| IUGR is defined as impaired growth and development of the mammalian embryo or its organs during pregnancy.IUGR is a major concern in domestic animal production,which can easily cause low birth weight,damage gastrointestinal function and reduce neonatal survival.Choline,water-soluble vitamin,is an essential nutrient that has also been proven to have a positive effect in animal production.The essential nutrient choline is prominent in eggs,meats and meat products,liver,fish,soy and wheat germ,It has a vital role in neurotransmission,membrane integrity and methylation pathways.1.Effects of IUGR on glucose metabolism and fat metabolism in pigletsEighteen pregnant sows with the similar parity and bodily condition were selected and after parturition,eighteen normal body weight(NBW)piglets and eighteen IUGR piglets were selected according to birth weight.Thus,all piglets were distributed into 2 groups(NBW and IUGR).Determination of enzyme and the gene expression of glucose metabolism and fat metabolism in muscle of pigs at 7 and 23 days of age.The results showed as follows:(1)At the age of 7,compared with NBW piglets,the LDH,SDH,PEPCK and G-6-Pase in muscle were significantly increased in IUGR piglets(P<0.05),and a tendency toward to increase in CK of muscle(P=0.070);IUGR could increase the GS,PFKM mRNA expression in muscle significantly(P<0.05),and a tendency toward to increase the PKM2 mRNA expression in muscle(P=0.077);At the age of 23,compared with NBW piglets,the enzyme activity CK were significantly increased in IUGR piglets(P<0.05),while the enzyme activity of PEPCK and G-6-Pase were significantly decreased in IUGR piglets.GS mRNA expression was significantly lower than NBW piglets in IUGR piglets(P<0.05),while the mRNA expression of PFKM was significantly increased(P<0.05),but IUGR piglets had no effect on the GLUT4 and PKM2 mRNA expression(P>0.05).(2)At age of 7 days,compared with NBW group,IUGR piglets were significantly increased ACC and M-CPT activity(P<0.05);M-CPT and SREBP1 mRNA expression levels were significantly improved in IUGR piglets compared with NBW piglets(P<0.05),and the ACC mRNA expression had a tend to increase(P=0.059)in IUGR piglets,but no significant effect was found in FAS mRNA expression of IUGR piglets(P>0.05);At age of 23 days,ACC and M-CPT in IUGR piglets were significantly lower than that in NBW piglets(P<0.05);and compared with NBW piglets,ACC(P=0.083),M-CPT(P=0.069)and SREBP1(P=0.090)mRNA expression in IUGR piglets were decreased.In conclusion,at the age of 7,IUGR could enhance both fat metabolism and glucose metabolism in muscle;While at the age of 23 days,and glycogenolysis was increased while the fat metabolism was decreased in IUGR compared with NBW piglets.2.Effects of choline on growth performance and meat quality in IUGR pigsTwelve NBW and twelve IUGR newborn piglets were collected and distributed into 4 treatments(Normal:N,Normal+Choline:N+C,IUGR:I,IUGR+Choline:I+C)with 6 piglets each.At 23 d of age,NBW and IUGR piglets were fed control basal or choline supplemented diets,and 4 pigs of each group were slaughtered at 200 d of age,the longissimus dorsi muscle was collected for further study.The results showed that IUGR pigs were significantly lower(P<0.05)in body weight(BW)than that of NBW pigs at 23 d,73 d,and 120 d of age,and there was a slight decrease of BW in IUGR pigs than that of NBW pigs at 200 d(P>0.05).Compared with the NBW pigs,pH of meat was significantly decreased(P<0.05),and the meat color was improved in IUGR pigs.Furthermore,choline supplementation significantly increased(P<0.05)the MDA content as well as the O2ยท-scavenging activity in meat of IUGR pigs.The results suggested that IUGR pigs showed a permanent stunting effect on growth performance,and oxidative stress in muscle.However,choline supplementation improved the growth performance,and may have a positive effect on meat quality.3.Effects of choline on the glucose metabolism and fat metabolism in IUGR pigs.The experiment design was the same as Experiment 2.Determination of enzyme and the gene expression of glucose metabolism and fat metabolism in the muscle of pigs at 200 days of age.(1)Compared to the NBW group,the glycogen of IUGR pigs was decreased significantly while the content of LC and GP were markedly increased in muscle(P<0.05),there was a slight increase in the activity of LDH of IUGR pigs in muscle(P=0.057).The activities of PEPCK and G-6-Pase were significantly decreased in IUGR pigs compared with that of NBW pigs.Furthermore,a tendency toward decreased GLUT4 mRNA expression was observed in the muscle of IUGR pigs in muscle(P=0.071),IUGR significantly decreased the GS mRNA expression in muscle(P<0.05),and increased PKM2,PFKM mRNA expression in muscle compared to NBW pigs(P<0.05).With the supplementation of choline,the choline diet had a trend to increase muscle glycogen of pigs(P<0.05),also had a tend to decrease the content of LC(P=0.091)and GP(P=0.041),and CK activity was significantly increased after choline treatment(P<0.05).There was a significant increase in GS mRNA and GLUT4 mRNA expression(P<0.05),whilst a slight decrease in PFKM mRNA expression fed by dietary choline(P=0.087).(2)TG and IMF contents were significantly higher(P<0.05)in IUGR pigs than that of NBW pigs.And compared with the NBW pigs,IUGR could significantly increase the activity of ACC(P<0.05).Furthermore,IUGR up-regulated the levels of FAS,ACC and SREBP1 mRNA expressions and down-regulated the levels of M-CPT mRNA gene expressions;Dietary choline supplementation decreased the content of TG(P<0.05)and IMF(P=0.082),FAS and SREBP mRNA levels were increased(P<0.05)while the M-CPT mRNA(P<0.05)levels were decreased in the muscle of IUGR pigs by choline supplementation.In conclusion,glycogen synthesis and fat deposition were increased in the muscle of IUGR pigs,as well as the content of lactic acid by increasing the key enzyme of glycolytic and lipogenesis expression in muscle.However,choline supplementation could have a positive way to glucose metabolism and fat metabolism by relieving glycogen decomposition and facilitate lipolysis. |
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