高能饲粮对湖羊肝脏能量与脂代谢相关基因表达的影响

Effects of high-energy diet on the expression of energy and lipid metabolism related genes in the liver of Hu sheep

[目的]本试验旨在探讨高能饲粮对湖羊肝脏组织细胞增殖、能量代谢和脂代谢相关基因表达的影响。[方法]选取36只体况良好、体质量相近的3月龄湖羊公羔,随机分为正常日粮组(CON)和高能日粮组(HE),每组3个重复,每个重复6只。CON组和HE组个体饲喂日粮的能量水平分别为10和11 MJ·kg^(-1)。预饲14 d后正式饲喂60 d,试验结束后屠宰并采集肝脏组织,用于H&E染色、免疫组化检测和荧光定量PCR(qPCR)、Western blot检测。[结果]H&E染色显示HE组湖羊肝脏组织中出现轻度空泡样变性;免疫组化发现PCNA蛋白主要表达于肝细胞核中,mTOR和LXRα蛋白主要定位在肝细胞质中。高能饲粮饲喂显著提高肝脏组织PCNA和SREBP-1c的mRNA与蛋白表达水平(P<0.05),显著降低肝脏组织LKB1和AMPK的mRNA与蛋白的表达水平(P<0.05),显著降低肝脏组织PGC-1α和SIRT1的蛋白表达水平(P<0.05)。此外,DGAT1和mTOR的mRNA和蛋白表达水平在CON组和HE组湖羊肝脏中差异不显著(P>0.05)。[结论]提高湖羊的日粮能量水平能增强湖羊肝脏组织的细胞增殖及脂肪合成能力。

[Objectives]The purpose of this experiment was to investigate the effects of high energy diet on the expression of cell proliferation,energy metabolism and lipid metabolism related genes in the liver of Hu sheep.[Methods]Thirty-six 3-month-old Hu sheep male lambs with good body condition and similar body weight were selected and randomly divided into control diet group(CON)and high energy diet group(HE),and each group had 3 replicates and each replicate had 6 individuals.The energy levels of the diets in the CON and HE group were 10 and 11 MJ·kg^(-1),respectively.The experiment lasted for 74 d,including a 14 d pre-feeding period.After the feeding period,experimental Hu sheep were smeared and liver tissue was collected.One part was placed in 4%paraformaldehyde and embedded in paraffin for H&E staining and immunohistochemical detection.The other part was placed in liquid nitrogen used to extract RNA and protein for quantitative PCR(qPCR)and Western blot detection.[Results]H&E staining showed mild vacuolation degeneration in liver tissues of Hu sheep in high-energy feeding group.Immunohistochemistry showed that PCNA protein was mainly expressed in the nucleus of liver cells,and mTOR and LXRαproteins were mainly localized in the cytoplasm of liver cells.The mRNA and protein expression levels of PCNA and SREBP-1c in liver tissues significantly increased with high energy diet,respectively(P<0.05).Whereas,the mRNA and protein expression levels of LKB1 and AMPK,and the protein expression levels of PGC-1αand SIRT1 in liver tissue significantly decreased with high energy diet,respectively(P<0.05).In addition,the mRNA and protein expression levels of DGAT1 and mTOR were not significantly different between high energy and normal diet group(P>0.05).[Conclusions]Improving the dietary energy level can enhance the ability of cell proliferation and fat synthesis in Hu sheep liver tissue.