,2, 姚刚,1Comparison of the Carcass and Beef Quality Traits with the Expression of the Lipid Metabolism Related Genes Between Xinjiang Brown Cattle and Angus Beef Cattle
CHEN LiJing1, CHEN Zhuo1, LI Na1, SUN YaWei1, LI HongBo2, SONG WenWen1, ZHANG Yang,2, YAO Gang,1通讯作者:
责任编辑: 林鉴非
收稿日期:2019-12-11接受日期:2020-05-29网络出版日期:2020-11-16
| 基金资助: |
Received:2019-12-11Accepted:2020-05-29Online:2020-11-16
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陈俐静,E-mail：
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陈俐静, 陈卓, 李娜, 孙亚伟, 李红波, 宋雯雯, 张杨, 姚刚. 新疆褐牛与安格斯牛胴体及肉质性状及脂代谢相关基因表达差异比较[J]. 中国农业科学, 2020, 53(22): 4700-4709 doi:10.3864/j.issn.0578-1752.2020.22.016
CHEN LiJing, CHEN Zhuo, LI Na, SUN YaWei, LI HongBo, SONG WenWen, ZHANG Yang, YAO Gang.
开放科学（资源服务）标识码（OSID）：
0 引言
【研究意义】肉牛养殖业是新疆畜牧业主导产业,新疆褐牛及其杂交牛是新疆肉牛业主导品种之一。目前,新疆褐牛及其杂种后代总存栏数约为150万头,纯种新疆褐牛占总数的30%左右[1]。随着人们生活质量的提高,牛肉作为重要的肉食品,优质、高档牛肉供不应求[2,3]。牛肉的食用品质主要包括嫩度、多汁性和风味[4]。而影响畜肉品质的因素有很多,其中肌内脂肪（intramuscular fat,IMF）,又称为大理石花纹,其含量会影响牛肉的食用品质[5,6]。高水平的IMF含量很可能会增加油脂含量和肌红蛋白的氧化[7],进而影响肉色。适当地提高IMF含量,可以提高肌肉的嫩度、多汁性等食用品质[8]。因此,调控IMF的沉积成为提高肉品质的一个重要途径[9]。【前人研究进展】瘦素（leptin,LEP）基因多态性已经被作为肉牛的大理石纹、背膘厚度、嫩度、胴体重、牛肉质量评价等性状的候选基因[10]。SCHENKEL等[11]研究发现肉牛产肉率、背膘厚度和嫩度与LEP基因显著相关。说明LEP可作为评定肉品质及肉质脂肪沉积的指标。脂肪酸合成酶（fatty acid synthesase,FAS）在脂肪代谢中主要作用是合成长链脂肪酸,而激素敏感酯酶（hormone-sensitive lipase,HSL）则是脂肪分解的关键限速酶[12]。FAS、HSL和脂蛋白脂酶（lipoprotein lipase,LPL）基因mRNA表达与皮下脂肪、IMF沉积存在密切相关[13,14]。HILLER等[13]研究发现FAS、LPL和HSL基因mRNA表达与皮下脂肪、IMF沉积存在密切相关。JEONG等[14]研究了韩国肉牛16个脂肪代谢相关基因,证明FAS、LPL和HSL基因表达与IMF代谢均呈显著相关,其中LPL基因上调可增加脂肪细胞膜对脂肪酸的摄取,从而增加IMF沉积。脂肪酸结合蛋白4（fatty acid-binding protein 4,FABP4）是脂肪细胞型脂肪酸结合蛋白,能在脂肪细胞中沉积甘油三酯,增加IMF的含量。FABP4基因与肉牛IMF沉积、大理石纹形成密切相关[15,16,17]。【本研究切入点】由于新疆褐牛遗传背景复杂,其IMF沉积能力、大理石纹含量、嫩度等与脂肪代谢相关的肉品质形成机理等方面缺乏与国内外优良肉牛品种的比较研究。【拟解决的关键问题】本试验选取新疆褐牛与安格斯肉牛进行屠宰性状、肉品质及其脂代谢相关基因的比较研究,探明新疆褐牛与安格斯肉牛上述关键体脂代谢基因mRNA和蛋白表达的脂肪组织和品种差异性,为今后改善新疆褐牛的肉品质性状奠定科学基础。1 材料与方法
1.1 试验动物
本研究动物饲养试验在新疆某集约化肉牛养殖场进行。2016年12月选取生长发育正常、健康,品种特征明显的新疆褐牛（Xinjiang brown cattle,XBC）和纯种安格斯牛（Angus beef cattle,ABC）3月龄断奶公犊各7头,单独分栏组群,专人负责,按照该场统一饲养管理方式饲养,于2018年9月达到24月龄后进行屠宰。1.2 仪器设备与试剂
仪器设备：背膘测定仪（Mylab Touch vet）;显微镜（NIKON）;电热恒温鼓风干燥箱（DHG-9140A）;半自动切片机（LEICA CM3050 S）;Motic显微成像系统（Advance 3.5软件）;光学显微镜BA400（Motic实业集团有限公司）;离心机5415D（Eppendrof）;PCR仪PTC-225（Bio-Rad）;凝胶成像系统CBC/UVP I-D001（CapitalBio）;实时荧光定量PCR仪（Applied Biosystems）;超声波细胞破碎仪JY92-2D（宁波新芝生物科技股份有限公司）;立式压力蒸汽灭菌器LDZX-30KBS（上海申安医疗器械厂）;恒温培养振荡器TS-2102C（上海智城分析仪器制造有限公司）;酶标仪DG5031（上海齐欣有限公司）。试剂：苦味酸购自台山粤桥试剂有限公司;固体石蜡、苏木素、尹红、中性树胶均购自中国上海标本模型厂;mirVana miRNA Isolation Kit、r-Taq酶、cDNA第一链合成试剂盒、SYBR Green PCR Master Mix、Micro Amp Optical 96-well Reaction Plate、Micro Amp Optical Adhesive Covers 4311971均购自abm（Master Mix-EL）公司;RIPA裂解液、BCA蛋白定量试剂盒、蛋白变性缓冲液、SDS-PAGE凝胶试剂盒、化学发光显色液均购自Thermo Fisher公司;小鼠抗beta-actin单克隆抗体ab6276、小鼠抗LPL单克隆抗体ab21356、辣根过氧化物酶标记山羊抗小鼠ab97240均购自Abcam公司;大鼠抗FAS单克隆抗体05-351购自Merck Millipore公司;兔抗HSL单克隆抗体NBP1-76735购自Novus公司;辣根过氧化物酶标记山羊抗大鼠abs20031购自Absin公司;辣根过氧化物酶标记山羊抗兔111-305-003购自Jackson公司。
1.3 方法
1.3.1 采样 前述24月龄XBC和ABC各7头试验牛在屠宰前一天,采用背膘仪活体测定背膘厚度、眼肌面积和肌内脂肪参数,并进行活体称重,记录耳标号。试验牛经待宰圈12 h禁食后,进入屠宰车间自动化屠宰,测定胴体及产肉性状。并采集背最长肌和皮下脂肪等相关样品液氮保存后于实验室进行后续指标测定。1.3.2 胴体性状
胴体重：除去头、皮、尾、蹄、内脏所余体躯重量;
净肉重：胴体除去骨胳之后的净肉和脂肪的重量;
屠宰率=胴体重/活重×100%;
净肉率=净肉重/活重×100%;
肉骨比=胴体净肉重/骨骼重×100%。
用背膘仪测量肌间脂肪、背膘厚度、眼肌面积。
1.3.3 肉品质性状 利用色度仪对每块背最长肌测定肉色,分别记录肉样的亮度（L*）值、红度（a*）值和黄度（b*）值;IMF根据《食品中脂肪的测定》（GB 5009.6—2016）测定;水分根据《食品中水分的测定》（GB 2019.3—2016）测定;灰分根据《食品中灰分的测定》（GB 5009.4—2016）测定;剪切力根据《肉嫩度的测定 剪切力测定法》（NY/T 1180—2006）测定。
1.3.4 肌肉及皮下脂肪形态学测定 肌肉及皮下脂肪制备常规石蜡切片,H.E染色[18]。利用Motic Advanced 3.5显微成像系统观察并测量肌肉及皮下脂肪,借助FastStone Capture软件[19]计算细胞单位面积及数量。
1.3.5 脂代谢相关基因的mRNA表达
（1）组织样本总RNA提取
1）在液氮预冷砂浆中取30—50 mg最长的肌肉样品,充分研磨成液氮,加入1 mL Trizol,混匀后冰上静置5 min裂解并转入新EP管。
2）加入0.2 mL预冷过的氯仿,混匀15—30 s,冰上静置2—3 min。
3）4℃离心,12 000 g×15 min,分层。
4）吸清液400—500 μL并加入0.5 mL异丙醇,将管中液体轻轻混匀,-80℃静置30 min。
5）4℃离心,12 000 g×15 min。
6）弃上清,加入75%乙醇（冰冷）1 mL,振摇,4℃离心,12 000 g×5 min。
7）弃上清,短暂离心,弃剩余上清。
8）加入适量（20—30 μL）DEPC（Rnase Free）H2O溶解RNA,测浓度,储存-80℃。
（2）基因组消化和反转录 基因组消化的反应体系：1 μg总RNA,2 μL 5×gDNA buffer,42℃、3 min。
