Multienzyme Super-Dosing in Broiler Chicken Diets: The Implications for Gut Morphology, Microbial Profile, Nutrient Digestibility, and Bone Mineralization

SIMPLE SUMMARY: Optimizing the gut microbial community and morphometrical traits has become an increasingly prominent area of research due to recent evidence that suggests gut health and functionality affects the production performance of broilers. Creating a diverse microbial population can increase the nutrient digestibility of feed, as the microbes can break down a large portion of macromolecules and convert them into bioavailable substrates to be utilized by the host. A diverse microbiome can be promoted by a variety of additives, including feed enzymes. This study investigated the impact of the application of super-dosing multienzymes on gut morphology, microbial profile, nutrient digestibility, and bone mineralization in broiler chickens. Results found that super-dosing multienzymes improved nutrient digestibility, maintained a diverse microbial population, and tended to increase the overall villi morphology. Bone mineralization was not affected by increasing multienzyme doses. Additionally, the present study found three bacteria that were unique to multienzyme inclusion at a super-dose level. ABSTRACT: Optimizing gut health has a large impact on nutrient digestibility and bioavailability, and super-dosing feed enzymes may be one solution to achieve this. A 42-day grow-out trial was conducted using 192 Ross 308 broilers to determine if super-dosing Natuzyme at 0 g/t, 350 g/t, 700 g/t, and 1000 g/t dose rates could improve the gut morphology, alter the cecal microbial profile, enhance bone mineralization, and improve nutrient digestibility of a wheat–corn–soybean diet (six replicates per treatment, eight birds per pen). One bird per pen was slaughtered at day 42 and gut morphology, cecal microbial profile, and nutrient digestibility were studied. The addition of enzymes tended to increase the villus height in the duodenum, villus height, width, and crypt depth in the jejunum, and villus width and the number of goblet cells in the ileum. Microbial profiling revealed diverse communities; however, they did not significantly differ between treatment groups. Yet, 700 g/t Natuzyme promoted microbes belonging to the genus Romboutsia and Ruminococcus gauvreauii, while 1000 g/t Natuzyme promoted Barnesiella species. The nutrient digestibility demonstrated a significant improvement in all enzyme doses compared to the control. In conclusion, based on the outcomes of this study, a dose rate of 700 g/t Natuzyme is recommended to improve gut morphology and nutrient digestibility, and promote unique microbes which aid in feed efficiency.