Potential Mechanism Of Nicotinamide Supplementation In Perinatal Dairy Goat On Glucose And Lipid Metabolism Of Lambs

Lamb forsterage is an important stage of the dairy goat aquaculture industry,lambs at a good foundation is crucial for the performance of adult dairy goat.The metabolism of offspring is sensitive to maternal nutrition supplementation.Nicotinamide could regulate lipid and glucose metabolism,however,the regulatory effects of maternal nicotinamide supplementation on glucose and lipid metabolism of offspring are still unknown.In the present experiment,we hypothesized that nicotinamide supplementation in dairy goat would regulate glucose and lipid metabolism of lambs through PGC1αpathway,regulating growth and development of lmbs finally.So the experiment is based on maternal nicotinamide supplementation,trying to explore the effects and mechanism of nicotinamide supplementation in perinatal dairy goat on glucose and lipid metabolism and the intestinal morphological development of the offspring,and aiming to provide a theoretical basis for the nourishments controlling research of the growth and development of lambs.Experiment 1 Effect of nicotinamide supplementation in perinatal dairy goat on intestinal morphology and the expression of nutritional transporter of lambsFifteen perinatal dairy goats（prenatal 21 days）were paired and assigned randomly within block to 3 groups.In group C（control group）,ewes were fed with basal diets without nicotinamide supplementation.In group P（postpartum group）,ewes were fed with basal diets with nicotinamide supplementation from postpartum 1 to 28 days.In group EP（prenatal group）,ewes were fed with nicotinamide supplementation from prenatal 21 days to postpartum 28 days.The lambs from each treatment were named group L_C,group L_P and group L_EP respectively.Lambs were slaughtered at the age of 28 days,duodenum,jejunum and ileum were collected to analyze the intestinal morphology.Results showed that duodenum villus height in group L_P and group L_EP was significantly（P<0.05）increased compared with group L_C,and duodenum V/C in L_P and L_EP was extremely significantly（P<0.01）increased compared with L_C.Jejunum V/C in L_P and L_EP was significantly（P<0.05）increased whencompared with L_C.Ileum villus height in L_EP was significantly（P<0.05）increased compared with L_C and L_P,and ileum V/C in L_EP was extremely significantly（P<0.01）increased compared with L_C and L_P.There has no effect on crypt depth in duodenum,jejunum and ileum（P>0.05）.The expression of intestinal mucosal glucose transporter was determined using real-time quantitative PCR（RT-qPCR）,results showed that there has no effect on the expression of duodenum GLUT2 and SGLT1（P>0.05）.The expression of jejunum GLUT2 in group L_P was extremely significantly（P<0.01）increased compared with L_C and L_EP,and the expression of jejunum SGLT1 in L_P and L_EP was extremely significantly（P<0.01）decreased compared with L_C.The expression of ileum GLUT2 in L_EPP was significantly（P<0.05）increased compared with L_C and L_P,and the expression of ileum SGLT1 in L_P and L_EP was extremely significantly（P<0.01）decreased compared with L_C.The results of exp.1 show that nicotinamide supplementation in perinatal dairy goat would facilitate intestinal morphology development of small intestine,and improve the expression of jejunum GLUT2and SGLT1 and ileum GLUT2,which have benefit for improving the glucose absorption of jejunum and ileum.Experiment 2 Effect of nicotinamide supplementation in perinatal dairy goat on glucose metabolism and blood biochemical indexes of lambsFasting blood from lambs was obtained from jugular vein 3 hours after morning feeding on 14th and 28th days to measure blood parameters;Lambs were slaughtered at the age of 28days,liver were collected to measure the bio-markers of glucose metabolism.Results at14-day age showed that the concentration of plasma glucose and PUN in group L_EP and L_P was extremely significantly（P<0.01）increased compared with group L_C.The level of plasma VLDL in group L_EP and L_P was significantly（P<0.05）decreased compared with group L_C.The plasma TG,FFA,HDL-C,VLDL,GOT,GPT we tested were not significantly different among groups（P>0.05）.Results at 28-day age showed that the PUN in group L_EPP was significantly（P<0.05）increased compared with group L_C.Plasma TG in group L_EP was extremely significantly（P<0.01）increased compared with group L_C and L_P,and GPT in group L_P and L_EP was extremely significantly（P<0.01）decreased compared with L_C.Hepatic glycogen in group L_EP has a tendency（P=0.062）lower than group L_C and L_P.The key genes and transcription factors involved in glucose metabolism in liver was determined using real-time quantitative PCR（RT-qPCR）.Results showed that the mRNA expression of PEPCK in group L_P and L_EP was extremely significantly（P<0.01）decreased compared with L_C.The mRNA expression of GS,GLUT2,FoxO1 and PGC1αin group L_P and L_EP was significantly（P<0.05）decreased compared with L_C.The results of exp.2 show that nicotinamide supplementation in perinatal dairy goat would suppress hepatic gluconeogenesis and glycogenesis.Experiment 3 Potential mechanism of nicotinamide supplementation in perinatal dairy goat on lipid metabolism of lambsLambs were slaughtered at the age of 28 days,liver and abdominal adipose tissue were collected to measure the bio-markers.Results showed that the levels of hepatic FFA in group L_P and L_EP was significantly（P<0.05）increased compared with L_C,and the concentration of TG in abdominal adipose tissue was extremely significantly（P<0.01）increased compared with group L_C.The levels of FFA in abdominal adipose tissue in group L_EP was significantly（P<0.05）increased compared with L_C.The concentration of TG in group L_EP was extremely significantly（P<0.01）increased compared with L_P.The mRNA expression of key genes involved in lipid metabolism in liver and abdominal adipose tissue were determined using real-time quantitative PCR（RT-qPCR）.Results showed that the mRNA expression of hepatic FAS and ApoB was significantly（P<0.05）decreased compared with L_C.The mRNA expression of MTTP was extremely significantly（P<0.01）increased compared with L_C and L_P.The expression of HSL in group L_P was significantly（P<0.05）decreased compared with L_C.The expression of FAS in abdominal adipose tissue in group L_EP was significantly（P<0.05）increased compared with L_C and L_P.The expression of GPAM in group L_EP was extremely significantly（P<0.01）increased compared with L_C and L_P.The expression of AGPAT6 in L_P and L_EP was extremely significantly（P<0.01）increased compared with L_C.The activities of key enzymes involved in lipid metabolism in liver and abdominal adipose tissue was determined using enzyme-linked immunoassay（ELISA）kit.Results showed that the activities of hepatic AGPAT6 in L_EP was significantly（P<0.05）decreased compared with L_C and L_P,and the activities of HSL in L_P was significantly（P<0.05）increased compared with L_C.The results of exp.3 show that nicotinamide supplementation in perinatal dairy goat would facilitate lipolysis in liver of lambs,and also could facilitate fat deposition in abdominal adipose tissue of lambs,and promote growth and development of lambs.In conclusion,nicotinamide supplementation in perinatal dairy goat could facilitate the absorbsion of glucose by intestine,and suppress hepatic gluconeogenesis and facilitate lipolysis.Beyonds that,nicotinamide supplementation in perinatal dairy goat also would facilitate fat deposition in abdominal adipose tissue and improve intestinal morphology development,and promote growth and development of lambs.