【作者】 李良华；

【导师】 蒋思文；

【作者基本信息】 华中农业大学 ， 动物遗传育种与繁殖， 2003， 硕士

【摘要】 选择3个亲本品种(梅山猪、长白猪和大白猪)和4个杂交猪种(长大、大长、梅大和大梅)共350头猪作为试验材料，在相同饲养管理条件下饲养，体重达90kg左右时屠宰，取背最长肌(M.Longissimus dorsi，LD)和股二头肌(M.Biceps femoris，BF)样品。分析不同品种和杂交组合间肌纤维形态、结缔组织数量与分布、还原糖含量和矿质元素含量的差异，以及与肉质性状的相关关系。研究结果如下： 1．肌纤维形态与肉质的关系 (1)脂肪型梅山猪肌纤维面积、直径极显著低于瘦肉型长白猪和大白猪(p＜0.01)；密度则极显著较高(p＜0.01)；且异形指数较小，表明其肌纤维形态一致性较高。杂交组合大梅杂交猪和梅大杂交猪肌纤维面积分别呈超显性遗传和中间型遗传，大梅杂交组合面积杂种优辨率较高，为24.71％；长大猪和大长猪均呈超显性遗传。 (2)肌纤维性状可归纳为两个主成分，第一类形态定量指标包括面积、直径、长径、短径和密度，密度作用是负向的；第二类形状定性指标包括圆形度、异形指数和长短径比，圆形度起负向决定作用。两个主成分贡献率累计为89.03％。 (3)肌纤维面积、直径、长径和短径增大，有增加肌肉水分含量、提高失水率，降低系水力(water holding capacity，WHC)、肌内脂肪(intramuscular fat，IMF)、肉色和pH值，有降低肉质的趋势；密度增加则有改善肉质的趋势；圆形度高可以提高肉色，异形指数和长短径比作用与圆形度相反。 2．结缔组织数量和分布与肉质的关系 采用Van Gieson特殊染色法，结缔组织在切片中被真实反映出来，依据其数量和分布特征，将其数量分为1～5分，分布分为致密型与疏松型、连续型与间断型两对相对性状，组成8种表型。 (1)瘦肉型猪种个体间结缔组织数量高度不均，梅山猪比较均一，因而数量平均分值较高。BF结缔组织数量极显著高于LD(p＜0.01)。结缔组织与pH1值呈显著正相关(r=0.2902，p＜0.05)。 (2)瘦肉型猪致密型与不连续型结缔组织比例较高，梅山猪则多为疏松型与连续型。结缔组织间断型对应的WHC、肉色和IMF含量相对较连续型低；而疏松型3个亲本品种和4个杂交猪种肌肉的组织生化研究中脂肪细胞较多见，有利于提高IMF，也有提高WHC的趋势。建议选择疏松、连续型结缔组织类型个体，有利于提高、改善肉质。 3.总还原糖含量 猪肉经一20℃冷冻，总还原糖含量显著降低，而14士2℃常温保存能够有效维持其含量，总还原糖含量大幅度降低可能是冷冻降低肉风味的主要原因之一。 4.肌肉中K、Mg、Na、ea、eu和zn元素含量与肉质的关系 (l)梅山猪LD中K、Mg含量相对较低。 (2)K、Mg、Na、Ca、Cu和Zn各元素除Cu略具促进肉色的趋势外，几乎都不同程度降低肉色、pH值、wllC和IMf，其浓度的提高有降低肉质的趋势。更多还原

【Abstract】 Three kinds of parent pig (Meishan, Landrace and Larger White) and four crossbred pigs (Landrace×Larger White (L×W) , Larger White×Landrace (W ×L), Me ishan×Larger White (M×W), larger White×Meishan (W×M) ), which in total number was 350, were raised under similar conditions. They were slaughtered when they reached 90 kg. The M. Longissimus dorsi(LD) and M. Biceps feraoris(BF) were sampled and the morphology of muscle fiber, the number and distribution of connective tissue, the content of total reducing sugar and mineral element and the correlation between these parameters and meat quality were examined in different species.1. Correlation between the muscle fiber character and meat quality(1) The area and diameter of muscle fiber of Meishan with supreme fat were significantly lower than those of the Landrace and Large White with supreme Lean(p<0. 01). The heteromorphism index of Meishan was also lower than that of Landrace and Larger White, which signified the high homogeneity of muscle fiber. The muscle fiber diameter of (crossbreeding combination) W XM pigs and M×W pigs are overdominance genetic and mediate genetic, respectively. The heterosis percentage of WXM pigs was high, which was 24.71%. The muscle fiber diameter of Landrane and Larger White were overdominance genetic, respectively.(2)The characters of muscle fiber could be classified into two principal component. The morphological quantity parameters were area, diameter, Long diameter and short diameter and density, to which the function of density was negative. The morphological qualitative parameters were roundness degree, heteromorphism index and ratio of long diameter and short diameter, to which the function of roundness degree was negative. The two principal component contribute to 89.0309%.(3). The area of muscle fiber, diameter, long diameter, short diameter increased, there was a trend of increase of moisture and water loss percentagein the muscle, decrease of water holding capacity (WHO and intramuscular fat (IMF) , color of muscle and pH. The increase of density signified the improvement of meat quality. Roundness degree signified improvement of meat color, function of IMF, the function of heteromorphism index and ratio of long diameter and short diameter are just in contrast with roundness degree. 2. Correlation between connecting tissue character and meat quality Connecting tissue was shown clearly in the sections with Van Gieson staining. It could be classified into five kind (1-5) according to quantity and distribution. It could be classified into substantial vs loose, continuous vs disconnected, which make up to 8 phenotypes.1) There was great heterogeneity in individuals of lean type pigs, while in Meishan pig there is homogeneity. The number of connective tissue were in BF higher than that of LD (P<0. 01) . There is positive correlation between number of connective tissue and pH1 value(r=0. 2902, P<0. 05).2) There was a majority of substantial or disconnected connective tissue type in Lean pigs .while there is loose and continuous connective tissue in Meishan pigs. There was decrease on water holding capacity, meat color and IMF in disconnected connective tissue type. There was more fat cells in loose tissues, which could improve IMF and WHC. So pigs of loose and continuous connecting tissue were more favorable in order to improve meat quality.3) Content of total reducing sugarThe content of total reducing sugar in the meat decreased significantly after storage at -20℃, while there was no much change after storage at (14 ±2)℃. The big decrease in content of reducing sugar may be the main course of decrease of meat flavor.4. The correlation between mineral element and meat quality.1) There was a low content of K and Mg in Meishan pigs with high IMF.2) Mineral element could weaken the meat color, pH value, IMF and WHC.更多还原