Maternal effects of choline on skeletal muscle development and intramuscular fat deposition in broiler offspring

Low-protein diets with low inclusion of soybean meal have been used in breeder hens and not affected the laying performance, however, it's usually observed the detrimental effects on skeletal muscle growth and intramuscular fat deposition in the offspring. One of the major reasons is the reduced supply of choline when the dietary inclusion of soybean meal is limited. Choline is an essential methyl donor and a critical regulator of lipid metabolism. The underlying mechanisms through which maternal chloride supplementation affects offspring muscle growth and lipid metabolism remain largely unclear. This study aimed to clarify the maternal effect of choline on regulating embryonic and post-hatch skeletal muscle development and intramuscular fat deposition in broiler offspring. Maternal choline chloride (CC) supplementation improved egg weight, Haugh unit, and shell strength, and increased yolk S-adenosylmethionine concentration (P < 0.01). It also elevated phosphatidylcholine (PC) levels in serum and yolk of hens and in the serum of newly hatched chicks (P < 0.05). Enhanced embryonic breast muscle fiber formation and higher half-eviscerated yield at 42 d of age were observed in the CC group (P < 0.05). Maternal choline increased lipid droplet accumulation in the liver and breast muscle of embryos at day 19. In cultured chicken myotubes, choline chloride upregulated the expression of SLC16A7 and FASN and increased intracellular malonyl-CoA and triglyceride (TG) contents (P < 0.01). At 42 d, maternal choline supplementation enhanced TG deposition in the breast muscle by activating SLC16A7 and FASN-mediated fatty acid synthesis. Targeted metabolomics further revealed elevated concentrations of myristic and palmitic acids in the offspring muscle (P < 0.01). Collectively, maternal choline supplementation improved egg quality and yolk PC deposition in breeder hens and promoted muscle growth and intramuscular fat accumulation in the offspring. These findings provide a new insight into the significance of the trans-generational effects of choline nutrition for optimizing broiler breeder diets and improving meat quality of the offspring.