Are there consistent relationships between major connective tissue components, intramuscular fat content and muscle fibre types in cattle muscle?

Abstract

Intramuscular connective tissue (IMCT) is mainly composed of several fibrils (known as total collagen (TCol)) linked between each other by different chemical cross-links (CLs), the whole being embedded in a matrix of proteoglycans (PGs). In the field of beef quality, there is limited information on the role of CLs and PGs. Accordingly, several authors suggest that, to investigate the role of IMCT, it is important to investigate them just like TCol and insoluble collagen (ICol). In muscle, there are two other components, the muscle fibres and intramuscular fat (IMF) content. There are limited data on the relationships between these three components of muscle and then on possibility to independently manipulate these characteristics in order to control the final quality of meat. The present study aimed to investigate whether consistent relationships exist between these different components of muscle. Therefore, the present study compared four muscles of two cattle types (dairy and beef) to determine associations between TCol, ICol, CLs and PGs. Data were analysed across and within muscle (M) and animal type (AT) based on residuals. There was a strong M and AT effect for all muscle characteristics and an interaction M × AT for type I muscle fibres and IMF. Correlations between TCol, ICol and their CLs were M- and AT-independent. Total proteoglycans were positively correlated with TCol and ICol in a muscle-dependent manner irrespective of AT, but no correlation was found with CLs. On the contrary, CLs were negatively correlated with the ratio TPGs : TCol in an M-dependent manner, irrespective of AT. TCol, ICol and CLs were positively and negatively correlated with type IIA and IIB+X muscle fibres only in longissimus thoracis (LT) muscle, regardless the AT. Insoluble collagen was the only parameter of IMCT to be correlated with type I muscle fibres but only in LT muscle, irrespective of AT. There was no correlation between PGs and muscle fibre types, but PGs were the only IMCT component to be related with IMF in an M-dependent manner, irrespective of AT. Finally, there was no correlation between muscle fibre types and IMF content within M and AT. This study revealed that there is a strong relationship between IMCT components irrespective of M, an M-dependent relationship between the IMCT components and muscle fibre types and few (only with PGs) or no relationship between IMF and IMCT and muscle fibres.

Combining label‐free and label‐based accurate quantifications with SWATH‐MS: Comparison with SRM and PRM for the evaluation of bovine muscle type effects

“…The low abundance of PKM, GPI and PGK1 in the oxidative highly marbled LT muscle was also consistent with the negative correlation between the abundance of these proteins and the IMF values reported by Bazile et al [22]. Among proteins annotated by the GO term (GO:0006099) involved in tricarboxylic acid cycle, FH, DLST and MDH2 were less abundant in the ST muscle, LT and SM being equal in accordance with the contractile and metabolic properties of these muscles described in the literature [39].…”

Contribution of connective tissue components, muscle fibres and marbling to beef tenderness variability in longissimus thoracis, rectus abdominis, semimembranosus and semitendinosus muscles

“…The differences in biochemical composition between the M and AT are presented elsewhere. 16 For any comparisons including interactions, a Student-Newman-Keuls test was used to separate the least-squares means (LSmeans). P < 0.05 was considered statistically significant.…”

“…The muscles were removed from carcasses 48 h post mortem using the same protocol, between the fifth and tenth rib for LT and from the middle part of the muscle for ST, SM and RA. 16 Each muscle was divided into two parts. The first one was stored under vacuum for 7 days for ageing, and then stored at −20°C until sensory analysis.…”

“…This result was coherent because, in the experimental same design, we previously found that ICol and CLs were highly correlated irrespective of muscle. 16 CLs are known to be involved in determinism of collagen solubility. 35 The only muscle for which the CLs were not correlated with tenderness was LT muscle, which is an expected result because this muscle had the lowest CL content.…”

Muscle fiber characteristics and postmortem quality of longissimus thoracis, psoas major and semitendinosus from Chinese Simmental bulls

“…Muscle fiber types significantly affect glycogen and mitochondria contents, determined the glycolytic rate, then influenced myofibrillar protein degradation, enzymatic activity of glycolytic enzymes and calcium‐dependent proteolysis system, and finally affected the ultimate meat quality (Choi & Kim, 2009; Picard & Gagaoua, 2020). Studies showed that total collagen, insoluble collagen, and chemical cross‐links were positively and negatively correlated with type IIA and IIB + X muscle fibers, insoluble collagen, and sensory tenderness was correlated with type I muscle fibers in cattle muscle, regardless of muscle and animal type (Listrat, Gagaoua, Normand, Andueza, et al, 2020; Listrat, Gagaoua, Normand, Gruffat, et al, 2020). Type IIB muscle fibers have higher calpain/calpastatin ratios compared to type I fibers in porcine muscle; myosin heavy chain (MHC) slow isoform contents are positively correlated with calpastatin activity (Choi & Kim, 2009; Ouali & Talmant, 1990).…”