反转录用cDNA第一条链合成试剂盒反转录1 μg总RNA成cDNA,反应体系：2 μL 10×Fast-RT Buffer,2 μL FQ-RT Primer Mix,1μL RT Enzyme Mix,5 μL RNase-Free Water,加入消化产物总体积20 μL,反应条件：42℃、15 min,95℃、3 min,-80℃保存。
（3）荧光定量PCR引物 使用DNAMAN软件设计引物[20],由生工生物工程（上海）股份有限公司合成,信息见表1。
Table 1
表1
表1引物信息
Table 1
| 基因名称 Gene name | 序列5′-3′ Sequence | 产物大小 Product size(bp) |
|---|---|---|
| LEP | F: CTTCAGTGGATGGTCCCTCG | 148 |
| R: AATGGCAGGTTGGTGGGAAA | ||
| FAS | F: TGAGACAGACCCGAAGTCCT | 127 |
| R: CTCCTCGGGCTTGTCTTGTT | ||
| FABF4 | F: AGATGGTGCTGGAATGTGTCA | 103 |
| R: GGAGTTCGATGCAAACGTCA | ||
| HSL | F: AGAGTGCTTCTATGCCTACTGC | 117 |
| R: GACACGGTGAAGCAGAGGTTC | ||
| LPL | F: CCCGGCTTTGATATTGGGAAG | 142 |
| R: TCAGGGACTTGTCATGGCATT | ||
| Beta-actin | F: CATGTACGTTGCTATCCAGGC | 250 |
| R: CTCCTTAATGTCACGCACGAT |
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（4）检测LEP、FAS、FABP4、HSL、LPL基因转录水平测定 利用Power SYBR Green PCR Master Mix试剂盒和Quant Studio Flex Real Time PCR system仪器进行相对定量。反应体系如表2。
Table 2
表2
表2荧光定量PCR反应体系
Table 2
| 试剂 Reagent | 剂量 Dose |
|---|---|
| Power SYBR Green PCR Master Mix（2×） | 5 μL |
| cDNA | 0.5 μL |
| 正向引物Forward primer | 0.25 μL |
| 反向引物Reverse primer | 0.25 μL |
| 无酶水RNase free dH2O | 4 μL |
| 总容积Total volume | 10 μL |
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反应条件：95℃预变性10 min,95℃、15 s,95℃、1 min,40个循环。每个试验组设定3个重复,扩增结束用ABI 7500 Fast软件收集CT值并用2-△△CT分析目的基因表达水平,用内参基因Beta-actin矫正。
（5）实时荧光定量PCR产物电泳检测扩增特异性
取扩增产物4 μL与4 μL 2×Loading buffer混匀,电泳条件为120 V,15 min。
1.3.6 肌肉与皮下脂肪组织Western blot测定
（1）提取总蛋白方法参照RIPA裂解液说明书进行。
（2）用酶标板法测定蛋白浓度,操作参照BCA蛋白定量试剂说明书进行。
（3）制胶槽灌入分离胶,无水乙醇压平胶平面,待分离胶凝固后加入浓缩胶。凝固后每孔加40 mg蛋白,电压80 V,待蛋白跑过浓缩胶将电压调成120 V,直到溴酚蓝指示剂跑至分离胶底部。
（4）取电泳分离条带,参照蛋白Marker切下目的基因和内参条带。按照滤纸、凝胶、PVDF膜、滤纸的顺序,每层之间不能有气泡。确保正负极连接正确,电压120 V开始转膜。
（5）将PVDF膜放入5%脱脂奶粉室温封闭2 h。封闭后PVDF膜用TBST缓冲液浸洗3次,每次5 min,分别加入第一抗体（均按1﹕1 000稀释）置于脱色摇床4℃孵育过夜。次日取出PVDF膜用TBST缓冲液浸洗5次,每次5 min,加入辣根过氧化物酶标记的第二抗体（均按1﹕1 000稀释）,置于脱色摇床室温孵育2 h。
（6）按照ECL显色液说明书配制显色液,避光显色1 min,用化学发光凝胶系统曝光后,确定最佳曝光条件、采集图像。用Image J软件处理目的条带,计算灰度值,以Beta-actin为管家基因计算目的条带的相对表达量。
1.4 数据处理
数据用平均值±标准误（Mean±SE）表示。采用GraphPad Prism 5.0（GraphPad Software公司,美国圣地亚哥）统计软件对两品种间进行独立样本非配对T检验统计分析并作图。两组间不同小写字母表示P＜0.05,不同大写字母表示P＜0.01。2 结果
2.1 XBC和ABC胴体性状比较
由表3可见,XBC净肉率极显著高于ABC（P＜ 0.01）,而背膘厚度显著低于ABC（P＜0.05）。XBC与ABC体重、胴体重、净肉重、骨重、屠宰率、肉骨比、肌间脂肪等胴体性状品种间无显著差异（P＞0.05）。Table 3
Table 3Comparison of carcass traits between XBC and ABC
| 性状 Traits | 单位 Unit | XBC | ABC | P值 P value |
|---|---|---|---|---|
| 活体重Body weight | kg | 704.0±29.90 | 798.0±33.60 | 0.077 |
| 胴体重Carcass weight | kg | 423.0±15.60 | 459.0±28.60 | 0.306 |
| 净肉重Net meat weight | kg | 320.0±11.40 | 300.0±23.90 | 0.464 |
| 骨重Bone weight | kg | 69.7±3.96 | 75.6±2.73 | 0.251 |
| 屠宰率Slaughter rate | % | 60.3±2.28 | 59.4±0.41 | 0.735 |
| 净肉率Net meat rate | % | 45.6±1.50A | 39.9±0.60B | 0.010 |
| 肉骨比Meat bone ratio | % | 4.6±0.18 | 4.0±0.31 | 0.097 |
| 肌间脂肪Intermuscular fat | % | 6.98±1.36 | 8.8±0.84 | 0.278 |
| 背膘厚度Backfat thickness | cm | 1.0±0.10a | 1.7±0.22b | 0.021 |
| 眼肌面积Loin eye muscle area | cm2 | 92.7±3.09 | 98.1±3.35 | 0.261 |
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2.2 XBC和ABC肉品质性状比较
由表4可见,XBC肉色亮度L*显著低于ABC（P＜0.05）,XBC肉色泽偏暗,其余肉色a*、b*均差异不显著（P＞0.05）。XBC与ABC水分、灰分、IMF、嫩度均差异不显著（P＞0.05）。Table 4
表4
表4XBC和ABC部分肉品质性状比较
Table 4
| 性状 Traits | 单位 Unit | XBC | ABC | P 值 P value |
|---|---|---|---|---|
| 肉色L*值 Meat Color-L* | - | 28.69±2.06a | 31.43±2.15b | 0.032 |
| 肉色a*值 Meat Color-a* | - | 11.99±5.87 | 15.91±3.29 | 0.149 |
| 肉色b*值 Meat Color-b* | - | 3.64±1.86 | 4.60±1.37 | 0.296 |
| 灰分Ash | % | 1.56±0.78 | 1.05±0.27 | 0.131 |
| 水分Muscle moisture | % | 74.20±2.61 | 73.2±2.69 | 0.505 |
| 肌内脂肪Intramuscular fat | % | 1.80±0.37 | 1.81±0.17 | 0.993 |
| 嫩度Tenderness | N | 5.65±1.52 | 5.78±1.91 | 0.922 |
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2.3 XBC和ABC背最长肌及皮下脂肪组织形态比较
由表5、图1所示,XBC肌纤维直径和单根肌纤维横截面积均显著大于ABC（P＜0.05）,而肌纤维密度无明显差异（P＞0.05）。由表6、图2所示,XBC皮下脂肪单位面积脂肪细胞个数极显著多于ABC（P＜0.01）,而皮下脂肪细胞面积两品种牛之间差异不显著（P＞0.05）。图1
新窗口打开|下载原图ZIP|生成PPT图1XBC与ABC背最长肌断面,H.E染色（10×20）
Fig. 1Slice of longissimus dorsi in XBC and ABC, H.E stain (10×20)
图2
新窗口打开|下载原图ZIP|生成PPT图2XBC与ABC皮下脂肪切片,H.E染色（10×20）
