【作者】 秦召；

【导师】 康相涛；

【作者基本信息】 河南农业大学 ， 动物营养与饲料科学， 2007， 硕士

【摘要】 肌肉的组织学特性是影响肌肉品质的组织学基础,是评定肉质的一项重要指标。大量研究发现畜禽的肌肉品质与其肌肉组织学特性有显著的相关性,特别是肌纤维密度、肌纤维直径对肌肉品质的影响非常显著,而肌纤维特性大多是数量性状,一般受微效多基因控制。在肌纤维的形成过程中,肌细胞的增殖、分化由一些正向调控因子和负向调控因子进行双向调节,肌细胞生成素基因属于正向调控因子,被认为是影响肌纤维特性的候选基因。本研究以地方品种固始鸡和快大型肉鸡安卡鸡按F-2设计的资源群体为实验素材,对鸡的肌肉组织学特性,及其与鸡胴体肉质性状之间的关系进行研究;同时克隆了鸡肌细胞生成素基因的第二内含子片段,并采用PCR-SSCP技术检测了肌细胞生成素基因部分编码区的突变。主要研究结果如下:1、对资源群体F₂代胸肌、腿肌肌纤维特性表型值进行了测定及统计分析,结果表明:F₂代群体中各性状的分离范围均较大,大部分指标的变异系数都超过10%。并且腿肌的变异系数大于胸肌,也就是说F2代各性状的表型值产生了较好的分离效果。各性状的偏度系数、峰度系数的绝对值有的大于1,有的小于1,近似服从正态分布但存在偏态,表明这些性状可能是主效基因存在的多基因控制的数量性状。2、通过对肌纤维特性间的相关分析发现,不同部位肌纤维横截面积、长径、短径、周长与肌纤维密度均呈极显著负相关,其中,胸肌的这些指标间的相关系数分别为-0.797、-0.756、-0.780、-0.704:腿肌的这些指标间的相关系数分别为-0.740、-0.739、-0.762、-0.712。据对肌纤维横截面积、密度与胴体肉质性状间的相关分析发现,胸肌肌纤维横截面积与所有屠体性状（除屠宰率外）呈极显著性正相关（P＜0.01）,与屠宰率相关不显著（P＞0.05）,与失水率呈显著负相关（0.01＜P＜0.05）,与剪切力值呈显著正相关（0.01＜P＜0.05）;腿肌肌纤维横截面积与屠体性状呈显著或极显著正相关,与失水率呈极显著负相关（P＜0.01）,与剪切力值呈显著正相关（0.01＜P＜0.05）。胸肌密度与屠体性状（除屠宰率外）呈极显著负相关（P＜0.01）。与屠宰率相关不显著（P＞0.05）,与失水率相关不显著（P＞0.05）,与剪切力值呈显著负相关（0.01＜P＜0.05）;腿肌密度与屠体性状呈负相关,与失水率相关不显著（P＞0.05）,与剪切力值呈显著负相关（0.01＜P＜0.05）。3、部位、交配类型（正、反交）、性别对肌纤维特性的表型值均有一定的影响。由因子互作来看,肌纤维鲜样直径受部位和性别的影响显著（P＜0.05）,肌纤维面积比受交配类型和性别的影响极显著（P＜0.01）;三因子互作对各性状没有影响。4、本研究采用在基因内含子两端的保守区即外显子上设计特异性引物进行PCR扩增,成功地获取鸡肌细胞生成素基因的第二内含子序列,已提交GENEBANK（序列号为EF031036）。其长为452bp,剪切方式符合常见的GT-AG的法则。5、采用PCR-SSCP方法检测了鸡肌细胞生成素基因部分编码区的突变,在第一外显子上发现了G102A的同义突变,并对突变产生的基因型与肌纤维特性进行关联分析,发现基因型对横截面积、长径、短径、周长的影响达到显著水平（P＜0.05）,而且BB基因型的各项指标显著大于AA基因型;对密度的影响达到极显著水平（P＜0.01）,AA基因型的肌纤维密度极显著高于BB基因型;对长短径比和鲜样直径的影响存在部位上的差别,胸肌的这两项指标在不同基因型间的差异未达到显著水平,腿肌的长短径比在三种基因型间的差异达到显著水平（P＜0.05）,腿肌的鲜样直径的差异则达到极显著水平（P＜0.01）;基因型对肌纤维面积比的影响不显著。以上结果说明肌细胞生成素基因对肌纤维的生长发育有重要的作用。6、不同基因型间半净膛重、全净膛重、全净膛率、12周龄体重、胸肌重、胸肌率、腿肌重、腿肌率的差异或达到显著水平或达到极显著水平;其他屠体指标和失水率、剪切力值两项肉质性状的差异均未达到显著水平。以上结果说明肌细胞生成素基因的变异在影响肌纤维特性的同时造成了肌肉屠宰指标的差异,但对肉质的影响不大。更多还原

