Synergism of fermented feed and ginseng polysaccharide on growth performance, intestinal development, and immunity of Xuefeng black-bone chickens

Abstract Microbial fermented feed (MF) is considered a valuable strategy to bring advantages to livestock and is widely practiced. Oral supplementation of Ginseng polysaccharide (Gps) eliminated weight loss in chickens following vaccination. This study investigated the effects of the combined use of Gps and MF on growth performance and immune indices in Xuefeng black-bone chickens. A total of 400 Xuefeng black-bone chickens at the age of 1 day were randomly assigned to four groups. Normal feed group (Control group), ginseng polysaccharide (200 mg/kg) group (Gps group), microbially fermented feed (completely replace the normal feed) group (MF group), and microbially fermented feed and add ginseng polysaccharide just before use (MF + Gps group). Each group contained 5 pens per treatment and 20 birds per pen. The body weight and average daily gain in the Gps, MF, and MF + Gps groups increased significantly ( P  < 0.01), while the feed conversion ratio decreased significantly ( P  < 0.01). The combined use of MF and Gps showed a synergistic effect. There was no significant difference in villus height (cecal) between the experimental group and the Con group. The crypt depth of the three experimental groups exhibited a significantly lower value compared to the Control group ( P  < 0.05). The V/C ratio of the Gps group and MF + Gps was significantly increased ( P  < 0.05), but there was no significant difference in the MF group. Moreover, the diarrhea rate of the Gps and the MF + Gps groups was lower than that of the Con group, while that of the MF + Gps group decreased the mortality rate ( P  < 0.05). The serum tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) levels in the MF, Gps, and MF + Gps groups decreased significantly ( P  < 0.01), the serum immunoglobulin G (IgG) levels increased significantly ( P  < 0.01), while the combination of MF and Gps had a synergistic effect. The combined use of Gps and MF not only further improved growth performance and immune parameters, but also reduced the diarrhea rate and mortality.