影响猪肌内脂肪含量的几个基因研究现状

猪肉肌内脂肪是决定肉质的一个重要指标，主要由遗传因素控制，利用DNA标记进行标记辅助选择(MAS)来改良猪肌内脂肪含量应是行之有效的方法。基于此，本文简要介绍了影响猪肌内脂肪含量的主基因、候选基因及PPARγ基因的当前研究状况，及其与猪肌内脂肪含量的关系，旨在为猪肌内脂肪的改良提供参考。     

肌肉脂肪含量相关的的候选基因遗传变异的研究

随着人们生活水平的提高,人们不再单纯要求瘦肉含量而越来越看重肉的品质.肌内脂肪(Intramuscular fat,IMF)的含量影响着肉质的嫩度、风味和多汁性.Patrici等(1985)等对丹麦商品猪的肉质研究发现,肉的风味多汁性随肌内脂肪含量的增加而持续改善,提高肌内脂肪的含量会增加肉质的嫩度和多汁性.     

动物肌内脂肪沉积相关候选基因的研究进展

肌内脂肪(IMF)含量是评价肉品质的重要因素,对风味、嫩度、纹理等肉类感官品质起着重要作用,而IMF的沉积主要受脂肪摄取、合成、分解3条代谢途径的调控。本文综述了影响IMF沉积的相关候选基因,初步揭示了影响脂肪代谢的机理,旨在为今后调控IMF沉积的相关研究提供理论依据。     

FABP家族与肌内脂肪相关的基因遗传变异的研究

随着人们生活水平的提高,人们不再单纯要求瘦肉含量而越来越看重肉的品质.肌内脂肪(Intramuscular fat,IMF)的含量影响着肉质的嫩度、风味和多汁性.Patrici等[1,2]对丹麦商品猪的肉质研究发现,肉的风味多汁性随肌内脂肪含量的增加而持续改善,提高肌内脂肪的含量会有肉质嫩度和多汁性的改进,所以提高猪肉肌内脂肪的含量具有广泛的研究前景.但是由于IMF含量在活体中的测定有一定的难度,所以利用DNA标记辅助选择(MAS)即利用生物技术手段去寻找控制IMF的基因并对其进行选育来提高IMF含量,改善肉质.     

鸡肉质风味性状相关候选基因的研究进展

家禽的肉质性状已经成为育种工作者一个重要的研究方向,而影响家禽肉质的因素有很多,如:遗传、营养、环境、疾病等。研究结果表明,肌内脂肪与肉的嫩度及肉质相关;另外,肌苷酸(IM P)是鸡肉质鲜味特性的主要物质基础,影响IM P生成的各种基因都是潜在的候选基因。作者综述了与肌内脂肪及肌苷酸合成代谢相关的脂蛋白脂酶(LPL)、细胞外脂肪酸结合蛋白(EX-FABP)、瘦蛋白受体(OBR)、解偶联蛋白(UCP)、腺苷琥珀酸裂解酶(ADSL)、腺苷一磷酸脱氨酶1(AM PD 1)等基因的研究进展。     

鸡H-FABP基因多态性及其与肌内脂肪含量的相关研究

根据GenBank发表的鸡H-FABP基因序列设计引物,以广东省农科院畜牧研究所提供的4个地方优质肉鸡品种,2个培育品种和1个引进的肉鸡品种为试验材料,通过测序和PCR-SSCP的方法进行SNP检测和基因型分析,探讨H-FABP基因多态性与肌内脂肪含量(IMF)之间的关系。结果发现在H-FABP基因260 bp和675 bp处存在T/C和G/A的突变位点,对2个突变位点在研究群体中进行基因型分析,结果产生3种基因型。基因型与IMF的相关分析结果表明:在T260C位点上,所有品种中AA基因型的IMF含量显著(P<0.05)高于BB基因型个体,但对于不同的品种来说,AA和BB基因型只对封开杏花鸡和岭南黄鸡II号的IMF含量有显著影响(P<0.05),而对其他各鸡种均无显著影响(P>0.05);在G675A位点上,所有品种中AA型和AB型肌内脂肪含量差异显著(P<0.05)。     

