The response of gene expression associated with intramuscular fat deposition in the longissimus dorsi muscle of Simmental × Yellow breed cattle to different energy levels of diets

This study was designed to estimate dietary energy level on intramuscular fat (IMF) deposition in Simmental × Yellow breed cattle. Results showed that ultimate weight and average daily gain in high and medium energy groups were significantly higher than low‐energy group, yet feed conversion ratio was significantly lower. IMF content was significantly increased by dietary energy increasing, whereas longissimus muscle shear force significantly decreased. Serum‐free fatty acids, triglycerides and glucose significantly increased by dietary energy increasing, whereas growth hormone (GH) significantly decreased. Enzyme activities of lipoprotein lipase (LPL), fatty acid synthase (FAS), and acetyl‐CoA carboxylase (ACC) significantly increased by dietary energy increasing, whereas hormone‐sensitive lipase (HSL) and carnitine palmitoyltransferase‐1 (CPT‐1) significantly diminished. Peroxisome proliferator‐activated receptor γ, sterol regulatory element‐binding protein 1, stearoyl‐CoA desaturase, adipocyte‐fatty acid‐binding proteins, ACC, LPL, and FAS gene or protein expression significantly increased by dietary energy increasing, whereas HSL, CPT‐1, and GH gene or protein expression significantly decreased. These results indicated that high dietary energy promoting IMF deposition is mainly by downregulating pituitary GH gene expression, decreasing serum GH concentration, increasing lipogenic genes levels of mRNA, enzyme activities and protein expression, and decreasing lipolytic genes levels of mRNA, enzyme activities, and protein expression.     

家畜DGAT1基因的生物学功能及其在遗传育种中的应用研究

DGAT1基因属于酰基辅酶A胆固醇酰基转移酶(acyl CoA:cholesterol acyltransferase,ACAT)基因家族,DGAT1基因催化反应的底物为二酰甘油和乙酰辅酶A(fatty acyl CoAs),该基因一方面参与脂肪的合成,在细胞中起到重要的中心代谢作用,另一方面作为影响家畜泌乳性状和脂肪沉积的重要候选基因,被认为对乳脂合成、脂肪含量和食用价值均有显著影响。本文通过对DGAT1基因的生物学功能、分子结构以及该基因多态性与各类家畜经济性状的关联性进行综述,阐明该基因在家畜发育中的遗传表达规律,并对DGAT1基因在家畜育种方面的研究前景做出展望。     

Antibiotics promote abdominal fat accumulation in broilers

Antibiotics stimulate the growth of animals but result in drug residues and bacterial resistance. In this study, the negative effect of antibiotics on abdominal fat deposition was evaluated in broilers. The results showed that adding both chlortetracycline (50 g/1,000 kg) and tylosin (50 g/1,000 kg) significantly increased abdominal fat weight, abdominal fat percentage (p < .05), and triglyceride and cholesterol levels (p < .05) in blood. Also, both products synchronously stimulated intestinal absorption and synthesis of liver fat. The expression levels of the peroxisome proliferator‐activated receptor γ (PPARγ), diacylgycerol acyltransferase 2 (DGAT2), lipoprotein lipase (LPL), and fatty acid‐binding protein (FABP4) genes in abdominal fat tissue significantly increased (p < .05 or 0.01) when antibiotics were added to the feed. However, no significant difference was found in expression of the fatty acid synthesis (FAS) or acetyl CoA carboxylase (ACC) genes. Further in vitro study results revealed that antibiotics had no effect on fat content or the related gene expression levels in preadipocytes. In summary, the antibiotics induced fat deposition in adipose tissues by activating extracellular absorption of fatty acids from intestinal absorption and synthesis of liver fat. However, it shows no direct regulation by adipose tissue.     

