Influence of Rhodotorula mucilaginosa yeast on the microbiocenosis and productive qualities of broiler chickens

Relevance. Yeast and its derivatives have a comprehensive positive effect on poultry, but the effect of the carotene-synthesizing yeast Rhodotorula mucilaginosa on the microbiome and performance of broiler chickens has been poorly studied. The aim of this study was to investigate the effect of a microbial supplement based on the carotene-synthesizing yeast R. mucilaginosa before and after freezing on the microbiome and performance of broilers. Methods. The study was conducted on broiler chickens of the Smena 9 cross (n = 78). Three groups of 26 birds each were formed using the analog group principle. Battery cage technology was used for rearing. Birds in the control group received the basic diet; those in the first experimental group additionally received native yeast R. mucilaginosa (3 g/bird/day, assuming that the carotenoid content was 312 μg/g biomass); and those in the second experimental group received yeast after freezing and thawing at the same dose. Zootechnical parameters and the microbial composition of the rectum and cecum contents were studied using real-time PCR at 25 and 45 days. Results. The introduction of R. mucilaginosa , especially after freezing, increased live weight by 4.52%, average daily gain by 9.9%, leg weight by 11.91% (p ≤ 0.001), and breast weight by 2.72% (p ≤ 0.05). A significant increase in the number of Bacteroides spp. , Prevotella spp ., and Bifidobacterium spp. in the intestines was observed, as well as the complete elimination of E. coli from the cecum of the experimental groups. These data confirm the potential of using R. mucilaginosa in broiler feeding, but require further study.