Fig. 2Slice of the subcutaneous fats in XBC and ABC, H.E stain (10×20)
Table 5
表5
表5XBC和ABC背最长肌肌纤维组织学测量
Table 5
| 单位 Unit | XBC | ABC | P值 P value | |
|---|---|---|---|---|
| 肌纤维直径 Muscle fiber diameter | μm | 41.52±0.42a | 32.86±0.24b | 0.024 |
| 肌纤维密度 Muscle fiber density | Number/mm2 | 236.95±45.34 | 291.21±24.66 | 0.260 |
| 单根肌纤维横截面积 Single muscle fiber cross-sectional area | μm2 | 1495.02±31.92a | 921.81±14.14b | 0.033 |
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Table 6
表6
表6XBC和ABC皮下脂肪组织细胞面积和数量比较
Table 6
| 单位 Unit | XBC | ABC | P值 P value | |
|---|---|---|---|---|
| 细胞面积 Adipocyte area | μm2 | 2012.15±532.54 | 2154.29±389.64 | 0.1520 |
| 细胞个数 Adipocyte number | Number/mm2 | 365.42±100.23A | 306.48±60.91B | 0.0011 |
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2.4 XBC和ABC背最长肌和皮下脂肪组织中脂代谢相关基因的mRNA表达
由图3可知,XBC与ABC背最长肌和皮下脂肪5个基因mRNA表达量差异不显著（P＞0.05）。图3
新窗口打开|下载原图ZIP|生成PPT图3两品种牛背最长肌与皮下脂肪中LEP、HSL、LPL、FAS、FABP4基因mRNA相对表达量
Fig. 3The mRNA expression levels of LEP, HSL, LPL, FAS and FABP4 gene in longissimus dorsi and subcutaneous fat between XBC and ABC
2.5 XBC和ABC FAS、HSL、LPL蛋白在背最长肌和皮下脂肪组织中的表达差异
如图4所示,利用Western blot检测XBC与ABC背最长肌和皮下脂肪组织中LEP、FABP4、HSL、LPL、FAS蛋白表达水平,只检测到FAS、HSL、LPL蛋白表达,与预期条带一致。由图5可知,XBC背最长肌组织中FAS的蛋白表达量极显著低于ABC（P＜0.01）,HSL蛋白表达量也显著低于ABC（P＜0.05）;而皮下脂肪组织中只有HSL蛋白表达量显著低于ABC（P＜0.05）。图4
新窗口打开|下载原图ZIP|生成PPT图4Western blot检测FAS、HSL、LPL蛋白的表达水平
Fig. 4The expression level of FAS, HSL and LPL proteins detected by Western blot
3 讨论
3.1 XBC和ABC胴体性状比较
胴体性状是评价肉牛产肉性能的重要指标。张明[21]比较了安西杂牛（黑安格斯牛×西门塔尔牛）与西门塔尔牛净肉率和背膘厚度,结果显示安西杂牛的净肉率和背膘厚度显著高于西门塔尔牛,并且表明安西杂牛产肉性能较好。本研究发现XBC净肉率极显著高于ABC,而背膘厚度显著低于ABC。说明不同品种牛之间胴体性状确实存在差异,XBC产肉性能较好。图5
新窗口打开|下载原图ZIP|生成PPT图5XBC和ABC背最长肌与皮下脂肪中FAS、HSL、LPL蛋白相对表达量比较
两品种间进行T-检验,*表示P＜0.05,差异显著,**表示P＜0.01,差异极显著
Fig. 5The differential expression level of FAS, HSL and LPL proteins in longissimus dorsi and subcutaneous fat between XBC and ABC
The student T-test was conducted between XBC and ABC, * means P＜0.05, indicating significant difference, while ** means P＜0.01, indicating extremely significant difference between XBC and ABC
王国富等[22]比较了36月龄ABC、海福特牛和中国西门塔尔牛3个品种牛的胴体性状,结果显示ABC和海福特牛背膘厚度极显著高于中国西门塔尔牛,并说明ABC和海福特牛脂肪沉积能力可能比中国西门塔尔品种牛强。本研究发现XBC背膘厚度显著低于ABC,说明ABC的脂肪沉积能力可能较强。
3.2 XBC和ABC肉品质性状
肉品质是涉及肉品的表观、质地、风味的综合性状,主要衡量指标包括肉色、风味物质、大理石花纹、嫩度、硬度、多汁性以及pH、系水力、肌肉纤维结构等[23,24,25]。胡猛等[26]比较了荷斯坦公牛与西门塔尔牛、XBC及新疆土种牛的肉色,结果显示荷斯坦奶公牛的肉色L*显著高于西门塔尔牛、XBC和新疆土种牛。闫向民等[27]比较了不同月龄XBC的肉色,发现高月龄组肉色L*显著小于低月龄组,且高月龄组肉色优于低月龄组。本研究发现XBC肉色指标L*显著低于ABC,说明XBC肉色优于ABC。肌纤维特性影响肉的嫩度,肌纤维直径越小,纤维密度越大,则肉的嫩度越好。曹芝等[28]研究了草原红牛及夏洛莱牛、西门塔尔牛、红安格斯牛的高代杂种牛背最长肌纤维组织学结构的差异及与嫩度的关系,结果显示红安格斯杂交牛的肌纤维直径最小,肌节长度最长,说明其嫩度最好。本研究结果显示XBC肌纤维直径和单根肌纤维横截面积均显著大于ABC,提示与XBC相比,ABC嫩度较好。
脂肪组织的形成和在不同部位的沉积直接影响肉品质和产肉性能,细胞大小与大理石花纹密切相关[29]。ALBRECHT等[30]研究表明11月龄以后牛的脂肪细胞数量相对稳定,脂肪细胞的沉积主要是由于脂肪细胞体积的增大。本结果显示XBC与ABC皮下脂肪组织细胞面积无显著差异,可XBC皮下脂肪组织中单位面积脂肪细胞个数极显著多于ABC,提示XBC脂肪组织细腻程度高于ABC,这可能与XBC背膘厚度显著低于ABC有关。
3.3 XBC和ABC 5种脂肪代谢调控相关基因及其产物的表达
大量研究表明,LEP可以促进甘油三酯转化,抑制脂肪酸从头合成、刺激脂肪酸氧化来抑制脂质在脂肪细胞中积累,因此LEP与肌内脂肪的沉积有关。BONNET等[10]比较了ABC、利木赞牛、日本和牛与安格斯杂交牛3个品种肌内脂肪LEP基因mRNA表达水平,结果表明3个品种皮下脂肪组织中LEP基因mRNA表达差异不显著。而FABP4也是影响牛肉和肌内脂肪含量的候选基因之一[31]。魏胜娟等[32]研究FABP4对牛脂肪细胞分化影响时发现FABP4正向调控脂质代谢。ALBRECHT等[30]连续检测了10—22月龄日本和牛与荷斯坦牛皮下脂肪组织中FABP4 mRNA表达水平,结果表明这一阶段这两个品种牛皮下脂肪组织中FABP4表达没有变化。FAS作为甘油三酯合成过程的关键酶,FAS基因表达水平的高低对肌内脂肪的沉积会产生一定的影响。曲桂娟等[33]比较了3种杂交牛背最长肌FAS mRNA表达量,发现在3个品种间FAS mRNA表达差异不显著。本试验测定结果显示XBC与ABC皮下脂肪与背最长肌中LEP mRNA、FABP4 mRNA和FAS mRNA表达均无品种间显著差异,这可能与本试验测定的XBC和ABC肌内脂肪含量无显著差异有关。但戢爽[34]在比较延边黄牛和延黄牛FAS mRNA表达中发现延黄牛显著高于延边黄牛的结果与前述研究者和笔者的结果不一致,可能是因为品种差异所致。脂肪沉积是一个合成与分解动态平衡过程,HSL基因和LPL基因在脂肪分解过程起关键作用。REN等[35]报道在荷斯坦与夏洛来牛网膜脂肪和皮下脂肪组织中LPL mRNA表达差异不显著,但未研究肌肉中的LPL mRNA表达。本结果表明XBC与ABC皮下脂肪中LPL mRNA表达差异不显著,与上述结果相似。
3.4 XBC和ABC 5种脂肪代谢调控相关蛋白表达
赵称赫[36]研究表明蒙古牛肌内FAS的活性相对较强。其实验结果表明蒙古牛背最长肌FAS表达量显著高于西门塔尔,FAS表达量与肌内脂肪含量存在正相关。本结果与上述研究结果一致。本试验发现XBC背最长肌组织中FAS蛋白表达量极显著低于ABC,可能与XBC背膘厚度显著低于ABC有关,其相关性有待进一步研究。HSL是动物脂肪代谢过程中的关键酶。有研究表明HSL与肌内脂肪含量存在正相关,并且会促进肌内脂肪的沉积[37]。本结果表明XBC皮下脂肪组织中HSL蛋白表达量显著低于ABC,背最长肌组织中HSL蛋白表达量显著低于安格斯牛,说明ABC脂肪沉积能力高于XBC。
LPL在脂蛋白的运输过程和能量代谢方面发挥着重要作用。BONNET等[10]报道利木赞牛皮下脂肪中LPL表达水平显著高于安格斯,指出LPL表达可能存在种间差异性。王刚等[38]也验证猪肌肉组织中LPL表达与肌内脂肪含量显著正相关,且品种不同其LPL与肌内脂肪含量相关程度不同。本结果表明XBC与ABC LPL在皮下脂肪和背最长肌表达差异不显著。
