| There have been many research reports on guanidinoacetic acid(GAA)and betaine in pigs and chickens.Adding GAA to the diet and feeding methyl donors at the same time can promote growth and improve metabolism.For ruminant livestock,what is the effect of supplementing betaine with GAA on the synthesis of GAA and creatine in gut,the synthesis of creatine in liver and the metabolism of creatine phosphate in muscle tissue of sheep? Therefore,in this study,rumen-protected betaine(RPB)was supplemented on the basis of adding guanidinoacetic acid to the diet of sheep to explore its effects on growth performance,nutrient digestion,and creatine metabolism in small intestine,liver,muscle and other tissues of sheep,so as to provide scientific basis for the application of guanidinoacetic acid and betaine in sheep production.Experiment I: Effects of dietary addition of guanidinoacetic acid and rumen betaine on growth performance and nutrient digestion of sheepThe experiment was conducted to analyze the effects of guanylacetic acid and betaine on growth performance,nutrient digestion in the diet and guanylacetic acid metabolism in jugular plasma by feeding guanylacetic acid alone or in combination with guanylacetic acid and rumen bypass betaine.Eighteen healthy Kazakh rams aged 3-4 months with an average body weight of(27.46 ± 0.10)kg were selected for the experiment.They were divided into control group,test group I and test group II(n=6)according to body weight.The control group was fed with basic diet,test group I was fed with 1500mg/kg GAA,and test group II was fed with 1500 mg/kg GAA+600 mg/kg RPB.The results showed that:1)During the test period from 1 to 30 days,the average weight gain and daily weight gain in test group II were significantly higher than those in test group I(P<0.05),and were extremely significantly higher than those in control group(P<0.01).2)The apparent digestibility of crude fat and phosphorus in test group II increased extremely significantly from 1 to 30 days(P<0.01);The apparent digestibility of crude fat in test group II increased extremely significantly from 1 to 58 days(P<0.01).3)On the 30 th day of the trial period,the plasma creatine content in the jugular vein of the sheep in the trial group II was significantly increased(P<0.05);On the 60 th day of the trial period,the plasma GAA of jugular vein in trial group II was significantly increased(P<0.05).Therefore,under the conditions of this experiment,the daily weight gain,apparent digestibility of dietary crude fat and phosphorus,and the concentration of GAA and creatine in jugular plasma can be improved by adding GAA and betaine to the diet from the 1st to the 30 th days,which preliminarily reflects that when the lambs are fed 1500 mg/kg GAA,the effect of adding 600 mg/kg RPB is better..Experiment II: Transcriptomic analysis of the effect of betaine supplementation on small intestinal creatine metabolism in sheepThis experiment was conducted to investigate the effects of supplemented guanidinoacetic acid and betaine on guanidinoacetic acid related metabolites in small intestinal mucosa and superior mesenteric vein plasma of sheep by supplementing guanidinoacetic acid and jointly feeding rumen bypass betaine,and further selected duodenal and jejunal mucosa tissues of test group I(1500 mg/kg GAA group)and test group II(1500 mg/kg GAA+600 mg/kg RPB group)for sequencing by transcriptomics,To screen out the related differential genes and related pathways in sheep small intestinal mucosa,and explore the molecular mechanism of the effect of guanidinoacetic acid plus betaine on absorption,transport and metabolism of sheep small intestine.The results showed that: 1)The content of GAA in duodenal mucosa and jejunum and ileum mucosa of sheep in test group Ⅱ were significantly increased(P<0.01,P<0.05);The content of creatine in plasma of duodenum,ileum mucosa and superior mesenteric vein in group Ⅱ sheep was significantly increased(P<0.05).2)In comparison with group II,in group I,the duodenal differential genes involved in the pathway significantly changed in oxidative phosphorylation and nonalcoholic fatty liver disease(P<0.05).The pathway significantly enriched in jejunum mainly involved in MAPK signal pathway,complement and coagulation cascade and B cell receptor signal pathway(P<0.05,P adj<0.05).The significantly differential expression genes involved were ATPase,SLC transporter,DHFR,SI,GCK,ACACA FASN,etc.