Number of intramuscular adipocytes and fatty acid binding protein-4 content are significant indicators of intramuscular fat level in crossbred Large White x Duroc pigs
Number of intramuscular adipocytes and fatty acid binding protein-4 content are significant indicators of intramuscular fat level in crossbred Large White x Duroc pigs
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DOI：
10.2527/2006.8451083x
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发表时间：
2006-05-01
影响因子：
3.3
通讯作者：
Gondret, F
中科院分区：
文献类型：
--
作者：
Damon, M;Louveau, I;Gondret, F
肌内脂肪含量通常与新鲜猪肉的感官品质改善和更好的可接受性相关。然而，对于i.m.的生物学机制仍然缺乏确凿的证据。猪脂肪含量的变化。目前的研究旨在确定i.m.背最长肌脂肪含量与肌内肌张力有关。脂肪细胞结构、脂质代谢或整个肌肉的收缩特性。为此，在107 +/- 7 kg BW下进一步研究了在70 kg BW下LM活检中表现出高（2.82 +/-0.38%，HF）或低（1.15 +/-0.14%，LF）脂质含量的杂交（大白色x杜洛克）猪。动物以相同的速度生长，但HIP猪在屠宰时呈现比LF猪更胖的尸体（P = 0.04）。i.m.的差异。两组之间的脂肪含量主要由i.m.的变化解释。脂肪细胞数量（HF组比LF组增加127%，P = 0.005）。更小的差异脂肪细胞直径增加（HIP组比LF组增加13%，P = 0.057），而全肌脂肪生成酶活性无显著变化（乙酰辅酶A羧化酶，P = 0.9，苹果酸酶，P = 0.35;葡萄糖-6-磷酸脱氢酶，P = 0.75），甾醇调节元件结合蛋白-1（P = 0.6）或二酰基甘油酰基转移酶1（P = 0.6）的mRNA水平。脂肪细胞脂肪酸结合蛋白（FABP-4）在整个脂肪组织中的含量，HIP组是LF组的2倍（P = 0.05），且FABP-4蛋白含量与脂肪细胞数（R-2 = 0.47，P = 0.02）和脂肪含量（R-2 = 0.58，P = 0.004）呈正相关。相反，相对于FABP-3 mRNA，（P = 0.46）或蛋白质（P = 0.56）水平，氧化酶活性（柠檬酸合成酶，P = 0.9; β-羟酰辅酶A脱氢酶，P = 0.7），线粒体（P = 0.5）和过氧化物酶体（P = 0.12）油酸的氧化速率，脂肪酸氧化相关基因的mRNA水平（肉毒碱棕榈酰转移酶1，P = 0.98;过氧化物酶体增殖物激活受体δ，P = 0.73）或能量消耗（解偶联蛋白2，P = 0.92;解偶联蛋白3，P = 0.84）或肌球蛋白重链mRNA比例（P > 0.49）。目前的研究表明，FABP-4蛋白含量可能是LM脂质沉积的一个有价值的标志物，脂肪含量和肌纤维类型组成可以独立地控制。
Intramuscular fat content is generally associated with improved sensory quality and better acceptability of fresh pork. However, conclusive evidence is still lacking for the biological mechanisms underlying i.m. fat content variability in pigs. The current study aimed to determine whether variations in i.m. fat content of longissimus muscle are related to i.m. adipocyte cellularity, lipid metabolism, or contractile properties of the whole muscle. To this end, crossbred (Large White x Duroc) pigs exhibiting either a high (2.82 +/- 0.38%, HF) or a low (1.15 +/- 0.14%, LF) lipid content in LM biopsies at 70 kg of BW were further studied at 107 +/- 7 kg of BW. Animals grew at the same rate, but HIP pigs at slaughter presented fatter carcasses than LF pigs (P = 0.04). The differences in i.m. fat content between the 2 groups were mostly explained by variation in i.m. adipocyte number (+127% in HF compared with LF groups, P = 0.005). Less difference (+13% in HIP compared with LF groups, P = 0.057) was noted in adipocyte diameter, and no significant variation was detected in whole-muscle lipogenic enzyme activities (acetyl-CoA carboxylase, P = 0.9; malic enzyme, P = 0.35; glucose-6-phosphate dehydrogenase, P = 0.75), mRNA levels of sterol-regulatory element binding protein-1 (P = 0.6), or diacylglycerol acyltransferase 1 (P = 0.6). Adipocyte fatty acid binding protein (FABP)-4 protein content in whole LM was 2-fold greater in HIP pigs than in LF pigs (P = 0.05), and positive correlation coefficients were found between the FABP-4 protein level and adipocyte number (R-2 = 0.47, P = 0.02) and lipid content (R-2 = 0.58, P = 0.004). Conversely, there was no difference between groups relative to FABP-3 mRNA (P = 0.46) or protein (P = 0.56) levels, oxidative enzymatic activities (citrate synthase, P = 0.9; beta-hydroxyacyl-CoA dehydrogenase, P = 0.7), mitochondrial (P = 0.5) and peroxisomal (P = 0.12) oxidation rates of oleate, mRNA levels of genes involved in fatty acid oxidation (carnitine-palmitoyl-transferase 1, P = 0.98; peroxisome proliferator-activated receptor delta, P = 0.73) or energy expenditure (uncoupling protein 2, P = 0.92; uncoupling protein 3, P = 0.84), or myosin heavy-chain mRNA proportions (P > 0.49). The current study suggests that FABP-4 protein content may be a valuable marker of lipid accretion in LM and that i.m. fat content and myofiber type composition can be manipulated independently.