FAS和HSL分别为胴体脂肪合成代谢与分解代谢过程中的限速酶。在本试验中ABC在皮下脂肪和背最长肌中FAS、HSL蛋白表达均显著高于XBC。说明ABC脂肪沉积能力强。
4 结论
本研究比较发现新疆褐牛产肉性能较好;但纯种安格斯牛肉色较亮,且嫩度较好。纯种安格斯牛脂肪沉积能力强。两品种间脂代谢相关基因产物、脂肪酸合成酶和激素敏感酯酶蛋白差异可能与纯种安格斯牛背膘厚度差异有关。参考文献 原文顺序
文献年度倒序
文中引用次数倒序
被引期刊影响因子
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DOI:10.5713/ajas.18.0199URLPMID:29879824 [本文引用: 1]
Meat quality is a very difficult term to define because it means different things to different people. When purchasing beef, consumers in the United States are likely to consider color, price, marbling level, subcutaneous fat trim, or cut thickness when determining the quality of beef. Once consumers have consumed the product, meat quality becomes exponentially more difficult to define due to the subjective nature of this term. Traditionally, tenderness, juiciness, and flavor have been considered the three most important factors that determine the palatability of beef. Therefore, American meat science beef research and industry focus has turned to measuring and quantifying these 3 attributes objectively and subjectively, and to determining what influences them. In reviewing the scientific literature, attempting to meaningfully summarize the findings of the thousands of studies on beef meat quality is impossible due to the inherent differences in the objective and methodology of studies. Fortunately, the United States beef industry and their national trade association, the National Cattlemen's Beef Association (NCBA), have conducted numerous surveys and audits to characterize the quality of the products being produced and marketed by their cattlemen and the palatability perceptions of their consumers. The data produced by these studies is quite large and impossible to summarize in entirety in this review. Therefore, this review concentrates on the most important attributes that determine the value of a beef carcass and objectively measured and consumer-assessed palatability characteristics of fresh meat from these carcasses from 1987 through 2010.
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DOI:10.7150/ijbs.8.214URLPMID:22253565 [本文引用: 1]
During the finishing phase of bovines, large amounts of subcutaneous and visceral fats are deposited leading to production inefficiencies with major impact on meat quality. A better understanding of the cellularity features of the main fat depots could provide strategies for adipose tissue manipulation. This study assessed the effect of feeding diets with distinct forage to concentrate ratios on the cellularity of two fat depots of beef cattle and their implications on the fatty acid profile. Thus, two phylogenetically distant Portuguese bovine breeds, Alentejana and Barrosa, were selected. The results did not show differences in subcutaneous fat deposition nor in visceral fat depots partitioning. Plasma adipokines concentration failed to show a consistent relationship with fatness, as leptin remained constant in all experimental groups, whereas interleukin-6 was influenced by breed. Fat depot seems to determine the area and number of adipocytes, with larger adipocytes and a lower number of cells in subcutaneous fat than in mesenteric fat. Neither breed nor diet influenced adipocytes area and number. The contents of total fatty acids, partial sums of fatty acids and conjugated linoleic acid isomeric profile were affected by breed and fat depot. The incorporation of saturated fatty acids (SFA), trans fatty acids, polyunsaturated fatty acids (PUFA) and branched chain fatty acids (BCFA) was higher in mesenteric fat depot, whereas subcutaneous fat depot had greater percentages of monounsaturated fatty acids (MUFA). In addition, SFA and MUFA proportions seem to be breed-related. In spite of the less relevant role of diet, the percentages of PUFA and BCFA were influenced by this factor. Under these experimental conditions, the effect of fat depot on cellularity and fatty acid composition prevails over breed or diet, as reinforced by the principal component analysis.
