纳米氧化锌对育肥牛生产性能、血清指标和背最长肌肌内脂肪沉积相关基因表达的影响

本试验旨在研究纳米氧化锌对育肥牛生产性能、血清指标及背最长肌肌内脂肪(IMF)沉积相关酶活性和基因表达的影响。选用16头西杂阉公牛(西门塔尔牛×本地黄牛)，随机分2组，每组8个重复，每个重复1头牛。对照组饲喂基础饲粮(不添加锌)，纳米氧化锌组在基础饲粮的基础上添加80 mg/kg锌(纳米氧化锌形式)。试验期为60 d。结果表明：1)与对照组相比，添加纳米氧化锌显著提高了育肥牛的平均日增重(P<0.05)，显著降低了料重比(P<0.05)。2)与对照组相比，添加纳米氧化锌极显著提高了血清游离脂肪酸、甘油三酯、总胆固醇、高密度脂蛋白、低密度脂蛋白、葡萄糖和胰岛样生长因子-Ⅰ含量(P<0.01)，显著提高了胰岛素含量(P<0.05)，极显著降低了葡萄糖/胰岛素比值(P<0.01)。3)与对照组相比，添加纳米氧化锌显著提高了背最长肌IMF含量和乙酰辅酶A羧化酶(ACC)活性(P<0.05)，极显著降低了激素敏感脂肪酶(HSL)活性(P<0.01)，显著降低肉碱转移酶-1(CPT-1)和脂蛋白脂肪酶(LPL)活性(P<0.05)。4)与对照组相比，...

Effects of Nano-Zinc Oxide on Performance,Serum Indexes and Expression of Intramuscular Fat Deposition Related Genes in Longissimus dorsi Muscle of Fattening Cattle

The purpose of this experiment was to study the effects of nano-zinc oxide on performance,serum indexes and intramuscular fat(IMF)deposition related enzyme activities and gene expression in longissimus dorsi muscle of fattening cattle. Sixteen western hybrid steers(Simmental×local yellow cattle)were randomly divided into 2 groups with 8 replicates per group and 1 cattle per replicate. In control group,cattle were fed a basal diet(without zinc),and those in experimental nano-zinc oxide group were fed the basal diet supplemented with 80 mg/kg zinc(nano-zinc oxide form). The experiment lasted for 60 days. The results showed as follows:1)compared with the control group,adding nano-zinc oxide significantly increased the average daily gain(P<0.05),and significantly decreased the feed/gain(P<0.05). 2)Compared with the control group,adding nano-zinc oxide extremely significantly increased the contents of serum free fatty acid,triglyceride,total cholesterol,high density lipoprotein,low density lipoprotein,glucose and insulin like growth factor-1(P<0.01),significantly increased insulin content(P <0.05),and extremely significantly decreased the ratio of glucose to insulin(P<0.01). 3)Compared with the control group,adding nano-zinc oxide significantly increased the IMF content and acetyl coenzyme A carboxylase(ACC)activity in longissimus dorsi muscle(P<0.05),extremely significantly decreased the hormone sensitive lipase(HSL)activity(P<0.01),and significantly decreased the activities of carnitine transferase-1(CPT-1)and lipoprotein lipase(LPL)(P<0.05). 4)Compared with the control group,adding nano-zinc oxide significantly increased the expression levels of sterol regulatory element binding protein-1(SREBP-1),peroxidase proliferation-activated receptorγ (PPARγ),fatty acid synthetase(FAS)and ACC genes in longissimus dorsi muscle(P<0.05),and significantly decreased the expression levels of HSL and CPT-1 genes in longissimus dorsi muscle(P<0.05). In conclusion,dietary nano-zinc oxide(80 mg/kg zinc)can up-regulate the expression of fatty acid synthetase related genes(FAS,ACC,SREBP-1 and PPARγ),down-regulate the expression of fatty acid decompose-related genes(HSL and CPT-1),and enhance the activities of fat synthetases(FAS and ACC)in longissimus dorsi muscle of fattening cattle,inhibit the activities of lipolytic enzyme(HSL and CPT-1),promote the deposition of IMF,improve the muscle quality and performance of fattening cattle.[Chinese Journal of Animal Nutrition,2022,34(2):1067-1075]