The effects of a Bacillus licheniformis and phytase mixture added to broiler diets on growth performance, nutrient digestibility, and cecal microecosystem

This study aims to evaluate the effects of Bacillus licheniformis and 6-phytase added alone or in combination to broiler chicken diets on the growth performance, apparent ileal digestibility coefficient (AID) of nutrients, microbial activity, and cecal bacterial communities. In total, 400 one-day-old female Ross 308 chicks were randomly allocated to 4 dietary treatments (10 replicate pens, 10 birds each). The following groups were defined: NC (negative control), basal diet without any feed additive supplementation; NC+Pro, basal diet with addition of the B. licheniformis preparation (500 g/t of diet); NC+Phy, basal diet with addition of phytase (200 g/t of diet); and NC+Pro+Phy, basal diet combined with both studied additives. B. licheniformis positively affected (P<0.05) the feed intake (FI) and feed conversion ratio (FCR) in the first 10 d of bird rearing. Moreover, phytase supplementation elevated the FCR from 21 to 35 d. In the entire experiment, an interaction between phytase and probiotic was observed only in terms of decreasing the bird FI (P=0.005) without a negative effect on the FCR (P>0.05). Furthermore, the AID of ether extract was improved by phytase supplementation. In terms of the cecal microecology, both separately administered factors promoted Lactobacillaceae in the ceca. Interactions between probiotic preparation and phytase were noted that indicated a decreased Clostridiales population and favored Ruminococcaceae proliferation. It can be concluded that for the first time in the available literature, the favorable interactions between B. licheniformis and phytase resulted in improved performance and cecal microbiota changes in broilers.