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Abstract
Lipid oxidation and myoglobin oxidation in meat lead to off-flavor development and discoloration, respectively. These processes often appear to be linked and the oxidation of one of these leads to the formation of chemical species that can exacerbate oxidation of the other. Several investigators have reported preservation of fresh meat color following the inclusion of antioxidant ingredients. An understanding of the complementary oxidation interaction provides a basis for explaining quality deterioration in meat and also for developing strategies to maintain optimal sensory qualities..
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Abstract
The objective of this study was to determine the association of single nucleotide polymorphisms (SNP) in selected candidate genes with sensory and technological meat quality traits in commercial cattle. SNP in seven candidate genes were genotyped in 130 crossbred Bos taurus cattle using PCR-RFLP. Reported associations between calpastatin (CAST) and Warner–Bratzler shear force and carboxypeptidase E (CPE) and intra-muscular fat were not confirmed. However, SNP in CAST, amp-activated protein kinase, gamma-3 subunit (PRKAG3), growth hormone receptor (GHR) and stearoyl coA desaturase (SCD) genes were significantly associated with colour traits (p < 0.05). The PRKAG3 SNP was additionally associated with cook loss in M. longissimus thoracis et lumborum (p < 0.05) and tended towards association in M. semimembranosus (p < 0.1). An association with pH was identified for the SCD SNP (p < 0.001). The GHR polymorphism was influential on moisture and intra-muscular fat in M. semimembranosus and protein content in both muscles (p < 0.05). Only CPE was associated with sensory traits (flavour in M. longissimus, p < 0.01).[本文引用: 1]
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DOI:10.2527/2005.8392009xURLPMID:16100055 [本文引用: 1]
Studies with different populations are required to properly characterize the robustness of associations of polymorphisms in candidate genes with economically important traits across beef cattle populations before this sort of genetic information can be used efficiently in breeding and management decisions. The objective of this study was to evaluate the association of previously reported SNP in the bovine leptin gene with carcass and meat quality traits from a large sample of crossbred beef cattle. Five SNP (UASMS1, UASMS2, UASMS3, E2JW, and E2FB) were genotyped on 1,111 crossbred bulls, heifers, and steers. The measured traits included fat, lean, and bone yield (%) by partial rib dissection, grade fat, LM area, HCW, quality grade, LM i.m. fat, and tenderness evaluation of LM and semitendinosus muscle. Only four SNP were analyzed (UASMS1, UASMS2, E2JW, and E2FB), because UASMS1 and UASMS3 were completely linked. A uni-variate mixed-inheritance animal model was used to evaluate the association of either genotypes or haplo-types with the traits. The two leptin exon 2 SNP were associated with fat and lean yield and grade fat (E2JW, P < 0.01; E2FB, P < 0.05), and they interacted in their effect on LM tenderness (P < 0.01). The leptin promoter SNP were either not associated with any of the traits (UASMS2) or with fat yield only (UASMS1). Three haplotypes (TCAC, CCAT, TTAC) were at high frequency in the population (88%) and had similar effects on all the traits. Compared with the common haplotypes, one haplotype (CCTT) showed a significantly different effect on fat and lean yield and grade fat (P < 0.01), and one haplotype (TTTT) had a different effect on LM tenderness (P < 0.03). Therefore, important associations between SNP within the leptin gene with lean yield, fatness (fat yield and subcutaneous fat), and tenderness were detected. Results confirm some of the previously reported associations, but diverge with respect to others, showing that further efforts are required to validate some prospective associations.