鸡肌内脂肪性状研究的方法和策略

近年来，随着人们消费水平的提高，在追求肉品高瘦肉率的同时，对其香味、感观满意程度以及保健功能也提出了更高的要求。肌内脂肪不仅是畜禽机体能量贮备物质，而且与肌肉的风味品质和食用价值有很大的关系，是影响肉质的重要因素。因此进行肌内脂肪性状的研究，是改善快大鸡种肉质和保持地方鸡种特殊肉质风味的重要举措。     

猪H-FABP基因多态性及其与肌内脂肪含量的相关研究

旨在研究猪H-FABP基因的遗传多态性及其与肌内脂肪含量的遗传效应。利用PCR-RFLP(HinfⅠ、MspⅠ、HaeⅢ、Hinf*Ⅰ4种限制性内切酶)分子标记技术检测了中国地方猪种雅南猪、大河猪,培育品种大河乌猪以及杜洛克与长白和约克三元杂交商业群体共148头猪心脏型脂肪酸结合蛋白(H-FABP)基因5′-上游区和第二内含子的遗传变异,并利用固定效应模型分析了H-FABP基因在杜洛克与长白和约克三元杂交商业群体中对肌内脂肪含量的遗传效应。结果表明:(1)在HinfⅠ和MspⅠ位点上,所有4个猪群都存在多态;在HaeⅢ位点上,除雅南猪只出现单态外,其余3个猪群都出现多态;在Hinf*Ⅰ位点上,除杜洛克与长白和约克三元杂交商业群体出现多态外,其余3个猪群只表现单态。(2)4个位点对肌内脂肪含量的影响差异显著,各基因型肌内脂肪含量最小二乘均值关系即HhHH,bbBbBB,AaAA,DDDddd。结合H-FABP基因的生理功能和已有的研究结果来看,可在特定的群体中将其作为影响猪肌内脂肪含量的候选基因。     

影响猪肌内脂肪含量的QTL研究进展

肌内脂肪含量是评定猪肉品质的重要指标之一。分子生物学技术的飞速发展及其应用，为人们在DNA水平上研究猪重要经济性状的遗传机制奠定了坚实的基础。本文从可能的主效基因、可以考虑的候选基因以及其他影响猪肌内脂肪含量的QTL等方面概述了猪肌内脂肪含量的QTL研究进展，并对在育种实践中利用DNA标记辅助选择来改良猪肌内脂肪含量的应用前景、研究方向和存在的问题进行初步的探讨。     

影响猪肌内脂肪含量的几个基因研究现状

猪肉肌内脂肪是决定肉质的一个重要指标,主要由遗传因素控制,利用DNA标记进行标记辅助选择(MAS)来改良猪肌内脂肪含量应是行之有效的方法。基于此,本文简要介绍了影响猪肌内脂肪含量的主基因、候选基因及PPARv基因的当前研究状况,及其与猪肌内脂肪含量的关系,旨在为猪肌内脂肪的改良提供参考。     

肉牛肌内脂肪沉积相关基因的研究

相关基因对肌内脂肪含量的影响,已引起国内外研究人员的广泛关注,尤其是高档肉牛的育种方面。本文就影响肌内脂肪沉积的几个相关基因的发现、表达部位以及对肉牛肌内脂肪沉积的影响进行了综述和展望。     

