Effects Of Maternal Methyl-donor Micronutrient Supplementation During Pregnancy On Muscle Development,gut Microbiota,and Metabolism Of Offspring

Maternal nutritional programming affects the development and metabolism of the fetus after birth,and the establishment of the intestinal microflora in the early neonatal period is a key process of infant development.Intestinal microbes can influence muscle metabolism,regulate muscle development and muscle fiber ratio through the Gut-muscle axis.In addition,previous studies have shown that the embryonic development process relies on the effective methyl donor content in the placental circulation to meet the cell division during organ growth and promote tissue development and metabolic renewal.Thus,this study aimed to investigate the effects of maternal methyl-donor micronutrient supplementation during pregnancy on muscle development and and gut microbiota and metabolism of offspring.A total of 43 gilts(Duroc×Erhualian)with initial body weight(BW)of 102.8±6.3 kg and the same genetic background were artificially inseminated with purebred Duroc semen(littermate Duroc boars),and then were assigned to two dietary groups during gestation:control diet(CON,n=21)and CON diet supplemented with MET(folic acid,methionine,choline,vitamin B₆ and vitamin B₁₂,n=22).During lactation,sows received a standard lactation diet.Lactation lasted 24 days.The results showed that:1)Maternal MET exposure during pregnancy has no significant effect on reproductive performance of sows,but increased the body weight at weaning,average daily gain,and the muscle fiber cross-sectional area of weaned piglets(P<0.05).2)Colostrum obtained from the MET-fed sows had a higher protein,Ig M,T₃,and T₄ concentrations than that from the CON-fed sows(P<0.05),Moreover,serum prolactin was higher in the supplemented than in the control sows(P<0.05).3)Maternal MET exposure during pregnancy significantly increased the concentration methyl metabolites,including S-adenosylmethionine(SAM),S-adenosyl-L-homocysteine(SAH),5-methyl-tetrahydrofolate(5-MTHF),and betaine,and decreased serum homocysteine concentration in the maternal,umbilical vein serum,and offspring piglets(P<0.05).In addition,maternal MET supplementation significantly increased the m RNA expression of DNMT1,DNMT3a,DNMT3b,SHMT,and MAT2B in longissimus dorsi muscle of newborn piglets,and increased the m RNA expression of DNMT3b and MTHFR in longissimus dorsi muscle of weaning piglets(P<0.05).4)Maternal MET supplementation significantly increased the concentration of offspring serum insulin-like growth factor 1(IGF-1),T₃,and T₄,up-regulated the m RNA expression of IGF-1 and IGF-1 receptor(IGF-1r)and the phosphorylation level of protein kinases in offspring longissimus dorsi muscle and up-regulated the expression of myogenic genes and fast myosin heavy chain(fast My HC)in offspring skeletal muscle.5)Maternal MET supplementation during pregnancy significantly increased the activities of glycogen phosphorylase a(GPa),phosphofructokinase(PFK),pyruvate kinase(PK),hexokinase(HK),lactate dehydrogenase(LDH),and creatine kinase(CK)enzymes in longissimus dorsi muscle of weaned piglets(P<0.05).6)Compare with the control group,maternal MET supplementation during pregnancy significantly adjusted promoter methylation of Py GM,PKM,HK2,GLUT4,and LDHA in longissimus dorsi muscle of weaned piglets,up-regulated the m RNA expression of GYS1,GLUT4,PYGM,GDE,PFKM,and CBS of newborn piglets,and the m RNA expression of PRKAG3,PYGM,GDE,HK2,PDK4,and LDH of weaning piglets(P<0.05).In addition,maternal MET supplementation during pregnancy significantly up-regulated the expression of HK2,PYGM,and PKM2 of offspring(P<0.05).7)Maternal MET supplementation increased the microbiota diversity and uniformity in feces of 21-day-age offspring,at phylum level,the relative abundance of Firmicutes,and the Firmicutes to Bacteroidetes ratio were elevated by maternal treatment.At genus level,the relative abundance of SCFA-producing Dialister,Megasphaera,and Turicibacter,lactate-producing Sharpea,as well as Akkermansia,Weissella,Pediococcus were increased in MET group(P<0.05).8)The metabolic analysis show that maternal methyl-donor micronutrient addition increased the concentrations of individual and total SCFAs of 21-day-age piglets,and increased metabolism mainly involving amino acids,pyrimidine,and purine biosynthesis(P<0.05).Collectively,Maternal MET exposure during pregnancy has no significant effect on reproductive performance of sows,but can promote the growth and development of offspring during lactation,which was associated with improved colostrum quality,the muscle development,and the transformation of muscle fiber type,improved methyl metabolism and muscle metabolism of offspring,increased the microbiota diversity and uniformity of offspring,promote the colonization of intestinal microflora in lactation period of offspring,increased the relative abundance of SCFA-producing Dialister,Megasphaera,and Turicibacter,lactate-producing Sharpea,as well as Akkermansia,Weissella,Pediococcus in MET group,increased the concentrations of individual and total SCFAs of 21-day-age piglets,and altered metabolism mainly involving amino acids,pyrimidine,and purine biosynthesis.