Abstract
This paper aims to identify Poria cocos polysaccharides (PCPs) as a potential feed additive used for swine production; thus, we explored the effects of different dietary inclusion levels of PCP on growth performance, immunity, and cecal microflora composition in weaned piglets. For this, a total of 120 28-day-old Duroc × Landrace × Yorkshire weaned piglets (8.51 ± 0.19 kg; 28 ± 1 days of age) were randomly allocated to five groups that were fed a basal diet supplemented with 0, 0.025%, 0.05%, 0.1%, and 0.2% PCP, respectively, for 42 days. The results indicated that the average daily gain (ADG) and gain/feed ratio were higher in the PCP treatment groups than in the control group, with a linear effect. The serum concentrations of IgG, IgA, IL-2, IFN-γ, the number of CD4(+) T cells, and the CD4(+)-to-CD8(+) T-cell ratio (CD4(+)/CD8(+)) were increased, while the levels of IL-6 and TNF-α were decreased in the PCP supplementation groups compared with those in the control group. Furthermore, the cytokine mRNA expression levels exhibited a similar trend in the spleen. PCP supplementation also reduced the abundance of Escherichia coli and Salmonella and enhanced that of Lactobacilli and Bifidobacteria in the cecum. In summary, dietary PCP inclusion exerted positive effects on the growth performance, immunity, and cecal microbiota of piglets and showed potential for use as a feed additive for improving the health of weaned piglets, with 0.1% being the optimal dosage.