Effects of Qiamagu (Brassica rapa L.) polysaccharide on growth performance, immunity and gut health of yellow-feathered broilers

This study aimed to investigate the effects of adding Qiamagu polysaccharides to feed on the growth performance, immunity and gut health of yellow-feathered broilers. A total of 240 healthy, day-old, male yellow-feathered broiler chickens with similar body weights were randomly divided into four groups, each with six replicates and 10 chickens per replicate. The groups consisted of a control group (CON) and three treatment groups: TP1 (250 mg/kg), TP2 (500 mg/kg), and TP3 (1000 mg/kg) of Qiamagu polysaccharide in the diet, with a feeding period of 64 days. The average daily weight gain of all experimental groups were significantly higher than those of the CON group (P < 0.05) in 1-21 days. The average daily gain of TP1 and TP2 groups was increased (P < 0.05), and the ratio of feed to gain was decreased (P < 0.05), at 43-63 days. The levels of IgM, IgA, IgG, IL-1β, IL-2 and TNF-α in the serum of broilers in the TP1 and TP2 groups exhibited a consistent increase at 21,42 and 63 day (P < 0.05). At 22-42 days, the villus length of duodenum and ileum and the ratio of Villus height to crypt depth ratio were increased in TP2 group (P < 0.05). The ileal mucosa IL-1β and IL-2 mRNA levels of broilers in TP3 group were down-regulated in 1-42 days (P < 0.05). The mRNA levels of MUC2, ZO-1 and Occluding in ileum mucosa of broilers in TP3 group were up-regulated in 1-63days (P < 0.05). The total number of cecal flora species in TP1, TP2 and TP3 groups was higher than that in control group (P < 0.05). The relative abundance of Lactobacillus in TP2 group was increased (P < 0.05). In conclusion, this study showed that the addition of Qiamagu polysaccharide improved the growth performance, enhanced the immune response and had better impact on intestinal health of yellow-feathered broilers.