Effects Of Maternal Dietary Supplementation Of Phytosterol Esters In Mammalian During Gestation On Muscle Development Of Its Offspring

In livestock production,meat production of animals is directly determined by the fiber type,quantity and cross-sectional area of skeletal muscle.The development of skeletal muscle,especially number of muscle fibers,is determined at the embryonic stage.The development of embryonic muscle plays an important role in the growth of skeletal muscle after birth.Much has been learned during the past several decades about the role of maternal nutrition in the outcome of pregnancy.Therefore,the maternal nutritional level during pregnancy plays an important role in the development of offspring,especially muscle development.Recent studies reported that circulating deoxycholic acid content was associated with a reduced skeletal muscle volume.While,little is known about the effects of embryonic bile acid levels on the growth and development of skeletal muscles.Based on the preliminary testing,we found that phytosterol esters(PE)and stearic acid can affect bile acid levels in female mice,but PE has a stronger regulatory effect on serum bile acid levels in pregnant female rats.PE is produced by the esterification of plant sterols and fatty acids,and can regulate the lipid metabolism of animals.Studies have shown that PE can mediate the turnover of bile acids in the body.By bounding to FXR or TGR5,different BA can impair or improve glucose homeostasis in skeletal muscle.Less is known about mechanism of maternal and embryo BA affect growth and differentiation of skeletal muscle fibers.In order to reveal the effect of maternal PE supplementation on the growth of offspring,PE were added in the diet of pregnant mice.Based on quantitative analysis of maternal lipid metabolism,placental lipid transport and amniotic fluid lipid levels,proteins and m RNA level of muscle development related genes in offspring,the possible mechanism underlined effects of PE in pregnant maternal diet on growth and development of progeny was preliminarily explored.In addition,PE was supplied to pregnanted sow during the late pregnancy period,and the possibility of PE application in production was preliminarily verified.The results show that:(1)Maternal dietary supplementation of PE during gestation decreased serum TBA levels at 17.5 days of gestation.As a raw material for bile acid synthesis,cholesterol was decreased significantly at 12.5 days of gestation and on the day of delivery.Further studies found that the m RNA expression levels of bile acid and cholesterol transporter in the placenta of the PE group were significantly decreased,and the levels of TBA,TG and TC in the amniotic fluid were significantly decreased.(2)The body weight of the progeny mice in the PE group were increased significantly from birth to the sixth week.Further study about the muscle development of the mice offspring at different growth stages showed that the day 1 fiber number of soleus muscle in PE group offspring were significantly increased;In 3 weeks old,the m RNA expression level of type IIa My HC in the gastrocnemius of the offspring was significantly increased;In adult(8-week-old)offspring,the muscle content of the male rats increased,and the fat content decreased.While,the grip strength,the proportion of type IIb muscle fibers in the gastrocnemius were significantly increased,and the proportion of type I muscle fibers decreased.(3)In order to explore the possible mechanism of these effects,the expression level of muscle development-related genes and receptor of bile acid in the late embryo(17.5 days)were detected.As a result,the m RNA level of myogenin in the PE group offspring was significantly decreased,while the protein level was significantly increased in the late embryo and 1 day.The decreased protein level of the bile acid receptor(FXR)lead to a significant decrease in the expression of decorin and increased myostatin activity.(4)Maternal supplyment of 1% PE in sows during the late period of pregnancy can promote the total litter size and birth weight per litter.In summary,the addition of PE in maternal diet can affect bile acid transport and lipid metabolism between maternal and fetal,and may promote the development of offspring muscles through bile acid receptors.