Etablissement National d'Enseignement Supérieur Agronomique de Dijon (ENESAD), BP 87999, 21079 Dijon Cedex, France.
BMC Biochem. 2010 Mar 5;11:12. doi: 10.1186/1471-2091-11-12.
An important variability of contractile and metabolic properties between muscles has been highlighted. In the literature, the majority of studies on beef sensorial quality concerns M. longissimus thoracis. M. rectus abdominis (RA) is easy to sample without huge carcass depreciation and may appear as an alternative to M. longissimus thoracis for fast and routine physicochemical analysis. It was considered interesting to assess the muscle fibres of M. rectus abdominis in comparison with M. longissimus thoracis (LT) and M. triceps brachii (TB) on the basis of metabolic and contractile properties, area and myosin heavy chain isoforms (MyHC) proportions. Immuno-histochemical, histochemical, histological and enzymological techniques were used. This research concerned two populations of Charolais cattle: RA was compared to TB in a population of 19 steers while RA was compared to LT in a population of 153 heifers.
RA muscle had higher mean fibre areas (3350 microm(2) vs 2142 to 2639 microm(2)) than the two other muscles. In RA muscle, the slow-oxidative fibres were the largest (3957 microm(2)) and the fast-glycolytic the smallest (2868 microm(2)). The reverse was observed in TB muscle (1725 and 2436 microm(2) respectively). In RA muscle, the distinction between fast-oxidative-glycolytic and fast-glycolytic fibres appeared difficult or impossible to establish, unlike in the other muscles. Consequently the classification based on ATPase and SDH activities seemed inappropriate, since the FOG fibres presented rather low SDH activity in this muscle in comparison to the other muscles of the carcass. RA muscle had a higher proportion of I fibres than TB and LT muscles, balanced by a lower proportion either of IIX fibres (in comparison to TB muscle) or of IIA fibres (in comparison to LT muscle). However, both oxidative and glycolytic enzyme activities were lower in RA than in TB muscle, although the LDH/ICDH ratio was higher in RA muscle (522 vs 340). Oxidative enzyme activities were higher in RA than in LT muscle, whereas glycolytic enzyme activity was lower. In RA muscle, contractile and metabolic properties appeared to be less well-correlated than in the two other muscles.
RA muscle has some particularities in comparison to the LT and TB muscles, especially concerning the unusual large cross-section surface of SO fibres and the very low oxidative activity of intermediate IIA fibres.
人们已经强调了肌肉之间收缩和代谢特性的重要可变性。在文献中，大多数关于牛肉感官质量的研究都涉及到背最长肌。腹直肌（RA）易于取样，不会对胴体造成巨大损失，并且可以作为背最长肌的替代品，用于快速和常规的理化分析。因此，人们认为评估 RA 肌纤维的代谢和收缩特性、面积和肌球蛋白重链同工型（MyHC）比例与背最长肌（LT）和肱三头肌（TB）相比很有意义。使用了免疫组织化学、组织化学、组织学和酶学技术。这项研究涉及两个夏洛莱牛种群：在 19 头公牛中，RA 与 TB 进行了比较，而在 153 头小母牛中，RA 与 LT 进行了比较。
RA 肌的平均纤维面积（3350μm2）高于其他两种肌肉（2142-2639μm2）。在 RA 肌中，慢氧化纤维最大（3957μm2），快糖酵解纤维最小（2868μm2）。而在 TB 肌中则相反（分别为 1725μm2和 2436μm2）。在 RA 肌中，与其他肌肉不同，很难或不可能确定快氧化糖酵解纤维和快糖酵解纤维之间的区别。因此，基于 ATPase 和 SDH 活性的分类似乎不合适，因为与其他肌肉相比，该肌肉的 FOG 纤维的 SDH 活性较低。RA 肌的 I 纤维比例高于 TB 和 LT 肌，而 IIX 纤维（与 TB 肌相比）或 IIA 纤维（与 LT 肌相比）的比例较低。然而，RA 肌的氧化和糖酵解酶活性均低于 TB 肌，尽管 RA 肌的 LDH/ICDH 比值较高（522 比 340）。RA 肌的氧化酶活性高于 LT 肌，而糖酵解酶活性较低。在 RA 肌中，收缩和代谢特性似乎不如其他两种肌肉相关。
RA 肌与 LT 和 TB 肌相比具有一些特殊性，尤其是涉及到 SO 纤维的异常大横截面和中间 IIA 纤维的极低氧化活性。