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DOI:10.1007/s10695-017-0442-4URLPMID:29147968 [本文引用: 1]
To investigate the effects of fasting on lipid metabolism in spotted seabass muscle and liver tissues, we analyzed mRNA levels and enzyme activities of lipoprotein lipase (LPL), hormone-sensitive lipase (HSL) and fatty acid synthetase (FAS), and the relationship among fat content, mRNA level, and enzyme activity during fasting of 35 days. The results showed that expressions of all the three genes were ubiquitous. During the fasting experiment, the hepatosomatic index (HSI) and fat content of muscle and liver tissues significantly decreased before 5 days of fasting (P < 0.05). mRNA levels of LPL increased significantly after 5 days of fasting in liver and 7 days in muscle. Abundance of HSL transcripts increased significantly after 14 days of fasting in both muscle and liver. The activities of LPL and HSL presented a trend that increased firstly, decreased subsequently, and then raised again with the prolonged fasting experiment (P < 0.05). However, activities and mRNA levels of FAS decreased significantly after 1 day of fasting in both muscle and liver. Moreover, activities and mRNA levels of FAS showed a moderate correlation in muscle. These results suggested that FAS had a sooner response to fasting than LPL and HSL in both muscle and liver tissues. LPL and HSL played important roles in lipolysis mainly by increasing enzyme activities in the early stage of fasting and mRNA levels in the later stage of fasting in both muscle and liver. Our results also provided useful information on regulating muscle fat content by fasting.
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DOI:10.1007/s11745-011-3571-zURL [本文引用: 2]
Changes in fatty acid composition of longissimus muscle and subcutaneous adipose tissue of German Holstein bulls induced by a grass-silage/n-3 fatty acid based intervention diet versus a maize-silage/n-6 fatty acid based control diet were analyzed and related to shifts in lipogenic gene expression, protein expression, and enzyme activity patterns. Significantly higher amounts of n-3 fatty acids and by mean factors of 2.2-2.5 decreased n-6/n-3 fatty acid ratios in both tissues were obtained upon n-3 fatty acid intervention. In longissimus muscle, these changes of fatty acid profiles were associated with reduced SREBP1c (p = 0.02), ACC (p = 0.00), FAS (p = 0.10) and SCD (p = 0.03) gene expression, Delta 6D (p = 0.03) and SCD (p = 0.03) protein expression as well as SCD enzyme activity (p = 0.03). In subcutaneous adipose tissue, significantly reduced ACC (p = 0.00) and FAS (p = 0.01) gene expression, SCD protein expression (p = 0.02) and SCD enzyme activity (p = 0.03) were detected upon n-3 fatty acid intervention, although lower degrees of correlation between gene and corresponding gene products were obtained in relation to longissimus muscle. The study elucidates tissue-specific functional genomic responses to dietary fatty acid manipulation in regard to fatty acid profile tailoring of animal tissues.
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DOI:10.2527/jas.2011-4753URL [本文引用: 2]
Intramuscular fat (IMF) in cattle is an important component of traits that influence meat quality. We measured carcass characteristics and gene expression in Korean steers to clarify the molecular mechanism(s) underlying IMF deposition in LM tissue by determining the correlation between IMF content and gene expression abundance and by developing models to predict IMF content using gene expression abundance. The deposition of IMF is determined by a balance between fat deposition and fat removal in the LM. We measured mRNA abundance of lipid metabolic genes including lipogenesis [acetyl CoA carboxylase (ACC), fatty acid synthase (FASN)], fatty lipid uptake [lipoprotein lipase (LPL), fatty acid translocase (CD36), fatty acid transport protein 1 (FATP1)], fatty acid esterification [glycerol-3-phosphate acyltransferase 1 (GPAT1), acylglycerol phosphate acyltransferase 1 (AGPAT1), diacylglycerol acyltransferase 1 (DGAT1), DGAT2], lipolysis [adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), monoglyceride lipase (MGL)], and fatty acid oxidation [carnitine palmitoyl transferase 1B, very long-chain acyl-CoA dehydrogenase (VLCAD), medium-chain acyl-CoA dehydrogenase (MCAD)] in the LM. The mRNA abundance of the GPAT1 gene showed the greatest correlation (r = 0.74; P < 0.001) with IMF content among 9 fat deposition genes. The gene expression abundance of other fat deposition genes including ACC, FASN, LPL, CD36, FATP1, AGPAT1, DGAT1, and DGAT2 also exhibited significant positive correlations (P < 0.05) with IMF content in the LM. Conversely, ATGL mRNA abundance showed the greatest negative correlation (r = -0.68; P < 0.001) with IMF content in the LM among 6 fat removal genes. The expression of other fat removal genes including MGL, VLCAD, and MCAD showed significant negative correlations (P < 0.05) with IMF content. Our findings show that the combined effects of increases in lipogenesis, fatty acid uptake, fatty acid esterification, and of decreases in lipolysis and fatty acid oxidation contribute to increasing IMF deposition in Korean steers. The multiple regression analysis revealed that the mRNA abundance of the GPAT1 gene in the LM was the first major variable predicting IMF content (54%) among 15 lipid metabolic genes. The second was mRNA abundance of ATGL (11%). In conclusion, these results suggest that GPAT1 and ATGL genes could be used as genetic markers to predict IMF deposition in the LM.
DOI:10.1016/j.meatsci.2010.02.025URL [本文引用: 1]
Abstract
Previous studies have indicated that single nucleotide polymorphisms (SNPs) in the diacylglycerol-O-acyltransferase1 (DGAT1), thyroglobulin (TG) and adipose fatty acid binding protein (FABP4) genes are associated with intramuscular fat (IMF) levels or marbling scores in beef. The objectives were to estimate the frequency of SNPs in these candidate genes in purebred Irish cattle (n = 459) and to determine if individual SNPs are associated with IMF values of longissimus thoracis et lumborum (LTL) and semimembranosus (SM) muscle of crossbred animals (n = 138). Results indicated no significant association between the SNPs and IMF, despite the power of this study being sufficient to detect an association with SNPs in the DGAT1 and FABP4 genes. The results confirm the lack of an association found by many other studies and suggest that these SNPs are not influential on the divergent IMF levels in the crossbred population tested..
