Effect of zinc source on the expression of ZIPII transporter genes in Guanzhong dairy goats

The expression and function of the zinc transporter genes SLC39A1, SLC39A2, and SLC39A3 in the Zrt/Irt-like proteins (ZIP)II subfamily have been reported in monogastric but not ruminant animals. Thus, the response of these three ZIPII genes to different sources of zinc in ruminants was examined in goats in the present study. A total of 18 Guanzhong dairy goats were randomly divided into three groups of 6 goats each. The goats were fed one of three diets. The control group received a basic diet with no additional zinc. The second and third groups ate the same diet but with 60 mg/kg of zinc sulfate or zinc amino acid chelate (Zn-AA) complex added, respectively. After 7 days of treatment, the goats were sacrificed, 23 tissue samples were collected from each goat, and the expression and distribution of the ZIPII genes were determined with PCR analyses. In addition, seven tissues relevant to digestion or metabolism were examined using real-time PCR to identify the responses of the three genes to different zinc sources. The results showed that the expression of SLC39A1-3 mRNA could be detected in 21 of the 23 tissue types examined in the dairy goats, with no expression detected in heart or testis. The levels of expression for the three genes in the tissues relevant to digestion or metabolism were tissue specific and varied with the zinc source, indicating that the source of zinc affects the SLC39A1-3 mRNA expression.