莱芜猪脂肪代谢酶活性的发育性变化及其对肌内脂肪沉积的影响

Studies on the Development Changes of Fatty Enzymatic Activities and Their Association with Intramuscular Fat in Laiwu Pig

以40-90kg6个体重阶段莱芜猪和新莱芜猪共72头为试验对象，研究了不同组织中脂肪代谢酶活性的发育性变化规律及其与肌内脂肪含量、背膘厚的关系。结果表明：（1）在生长期随着体重的增大，肌肉组织中脂肪合成酶异柠檬酸脱氢酶（ICDH）活性显著高于苹果酸脱氢酶（MDH）活性（P〈0．01）；ICDH活性在60-70kg时达到峰值，而后开始下降，MDH活性规律不明显；脂肪分解酶激素敏感脂酶（HSL）的活性先降后升，70～80kg时活性最高。（2）背膘中合成酶MDH活性显著高于ICDH活性（P〈0．01）；MDH和ICDH活性都是先降后升，但总体升降幅度不大；HSL活性40～50kg基本稳定，而后逐步增强。（3）肝脏组织中合成酶ICDH活性显著高于MDH活性（P〈0．01）；ICDH、MDH活性逐渐升高，至60kg以后其活性趋于稳定，脂肪分解酶HSL活性的发育性变化规律不明显。（4）肌肉组织中的MDH、HSL活性与肌内脂肪含量呈极显著相关（P〈0．01）；肝脏组织中的MDH、ICDH与肌内脂肪含量呈显著正相关，ICDH还与背膘厚呈极显著正相关；背膘组织中的MDH、HSL与背膘厚呈极显著相关（P〈0．01）。研究结果提示：肌内脂肪的沉积与背膘脂肪的沉积既存在一定的内在联系（通过肝脏），又具有一定的独立性，通过选择肌肉组织中脂肪代谢酶活性，在不显著影响皮下脂肪沉积量的前提下可望提高肌内脂肪的沉积量。

Seventy-two Laiwu Black and Xin Laiwu pigs （weight of 40-90 kg） were used to study the development changes of fatty enzymatic activities and their association with intramuscular fat （IMF）, backfat thickness （BFT）. Results showed as follows. （1） With gaining of body weight, the activity of ICDH was significantly higher than that of MDH in muscle（P〈0.01）. The activity of ICDH reached a peak at 60-70 kg of weight and decreased thereafter. MDH had no significant development changes. The activity of HSL fell firstly and reached a peak at 70-80 kg of weight. （2） The activity of MDH was significantly higher than that of ICDH in backfat（P〈0. 01）. Both MDH and ICDH activities, to some extent, de- creased firstly and then increased. The activity of HSL was stable at 40-50 kg and then increased gradually. （3） The activity of ICDH was significantly higher than that of MDH in liver. The activities of ICDH and MDH increased firstly and tended to stabilize after 60 kg. The activity of HSL had no significant development changes. （4） The activities of MDH, HSL in muscle were highly correlated to IMF content （P〈0.01）. MDH, ICDH in liver positively correlated with IMF, and ICDH also with BFT（P〈0.01）. The activities of MDH, HSL in backfat were strongly correlated to BFT （P〈0.01）. It implied that there was not only some immanent contact between the depositions of IMF and BFT via liver, but also some independence from each other. By selecting fatty enzymatic activity in muscle, it is possible to improve IMF content but not to change BFT.