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DOI:10.5483/bmbrep.2008.41.1.029URLPMID:18304447 [本文引用: 1]
The aim of this study was to determine whether single nucleotide polymorphisms (SNP) in the beef cattle adipocyte fatty-acid binding protein 3 and 4 (FABP3 and FABP4) genes are associated with carcass weight (CW) and back fat thickness (BF) of beef cattle. By direct DNA sequencing in 24 unrelated Korean native cattle, we identified 20 SNPs in FABP3 and FABP4. Among them, 10 polymorphic sites were selected for genotyping in our beef cattle. We performed SNP, haplotype and linkage disequilibrium studies on 419 Korean native cattle with the 10 SNPs in the FABP genes. Statistical analysis revealed that 220AG (I74V) and 348+303TC polymorphisms in FABP4 showed putative associations with BF traits (P=0.02 and 0.01, respectively). Our findings suggest that the polymorphisms in FABP4 may play a role in determining one of the important genetic factors that influence BF in beef cattle.
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DOI:10.1016/j.meatsci.2018.01.023URLPMID:29413674 [本文引用: 1]
The effect of cattle feed on beef quality and oxidative stability was investigated. A corn silage (CS)-based finishing diet was compared with the diets based on corn stalk silage (SS) or corn stalk silage combined with its expected corn grain (SSC), containing a ratio of stalk to grain of corn plant of 1.5:1. Replacing CS with SS in the finishing diet had no effect on the proximate nutrients, cholesterol content, fatty acids profile, pH, color, water holding capacity, tenderness, texture profile, or oxidative stability of beef muscle. Compared to the CS diet and SS diet, cattle fed SSC diet showed an inferior antioxidant capacity, lower SOD and higher MDA concentrations in blood. SSC diet fed cattle also showed higher MDA and protein carbonyl concentrations in beef muscle indicating increased oxidation damage, and potentially resulting in a greater drip loss of the beef muscle. Corn silage can be replaced in the finishing feed of beef cattle with corn stalk silage without any negative effects on measures of beef quality.
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Beef biceps femoris muscles were used to comparatively analyze differences in physcio-chemical properties and gel properties of DFD beef and normal colored beef. The results showed that DFD beef and normal colored beef significantly differed in their moisture content (P ＜0.05), but their differences in crude protein, crude fat and crude ash contents had no statistical significance (P＞0.05). There was no significant difference in their tenderness (P＞ 0.05). Furthermore, DFD beef exhibited significantly higher gel strength and water hold capacity (WHC) as compared to normal colored beef.
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Beef biceps femoris muscles were used to comparatively analyze differences in physcio-chemical properties and gel properties of DFD beef and normal colored beef. The results showed that DFD beef and normal colored beef significantly differed in their moisture content (P ＜0.05), but their differences in crude protein, crude fat and crude ash contents had no statistical significance (P＞0.05). There was no significant difference in their tenderness (P＞ 0.05). Furthermore, DFD beef exhibited significantly higher gel strength and water hold capacity (WHC) as compared to normal colored beef.
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通过对育成荷斯坦奶公牛与西门塔尔牛、新疆褐牛及新疆土种牛肉品质部分指标的比较分析研究,旨在探讨荷斯坦奶公牛的肉品质。选择在相同营养模式下18月龄左右4个品种牛各3头进行屠宰,取右半边胴体的背最长肌作为肉品质试验样品,分别对牛肉的肉品质、常规营养成分及氨基酸含量进行测定和分析。结果表明,荷斯坦奶公牛肉色、失水率、系水力、熟肉率、大理石花纹等指标均优于新疆褐牛、新疆土种牛,次于西门塔尔牛;荷斯坦奶公牛嫩度优于新疆土种牛;粗蛋白质、粗灰分含量分别为20.14%、1.11%,且各品种间差异均不显著(P>0.05),干物质含量为26.30%,显著高于新疆褐牛和新疆土种牛(P<0.05),低于西门塔尔牛(P>0.05),粗脂肪含量为10.04%,显著高于其他品种牛(P<0.05);荷斯坦奶公牛含有人体需要的各种氨基酸,其中蛋氨酸、谷氨酸、甘氨酸、组氨酸、牛磺酸等含量丰富,氨基酸组成比例良好。
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URL [本文引用: 1]
通过对育成荷斯坦奶公牛与西门塔尔牛、新疆褐牛及新疆土种牛肉品质部分指标的比较分析研究,旨在探讨荷斯坦奶公牛的肉品质。选择在相同营养模式下18月龄左右4个品种牛各3头进行屠宰,取右半边胴体的背最长肌作为肉品质试验样品,分别对牛肉的肉品质、常规营养成分及氨基酸含量进行测定和分析。结果表明,荷斯坦奶公牛肉色、失水率、系水力、熟肉率、大理石花纹等指标均优于新疆褐牛、新疆土种牛,次于西门塔尔牛;荷斯坦奶公牛嫩度优于新疆土种牛;粗蛋白质、粗灰分含量分别为20.14%、1.11%,且各品种间差异均不显著(P>0.05),干物质含量为26.30%,显著高于新疆褐牛和新疆土种牛(P<0.05),低于西门塔尔牛(P>0.05),粗脂肪含量为10.04%,显著高于其他品种牛(P<0.05);荷斯坦奶公牛含有人体需要的各种氨基酸,其中蛋氨酸、谷氨酸、甘氨酸、组氨酸、牛磺酸等含量丰富,氨基酸组成比例良好。
