Dietary β-Glucan Supplementation Enhances Somatotropic Axis Activity, Growth Performance, and Breast Muscle Meat Quality in Ross 308 Broiler Chickens

The global push to eliminate antibiotic growth promoters in poultry has accelerated the demand for effective natural alternatives. β-Glucans—branched polysaccharides derived from Saccharomyces cerevisiae cell walls—enhance immunity and gut health; however, their mechanistic effect on the somatotropic axis and meat quality in broilers remains unresolved. Herein, the hypothesis that dietary β-glucan modulates somatotropic signaling to improve growth performance and breast muscle quality was tested with 240 one-day-old Ross 308 chicks allocated to three groups—untreated control, 250 mg β-glucan/kg feed, and 1 g β-glucan/kg feed—and reared for 35 d. Growth performance, plasma growth hormone (GH) and prolactin (PRL), somatotropic axis gene expression in liver and breast muscle, and postmortem meat quality were assessed. β-Glucan supplementation significantly elevated final body weight, breast muscle weight, and plasma GH and PRL, and upregulated hepatic IGF-1 and muscle GH receptor mRNA at 35 d, and hepatic GH receptor mRNA at 17 d. Muscle pH was higher and relative drip loss lower in supplemented birds 72 h postmortem. These results support the hypothesis and identify 1 g β-glucan/kg feed as an effective dose for improving growth and meat quality through somatotropic axis modulation—a novel mechanistic demonstration in broiler chickens.