Weaning stress decreases the growth performance of piglets and is one of the main concerns of pig industries. Traditional Chinese herbal medicines have been used to reduce the adverse effects of weaning stress as both nutritional supplements and antibiotic substitutes. This study aimed to evaluate the effects of a Chinese herbal mixture (Kangtaile, which contained Paeonia lactiflora, licorice, dandelion, and tea polyphenols) on the growth performances, immune response, antioxidant capacity, and intestinal microbiota of weaned pigs. A total of 400 weaned pigs [Duroc × (Landrace × Yorkshire)] were randomly allocated into one of four treatments: the CON group, fed with basic diet; the HM1 group, fed with basal diet supplemented with 0.5 g herbal mixture/kg diet; the HM2 group, fed with basal diet supplemented with 1.0 g herbal mixture/kg diet; or the HM3 group, fed with basal diet supplemented with 1.5 g herbal mixture/kg diet. The results revealed that dietary supplementation with the herbal mixture for 28 days improved average daily gain and feed conversion ratio, while decreased the diarrhea rate of weaned pigs. Moreover, dietary supple-mentation with the herbal mixture improved the antioxidant capacity through increasing the activity of catalase (CAT) and the total antioxidant capacity (T-AOC) level, while decreasing the concentration of malondialdehyde (MDA) in the serum. Pigs supplemented with herbal mixture presented an increased serum immunoglobulin (Ig)M level on day 14 compared with control pigs. The herbal mixture altered the composition of intestinal microbiota by influencing the relative abundances of Firmicutes and Bacteroidetes at the phylum level. The relative abundances of the Firmicutes and Bacteroidetes were significantly related to the body weight gain of pigs. In conclusion, supplementation of herbal mixture to the diet improved growth performance, immunity, and antioxidant capacity and modified the composition of intestinal microbiota in weaning pigs. This study provided new insights into the nutritional regulation effects of the herbal mixtures on weaned pigs.

As a by-product, apple pomace (AP) is very rich in pectin, polyphenols, carbohydrates and minerals, which have antioxidant and immune-enhancing functions on animals. To investigate the effects of fermented AP on pigs, a total of 120 weaned pigs were allocated into one of two treatments: the control (CON) group, fed with diets containing 5% silage AP; or the AP group, fed with diets containing 5% silage corn-AP for 28 d. The average daily gain was increased (p < 0.001) in the AP group compared with the CON group. The concentration of albumin and superoxide dismutase were increased by 8.98 g/L (p < 0.001) and 2.9 U/mL (p = 0.001), while the concentration of aspartate aminotransferase and malondialdehyde were decreased by 23.59 U/L (p < 0.001) and 2.33 nmol/mL (p = 0.003) in the AP group, respectively. There were 46 and 125 unique OTUs in the AP and CON groups, respectively. In the AP group, the abundance of Lactobacillus was increased (p < 0.003), but the abundances of Clostridium_sensu_stricto_1 (p = 0.001), Terrisporobacter (p = 0.026), Ruminococcus (p = 0.001) were decreased. In addition, the relative abundance of genetic information processing pathways was increased (p = 0.001) in the AP group, while the relative abundance of cellular processes had a tendency to decrease (p = 0.056) in the AP group. Above all, the supplementation of fermented AP has beneficial impacts on the growth, plasma biochemistry and immune indicators, and gut microbiota of weaned pigs.