| L-carnitine(L-carnitine)is a key factor restricting lipid metabolism and oxidation,and it is also the only carrier for the transport of fatty acids to cell mitochondria.The energy generated by fatty acid oxidation is necessary for maintaining body temperature,exercise,basic metabolism and other physiological processes.Therefore,L-carnitine additive plays an important role in animal fattening and growth.This study intends to investigate the effect of L-carnitine on lipid metabolism during early fattening and growth of lambs,so as to lay a practical foundation for fattening lambs in animal husbandry production.24 3-month-old hybrid Small Tailed Han sheep rams with uniform body shape and similar body weight were selected as experimental animals.The experiment was randomly divided into three groups,with 8 lambs in each treatment group and1 lamb in each repetition,that is,control group(Group C,fed with basic diet),low concentration L-carnitine group(group L,fed with + 0.01% L-carnitine in basic diet),high concentration L-carnitine group(Group H,fed with basic diet + 0.05%L-carnitine),and fed in the diet mode of crude to concentrate ratio of 3:7.The pre feeding period was 15 days and the formal period was 45 days.The effects of real-time PCR and L-carnitine on the metabolism of fat in sheep were explored.At the same time,sheep preadipocyte model was selected in vitro to verify the effect of L-carnitine on lipid metabolism genes in preadipocytes of Small Tailed Han sheep.The test results show that:(1)The effects of dietary L-carnitine on blood indexes of Small Tail Han sheep were studied: the content of triglyceride(TG)in plasma of Small Tail Han sheep decreased significantly when L-carnitine was added(P < 0.01);However,when L-carnitine was added,the plasma concentrations of carnitine transferase 1(CPT1)and carnitine transferase 2(CPT2)in Small Tail Han sheep were significantly higher than those in the control group(P < 0.01),and the concentration of malonyl COA in group L was significantly higher than that in group C(P < 0.01),and that in group H was significantly higher than that in group C(P < 0.05).The results showed that the addition of L-carnitine accelerated the of fatty acids β-Oxidation further increased the contents of CPT1 and CPT2,indicating that L-carnitine promoted the synthesis of malonyl COA from acetyl CoA,and high-dose L-carnitine could reduce the inhibitory effect of malonyl COA while promoting fatty acid metabolism in Small Tail Han sheep.(2)The effects of dietary L-carnitine on fatty acid metabolism of Small Tail Han sheep were studied: after adding L-carnitine,Σ FA in high-dose L-carnitine group increased significantly(P < 0.05),Σ FA in high-dose L-carnitine group in blood(P < 0.05),and Σ FA in low-dose L-carnitine group in liver(P < 0.01).After adding L-carnitine,the ratio of n-6 / n-3 in blood,adipose tissue and liver of Small Tail Han sheep decreased in varying degrees(P < 0.05);After adding L-carnitine,the total amount of omega-3 in blood and adipose tissue of Small Tail Han sheep increased significantly(P < 0.05),and the total amount of omega-6 decreased significantly(P < 0.05).The contents of La(linolenic acid,18:2n-6)and Ara(arachidonic acid,20:4n-6)in omega-6 polyunsaturated fatty acids in liver decreased significantly in group L(P < 0.05),and increased significantly in group H(P < 0.05).ALA in omega-3 polyunsaturated fatty acids(α-Linolenic acid,C18:3(N3)),EPA(c22:6(N3))and DHA(c20:5(N3))in liver increased significantly in group L(P < 0.05),and decreased significantly in group H(P < 0.05).The results showed that exogenous L-carnitine could promote the oxidative metabolism of fatty acids in Small Tailed Han sheep,reduce the ratio of n-6 / n-3 and improve the metabolic pathway of fatty acids.(3)The effects of dietary L-carnitine on lipid metabolism genes of Small Tail Han sheep were studied: the expression of CPT1 in group L was significantly higher than that in group C(P < 0.05),while the expression of carnitine transferase 1(CPT1)in group H was significantly higher than that in group L and group C(P <0.01).The expression of LPL(lipoprotein esterase)in group L was significantly higher than that in group C(P < 0.01),while the expression of LPL in group H was significantly higher than that in group L and group C(P < 0.01).The expression of fatty acid binding protein 4(FABP4)in group C was significantly higher than that in group C(P < 0.01),while the expression of FABP4 in group H was significantly higher than that in group L and group C(P < 0.01).Group H peroxisome proliferator activated receptor(PPAR)γ)The expression of was significantly lower than that in group L and group C(P < 0.01).The results showed that the addition of L-carnitine enhanced the activity of lipolytic factor of Small Tail Han sheep.(4)In the experiment of sheep preadipocytes in vitro,it was also found that the expression of CPT1 mRNA,lplmrna and FABP4 mRNA when L-carnitine was added was significantly higher than that in group C(P < 0.01).But after adding L-carnitine,the PPAR of Small Tailed Han Sheep γ The expression of in group C was significantly lower than that in control group(P < 0.05).It was further verified that the addition of L-carnitine enhanced the activity of lipolytic factor of Small Tail Han sheepTo sum up: the effect of L-carnitine on lipolysis and fatty acids β-The activities of oxidation and lipolysis factors can promote the metabolism of unsaturated fatty acids,and tend to omega-6 polyunsaturated fatty acids and reduce the ratio of n-6 / n-3. |
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