<i>Bacillus</i>-based probiotics on broiler chicken performance under coccidiosis and <i>Clostridium perfringens</i> challenge

The study analyzed the impacts of two probiotics (Ecobiol® and GutCare®) on growth performance, carcass and cut yields, intestinal morphometry and lesion score, biochemical parameters, and short-chain fatty acid concentration in chickens using a challenge model combining coccidiosis vaccine and Clostridium perfringens. A total of 880 one-day-old male broilers (Cobb 500) were randomly assigned to four treatments with 10 replicates and 22 birds per experimental unit (EU). The treatments consisted of: PC: positive control with the inclusion of 80 g ton-1 of Enramax® (8% enramycin) until 35 d of age; NC: negative control without the inclusion of growth-promoting probiotic; BA: NC with the inclusion of 1000 g ton-1 of Ecobiol® (Bacillus amyloliquefaciens - CECT 5940); BS: NC with the inclusion of 500 g ton-1 of GutCare® (Bacillus subtilis - DSM 32315). Diets used maize–soybean meal in a threephase plan. Broiler chickens on the BA and BS diets had higher feed consumption, body weight gain, and improved feed conversion efficiency at 28 and 42 d when compared to the birds in the negative control. Broiler chickens fed PC, BA, and BS diets had a higher villus height and absorption area in the jejunum at 28 d, compared to the birds in the negative control. There was more butyric acid production by the intestinal microbiota at 28 d of age in broilers on the BA diet. Supplementing with 1000 g/ton of BA and 500 g/ton of BS effectively substituted the 8% enramycin antibiotic, enhancing broiler growth during an induced intestinal challenge.