The effects of probiotic and threonine application on the carcass yield, internal organ development, intestinal morphology and cecal microbiota of broilers challenged with Clostridium perfringens

The aim of this study was to explore the effects of probiotics (Ecobiol (R)) and threonine supplements on broiler internal organs and intestinal health under Clostridium perfringens challenge. A total of 1600 male Ross 308 broiler chicks were randomly assigned to eight treatments with eight replicates each of 25 birds. Dietary treatments consisted of two levels of supplemented threonine (without and with threonine supplementation), two levels of probiotics (Ecobiol (R)) supplement (0 and 0. 1% of diet), and two levels of challenge (without and with 1 ml of the C. perfringens inoculum (similar to 10(8) cfu/ml) on d 14, 15, and 16 of the experiment), which fed to the birds during a 42 d feeding trial. The results showed that adding threonine and probiotic supplements to the diets of C. perfringens-infected birds reduced the relative gizzard weight by 22.9% compared to those fed unsupplemented diet (P < 0.024). As compared to the non-challenged group, the C. perfringens challenge significantly reduced the carcass yield of broilers by 1.18% (P < 0.0004). The groups receiving threonine and probiotic supplementation had higher carcass yield, and the inclusion of probiotics in the diet decreased abdominal fat by 16.18% compared with the control treatment (P < 0.001). Adding threonine and probiotic supplements to the diets of broilers challenged with C. perfringens increased the jejunum villus height in comparison with C. perfringens-infected group fed an unsupplemented diet on day 18 (P < 0.019). The number of cecal E. coli increased in birds under C. perfringens challenge in comparison with the negative group. Based on the findings, dietary inclusion of threonine and probiotic supplement could beneficially affect intestine health and carcass weight during the C. perfringens challenge.