The Facilitating Effect of Tartary Buckwheat Flavonoids and Lactobacillus plantarum on the Growth Performance, Nutrient Digestibility, Antioxidant Capacity, and Fecal Microbiota of Weaned Piglets

SIMPLE SUMMARY: There has been a growing interest in the use of flavonoids and probiotics as alternatives of antibiotics in livestock production and as natural products for human health benefit. The effect of tartary buckwheat flavonoid supplementation in the diet has not been clearly investigated. The supplementation of tartary buckwheat flavonoids or Lactobacillus plantarum improved the growth performance, nutrient digestibility, and antioxidant capacity of weaned piglets. In combination, they exhibited a synergistic effect on nutrient digestibility. ABSTRACT: Natural plant extracts and probiotics has been proved as the most preferred and effective alternatives for antibiotics in animal feeding. The current study aimed to investigate the facilitating effect of tartary buckwheat flavonoids and Lactobacillus plantarum on the growth performance, nutrient digestibility, antioxidant capacity, and microbiota of weaned piglets. Fifty 35-day-old weaned piglets (7.85 ± 0.67 kg) were randomly divided into five treatments with 10 piglets per treatment. Piglets in the negative control (NC) group were fed a basal diet, and others were fed basal diets supplemented with 40 mg/kg of colistin sulfate (positive control, PC), 10(9) CFU/kg Lactobacillus plantarum (LP), 40 mg/kg of tartary buckwheat flavonoids (BF), and a combination of 10(9) CFU/kg Lactobacillus plantarum and 40 mg/kg of tartary buckwheat flavonoids (LB). Supplementation of BF increased the average daily gain of piglets in the BF group (p < 0.05). The nutrient digestibility of piglets in the NC group was lower than that in other groups, while the digestibility of gross energy, dry matter, organic matter, and phosphorus of piglets in the LB group was higher than the other four groups (p < 0.05). Compared with the NC and pC group, supplementation of Lp increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and catalase (CAT), while the BF increased the content of IgA and IgM (p < 0.05). Supplementation of colistin sulfate decreased the alpha diversity index, including chao and observed species, while the addition of Lp or combination of Lp and BF increased the abundance of Selenomonas or Mitsuokella in fecal samples, respectively. The results indicated that supplementation of Lactobacillus plantarum can improve the antioxidant capacity, while tartary buckwheat flavones can increase the growth performance and immune ability of weaned piglets. Moreover, in combination, they promote nutrient digestibility.