Dried yeast tablets

The restriction of antibiotic growth promoter use in poultry production has increased interest in alternatives such as yeast and yeast-derived products. However, studies on yeast supplementation have reported inconsistent results. Hence, this study evaluated the effects of dietary yeast supplementation on the growth performance and intestinal morphology of broiler chickens using a meta-analysis and meta-regression approach. A systematic search conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA; 2020) guidelines across three databases found 1,397 records, and 41 controlled broiler studies that met the inclusion criteria. Subgroup analysis, meta-regression, heterogeneity, and robustness to publication bias tests were all performed. Yeast supplementation significantly improved body weight gain (mean difference (MD) = 72.8; 95% CI: 58.2 to 87.4; P< 0.001) and feed conversion ratio (MD = 0.055; 95% CI: 0.045 to 0.065; P< 0.001), indicating consistent benefits for growth performance and feed efficiency. Feed intake was not affected (MD = 3.57; 95% CI: -17.6 to 24.7; P= 0.741), suggesting that improvements in growth may be primarily driven by enhanced nutrient utilization rather than increased feed consumption. Intestinal morphology was also positively affected, with increased villus height (MD = 89.7; P< 0.001), improved crypt depth (MD = 24.1; P< 0.001), and a higher villus height-to-crypt depth ratio (MD = 1.57; P< 0.001), indicating beneficial effects on gut health. Subgroup analysis showed that Arbor Acres birds had the greatest improvement in villus height (P< 0.001). Meta-regression analysis revealed that yeast inclusion dose significantly influenced growth performance and intestinal villus height (P< 0.001). Publication bias assessment confirmed the robustness of the body weight gain, feed conversion ratio, villus height, crypt depth, and villus height-to-crypt depth ratio results. Overall, these findings support yeast supplementation as an effective feed additive in broiler chicken production, with consistent improvements in growth and intestinal morphology. Therefore, this study reinforces its potential role as an alternative to antibiotic growth promoters.

Abstract licence: CC BY-NC-ND