(P<0.05).Therefore,dietary supplementation of betaine with guanidinoacetic acid may improve energy metabolism,methyl metabolism and glycolipid metabolism in the small intestine by regulating solute transporter gene,ATPase gene and glycolipid metabolism related genes.Experiment III: Transcriptomic analysis of the effect of supplemented betaine in diet containing guanidinoacetic acid on creatine synthesis in sheep liverThe contents of guanidinoacetic acid,creatine and creatinine in liver tissue,portal vein and hepatic vein plasma of sheep were determined by feeding guanidinoacetic acid and rumen bypass betaine,and the effects of feeding guanidinoacetic acid and betaine on the synthesis of creatine in sheep liver were studied.Further,transcriptomics was used to select the differential genes and related pathways in the liver tissues of test group I and test group Ⅱ for comparison,to explore the differential effects of guanidinoacetic acid and betaine on gene expression in the liver tissues of sheep,with a view to revealing the mechanism of creatine synthesis in the liver.The results showed that: 1)GAA content test group II significantly increased in the liver tissues(P<0.05),and extremely significantly decreased in the liver veins(P<0.01);The content of creatine in liver tissue and hepatic vein of group Ⅱ was extremely significantly higher than that of the control group(P<0.01),and increased in portal vein(P<0.05).2)The GO enrichment items in the liver tissues of Group II and Group I were signal sensor activity,signal receptor activity,and molecular sensor activity(P<0.05,P adj<0.05).The differential genes involved in significant changes in the pathways were carbohydrate digestion and absorption,nitrogen metabolism,galactose metabolism,HIF-1 signal pathway,bile secretion,and one carbon pool folate(P<0.05).The significant differential expression genes involved were ATPase,DHFR,PFKP,GBE1 HK2,fat transporter,SCD,FASN,HADHB,etc.(P<0.05).Therefore,the diet containing guanidinoacetic acid was supplemented with betaine to improve methyl metabolism and creatine synthesis by regulating the active methyl and ATP synthase genes produced by methionine cycle involved in folic acid metabolism,and the body’s glucose and lipid metabolism was improved by regulating the genes related to sugar metabolism and fat decomposition involved in glycolysis.Experiment IV: Transcriptomic analysis of the effect of dietary supplement with betaine containing guanidinoacetic acid on muscle creatine metabolism in sheepThe changes of guanidinoacetic acid related metabolite and energy metabolism related metabolite in quadriceps femoris and longissimus dorsi muscle tissues of sheep were determined by supplementing guanidinoacetic acid and rumen bypass betaine to explore the effects of supplementing guanidinoacetic acid and betaine on the metabolism of muscle creatine and creatine phosphate.The transcriptomics technology was further used to select the differential genes and related pathways of quadriceps femoris muscle tissue in the test group I for comparison,and to explore the molecular mechanism of the effect of guanidinoacetic acid and betaine supplementation on creatine metabolism in sheep muscle.The results showed that: 1)The content of creatine kinase,creatine,ATP,ADP in quadriceps femoris of the test group II was significantly higher than that in the control group(P<0.01),The contents of creatine kinase,creatine phosphate and ATP in the muscle tissue of the longissimus dorsi muscle of the sheep in test group II and test group I were extremely significantly higher than those in the control group(P<0.01).2)The GO enrichment items in the muscle tissue of Group I in Group II were cell growth regulation,cell growth,growth regulation,insulin-like growth factor binding,growth factor binding(P<0.05,P adj<0.05).The genes involved in significant changes in the pathways were fatty acid metabolism,PPAR signal pathway,unsaturated fatty acid biosynthesis,fatty acid degradation,m TOR signal pathway,AMPK signal pathway,c AMP signal pathway Purine metabolism(P<0.05),the significant differentially expressed genes involved were ATPase,AK3,ACACB,ND2,FASN,FABP3,ELOVL6,fat transporter,GHSR,etc.(P<0.05).Therefore,the diet containing guanidinoacetic acid supplemented with betaine can improve muscle energy metabolism by regulating the high expression of ATPase gene and mitochondrial respiratory chain related genes,improve muscle lipid metabolism ability by regulating the high expression of fat and fatty acid decomposition related genes,and promote muscle growth by regulating the high expression of growth factor related genes.In conclusion,the diet supplemented with 1500 mg/Kg guanidinoacetic acid and 600 mg/kg rumen bypass betaine improved the daily gain of sheep,the apparent digestibility of dietary crude fat,the levels of guanidinoacetic acid and creatine in small intestinal mucosa,liver tissue and related blood,the levels of creatine kinase,creatine,ATP and ADP in muscle tissue,and regulated the ATP enzymes,fat metabolism enzymes,solute transport proteins,sugar metabolism enzymes The high expression of key genes such as amino acid metabolism enzymes promotes the body to supply more active methyl through methyl metabolism to participate in creatine synthesis,and promotes the growth and development of sheep by improving the energy metabolism,amino acid metabolism,sugar metabolism and lipid metabolism of the body. |
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