Candidate gene expression and intramuscular fat content in pigs

Seventy-two pigs of three genetic groups (Brazilian indigenous breed Piau, Commercial line and Crossbred) of both sexes were slaughtered at four live weights (30, 60, 90 and 120 kg). Intramuscular fat (IMF) content in Longissimus dorsi muscle of each animal was extracted and correlated with candidate gene mRNA expression (ATN1, EEF1A2, FABP3, LDLR, MGP, OBSCN, PDHB, TRDN and RYR1). Within slaughter weight of 120 kg, Piau and Crossbred pigs showed higher IMF content (p < 0.05) than commercial animals, with 2.48, 2.08 and 1.00% respectively. Barrows presented higher values of IMF (p < 0.05) than gilts (1.54 and 1.30% respectively). Gene expression of EEF1A2, FABP3, LDLR, OBSCN, PDHB, TRDN and RYR1 were correlated with IMF (p < 0.05) using the whole dataset. For Piau data only, expression of FABP3, LDLR, MGP, OBSCN, PDHB, TRDN and RYR1 showed correlation with IMF (p < 0.05). Genes that have important roles in lipid transportation inside the cell (FABP3) and tissues (LDLR) showed correlation with IMF of, respectively, 0.68 and 0.63 using the whole data set, and 0.90 and 0.91 using data from Piau animals. The highly positive correlation of the LDLR and FAPB3 expression with IMF content may confirm that these genes are important for fat deposition in the porcine L. dorsi muscle.     

Ultrasound prediction of intramuscular fat content in lean cattle

Accuracy and precision of intramuscular fat prediction by ultrasound (USIMF) in lean cattle were studied by developing a prediction model based on 172 pure and crossbred beef and dual purpose bulls and steers from commercial herds. The animals were scanned across the 13th thoracic vertebrae using a Pie 200 SLC scanner. Five images were collected per individual. A 2.5 cm cross sectional muscle sample at the 13th thoracic vertebrae was collected from each carcass for chemical analysis of intramuscular fat % (CHIMF; Mean 2.0%, SD 1.5%) at the scanning site. The prediction model was developed using stepwise regression procedures. The validation model R², RMSE, overall mean bias, SEP and r_P correlation between CHIMF and USIMF based on the final prediction model was 0.80, 0.66%, − 0.15%, 0.65% and 0.90, respectively. The rank correlations varied over the CHIMF parameter space (from 0.26 to 0.87). The causes of this and the implications that follow are discussed. The overall results imply that ultrasound can predict IMF in lean cattle with acceptably high accuracy and precision. Ultrasound may thus be a valuable selection tool for meat quality in such cattle populations. The importance of developing optimised prediction models, based on data representative for the actual population, is highly emphasised.     

Association of H-FABP gene polymorphisms with intramuscular fat content in Threeyellow chickens and Hetian-black chickens

Background: To explore the relationship between the heart-type fatty acid binding protein(H-FABP) gene and intramuscular fat(IMF), a polymorphism of the second exon of the H-FABP gene was investigated in 60 Three-yellow chickens(TYCs) and 60 Hetian-black chickens(HTBCs).Results: The IMF contents of the cardiac, chest and leg muscles in HTBC were increased compared with TYC. Both TYC and HTBC populations exhibited Hardy-Weinberg Equilibrium(HWE) according to the χ2test. Three variations of the two birds were detected, namely, G939 A, G982 A and C1014 T. HTBCs with the TT genotypes exhibit increased IMF content in the chest muscles compared with the TC genotype. Thus, the G982 A site could be considered a genetic marker for selecting increased IMF content in the chest muscles of HTBC. The correlation coefficients revealed that H-FABP m RNA expression was negatively correlated with the IMF content in the cardiac, chest and leg muscles of HTBC and in the cardiac and chest muscles of TYC. The relative m RNA expression of H-FABP was reduced in the cardiac and leg muscles of HTBC compared with TYC, but this difference was not observed at the protein level, as assessed by Western blot analysis.Conclusions: These findings offer essential data that can be useful in the breeding program of HTBC and future research exploring the role of H-FABP in IMF deposition and regulation in chickens.     

Selection against abdominal fat percentage may increase intramuscular fat content in broilers

Excessive abdominal fat content (AFC) has negative impacts on feed efficiency and carcass quality. Unlike AFC, intramuscular fat content (IMFC) could be a favourable trait, which has a positive impact on meat quality. To meet consumers' needs, a long‐term goal of broiler breeders is to decrease AFC and improve the IMFC simultaneously. The current study was designed to investigate the relationship between AFC and IMFC and to compare IMFC, including the pectoral major muscle fat content (PIMFC) and intramuscular fat content of leg muscle (LIMFC), between two broiler lines divergently selected for abdominal fat percentage over 17 generations. The results showed that there was a significant difference in PIMFC and LIMFC between the two lines in all five generation populations used. The birds in the lean line had significantly lower AFC but higher PIMFC and LIMFC than the birds in the fat line. We also detected differences in the liver fat content (LFC) between the two lines and the results showed that birds in the fat line had significant higher LFC than birds in the lean line. Our results indicated that a desirable broiler line with higher IMFC but lower AFC could be obtained by genetic selection.     

