Albrecht E, Teuscher F, Ender K, Wegner J
Research Institute for the Biology of Farm Animals, D-18196 Dummerstorf, Germany.
J Anim Sci. 2006 May;84(5):1067-75. doi: 10.2527/2006.8451067x.
The objective of this study was to investigate the growth- and breed-related changes of marbling characteristics in cattle. Four cattle breeds with different growth impetus and muscularity were reared and slaughtered under experimental conditions. German Angus, as a typical beef cattle; Galloway, as a smaller, environmentally resistant beef cattle; Holstein-Friesian, as a dairy-type cattle; and double-muscled Belgian Blue, as an extreme type for muscle growth, were used. These 4 breeds were expected to have differences in muscle development and i.m. fat deposition. Between 5 and 15 bulls of each breed were slaughtered at 2, 4, 6, 12, or 24 mo of age. Marbling characteristics were determined and classified in LM and semitendinosus muscle by computerized image analysis. Among breeds, differences appeared in the quantity, structure, and distribution of the marbling flecks in both muscles. The deposition of fat in the double-muscled Belgian Blue bulls remained substantially inferior to that of the other breeds, up to the age of 24 mo. Marbling in German Angus bulls particularly showed larger (P < 0.05) marbling fleck areas. Galloway cattle had the greatest (P < 0.05) number and the most regular (P < 0.05) distribution of the marbling flecks in young animals. Furthermore, for marbling characteristics in Holstein-Friesian animals, a great number and slightly finer structure were observed compared with the other breeds investigated. Postnatal growth-related changes of marbling in LM were characterized by as much as a 40-fold increase in the number of marbling flecks from 2 to 24 mo of age but also by up to a 4-fold enlargement in the area of the marbling flecks. The structure of marbling flecks was determined by 2 development trends. On the one hand, the marbling flecks became larger (P < 0.05), and the structure became coarser, which was reflected by an increasing (P < 0.01) proportion of long marbling flecks as well as an increasing (P < 0.01) maximum skeleton line length. On the other hand, continually new small, round marbling flecks appeared. This caused a decrease (P < 0.01) in the proportion of the 3 largest marbling fleck areas. The distribution of the marbling flecks became more regular (P < 0.05) with increasing proportion and number of marbling flecks. The results suggest that hyperplasia of adipocytes plays an important role in marbling during growth of muscle in cattle.
本研究的目的是调查牛大理石花纹特征与生长及品种的相关变化。在实验条件下饲养并屠宰了四个具有不同生长动力和肌肉发达程度的牛品种。德国安格斯牛，作为典型的肉牛品种；加洛韦牛，作为体型较小、适应环境能力较强的肉牛品种；荷斯坦 - 弗里生牛，作为奶牛型品种；以及双肌比利时蓝牛，作为肌肉生长的极端类型品种。预计这4个品种在肌肉发育和肌内脂肪沉积方面存在差异。每个品种在5至15头公牛之间，于2、4、6、12或24月龄时进行屠宰。通过计算机图像分析确定并分类了腰大肌和半腱肌中的大理石花纹特征。在品种之间，两个肌肉中大理石花纹斑点的数量、结构和分布均出现差异。直到24月龄，双肌比利时蓝牛公牛的脂肪沉积仍明显低于其他品种。德国安格斯牛公牛的大理石花纹斑点面积特别大（P < 0.05）。加洛韦牛在幼龄动物中大理石花纹斑点数量最多（P < 0.05）且分布最规则（P < 0.05）。此外，对于荷斯坦 - 弗里生牛的大理石花纹特征，与其他被调查品种相比，观察到数量较多且结构稍细。腰大肌中大理石花纹的出生后生长相关变化的特征是，从2月龄到24月龄大理石花纹斑点数量增加多达40倍，同时大理石花纹斑点面积增大多达4倍。大理石花纹斑点的结构由两种发育趋势决定。一方面，大理石花纹斑点变大（P < 0.05）且结构变粗，这表现为长大理石花纹斑点的比例增加（P < 0.01）以及最大骨架线长度增加（P < 0.01）。另一方面，不断有新的小圆形大理石花纹斑点出现。这导致三个最大大理石花纹斑点面积的比例下降（P < 0.01）。随着大理石花纹斑点比例和数量的增加，大理石花纹斑点的分布变得更规则（P < 0.05）。结果表明，脂肪细胞增生在牛肌肉生长过程中的大理石花纹形成中起重要作用。
