Effects of Different Energy Diets on FSHR mRNA Expression and DNA Methylation in Promoter Region of Duolang Sheep During Diestrus

The aim of this study was to study the relationship between the methylation level of the promoter region of follicle-stimulating hormone receptor (FSHR) gene and the mRNA expression of Duolang sheep fed different energy diets. In this experiment, three groups of diets with different energy levels (dietary nutrient level reference (NY/T816 - 2004)) were designed to obtain medium energy level diets with metabolic energy of 10.88 MJ/d. The treatments with high and low energy levels increased and decreased by 15%, 12.51, and 9.25 MJ/d, respectively, on the basis of medium energy level. Total RNA and genomic DNA were extracted from the ovaries of Duolang sheep, and qPCR was performed. Bisulfite genomic sequencing PCR and sequence alignment were used to detect the relationship between the relative expression level of FSHR and methylation. The results showed that the expression of FSHR in high-energy group and medium-energy group was significantly higher than that in low-energy group (p < 0.01), and there was no significant difference between high-energy group and medium-energy group (p > 0.05). The methylation rate of the target fragment in the promoter region of FSHR gene was 41.67% in the high-energy group, 75.00% in the medium-energy group, and 83.33% in the low-energy group. This study revealed that different dietary energy levels had certain effects on DNA methylation level of FSHR gene and then affected gene expression, and the expression level was negatively correlated with methylation level.