DOI:10.16431/j.cnki.1671-7236.2015.11.020URL [本文引用: 1]
选择相同营养模式下低月龄组(28~30月龄)12头、高月龄组(32~34月龄)8头新疆褐牛阉牛进行屠宰,分别对胴体性状、营养成分、部分食用品质指标进行测定和比较分析,旨在探索新疆褐牛阉牛生产高档牛肉的适宜月龄。结果表明,高月龄组大理石花纹、胴体等级、脂肪、肉色均优于低月龄组,低月龄组脂肪色泽、水分、蛋白质、蒸煮损失、剪切力值优于高月龄组,且脂肪、肉色L*值差异显著(P<0.05),其余组间差异均不显著(P>0.05);上脑、里脊、外脊作为高档牛肉,除肉色、pH外,脂肪、蛋白质、水分、蒸煮损失、剪切力值指标均优于其他部位,表现出了极好的营养价值和食用品质。28~34月龄阶段的新疆褐牛阉牛可以生产高档牛肉,其肉品都可作为牛排和涮牛肉的原材料。
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DOI:10.16431/j.cnki.1671-7236.2015.11.020URL [本文引用: 1]
选择相同营养模式下低月龄组(28~30月龄)12头、高月龄组(32~34月龄)8头新疆褐牛阉牛进行屠宰,分别对胴体性状、营养成分、部分食用品质指标进行测定和比较分析,旨在探索新疆褐牛阉牛生产高档牛肉的适宜月龄。结果表明,高月龄组大理石花纹、胴体等级、脂肪、肉色均优于低月龄组,低月龄组脂肪色泽、水分、蛋白质、蒸煮损失、剪切力值优于高月龄组,且脂肪、肉色L*值差异显著(P<0.05),其余组间差异均不显著(P>0.05);上脑、里脊、外脊作为高档牛肉,除肉色、pH外,脂肪、蛋白质、水分、蒸煮损失、剪切力值指标均优于其他部位,表现出了极好的营养价值和食用品质。28~34月龄阶段的新疆褐牛阉牛可以生产高档牛肉,其肉品都可作为牛排和涮牛肉的原材料。
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DOI:10.1016/S0739-7240(02)00179-0URL [本文引用: 1]
Abstract
Body weight and fat mass vary distinctly between German Holstein (dairy cattle) and Charolais (beef cattle). The aim of this study was to determine whether the expression of the obese (Ob) gene and lipoprotein lipase (LPL) gene in fat tissues and expression of the long isoform leptin receptor (Ob-Rb) gene in the hypothalamus were different between these two cattle breeds. Body weight and the area of longissimus muscle cross-section of German Holstein were lower (P<0.001), while body fat content, as well as the omental and perirenal fat mass were higher (P<0.001), compared to Charolais. Plasma insulin and leptin levels between two cattle breeds were determined by radioimmunoassay. Compared to Charolais, plasma insulin concentrations were significantly higher (P<0.01), and plasma leptin levels were tended to be higher (P<0.1) in German Holstein. Ob mRNA levels in subcutaneous and perirenal fat depots, but not in the omental fat depot, were significantly higher (P<0.05) in German Holstein than in Charolais. LPL mRNA expression in the perirenal fat depot of German Holstein was greater in abundance than that of Charolais. No significantly different LPL mRNA levels were found in subcutaneous and omental fat depots, and Ob-Rb mRNA levels in the hypothalamus between these two cattle breeds (P<0.05). Both Ob and LPL expression was greater in perirenal and omental fat depots than in the subcutaneous fat depot (P<0.05). Data indicated that in bovine the Ob and LPL gene expression levels in perirenal fats are an important index that is associated with body fat content, while Ob-Rb in hypothalamus is not.[D].
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DOI:10.11843/j.issn.0366-6964.2016.12.007URL [本文引用: 1]
旨在探究FAM134B、PPARγ、FAS和HSL基因在绵羊肌肉发育过程中的组织表达规律及其与肌内脂肪（Intramuscular fat, IMF）含量的关系，以期为研究绵羊IMF沉积的分子调控机制奠定理论基础。试验选取2、4、5、6和12月龄敖汉细毛羊公羊各5只，屠宰，采集背最长肌和股二头肌测定其IMF含量，应用实时荧光定量 PCR技术检测PPARγ、FAM134B、FAS和HSL基因在肌肉不同发育时期的mRNA表达量，并对基因表达量之间及表达量与IMF含量的关系进行分析。结果表明：（1）2~5月龄时，背最长肌和股二头肌的IMF含量均随着月龄的增加而增加；而5~12月龄时则基本保持不变；同月龄背最长肌IMF含量极显著高于股二头肌（P<0.01）。（2）背最长肌中FAM134B表达量呈上升-下降趋势，6月龄最高（P<0.01）；股二头肌中FAM134B表达量呈先上升后稳定趋势。FAS基因在两部位肌肉中表达量均呈上升趋势。PPARγ基因在两部位肌肉中表达量均呈下降-上升趋势。HSL基因在两部位肌肉中表达量均呈下降-上升-下降趋势。同月龄目的基因表达量在两部位肌肉中均表现出明显的差异。（3）关联分析显示，两部位肌肉中FAM134B与FAS表达量均呈显著正相关 （P<0.05），与PPARγ、HSL表达量呈不同程度负相关。背最长肌中，FAM134B、FAS表达量与IMF含量呈极显著或显著正相关（P<0.01，P<0.05），PPARγ表达量与IMF含量显著负相关（P<0.05）；股二头肌中，FAM134B表达量与IMF含量显著正相关（P<0.05）。综上，FAM134B、FAS可能会促进IMF的沉积，而PPARγ、HSL对IMF的沉积可能具有抑制作用；FAM134B可能通过刺激脂肪合成基因的表达，而抑制脂肪分解基因的表达来调控IMF的含量。结果可为进一步解析相关基因的功能和调控IMF沉积的分子机制提供参考。
DOI:10.11843/j.issn.0366-6964.2016.12.007URL [本文引用: 1]
旨在探究FAM134B、PPARγ、FAS和HSL基因在绵羊肌肉发育过程中的组织表达规律及其与肌内脂肪（Intramuscular fat, IMF）含量的关系，以期为研究绵羊IMF沉积的分子调控机制奠定理论基础。试验选取2、4、5、6和12月龄敖汉细毛羊公羊各5只，屠宰，采集背最长肌和股二头肌测定其IMF含量，应用实时荧光定量 PCR技术检测PPARγ、FAM134B、FAS和HSL基因在肌肉不同发育时期的mRNA表达量，并对基因表达量之间及表达量与IMF含量的关系进行分析。结果表明：（1）2~5月龄时，背最长肌和股二头肌的IMF含量均随着月龄的增加而增加；而5~12月龄时则基本保持不变；同月龄背最长肌IMF含量极显著高于股二头肌（P<0.01）。（2）背最长肌中FAM134B表达量呈上升-下降趋势，6月龄最高（P<0.01）；股二头肌中FAM134B表达量呈先上升后稳定趋势。FAS基因在两部位肌肉中表达量均呈上升趋势。PPARγ基因在两部位肌肉中表达量均呈下降-上升趋势。HSL基因在两部位肌肉中表达量均呈下降-上升-下降趋势。同月龄目的基因表达量在两部位肌肉中均表现出明显的差异。（3）关联分析显示，两部位肌肉中FAM134B与FAS表达量均呈显著正相关 （P<0.05），与PPARγ、HSL表达量呈不同程度负相关。背最长肌中，FAM134B、FAS表达量与IMF含量呈极显著或显著正相关（P<0.01，P<0.05），PPARγ表达量与IMF含量显著负相关（P<0.05）；股二头肌中，FAM134B表达量与IMF含量显著正相关（P<0.05）。综上，FAM134B、FAS可能会促进IMF的沉积，而PPARγ、HSL对IMF的沉积可能具有抑制作用；FAM134B可能通过刺激脂肪合成基因的表达，而抑制脂肪分解基因的表达来调控IMF的含量。结果可为进一步解析相关基因的功能和调控IMF沉积的分子机制提供参考。
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