鹅脂肪甘油三酯脂肪酶和长链脂酰辅酶A合成酶1基因表达差异及其对脂肪沉积和血清脂类代谢的调控

本试验旨在研究脂肪甘油三酯脂肪酶(ATGL)和长链脂酰辅酶A合成酶1(ACSL1)基因在鹅的不同组织器官中的表达差异,并探索2个基因表达对机体脂肪沉积和血清脂类代谢的调控。选取16周龄五龙鹅30只(公母各占1/2),屠宰后用实时荧光定量PCR检测不同组织器官(肝脏、心脏、皮下脂肪、腹部脂肪、胸肌、腿肌、肌胃、腺胃、小肠、肾脏、大脑、肺、脾脏)中A TG L、A CSL1基因表达量。结果表明:1)在鹅的皮下脂肪、腹部脂肪、肝脏、脾脏、肾脏、心脏、胸肌和腿肌中均检测出ATGL和ACSL1基因的表达;ATGL基因在皮下脂肪和腹部脂肪中表达量最高,其次是肝脏和脾脏,在肾脏、心脏、胸肌和腿肌中只有少量表达;ACSL1基因在皮下脂肪、腹部脂肪、肝脏、脾脏中表达量较高,在肾脏、心脏、胸肌和腿肌中有少量表达,而在肌胃、腺胃和肺中几乎不表达。2)ATGL基因表达量与腿肌肌内脂肪率、胸肌肌内脂肪率、腹部脂肪率、胸肌率和腿肌率呈显著或极显著负相关(P0.05或P0.01),与皮下脂肪率呈显著正相关(P0.05);ACSL1基因表达量与腿肌肌内脂肪率、胸肌肌内脂肪率、胸肌率呈正相关(P0.05),与腿肌率呈显著正相关(P0.05),与皮下脂肪率呈显著负相关(P0.05)。3)ATGL基因表达量与血清甘油三酯、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇和葡萄糖含量呈显著或极显著正相关(P0.05或P0.01);ACSL1基因表达量与血清总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇和葡萄糖含量呈负相关(P0.05),与甘油三酯含量呈显著负相关(P0.05)。由此可见,ATGL和ACSL1基因在鹅的不同组织器官中的表达具有明显差异性,对机体脂肪沉积和血清脂类代谢具有反向调控作用。     

Association of A‐FABP gene polymorphism and mRNA expression with intramuscular fat content (IMF) in Baicheng‐You chicken

This study aims to assess the association of polymorphisms and mRNA expression of adipocyte‐type fatty acid‐binding protein (A‐FABP) with intramuscular fat (IMF) in the breast muscle (BM) and leg muscle (LM) of Baicheng‐You chickens (BYCs). A total of 180 chickens, including sixty black Baicheng‐You chickens (BBYCs), sixty silky Baicheng‐You chickens (SBYCs) and sixty white Baicheng‐You chickens (WBYCs), were reared from 1 to 120 day. A polymerase chain reaction–single‐strand conformation polymorphism strategy (PCR‐SSCP) was used to detect the polymorphism of the A‐FABP gene in the first exon, and the C51T silent mutational site was found. The IMF content with the AA genotype was significantly higher than that with the AG genotype (p = 0.0473) in the LM of WBYC. Thus, this site could be taken as a molecular marker in selecting a higher IMF content of LM in WBYC. A‐FABP gene mRNA expression in the BM and LM of BYCs was detected, and a significant positive correlation was observed in the LM of WBYC. These findings provide fundamental data that might be useful in further study of the role of the A‐FABP gene in IMF content and fatty metabolism in chickens.     

不同乳脂率德宏奶水牛乳腺组织中FATP1基因表达研究

为研究不同乳脂率德宏奶水牛乳腺组织中FATP1基因的表达情况,试验选取216头处于泌乳盛期的健康德宏奶水牛,分为高乳脂率组(H组)、中乳脂率组(M组)和低乳脂率组(L组),采集乳样,用乳品分析仪测定乳脂率,利用气相色谱法测定脂肪酸含量。采集乳腺组织,利用荧光定量PCR法检测FATP1基因的mRNA表达水平,并与乳脂率和脂肪酸含量进行相关性分析。结果表明:H组乳脂率、总脂肪酸含量和长链脂肪酸含量均极显著高于M组和L组(P<0.01),M组显著高于L组(P<0.05)。不饱和脂肪酸含量H组极显著高于L组(P<0.01),显著高于M组(P<0.05),而M组与L组无显著差异(P>0.05)。FATP1基因mRNA表达水平为H组极显著高于L组(P<0.01),而H组与M组、M组与L组均无显著差异(P>0.05)。相关性分析表明,乳脂率与乳中总脂肪酸、长链脂肪酸和不饱和脂肪酸含量间呈极显著正相关(P<0.01),FATP1基因mRNA表达量与乳脂率、脂肪酸总量、长链脂肪酸含量、不饱和脂肪酸含量均呈极显著正相关(P<0.01)。研究表明在乳脂合成的过程当中FATP1基因对脂肪酸的摄取和转运起到重要的调控作用。     

