Effects of Dietary Zinc-Methionine Supplementation During Pregnancy on the Whole-Genome Methylation and Related Gene Expression in the Liver and Spleen of Growing Goats: a Short Communication

The effect of replacing inorganic zinc with organic zinc in diets of pregnant goats was investigated on the development of the liver and spleen of offspring. Pregnant goats (n = 14; Xiangdong black goat, local breed) of similar parity and body weight (BW, 37.17 ± 5.28 kg) were selected and divided randomly into two groups: the zinc sulfate group (ZnSO4; n = 7) and the methionine-chelated zinc group (Zn-Met; n = 7). Goats were fed for 45 days (day 106 of gestation to delivery). After delivering, lactating goats were fed a diet without extra zinc supplement. Kid goats were weaned at 2 months of age and both the groups were fed the same diet. All goats were fed a mixed diet and had free access to fresh water. Kid goats were slaughtered on day 100, and the liver and spleen were collected, weighed, and stored in liquid nitrogen for genomic DNA methylation and related gene expression determination. In the Zn-Met group, the liver organ index of kid goats showed an increasing trend (P < 0.10), but the methylation of the whole genome was not affected both in the liver and spleen (P > 0.10). Furthermore, the blood zinc content of the offspring was reduced (P < 0.05), and the expression of genes related to methylation were downregulated (P < 0.05) or showed a downward trend (P < 0.10) in the liver and spleen. These data indicated that goats feeding Zn-Met during pregnancy increased the offspring liver organ index without change in the genomic DNA methylation. It is speculated that the regulation of zinc finger protein Sp3 adjusted by blood zinc indirectly regulated the expression of methylation-related genes in the liver and spleen of the kid goats, thus enhancing the development and function of the immune system of the offspring.