Essén-Gustavsson B, Karlsson A, Lundström K, Enfält A C
Department of Medicine and Surgery, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden.
Meat Sci. 1994;38(2):269-77. doi: 10.1016/0309-1740(94)90116-3.
Immediately after exsanguination, samples were taken from M. longissimus dorsi (LD) and M. biceps fermorsi (BF) of halothane-gene-free Swedish Yorkshire pigs (entire males and gilts) fed a high-protein (18·5% crude protein, 0·96% lysine; n = 20) or a low-protein diet (13·1% crude protein, 0·64% lysine; n = 20). The lipid content, measured as triglyceride (TG), was analysed after the samples had been freeze-dried and dissected free from blood, fat and connective tissue. Fibre type composition (type I, IIA, IIB, IIC) was analysed by histochemical staining on all samples. In 14 samples of LD, representing the entire variation of the intramuscular fat content (IMF) among the 40 animals, fibre areas, lipid content and oxidative capacity within the fibre types were evaluated. IMF, meat colour and drip loss were measured in both muscles. Shear force was measured on cooked meat samples from LD. IMF was higher in both LD (2·5%) and BF (2·0%) from pigs on the low-protein diet compared with LD (1·5%) and BF (1·3%) from pigs on the high-protein diet. TG content did not differ between diets in BF but was higher in LD from pigs on low- vis-à-vis high protein diet. A significant correlation was seen in LD between IMF and TG content (r = 0·57; P < 0·001). Fibre type composition did not differ between pigs on the two diets. BF had a higher proportion of type I and IIA fibres and a lower proportion of IIB fibres, compared with LD. TG content in muscle was not correlated with fibre type composition or staining intensity for lipids and oxidative capacity. High staining intensity for lipid in LD was seen in all type I fibres and in some type IIA fibres. Meat quality parameters did not differ between groups except shear force, which was higher in pigs fed the high- vis-à-vis low-protein diet (4·7 and 4·0 kg/cm(2), respectively). Shear force was correlated significantly with TG content (r = -0·42; P < 0·01) and IMF (r = -0·43; P < 0·01) in LD. The results of this study show that lipids are stored mainly in type I fibres and in some type IIA fibres. Intracellular triglycerides account for only a small fraction of IMF. The results indicate that IMF and TG content in muscle fibres may be related to shear force.
放血后立即从无氟烷基因的瑞典约克夏猪（成年公猪和后备母猪）的背最长肌（LD）和股二头肌（BF）取样，这些猪分别饲喂高蛋白（粗蛋白18.5%，赖氨酸0.96%；n = 20）或低蛋白日粮（粗蛋白13.1%，赖氨酸0.64%；n = 20）。在样品冻干并剔除血液、脂肪和结缔组织后，分析以甘油三酯（TG）衡量的脂质含量。通过组织化学染色分析所有样品的纤维类型组成（I型、IIA型、IIB型、IIC型）。在14个LD样品中，代表40只动物肌肉内脂肪含量（IMF）的全部变化范围，评估纤维类型内的纤维面积、脂质含量和氧化能力。测定了两块肌肉的IMF、肉色和滴水损失。对LD的熟肉样品测定剪切力。与高蛋白日粮组猪的LD（1.5%）和BF（1.3%）相比，低蛋白日粮组猪的LD（2.5%）和BF（2.0%）的IMF更高。BF中日粮间TG含量无差异，但低蛋白日粮组猪的LD中TG含量高于高蛋白日粮组。LD中IMF与TG含量之间存在显著相关性（r = 0.57；P < 0.001）。两种日粮的猪之间纤维类型组成无差异。与LD相比，BF中I型和IIA型纤维比例更高，IIB型纤维比例更低。肌肉中的TG含量与纤维类型组成或脂质和氧化能力的染色强度无关。在LD中，所有I型纤维和一些IIA型纤维中脂质染色强度高。除剪切力外，各组肉质参数无差异，高蛋白日粮组猪的剪切力高于低蛋白日粮组（分别为4.7和4.0 kg/cm²）。LD中剪切力与TG含量（r = -0.42；P < 0.01）和IMF（r = -0.43；P < 0.01）显著相关。本研究结果表明，脂质主要储存在I型纤维和一些IIA型纤维中。细胞内甘油三酯仅占IMF的一小部分。结果表明，肌肉纤维中的IMF和TG含量可能与剪切力有关。
