Zinc Supplementation Forms Influenced Zinc Absorption and Accumulation in Piglets

The study aimed at determining the effect of different zinc (Zn) supplementation forms on Zn accumulation, activities of Zn-containing enzymes, gene expression of metallothionein (MT), and Zn transporters in piglets. Eighteen piglets were randomly divided into three groups: (a) a basal diet supplemented with 150 mg/kg Zn from Zn methionine (Zn-Met) in the feed (Zn-Met group), (b) a basal diet supplemented with 150 mg/kg Zn from Zn sulfate (ZnSO₄) in the feed (ZnSO₄, _feed group), and (c) a basal diet supplemented with the same dose of Zn as in ZnSO4,_feed group but in water (ZnSO₄, _water group). The results showed that Zn-Met added in feed and ZnSO₄ dissolved in drinking water significantly improved (p < 0.05) the Zn concentration in liver and jejunum and the apparent digestibility of Zn in comparison with the ZnSO₄ added in feed. In addition, dietary Zn supplementation as Zn-Met significantly increased (p < 0.05) the activity of alkaline phosphatase (AKP) in the jejunum of piglets in comparison with the ZnSO₄, _feed group. Furthermore, the Zn-Met and ZnSO₄, _water groups showed an improved total superoxide dismutase activity (T-SOD) in the ileum as compared to the ZnSO₄, _feed group. Meanwhile, the qPCR and western blot results showed that Zn-Met and ZnSO₄ dissolved in drinking water increased the expression of MT in the jejunum in comparison with the ZnSO₄ added in the piglets' feed. However, different Zn supplementation forms had no effect on the mRNA expressions of Zip4 and ZnT1 transporters. In conclusion, Zn-Met added in feed and ZnSO₄ dissolved in drinking water had higher bioavailability in piglets.