摘要
Intramuscular fat (IMF) has a large effect in the sensory properties of meat because it affects tenderness, juiciness and flavour. A divergent selection experiment for IMF in longissimus dorsi (LD) muscle was performed in rabbits. Since liver is the major site of lipogenesis in rabbits, the objective of this work is to study the liver metabolism in the lines of the divergent selection experiment. Intramuscular fat content, perirenal fat weight, liver weight, liver lipogenic activities and plasma metabolites related to liver metabolism were measured in the eighth generation of selection. Direct response on IMF was 0.34 g/100 g of LD, which represented 2.7 SD of the trait, and selection showed a positive correlated response in the perirenal fat weight. High-IMF line showed greater liver size and greater liver lipogenic activities of enzymes glucose-6-phosphate dehydrogenase and malic enzyme. We did not find differences between lines for fatty acid synthase lipogenic activity. With regard to plasma metabolites, low-IMF line showed greater plasma concentration of triglycerides, cholesterol, bilirubin and alkaline phosphatase than high-IMF line, whereas high-IMF line showed greater albumin and alanine transaminase concentrations than low-IMF line. We did not observe differences between lines for glucose, total protein and plasma concentrations. Phenotypic correlations between fat (IMF and perirenal fat weight) and liver traits showed that liver lipogenesis affects fat deposition in both, muscle and carcass. However, the mechanisms whereby liver lipogenesis affected IMF content remain to be clarified.
摘要译文
肌内脂肪（IMF）对肉的感官特性有很大影响，因为它会影响嫩度，多汁性和风味。在兔中进行了背最长肌（LD）肌肉中IMF的发散选择实验。由于肝脏是兔子脂肪生成的主要部位，这项工作的目的是研究分歧选择实验中的肝脏代谢。肌内脂肪含量，肾周脂肪重量，肝脏重量，在第八代选择中测量肝脏脂肪生成活性和与肝脏代谢相关的血浆代谢物。对IMF的直接反应为0.34克/ 100克LD，代表2。7性状的SD和选择显示肾周脂肪重量的正相关反应。高IMF系显示肝脏大小更大，酶 - 葡萄糖-6-磷酸脱氢酶和苹果酸酶的肝脏脂肪生成活性更高。我们没有发现脂肪酸合酶脂肪生成活性的品系之间存在差异。关于血浆代谢物，低IMF线表现出更高的血浆甘油三酯浓度，胆固醇，胆红素和碱性磷酸酶高于高IMF系，而高IMF系显示比低IMF系更高的白蛋白和丙氨酸转氨酶浓度。我们未观察到葡萄糖，总蛋白质和血浆浓度之间的差异。脂肪（IMF和肾周脂肪重量）和肝脏性状之间的表型相关性表明肝脏脂肪生成影响肌肉和胴体中的脂肪沉积。然而，肝脏脂肪生成影响IMF含量的机制仍有待澄清。
M. Martínez-álvaro (a1); Y. Paucar (a1); K. Satué (a2); A. Blasco (a1);P. Hernández (a1).... Liver metabolism traits in two rabbit lines divergently selected for intramuscular fat[J]. animal, 2018,12(6): 1217-1223