摘要
A divergent selection experiment for intramuscular fat (IMF) of LM at 9 wk of age was performed in rabbits. The objective of this work was to compare the lipid metabolism in muscles and fat tissues of the high-IMF and low-IMF lines. Lipogenic, catabolic, and lipolytic activities were studied in 2 muscles with different oxidative patterns (LM and semimembranosus proprius) and in the perirenal fat depot at 2 ages, 9 and 13 wk. In addition, adipocytes were characterized in perirenal fat. In the fifth generation, direct response to selection was 0.26 g IMF/100 g muscle. Lines showed differences in their lipogenic activities of muscles and fat tissues at 13 wk but not at 9 wk. The high-IMF line showed greater glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme (EM), and fatty acid synthase (FAS) activities in LM than the low-IMF line, with probabilities = 1.00, 0.93, and 0.90, respectively. Differences between lines were particularly great for G6PDH activity, representing 1.13 SD. The high-IMF line also showed greater G6PDH and FAS activities in semimembranosus proprius (P0 = 0.98 for G6PDH and 0.95 for FAS) and perirenal fat (P0 = 0.91 for G6PDH and 0.96 for FAS). However, in perirenal fat, EM activity was greater in the low-IMF line (P0 = 0.90). No differences between lines were found in almost any catabolic or lipolytic activities of muscles. Regarding adipocyte characteristics, the high-IMF line showed larger adipocytes in perirenal fat depot tissue (P0 = 0.97) compared to the low-IMF line, but no differences between lines were observed in the number of adipocytes. This study sheds light on the metabolic activities involved in the genetic differentiation of lipid deposition in rabbits. This study shows that lipogenic activities in muscles and fat tissues, in particular G6PDH in LM, are involved in the lipid accumulation in muscle and adipose tissues.
摘要译文
在兔子中进行了在9周龄时LM的肌肉内脂肪（IMF）的发散选择实验。这项工作的目的是比较高IMF和低IMF线肌肉和脂肪组织的脂质代谢。脂肪分解，分解代谢，并且在2个具有不同氧化模式的肌肉（LM和semimembranosus proprius）和2龄，9和13周的肾周脂肪库中研究脂解活性。此外，脂肪细胞表现为肾周脂肪。在第五代中，对选择的直接反应是0.26克IMF / 100克肌肉。线在13周时显示它们在肌肉和脂肪组织的脂肪生成活性上的差异，但在9周时不显示。高IMF线显示更大的葡萄糖-6-磷酸脱氢酶（G6PDH），LM中的苹果酸酶（EM）和脂肪酸合酶（FAS）活性低于低IMF系，概率分别为1.00,0.93和0.90。线之间的差异对G6PDH活性特别大，代表1.13 SD。高IMF线在半膜肌中也显示出更高的G6PDH和FAS活性（P 0 \x3d 0。对于G6PDH为98，对于FAS为0.95）和肾周脂肪（对于G6PDH P 0 \x3d 0.91，对于FAS为0.96）。然而，在肾周脂肪中，低IMF线的EM活动更大（P 0 \x3d 0.90）。在几乎任何肌肉的分解代谢或脂肪分解活动中都没有发现细胞系之间的差异。关于脂肪细胞特征，与低IMF系相比，高IMF线在肾周脂肪库组织中显示更大的脂肪细胞（P 0 \x3d 0.97），但是在脂肪细胞的数目中未观察到线之间的差异。本研究揭示了兔子脂质沉积遗传分化所涉及的代谢活动。这项研究表明，肌肉和脂肪组织中的脂肪生成活性，尤其是LM中的G6PDH参与肌肉和脂肪组织中的脂质积累。
M. Martínez-álvaro;S. Agha;A. Blasco;P. Hernández. Muscle lipid metabolism in two rabbit lines divergently selected for intramuscular fat[J]. Journal of Animal Science, 2017,95(6): 2576–2584