Effects of Dietary Supplementation with Tea Residue on Growth Performance, Digestibility, and Diarrhea in Piglets

Thirty-six healthy 21-day-old weaned ternary piglets (Duroc x Landrace x Yorkshire) were randomly divided into two treatments with 18 replicates per treatment and one pig per replicate. The control group was fed with a basal diet and the test group was fed with diets supplemented with 1 kg/t tea residue. The test period was 28 days. The results are as follows: The addition of tea residue in the diet had no significant effect on the growth performance of weaned piglets (p > 0.05), but it could significantly reduce the diarrhea rate of piglets from 1 to 7 days and 1 to 28 days (p < 0.05). Compared with the control group, the dietary supplementation of tea residue had no significant effect on nutrient apparent digestibility, plasma biochemical indexes and plasma immune indexes (p > 0.05) but increased the content of glutathione in plasma (p < 0.05). Tea residue had no significant effect on the morphology of the jejunum and ileum of piglets (p > 0.05), but it could significantly reduce the content of chloride ions in feces (p < 0.05). Compared with the basal diet group, there was no significant difference in the relative expression of TMEM16A and CFTR mRNA in the colon of weaned piglets (p > 0.05). The whole-cell patch clamp recording showed that the TMEM16A and CFTR ion channels could be activated by ionomycin and forskolin, respectively. However, when HT-29 cells transfected with TMEM16A and CFTR channels were treated with tea residue extract, it could significantly inhibit the chloride current of the TMEM16A and CFTR ion channels (p < 0.05).