动物DGAT基因的研究进展

DGAT基因包括二酰基甘油酰基转移酶1（DGAT1）基因和二酰基甘油酰基转移酶2（DGAT2）基因，前者属于酰基辅酶A胆固醇酰基转移酶（ACAT）基因家族，后者属于单酰甘油酰基转移酶（MGAT）基因家族，分别编码微粒体酶DGAT1和DGAT2，这两种酶控制着甘油三酯的合成，均是定位于内质网的跨膜蛋白，其膜拓扑结构具有与其他蛋白质和细胞器相互作用的能力，影响脂肪代谢及脂类在组织中的沉积，参与调节动物机体的能量合成和分解代谢，影响心脏和肝脏中甘油三酯的代谢；同时DGAT基因的多态性影响着牛乳中脂肪的含量及泌乳量。因此，了解DGAT基因的结构和生物学功能对畜禽生长发育和生产等相关研究具有重要的意义。文章简述了DGAT基因的基本结构和生物学功能及相关的作用机制，分析了其在畜牧生产中的基础应用，如参与哺乳动物生产调控的脂肪沉积、乳脂含量等方面的研究进展。     

猪脂肪性状相关基因的研究进展

随着人们对猪肉品质要求的提高,猪脂肪性状逐渐成为研究的热点。作者综述了影响猪脂肪性状的几个候选基因,即脂肪酸结合蛋白(FABP)基因、脂蛋白脂酶(LPL)基因、激素敏感脂酶(HSL)基因、二酰基甘油酰基转移酶1(DGAT1)基因、解偶联蛋白3(UCP3)基因、肥胖(Ob)基因等的研究进展,以期为改善猪脂肪性状提供参考。     

Dietary conjugated linoleic acids increase intramuscular fat deposition and decrease subcutaneous fat deposition in Yellow Breed × Simmental cattle

This study was conducted to estimate the effect of dietary conjugated linoleic acids (CLA) on intramuscular and subcutaneous fat deposition in Yellow Breed × Simmental cattle. The experiment was conducted for 60 days. The results showed that the average backfat thickness, (testicles + kidney + pelvic) fat percentage and subcutaneous fat percentage in dietary CLA were significantly lower than in the control group, while intramuscular the fat percentage was significantly higher. Compared to the control group, the Longissimus muscle enzyme activities of lipoprotein lipase (LPL), fatty acid synthase (FAS) and acetyl‐coenzyme A carboxylase (ACC) in dietary CLA and the subcutaneous fat enzyme activities of LPL, hormone‐sensitive lipase (HSL) and carnitine palmitoyltransferase‐1 (CPT‐1) were significantly increased. Similarly, compared to the control group, the Longissimus muscle sterol regulatory element binding protein 1 (SREBP‐1), FAS, stearoyl‐coenzyme A desaturase (SCD), ACC, peroxisome proliferator‐activated receptor γ (PPARγ), heart fatty‐acid binding protein (H‐FABP) and LPL gene expression in dietary CLA were significant increased, as were the subcutaneous fat of PPARγ, H‐FABP, LPL, CPT‐1 and HSL in dietary CLA. These results indicated that dietary CLA increases IMF deposition mainly by the up‐regulation of lipogenic gene expression, while decreasing subcutaneous fat deposition mainly by the up‐regulation of lipolytic gene expression.     

驴肌内脂肪沉积关键调控因子研究

旨在基于转录组(RNA-Seq)和代谢组(UPLC-MS/MS)关联分析,筛选驴肌内脂肪沉积的关键调控因子.本研究选用饲养条件相同、平均体重为236.10 kg的雌性广灵驴30头,对其背最长肌进行肌内脂肪(IMF)含量的测定,选择年龄一致的驴,并根据其IMF含量的高低分为两组:低肌内脂肪组(L组,每组3头)与高肌内脂肪...     

