Chen, Peng, Lv, Huimin, Du, Mengmeng, Liu, Weiyong, Che, Chuanyan, Zhao, Jinshan, and Liu, Huawei
This study investigated the effects of Bacillus subtilisHW2 on the growth performance, immune response, endoplasmic reticulum (ER) stress, and intestinal health in broilers with necrotic enteritis. Three hundred 1-day-old male Cobb 500 broilers (33.88 ± 2.34 g) were randomly allocated to 5 groups including non-infected control (NC group), basal diet + necrotic enteritis challenge (NE group), basal diet + 1 × 106CFU/g B. subtilisHW2 + necrotic enteritis challenge (L-Pro group), basal diet + 5 × 106CFU/g B. subtilisHW2 + necrotic enteritis challenge (M-Pro group), and basal diet + 1 × 107CFU/g B. subtilisHW2 + necrotic enteritis challenge (H-Pro group), with 6 replicates per group. All broilers except NC group were orally given with sporulated coccidian oocysts at day 14 and Clostridium perfringensfrom days 19 to 21. Results showed that L-Pro and M-Pro groups improved growth performance and intestinal morphology in necrotic enteritis-challenged broilers, and L-Pro, M-Pro, and H-Pro groups improved intestinal barrier function and immune response and decreased ER stress in necrotic enteritis-challenged broilers. Analysis of the gut microbiota revealed that L-Pro group increased the abundances of Alistipes, Coprobacter, Barnesiella, and Limosilactobacillus, decreased Erysipelatoclostridiumabundance on day 42 in necrotic enteritis-challenged broilers. M-Pro group increased Turicibacterabundance on day 28 and the abundances of Alistipes, Barnesiella, and Limosilactobacilluson day 42 in necrotic enteritis-challenged broilers. H-Pro group decreased Romboutsiaabundance on day 28 and unidentified_Clostridiaabundance on day 42 in necrotic enteritis-challenged broilers. Analysis of short-chain fatty acids (SCFAs) revealed higher isobutyric acid and isovaleric acid levels in L-Pro and M-Pro groups than NE group. Correlation analysis revealed the correlations between the biochemical parameters and gut microbiota as well as SCFAs, especially Romboutsia, Barnesiella, Coprobacter,isobutyric acid, and isovaleric acid. Overall, our results indicated that B. subtilisHW2 supplementation could ameliorate necrotic enteritis infection-induced gut injury. The optimal dietary supplementation dosage of Bacillus subtilisHW2 was 5 × 106CFU/g.