Impact of Bacillus subtilis Probiotic on Growth, Visceral and Lymphatic Organ Weights, Intestinal Histomorphology, and Pathogenic Bacteria of Broilers

This work aimed to examine the impacts of dietary Bacillus subtilis (BS) supplementation on several parameters. Twelve groups of 600 day-old male Ross chicks were created for the study. Each treatment was allotted into five replicates, with ten birds each. Four distinct diet treatments were provided for 42 days: diet A served as the control, whereas diets B, C, and D had 125, 250, and 500 mg of BS per kg of feed. Every diet was fed in three stages: continuous (days 1–42) and starter only (days 1–21), finisher only (days 22–42), and both. The results showed that the D-3 and C-3 groups had significantly higher feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), livability, and European Production Efficiency Factor (EPEF). The D-3 and C-3 groups also showed the largest relative weights of the liver, gizzard, pancreas, bursa, and spleen, as well as the enhanced weights of these organs. Groups D-3 and C-3 had highest villus height (VH), decreased crypt depth (CD), and enhanced VH: CD in the ileum, jejunum, and duodenum. The high levels of BS (D-3 and C-3) eliminated Salmonella, C. perfringens, and E. coli from the ileum, caecum, and colon. From the results above, a conclusion could be drawn that dietary BS supplementation could be a safe substitute for AGPs in broiler diets.