| The gestation of sow is a critical period for the proliferation and differentiation of fetal myoblasts and the transformation of muscle fibers.Cumulative evidences have shown that the development of fetal and postnatal skeletal muscle is closely associated with maternal nutrition and physiological status.Maternal nutritional deficiency usually lead to low birth weight neonates,muscular dysplasia.In contrast,maternal overnutrition also lead to a large variation of primary weight and make effects on the offspring.However,there were few studies about the maternal energy or protein malnutrition at the same time on skeletal muscle development of offspring.The objects of our study aim to investigate the effects of energy and protein levels of sows from day 1 of gestation to parturition on reproductive performance,and growth performance,muscle fiber development of offspring.In this study,a total of 72 LY(Landrace × Yorkshire)sows with weight and backfat similarity were allocated randomly at mating to four groups: NENP group(T1,a normal energy and protein intake following NRC(2012)recommendation for gestating sows),NEHP group(T2,a normal energy but a high protein intake),LENP group(T3,a low energy but a normal protein intake)and LEHP group(T4,a low energy but a high protein intake).During early pregnancy(d 1 to 30 of gestation),2.2 Kg diet was provided to each sow each day.The diets provided to the each sow during mid(d 31 to 90 of gestation)and late(d 91 of gestation to parturition)pregnancy was 2.4 Kg and 2.8 Kg each day,respectively.Tweenty-four piglets with weight close to the average level were selected from each group for slaughter at birth as well as at weaning.The main results were as follows:1).The weight on birth,weaning,60 d and 90 d of piglets were significantly decreased with the low energy level fed to the sow(P < 0.05).High protein level fed to sow had a tendency to increase(P < 0.1)the birth weight and significantly increased(P < 0.05)the weight on 60 d and the ADG from weaning to 60 d of weaned piglets.In addition,maternal energy and protein level had a tendency to make an interaction(P < 0.1)on birth weight of piglets.muscle2).Low energy level fed to sow decreased the longissimus muscle(LM),semitendinosus muscle(SM),psoas muscle(PM),gastrocnemius(GM)weight of the offspring and the LM,PM relative weight of newborn piglets(P < 0.05).However,high protein level fed to sow increased the LM,PM,SM and GM weight of the weaned piglets(P <0.05),and increased the LM,PM and musculi soleus relative weight of weaned piglets(P <0.05).In addition,maternal energy and protein level had an interaction(P < 0.05)on SM weight of weaned piglets.3).Low energy level fed to sow decreased the LM cross-sectional area of newborn piglets(P < 0.05)and had a tendency to decrease the diameter of muscle fiber(P < 0.1).However,high protein level fed to sow had a tendency(P < 0.1)to increase the LM cross-sectional area of newborn piglets,the diameter of muscle fiber of weaned piglets and decreased(P < 0.05)the LM density of weaned pig.Furthermore,maternal energy and protein level had an interaction(P < 0.1)on diameter of muscle fiber in newborn piglets.4).The LM protein concentrations and PM DNA concentration of low energy piglets were lower than those of normal energy piglets on newborn(P < 0.05).However,the SM DNA concentration of high protein piglets were higher than those of normal protein piglets on newborn(P < 0.05).5).No difference observed in the serum IGF-I and GH concentration of newborn and weaned piglets among all treatments(P > 0.05).6).Maternal energy and protein levels had an interaction(P < 0.05)on PM CK activity in newborn piglets.The LM and PM total CK and LDH activity of low energy piglets were lower than those of normal energy piglets on newborn(P < 0.05).However,the LM total CK activity of high protein piglets were higher than those of normal protein piglets on weaning(P< 0.05).7).Maternal energy and protein level had an interaction(P < 0.05)on LM MYHC-Ⅱb and PM MYHC-Ⅰ mRNA expression in newborn piglets but no difference in weaned piglets.8).High protein level fed to sow had a tendency(P < 0.05)to decrease the LM MSTN mRNA expression of newborn piglets and the LM IGF-Ⅰ,Myo G mRNA expression of weaned piglets.In addition,maternal energy and protein level had an interaction(P < 0.05)on PM MSTN mRNA expression of weaned piglets.However,low energy level fed to sow increased(P < 0.05)the PM Myo G mRNA expression of weaned piglets.Conclusion: The present results demonstrate that both energy and protein in sow gestation diets affect body weight and skeletal muscle development in offspring.The low energy diet significantly decreased birth weight and weaned weight,leaded to the skeletal development slowly and decreased the weight of skeletal muscle weight.Increasing sow gestational dietary protein levels,which suffered the low maternal energy,could improve the skeletal muscle development and the early growth disadvantage of offspring with lower body weight. |
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