPD. Better litter condition could be at least partially explained by the positive effect that B. subtilis 29784 has on gut health parameters, such as microbiota changes and inflammation reduction (Jacquier et al., 2016; Ghane et al., 2017).

In conclusion, the incorporation of B. subtilis 29784 into feed resulted in a concomitant improvement in both performance and well-being, as reflected by improvement of litter quality and reduction of severe FPD. These effects are probably a direct consequence of an improvement of gut health parameters, as shown in previous studies.