不同精粗比日粮对舍饲育肥牦牛组织中脂肪代谢相关酶活性及基因表达的影响

Effects of different concentration-to-roughage ratios on lipid metabolism enzyme activity and gene expression in the tissues of house-fed yaks

旨在通过对舍饲育肥牦牛饲喂不同精粗比日粮,探究其对牦牛体内组织脂肪代谢的影响。选取15头平均体重130.4 kg、年龄2~3岁的健康阉牦牛,随机分为精粗比为3∶7(A组)、5∶5(B组)和7∶3(C组)3个组,每组5头。饲喂90 d。试验最后一天进行屠宰,分别取肝脏、十二指肠和皮下脂肪组织,通过酶联免疫(ELISA)技术和荧光定量PCR(RT-PCR)法对脂代谢相关酶活性及基因表达进行分析。结果:与A组和B组相比,C组牦牛肝脏、十二指肠和皮下脂肪组织中,脂质合成酶固醇调节元件结合蛋白(SREBP-1c)、乙酰辅酶A羧化酶(ACC)、酯酰辅酶A去饱和酶1(SCD1)和脂肪酸合成酶(FASN)酶活性及基因mRNA相对表达量均显著升高(P<0.05);与A组和B组相比,C组牦牛肝脏、十二指肠和皮下脂肪组织中,脂肪酸氧化酶过氧化物酶体增殖物激活受体α(PPARα)、酯酰辅酶A氧化酶(ACO)、肉碱酯酰辅酶A转移酶1(CPT-1)和肉碱酯酰辅酶A转移酶2(CPT-2)酶活性及基因mRNA相对表达量均显著降低(P<0.05),脂质合成酶与脂肪酸氧化酶的酶活性和基因mRNA相对表达量在肝脏、十二指肠和皮下脂肪组织中的表达趋势一致。结论:日粮精粗比为7∶3时能更好地促进青海地区舍饲育肥牦牛体内脂肪的形成与沉积,达到快速育肥的目的。本试验为青海地区牦牛舍饲日粮的精粗配比改进及牦牛产业发展提供一定的基础资料。

This research was to evaluate the effects of different concentration-to-roughage ratios on lipid metabolism in the tissues of house-fed yaks. Fifteen healthy yaks with an average body weight of 130.4 kg and at 2-3 years of age were obtained and randomly divided into three groups with 5 heads in each group, and the concentration-to-roughage ratios in the diet of the three groups were 3∶7(Group A), 5∶5(Group B) and 7∶3(Group C). The experiment lasted for 90 days. On the last day of the experiment, the tested yaks were slaughtered, and samples of their liver, duodenum and subcutaneous adipose tissues were collected. Then, the lipid metabolism activity and gene expression in the samples were analyzed by enzyme-linked immunization(ELISA) and real-time quantitative PCR(RT-PCR). The results showed that, compared with Groups A and B, Group C had significantly increased levels of enzyme activity, relative mRNA expression of sterol regulatory element-binding transcription factor 1 c(SREBP-1 c), Acetyl-CoA carboxylase(ACC), stearoyl-CoA desaturase 1(SCD1) and fatty acid synthase(FASN) of lipid synthase in the liver, duodenum and subcutaneous adipose tissues(P<0.05), but significantly devreased levels of enzyme activity,relative mRNA expression of peroxisome proliferator-activated receptor α( PPARα),Acyl-CoA oxidase( ACO),carnitine palmitoyl transferase 1( CPT-1) and carnitine palmitoyl transferase 2( CPT-2) of fatty acid oxidase( P<0. 05). The enzyme activity and relative mRNA expression of lipid synthase and fatty acid oxidase were consistent in the liver,duodenum and subcutaneous adipose tissues of the animals. In conclusion,the concentration-to-roughage ratio of 7 ∶ 3 in the diet had the best effect on the formation and deposition of fat in house-fed yaks under the conditions in this experiment,realizing the purpose of rapid fattening of the animals. This experiment provided some basic data for the improvement of concentration-to-roughage ratios in the diet for house-fed yaks,was of significance in promoting the development of yak industry in the Qinghai area.