Effects Of Maternal Butyrate On Lipid Accumulation In Offspring Skeletal Muscle And The Relatived Mechanism

Maternal nutrition during gestation and lactation has profound effects on fetal growth and development with lifelong consequences.In recent years,the study of effects of maternal dietary fiber on the development of offspring has been paid more and more attention.Butyrate as a short-chain fatty acid is produced mainly by the anaerobic micro-organisms fermentation in the gastrointestinal tract.Butyrate can not only serve as the energy source for ruminants and monogastric animals,but also can regulate the growth and development of the offspring.The metabolic regulation of butyrate was through two ways:activation of GPR41and GPR43 and as a histone deacetylase inhibitor,to regulate the signaling pathways.In the previous study,the studies about butyrate are mostly concerned with the effects of butyrate on obesity and diabetes mellitus in the condition of high fat induced obesity.However,the effect of maternal butyrate on lipid metabolism in offspring skeletal muscle and the associative mechanism are still relatively unknown.Therefore,the purpose of this study is to investigate the effect of maternal butyrate during gestation and lactation on intramuscular fat deposition in offspring skeletal muscle and its molecular mechanism.1 Effects of maternal butyrate on the performance of mother and offspringThe offspring of rats,fed a control diet or a butyrate diet(1%sodium butyrate)throughout gestation and lactation,was studied at weaning and at 60 days of age.Food intake of the dams per week during gestation and lactation in the butyrate group did not change significantly compared with the control group.The body weight and gastrocnemius muscle weight(GW)(P<0.01)of adult offspring were significantly enhanced in the butyrate group compared with control,though both of them showed no obvious differences at weaning age.Serum concentrations of butyrate were increased(P<0.05)at weaning in dams of butyrate supplemented rats.Serum total cholesterol and total triglyceride were not affected in the offspring at weaning by butyrate supplementation of the dams(P>0.05).However,significantly higher(P<0.05)content of intramuscular triglyceride was observed in the butyrate group at weaning.Later in life,total cholesterol and triglyceride in serum were also not different between the butyrate group and the control group,while the content of intramuscular triglyceride further increased significantly(P<0.05)in the butyrate group.Oil-red O staining revealed the abundance of intramuscular adipocytes in muscle cross sections of butyrate group rats but not in that of controls.The present results suggested that maternal butyrate supplementation increased the intramuscular fat deposition.2 Effects of maternal butyrate supplementation on lipid metabolism in offspring skeletal muscle and its molecular mechanismCompared with control,PPARy mRNA(P<0.05)and protein expression(P<0.05)were higher in skeletal muscle of weaning rats in the butyrate group.Although C/EBPP and FAS mRNA expressions in weaning rats were not altered,their protein levels were higher(P<0.05)in the butyrate group.ATGL mRNA expression related to lipolysis was significantly decreased(P<0.05)while its protein level was still higher(P<0.05)in weaning rats of the butyrate group.On the other hand,CPTlb(P<0.05)and PDK4(P<0.05)mRNA expression were increased significantly in butyrate group while PGC-1α,UCP3,FOX03A mRNA expressions related to oxidation capacity were not altered.Protein expressions of CPTlb,UCP3,GLUT4 and PDK4 had no significant difference with maternal butyrate supplementation.During the offspring adult life,lipid related transcription factors including PPARy and C/EBPβ mRNA and protein abundances were enhanced(P<0.05)in gastrocnemius muscle of female rats in the butyrate group.ATGL and HSL mRNA expression did not change whereas the ATGL protein level(P<0.05)and the phosphorylation level of HSL(P<0.05)decreased.FAS mRNA and protein expression in adult rats showed no obvious changes between two groups.Among the genes involved in oxidation capacity,CPTlb,PDK4 and UCP3 mRNA expressions were decreased in skeletal muscle of butyrate group.mRNA expression of PGC-1α did not altered with maternal butyrate supplementation.Protein expression of CPTlb,UCP3 and PGC-1α had no significant difference in butyrate group compared with control.In the gastrocnemius muscle of weaning offspring,higher enrichment(P<0.05)of acH3K27 was found for PPARy and a trend for higher enrichment(P=0.07)for C/EBPβ in the butyrate group.Furthermore,in the gastrocnemius muscle of adult offspring,maternal butyrate supplementation during gestation and lactation significantly enhanced the enrichment of acH3K9 and acH3K27 on the promoters of C/EBPβ(P<0.05)and FAS(P<0.05).The higher enrichment of acH3K27 on the promoter of PPARy was observed in the adult offspring skeletal muscle.The current study highlights the importance of maternal nutrition for the offspring phenotype.It is the first to indicate that maternal butyrate supplementation during gestation and lactation induces intramuscular fat deposition in adult