Comparative analysis of differentially expressed genes related to triglyceride metabolism between intramuscular fat and abdominal fat in broilers

ABSTRACT

1. Lipid metabolism is an indispensable process in an organism, though little is known about the regulatory mechanisms of fat deposition in different types of adipose tissues.

2. The differentially expressed genes related to triglyceride (TG) metabolism between abdominal and intramuscular fat (IMF) of Beijing-You chickens were investigated in this study.

3. TG content in abdominal fat (AF) (349.7 mg/g) was significantly higher (P < 0.01) than in the breast and thigh (12.3 mg/g and 24.8 mg/g, respectively).

4. Using Agilent chicken gene-expression profiling in adipose tissues between AF and muscle (breast and thigh), certain representative genes related to fatty acid metabolism, lipoprotein catabolism and esterification reactions were significantly upregulated (P < 0.05 or P < 0.01).

5. Genes involved in fatty acid oxidation or carbohydrate utilisation were significantly up- or downregulated (P < 0.05 or P < 0.01), including those involved with highly enriched pathways of lipid metabolism (PPAR, Wnt pathway and inositol phosphate metabolism), cell junctions (focal adhesion and regulation of actin cytoskeleton) and muscle contraction.

6. Overall, higher TG levels were observed in AF tissue than in adipose tissues of breast and thigh, which could be regulated through gene expression of pathways related to lipid metabolism (PPAR, Wnt pathway and inositol phosphate metabolism), cell junctions (focal adhesion and regulation of actin cytoskeleton) and muscle contraction. These results provide clues to understanding the molecular mechanisms of TG metabolism between abdominal and IMF.     

Growth,carcase and meat traits and gene expression in chickens divergently selected for intramuscular fat content

1. Changes resulting from divergent selection after 5 generations for intramuscular fat (IMF) content in breast muscle in a population of purebred Beijing-You chickens were investigated. Female chickens from lines selected-up (UL) and selected-down (DL) for 5 generations and random-bred controls (CL) were studied at 120 d of age.

2. In the UL, IMF in breast muscle (4.65%) was 1.38 times that in the DL (3.36%). The IMF content in leg muscle was also higher in UL compared to DL.

3. There were significant differences in growth, carcase traits and meat quality between the two selected lines. However, ultimate pH (pHu) was lower and lightness (L*) and yellowness (b*) were higher in breast muscles of UL birds compared to DL birds. Similar trends for pHu and L* value between UL and DL were observed in leg muscle.

4. Significant mRNA expression differences of the heart fatty acid-binding protein (H-FABP) gene between UL and DL were observed in breast muscle, and a negative correlation between expression of mRNA and IMF% in breast and leg muscles pointed to H-FABP as a potential selection candidate gene.     

猪心脏脂肪酸结合蛋白及其基因与肌内脂肪含量关系的研究进展

我国是世界养猪和猪肉消费大国，随着人们生活水平的不断提高，消费者对猪肉品质的要求也越来越高，沉积在肌肉内的脂肪，即肌内脂肪(Intramuscularfat，简称IMF)含量与肉的嫩度和风味有直接关系(Wood，1988)。2%一3%的IMF含量可产生理想的口感(Bejerholm等，1986)。但是目前对高瘦肉率的选择已使IMF含量降到1%一1.5%，低于最佳范围。如何在保证瘦肉率的前提下，提高IMF含量，是育种者的新目标。Hovenier等(1992)研究表明，IMF具有较高的遗传力(0.6)，而与背膘厚的遗传相关是中等偏低(0.3)。Barton一Gade发现，IMF的遗传力为0.5-0…