FADS2基因在奶牛乳腺细胞中的过表达和干扰研究

为了研究脂肪酸脱氢酶2(fatty acid desaturases 2,FADS2)基因在奶牛乳腺细胞脂肪酸代谢中的作用,本研究在奶牛乳腺上皮细胞中对FADS2基因进行过表达和干扰,研究FADS2基因表达对脂肪酸合成相关基因的调控及对奶牛乳腺上皮细胞中甘油三酯含量的影响。针对FADS2基因的CDS序列设计siRNA和过表达载体pcDNA3.1-FADS2-EGFP,转染奶牛乳腺细胞检测FADS2基因过表达和干扰对脂肪酸代谢相关基因表达的影响及细胞中甘油三酯含量的变化。结果显示,试验成功获得过表达载体pcDNA3.1-FADS2-EGFP和干扰片段,转染细胞后具有良好的过表达和干扰效果。FADS2基因过表达后,1-酰基甘油磷酸酰基转移酶(AGPAT1)、固醇调节元件结合蛋白裂解激活蛋白(SCAP)、3-磷酸甘油转移酶(GPAM)、脂肪酸延长链5(ELOVL5)、乙酰辅酶A酰基转移酶1(ACAA1)、脂肪酸脱氢酶1(FADS1)、二酰基甘油转酰基酶1(DGAT1)和过氧化物酶体增殖激活受体α(PPARα)基因显著下调(P<0.05),脂滴蛋白2(PLIN2)基因极显著上调(P<0.01)。FADS2基因干扰过后可引起AGPAT1、GPAM、ELOVL5、ACAA1、PLIN2和FADS1基因显著上调(P<0.05),脂肪酸合成胰岛素诱导基因1(INSIG1)极显著上调(P<0.01),DGAT1和PPARα基因显著下调(P<0.05)。甘油三酯检测结果显示,FADS2基因过表达和干扰均可降低奶牛乳腺上皮细胞中甘油三酯的含量。综上所述,在奶牛乳腺上皮细胞中,FADS2基因能调控脂质合成相关基因的表达,对乳腺脂质合成具有调控作用。     

Adiponectin‐impaired adipocyte differentiation negatively regulates fat deposition in chicken

Adiponectin is a protein hormone secreted exclusively by adipocytes that plays an important role in the modulation of glucose and lipid metabolism. To investigate the effect of adiponectin on lipid metabolism in chicken, rosiglitazone (agonist of adiponectin) and dexamethasone (inhibitor of adiponectin) were used to treat 23‐day‐old broilers in vivo. To verify the functionality of adiponectin on fat deposition, chicken pre‐adipocytes were cultured in the medium containing 10 μg/ml adiponectin. Serum adiponectin and lipids and fat distribution were analysed. Oil Red O staining was used to determine lipid deposition in adipocytes. The expression levels of adiponectin, adiponectin receptors (AdipoR) and lipid metabolism–related genes in different tissues and pre‐adipocytes were measured using real‐time PCR, and the abundance of lipid metabolism–related proteins was measured by Western blot. Rosiglitazone increased serum adiponectin concentration and the expression levels of adiponectin and adiponectin receptor 1 (AdipoR1) in tissues and significantly decreased levels of serum lipids and fat deposition. Rosiglitazone significantly increased the expression levels of adipose triglyceride lipase (ATGL) and AdipoR1 and decreased the expression levels of fatty acid synthase (FAS). Dexamethasone had the converse effects compared with rosiglitazone. Oil red O staining results showed a marked decrease in fat deposition in cells treated with adiponectin. In adipocytes, adiponectin could decrease the expression levels of CCAAT/enhancer‐binding protein α (C/EBPα) and FAS and increased the expression levels of ATGL and AdipoR1. These results indicate that adiponectin has a remarkable effect on impairment of adipocyte differentiation, which contributes to the negative regulation of fat deposition in chicken.     

Expression analyses of candidate genes related to meat quality traits in squabs from two breeds of meat‐type pigeon

In this study, meat quality traits were compared between squabs from two pigeon breeds: one Chinese indigenous breed, the Shiqi (SQ) meat‐type pigeon, and an imported breed, the white king (WK) meat‐type pigeon. Breed differences were detected in the content of intramuscular fat (IMF) in the breast muscle. SQ squabs had significantly higher IMF content than the WK birds. The shear force value (an objective measure of meat tenderness) of SQ birds was also relatively lower than that of the WK squabs. Further analysis of fatty acids profile revealed that SQ squabs exhibited significant advantage in the synthesis of polyunsaturated fatty acids, while WK squabs were significantly higher in the sum of monounsaturated fatty acids. Breast muscle in the SQ squabs was also significantly higher in the ratio of polyunsaturated fatty acids to saturated fatty acids, as well as the sum of omega 6 fatty acids. Variability of expression levels of functional genes in relation to fat accumulation and meat tenderness was analysed by qRT‐PCR. Gene expression analyses showed that the hepatic expression of LPL (lipoprotein lipase), FABP4 (fatty acid‐binding protein 4), and CAPN2 (calpain‐2) were significantly higher in the SQ squabs. In the breast muscle tissue, the FABP3 (fatty acid‐binding protein 3) and CAPN2mRNA abundance was significantly higher in SQ squabs. Our results suggested that these differentially expressed genes might be candidate genes used in the programmes of targeted selection for squabs with higher IMF content, tender meat, and more favourable fatty acids composition.     

