Effects of Adding Different Dosages of Saccharomyces cerevisiae in Diet on Growth Performance, Carcass Characteristics, Intestinal Morphology, and Gut Microflora of Broilers

The aim of this study was to evaluate the effect of adding different dosages of live yeast (Saccharomyces cerevisiae) in diet on growth performance, carcass characteristics, intestinal morphology, and gut microflora of broilers. The study was conducted on 270 oneday old chickens (Ross 308) during a 42-day period. Broilers were randomly allocated to one of three dietary treatments that differed in the content of added yeast: no additional yeast; with 0.25 g/kg; and with 0.65 g/kg of added yeast. Each experimental group contained 90 animals. The results from our study showed that diet supplemented with 0.25 g/kg of yeast resulted in better growth performance and carcass quality (P < 0.05), improved intestinal morphology (P < 0.001), higher development of beneficial microflora (Lactobacillus spp.) (P < 0.01), and reduction of pathogenic bacteria (Escherichia coli) in guts of broilers than in the group fed only with the basic diet (P < 0.05). On the other hand, the group with the highest inclusion of yeast in diet (0.65 g/kg) achieved similar results for the examined parameters as did the group with no added yeast. Therefore, the adequate dose of S. cerevisiae in diet was 0.25 g/kg of yeast, while higher dose of live yeast in broiler diet (0.65 g/kg) did not achieve better results.