Effects of bamboo vinegar powder on growth performance and mRNA expression levels of interleukin-10, interleukin-22, and interleukin-25 in immune organs of weaned piglets

The aim of this study was to explore the effects of bamboo vinegar powder on growth performance, diarrhea situation and mRNA expression levels of cytokines i.e., interleukin-10 (IL-10), interleukin-22 (IL-22), and interleukin-25 (IL-25) in immune organs of weaned piglets, and to accumulate theoretical data for the application of bamboo vinegar powder in weaned piglet production. Forty-five crossbred (Duroc × Landrace × Yorkshire, all male) weaned piglets with similar body weight (6.74 ± 0.17 kg) at 31 days of age were randomly assigned to 5 treatments with 3 replicates per treatment and 3 piglets in each replicate. The five treatments were as follows: CON (a basal diet), ANT (the basal diet + 0.12% antibiotics), BV1 (the basal diet + 0.1% bamboo vinegar powder), BV5 (the basal diet + 0.5% bamboo vinegar powder), BV10 (the basal diet + 1.0% bamboo vinegar powder). This experiment lasted 35 days. The growth performance and diarrhea situation were recorded. The relative mRNA expression levels of IL-10, IL-22 and IL-25 in liver, spleen, duodenum and mesenteric lymph nodes were detected by real-time PCR. Feed: gain of BV5 was significantly lower than that of CON (P < 0.05). In comparison with CON, diarrhea rate and diarrhea index of BV1 and BV5 all tended to decrease (P < 0.1). Compared with CON, mRNA expression level of IL-10 in liver of ANT tended to be lower (P < 0.1) and these of BV1, BV5 and BV10 were significantly reduced (P < 0.05). The mRNA expression levels of IL-10 in duodenum of ANT, BV1, BV5 and BV10 were all lower than those of CON, of which BV10 had significantly decreased IL-10 mRNA expression in duodenum (P < 0.05). The mRNA expression levels of IL-22 in duodenum of ANT, BV1, BV5 and BV10 all tended to be inhibited compared with CON (P < 0.1). With the increase of bamboo vinegar powder dosage, mRNA expression levels of IL-25 in spleen and mesenteric lymph nodes of BV1, BV5 and BV10 tended to be up-regulated. Overall, bamboo vinegar powder could improve growth performance, and regulate mRNA expression levels of IL-10, IL-22 and IL-25 in immune organs of weaned piglets. The dosage at 0.5% showed optimum effects.