Effects of different levels of protein supplementary diet on gene expressions related to intramuscular deposition in early‐weaned yaks

This study was conducted to estimate different levels of protein supplementary diet on gene expressions related to intramuscular deposition in early‐weaned yaks. Results showed that supplementary dietary protein significantly increased final weight, average daily gain (ADG), intramuscular fat (IMF), serum free fatty acid (FFA), total triglycerides, total cholesterol (Ch), low‐density lipoprotein cholesterol (LDL) and high‐density lipoprotein cholesterol (HDL) content. There was a quadratic response of ADG, IMF, FFA, Ch, HDL and LDL to dietary crude protein (CP) level. Lipoprotein lipase (LPL), fatty acid synthase (FAS) and acetyl‐CoA carboxylase (ACC) enzyme activities were significantly increased by supplementary dietary CP, while hormone‐sensitive lipase (HSL) and carnitine palmitoyltransferase‐1 (CPT‐1) activities were significantly decreased. LPL, ACC and FAS enzyme activities showed quadratic increase as dietary CP increased. Peroxisome proliferator‐activated receptor γ (PPARγ), LPL, FAS, sterol regulatory element binding protein 1 (SREBP‐1), ACC, stearoyl‐CoA desaturase (SCD) and heart fatty‐acid binding protein (H‐FABP) gene expression were significantly increased by supplementary dietary CP, while HSL and CPT‐1 gene expression were significantly decreased. PPARγ, LPL, SREBP‐1, ACC and H‐FABP gene expression showed quadratic increase as dietary CP increased. These results indicated that supplementary dietary protein increased IMF accumulation mainly to increased intramuscular lipogenic gene expression and decreased lipolytic gene expression.     

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....     

动物脂肪酸转运蛋白1的研究进展

脂肪含量对人类和动物健康以及动物肉品质均有重要影响.脂肪酸转运蛋白1(fatty acid transport protein 1,FATP1)是整合的跨膜蛋白,属于脂肪酸转运蛋白家族(FATPs)成员,参与脂肪酸跨膜转运及脂肪酸代谢,是影响脂肪含量的关键基因之一,近年来引起了越来越多的关注.本文就FATP1的结构特点...     

不同胡麻品种TAG合成途径关键基因表达与含油量、脂肪酸组分的相关性分析

胡麻是一种富含不饱和脂肪酸尤其是α-亚麻酸的油料作物,明晰TAG合成途径中与胡麻含油量和脂肪酸组分相关的基因具有重要的理论意义。以3个含油量和脂肪酸组分有显著差异的胡麻品种(系)为材料,分析了不同品种(系)、不同组织和不同发育阶段胡麻油脂和脂肪酸组分的动态积累模式和TAG合成途径中7个关键基因的动态表达模式,以及含油量和不饱和脂肪酸与7个关键基因表达的相关性。结果表明,胡麻开花后10～20d,是种子油脂和亚麻酸的快速积累期,且不同胡麻品种(系)油脂和亚麻酸的动态积累模式差异显著。TAG合成途径中的7个关键基因(GPAT9、DGAT1、DGAT2、PDAT1、PDAT2、FAD2A和FAD3A)在胡麻不同发育阶段的不同组织中均有表达,在不同品种(系)间的表达模式各不相同。其中PDAT1、DGAT1和DGAT2基因的动态表达模式与含油量的动态积累模式显著正相关,PDAT1的动态表达模式与亚麻酸的动态积累模式显著正相关,且在高油高亚麻酸材料的种子动态发育阶段中PDAT1基因的累积表达量也显著高于低油低亚麻酸材料。因此,PDAT1可能是影响胡麻不同品种(系)中含油量和亚麻酸含量的关键基因。