Microbial fermented feed and ginseng polysaccharide synergistically improves growth performance and immune parameters of Xuefeng black-bone chicken

Abstract Oral supplementation of Gps dosages (100 mg/kg, 200 mg/kg, and 400 mg/kg) eliminated weight loss in chickens following vaccination (H5N1). Microbial fermented feed (MF) is considered as a valuable strategy to bring advantages to livestock and is widely practiced. This study investigated the effects of Gps, MF, and 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 as-signed to four groups, each group contained 5 pens per treatment and 20 animals per pen. Compared with the control group, the body weight and average daily gain in the Gps group, MF group, and MF+Gps group increased significantly, while the feed conversion ratio decreased significantly (P < 0.01). It is noteworthy that the combined use of MF and Gps showed a synergistic effect. Moreover, the diarrhea rate of the Gps group and the MF+Gps group was lower than that of the Con group, while that of the MF+Gps group decreased the mortality rate (P < 0.05). In this work, we also focused on the effects of MF, Gps and MF+Gps on immune function. Compared with the Con group, the serum TNF-α and IL-6 levels in the MF group, Gps group and MF+Gps group decreased significantly (P < 0.01), the serum IgG levels increased significantly (P < 0.01), while the combination of MF and Gps had a synergistic effect. In summary, Gps or MF can promote growth performance and immune indexes, and the combined use of Gps and MF not only further improved growth performance and immune parameters, but also reduced the diarrhea rate and mortality. Therefore, our research developed a new type of compound feed that could well improve the growth performance and immune parameters of chickens.