Cecal microbiota and Clostridium perfringens in broilers fed barley-based diets: Effects of enzyme supplementation and degree of grinding

Barley has been proposed as a promising and more sustainable alternative to common cereals in poultry diets. However, the use of barley in poultry diets has historically been limited, mainly due to observed negative impact on gastrointestinal health and performance. In this study, we explored the potential of incorporating barley into broiler diets, focusing on effects on Clostridium perfringens, the causative agent of necrotic enteritis in poultry, and the cecal microbiota. The study included four diets containing 54% barley, with or without the addition of non-starch polysaccharide-degrading enzyme (NSPase), and one control diet without barley. The main ingredients were ground to either a fine or coarse particle size. Low C. perfringens levels were maintained in the intestines of broilers fed barley-based diets, suggesting that barley did not predispose to necrotic enteritis in this study. Broilers fed the coarse barley-based diet with NSPase exhibited the lowest abundance of Lactobacillus and the highest abundance of Faecalibacterium, and their cecal microbiota resembled that of the group fed the control diet. In contrast, broilers fed the coarse barley-based diet without NSPase exhibited the highest abundance of Lactobacillus among all groups in this study, along with a lower abundance of Faecalibacterium. Among the groups that received diets with finely ground barley, regardless of NSPase supplementation, there was no clear shift in the abundance of the two bacterial genera. These observations suggest that feed particle size and NSPase supplementation influence the composition of the cecal microbiota in broilers fed barley-based diets, and that these factors could be utilized as tools to mitigate undesirable health effects associated with the inclusion of barley in poultry diets. The findings of this study highlight the potential of including increased levels of barley in broiler diets without compromising health or performance. Further studies are warranted to explore the effects of similar inclusion levels of different barley varieties on gastrointestinal health and microbiota under varied environmental conditions.