Dietary supplementation of polysaccharides from Millettia speciosa Champ. ex Benth on growth performance, immune function, antioxidant abilities and intestinal health of Wenchang chickens.

This study aims to systematically evaluate the effects of Millettia speciosa Champ. ex Benth polysaccharides (MSCP) on broiler chickens through comprehensive assessment of growth performance parameters, immune system modulation, and intestinal microbial community dynamics. A total of 576 healthy 80-day-old Wenchang chickens were randomly assigned to six experimental groups in a completely randomized design. The control group (Control) received a basal diet, while the antibiotic-treated group was supplemented with 2 g/kg chlortetracycline hydrochloride (CTC) as a positive control. Four experimental groups were supplemented with different concentrations of MSCP: 400 mg/kg (MSCP₄₀₀), 800 mg/kg (MSCP₈₀₀), 1600 mg/kg (MSCP₁₆₀₀), and 3200 mg/kg (MSCP₃₂₀₀). The study employed a replicated pen design with 8 replicates per treatment group, each containing 12 birds. The results showed that dietary MSCP significantly increased the final body weight (P < 0.001) and average daily gain of chickens (P = 0.017), particularly at a dosage of 800 mg/kg. We also found that serum CAT level (P = 0.030) and GSH-Px level (P = 0.011) were significantly higher in the MSCP group compared to the CTC group. Adding MSCP to the feed raised serum IL-4 level (P = 0.016) and significantly increased IgA level (P = 0.047) at 1600 mg/kg. MSCP at 400 and 800 mg/kg significantly increased villus height in the duodenum, jejunum, and ileum (P < 0.001 for duodenum and jejunum; P = 0.040 for ileum). Moreover, MSCP also increased the relative abundance of beneficial bacteria Synergistota, Parabacteroides, Megamonas and Faecalibacterium, and increased the diversity of intestinal flora. To sum up, adding MSCP to feed had a positive impact on production performance, comparable to antibiotics, particularly at a dosage of 800 mg/kg. This suggests that MSCP is a promising, safe, and effective alternative to antibiotics in feed additives.