Polysaccharide Supplements from Millettia speciosa Champ. ex Benth Enhance Growth and Meat Quality in Wenchang Chickens.

The polysaccharide of Millettia speciosa Champ. ex Benth (MSCP) has antioxidant properties, but its impact on chicken growth and development is not yet known. This study used chlortetracycline as a control to assess MCSP as a feed antibiotic substitute and its effects on Wenchang chicken production, slaughter performance, and meat quality. A total of 576 healthy 80-day-old Wenchang chickens were randomly allocated to six experimental groups. The control group (Control) received a basal diet, while the antibiotic group (CTC) was supplemented with 2 g/kg chlortetracycline (CTC). Four additional experimental groups were administered varying doses of MSCP: 400 mg/kg (MSCP(400)), 800 mg/kg (MSCP(800)), 1600 mg/kg (MSCP(1600)), and 3200 mg/kg (MSCP(3200)), respectively. The study discovered that incorporating MSCP and CTC into chicken diets significantly boosted the final body weight and average daily feed intake compared to the control group (p < 0.01), with MSCP notably enhancing average daily weight gain. With the addition of 800 mg/kg MSCP, chicken growth performance is comparable to that achieved with antibiotics in feed. However, it did not impact slaughtering performance (p > 0.05). In addition, MSCP significantly raised the pH after 24 h (p < 0.05) and decreased the yellowness (p < 0.01) of breast muscle. MSCP increased the essential amino acids (EAA) proportion in breast muscle (p < 0.05), EAA to nonessential amino acids (NEAA) ratio (p < 0.05), and diversity of fatty acids while decreasing C20:0 and increasing C18:2N6 and C22:1N9 content. Moreover, MSCP significantly reduced muscle fiber size (p < 0.01), increased fiber density (p < 0.01), boosted MYOD1 expression (p < 0.05), and decreased MSTN expression in breast muscle (p < 0.01). Overall, our study showed that supplementing the diet with MSCP, particularly at a dose of 800 mg/kg, enhanced growth, meat quality, muscle morphology, amino acid content, fatty acid composition, and gene expression related to muscle development in breast muscle. The results indicate that MSCP is a feed additive with the potential to replace antibiotics and improve meat quality, showing promising application potential.