【Abstract】 The histology characteristics of muscle affect meat quality remarkably, which is an important index for evaluating meat quality, most studies indicated that the histology characteristics of muscle has definitely pertinence with the meat quality,especially diameter of muscle fiber and density of muscle fiber. The myofiber characters are quantity traits,which are controlled by some genes. In development of myofiber, the proliferation and differentiation of muscle cell is controlled by some native and negative regulations. Myogenin is a native regulation, it should be the candidate gene for myofiber characters.In this study, samples were selected from F-2 chickens derived from GUSHI chick to ANKA chick,the histology characteristics of muscle was measured with paraffin section;the second intron of myogenin was cloned,and the mutation in part coding region of myogenin was detected with PCR-SSCP. The results were as follows:1,The analysis of phenotypic values indicated that the measured traits on myofiber performance were segregating well in F₂ individuals. Most coefficients of variability were above 10%,and C.V. of thigh were more than C.V. of breast. About absolute value of Skewness coefficient and Kurtosis coefficient,some were more than 1, another were less than l,so the traits were demonstrated as fit as to normal distribution, but some were of skewed distribution. Thus they were quantitative characters controlled by many genes with small and large efects.2,Correlation Analysis among the characters of Muscle fiber indicated that There was an extremely significant negative correlation between the cross section area of muscle fiber、the length diameter、diameter of major axis and minor axis、circumference、and density of muscle fiber,Correlative coefficient is -0.797、-0.756、-0.780、-0.704 individually for breast muscle;Correlation coefficient is -0.740、-0.739、-0.762、-0.712 individually for thigh muscle. There was an extremely significant native correlation between muscle fiber cross section area and carcass characters （except Slaughter ratio） , a significant negative correlation between muscle fiber cross section area and shear force, a significant native correlation between muscle fiber cross section area and shear force in breast muscle. There was an extremely significant native or significant native correlation between muscle fiber cross section area and carcass characters,an extremely significant negative correlation between muscle fiber cross section area and the percents of water-lossing,a significant native correlation between muscle fiber cross section area and shear force in thigh muscle. There was an extremely significant native or a significant native correlation between density of muscle fiber and carcass characters in breast or thigh muscle individually;There were no significant native correlation between density of muscle fiber and shear force in both parts,There was a significant negative correlation between density of muscle fiber and shear force in both parts.3, Part、mating model and sex had effect on performances of the myofiber characters,about interactions among factors,diameter of fresh muscle fibre was influenced by part and sex significantly,area ratio of myofiber was influenced by mating model and sex extremely significantly;interactions among three factors had an effect on each character.4,The 2nd intron of chicken myogenin was cloned and found that it’s splicing sites follow the consensus（5’AG/N, 3’N/GT）,The sequence which has 452bp? was submitted to GENEBANK（EF031036）.5,The mutation was found in the first exon, and have a significant association with myofiber characters. the association analysis on PCR-SSCP genetypes related with G102A polymorphism and myofiber characters shows,there was a significant association between genetype and cross section area、diameter or circumference,and BB genetype was significant more than that of AA genetype;density of muscle fiber of AA genetype was extremely significant more than that of BB genetype;the ratio of thigh muscle between major axis and minor axis has a significant difference among three genetypes. diameter of fresh muscle fibre of thigh muscle between major axis and minor axis has an extremely significant difference among three genetypes. All above demonstrated that myogenin had an important role on myofiber development.6,The association analysis on genetype and carcass characters or meat characters shows,there was a significant association or an extremely significant association between genetype and semi-eviscerated weight、eviscerated weight、eviscerated percentage、live weight aged 12 weeks、breast meat weight、breast meat percentage、thigh meat weight or thigh meat percentage. there was no significant association or an extremely significant association between genetype and other carcass characters、the percents of water-lossing or shear force.all above demonstrated that myogenin had effect on part carcass characters,but has no effect on meat characters.更多还原