female offspring although maternal butyrate supplementation had no effect on energy metabolism in offspring skeletal muscle,especially on oxidation capacity.Furthermore,the mechanisms involved in mediating the effects of maternal butyrate on the intramuscular fat deposition include increasing lipogenic and reducing lipolysis genes in offspring skeletal muscle partly via enhanced histone acetylation modification.3 Effects of maternal butyrate on insulin sensitivity in offspring skeletal muscle We found that the concentration of fasting glucose was higher(P<0.05)in the butyrate group of adult offspring rats.After fasting,adult offspring were challenged with a GTT and an ITT,butyrate group rats showed permanently increased serum glucose levels in15 min(P<0.05)、45 min(P<0.05)、60 min(P<0.05)、90 min(P<0.05)and 120 min(P<0.05),indicating decreased responsiveness as a sign for development of insulin resistance.Compared with control,HOMA-IR(HOMA-insulin resistance)was significantly increased in both weaning offspring(P<0.01)and adult offspring(P<0.05)belonging to the butyrate group.Serum concentrations of insulin and NEFA were increased(P<0.05)at weaning in offspring of butyrate supplemented rats.This difference was not observed in adult offspring.Compared with control,phosphorylation of IRS at ser1101 was increased(P<0.05)and the abundances of total PI3K/P85(P<0.05)and total AKT protein(P=0.07)were reduced in skeletal muscle of the butyrate group.With the higher concentration of fasting glucose in adult rats,GLUT4 related to glucose uptake in skeletal muscle was decreased(P<0.05)in the butyrate group.The results indicated that maternal butyrate supplementation leads to insulin resistance associated with the impaired insulin sigaling pathway and the decreased glucose uptake in offspring skeletal muscle.4 Effects of maternal crude fiber and butyrate on lipid metabolism in newborn and weaning offspring skeletal muscleSixty-eight Large White sows(multi-parity,2-5)were randomly assigned to the control group(CON group,n=21),the crude fiber group(fed 5.0%crude fiber,AH group,n=25)and the sodium butyrate group(0.1%sodium butyrate,SB group,n=22)during the whole pregnancy and lactation.At newborn and 22 days of age,one male piglet per litter close to the mean body weight was sacrificed for sampling.In newborn,maternal crude fiber(AH)and butyrate(SB)diets had no significant effects on body weight and LD muscle weight.Maternal AH significantly increased the serum concentration of cholesterol(P<0.05)and serum triglyceride had an increased tendency in AH group(P=0.09).Maternal AH did not altered cholesterol and triglyceride in offspring skeletal muscle.Maternal SB significantly increased the concentration of triglyceride in serum while the concentration of cholesterol and triglyceride in skeletal muscle did not change.In weaning piglets,body weight both in AH group and in SB group increased significantly(P<0.05)compared with control group.The concentrations of triglyceride in LD muscle both in AH group(P<0.05)and SB group(P<0.01)were higher than in control group although the concentration of triglyceride in serum did not change.Oil-red O staining revealed the abundance of intramuscular adipocytes in LD muscle cross sections of AH group and SB group but not in that of controls.Maternal AH supplementation significantly increased the concentrations of C10:0(P<0.05),C18:2n-6trans(P<0.05),C20:3n-3(P<0.05)in LD muscle of weaning piglets compared with control.The concentrations of C18:3n-3 in LD muscle of weaning piglets in SB group reduced significantly compared with control(P<0.05).The total SFA,MUFA and PUFA were not affected by different dietary diets.Total n-3 PUFA decreased with maternal butyrate supplementation(P<0.05).In newborn piglets,maternal AH diet significantly increased HSL mRNA expression in skeletal muscle while the mRNA expression of C/EBPβ,ATGL and FAS did not change.Maternal SB significantly increased mRNA expression of C/EBPβ,ATGL and decreased mRNA expression of FAS and LPL in skeletal muscle.Maternal AH and SB had no significant effects on protein expression of PPARy,C/EBPβ and SREBP1 in skeletal muscle.In weaning piglets,both mRNA and protein expression of PPARy in LD muscle of weaning piglets were increased significantly with maternal butyrate supplementation(P<0.05).In AH group,the gene expressions related to lipid metabolism including PPARy and C/EBPβ in LD muscle of weaning offspring had no altered compared with control group.Furthermore,the acytelation of H3K27 enrichment was increased in the promoter of PPARy of weaning skeletal muscle in AH and SB group.The protein expression of short chain fatty acid receptor 43(GPR43)and CD36 in LD muscle of offspring did not change with maternal AH or maternal butyrate supplementation.The results suggested that maternal AH and butyrate supplementation induced lipid accumulation in weaning offspring skeletal muscle.Maternal butyrate induced lipid accumulation with the increased expression of PPARy.However,high fiber intake had no effect on PPARy.Maternal butyrate supplementation influenced lipid metabolism in offspring skeletal muscle differently to dietary fiber intake.