The Duck RXRA Gene Promotes Adipogenesis and Correlates with Feed Efficiency

SIMPLE SUMMARY: Avoiding feed energy waste and breeding efficient growth ducks have become the main goals of duck breeders due to the increase in feed costs. The feed efficiency of ducks is closely related to adipogenesis. The purpose of this study was to explore the effect of the RXRA gene on duck preadipocytes and provide molecular markers for breeding ducks for feed efficiency. The results of this study showed that RXRA promoted fat accumulation in duck preadipocytes, and the mutation site of RXRA was significantly related to duck feed efficiency. ABSTRACT: Background: The accumulation of fat in ducks is the main cause of low feed efficiency and metabolic diseases in ducks. Retinoic acid X receptor alpha (RXRA) is a member of the nuclear receptor superfamily involved in lipid, glucose, energy, and hormone metabolism. The effect of the RXRA gene on lipid metabolism in duck preadipocytes (DPACs) and the relationship between SNPs and the feed efficiency traits of ducks are unclear. Methods: qRT-PCR and Western blotting analyses were used to detect changes in mRNA and protein in cells. Intracellular triglycerides (TGs) were detected using an ELISA kit. A general linear model analysis was used to determine the association between RXRA SNPs and feed efficiency. Results: The duck RXRA gene was highly expressed on the fourth day of DPAC differentiation. The RXRA gene increased the content of fat and TG in DPACs and promoted the expression of cell differentiation genes; g.5,952,667 correlated with average daily feed intake (ADFI), residual feed intake (RFI), and feed conversion ratio (FCR). Conclusions: Duck RXRA can accelerate fat accumulation, and the polymorphism of the RXRA gene is closely related to feed efficiency, which provides basic data for breeding high feed efficiency ducks.