Consequences of selection for higher growth rate on muscle fibre development in cattle

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Muscle contractile and metabolic characteristics were studied on nine cloned and eight non-cloned (control) heifers. The animals were submitted to repeated biopsies of the semitendinosus (ST) muscle at the ages of 8, 12, 18 and 24 months. The contractile type was determined from the proportion of the different myosin heavy chain (MyHC) isoforms separated by electrophoresis. Glycolytic metabolism was assessed by lactate dehydrogenase (LDH) activity, and oxidative metabolism was assessed by isocitrate dehydrogenase (ICDH), cytochrome-c oxidase (COX) and b-hydroxyacyl-CoA dehydrogenase (HAD) activities. In cloned heifers at 8 months of age, there was a greater proportion of MyHC I (slow oxidative isoform) and MyHC IIa (fast oxido-glycolytic isoform), a lower proportion of MyHC IIx (fast glycolytic isoform), greater COX and HAD activity and a lower LDH/ICDH ratio compared with control heifers. Thus, young cloned heifers had slower muscle types associated with a more oxidative muscular metabolism than control heifers. From 12 months of age onwards, no significant differences were observed between cloned and control heifers. A delay in muscle differentiation and maturation in cloned heifers is hypothesised and discussed.

Section: Discussionmentioning

confidence: 99%

Comparison of cloned and non-cloned Holstein heifers in muscle contractile and metabolic characteristics

Jurie

Picard

Heyman

et al. 2009

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“…Expressions of the developmental MyHC isoforms (embryonic, foetal, a-cardiac, etc.) decrease during this period (Gagniè re et al, 1999a;Picard et al, 2006). They are progressively replaced by the adult fast MyHCs.…”

Section: Cellular Events Triggering Myogenesismentioning

confidence: 99%

“…In addition, double-muscled compared with conventional cattle and Charolais selected for high v. low muscle growth capacity have muscles with a higher proportion of fast glycolytic fibres (Cassar-Malek et al, 2005;Picard et al, 2006) and a lower intramuscular fat content (Gotoh et al, 2009), as observed Interaction between adipose tissue and muscle between genotypes with a high v. low lean-to-fat ratio (May et al, 1994;Bellmann et al, 2004). This is accompanied by a reduced expression of proteins related to oxidative and lipid metabolism in muscle (Bouley et al, 2005;Wang et al, 2005;Bonnet et al, 2007;Jurie et al, 2007;Graugnard et al, 2009).…”

Section: Nutritional and Physiological Control Of Muscular And At Growthmentioning

confidence: 99%

Ontogenesis of muscle and adipose tissues and their interactions in ruminants and other species

Bonnet

Cassar-Malek

Chilliard

et al. 2010

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113

The lean-to-fat ratio, that is, the relative masses of muscle and adipose tissue, is a criterion for the yield and quality of bovine carcasses and meat. This review describes the interactions between muscle and adipose tissue (AT) that may regulate the dynamic balance between the number and size of muscle v. adipose cells. Muscle and adipose tissue in cattle grow by an increase in the number of cells (hyperplasia), mainly during foetal life. The total number of muscle fibres is set by the end of the second trimester of gestation. By contrast, the number of adipocytes is never set. Number of adipocytes increases mainly before birth until 1 year of age, depending on the anatomical location of the adipose tissue. Hyperplasia concerns brown pre-adipocytes during foetal life and white pre-adipocytes from a few weeks after birth. A decrease in the number of secondary myofibres and an increase in adiposity in lambs born from mothers severely underfed during early pregnancy suggest a balance in the commitment of a common progenitor into the myogenic or adipogenic lineages, or a reciprocal regulation of the commitment of two distinct progenitors. The developmental origin of white adipocytes is a subject of debate. Molecular and histological data suggested a possible transdifferentiation of brown into white adipocytes, but this hypothesis has now been challenged by the characterization of distinct precursor cells for brown and white adipocytes in mice. Increased nutrient storage in fully differentiated muscle fibres and adipocytes, resulting in cell enlargement (hypertrophy), is thought to be the main mechanism, whereby muscle and fat masses increase in growing cattle. Competition or prioritization between adipose and muscle cells for the uptake and metabolism of nutrients is suggested, besides the successive waves of growth of muscle v. adipose tissue, by the inhibited or delayed adipose tissue growth in bovine genotypes exhibiting strong muscular development. This competition or prioritization occurs through cellular signalling pathways and the secretion of proteins by adipose tissue (adipokines) and muscle (myokines), putatively regulating their hypertrophy in a reciprocal manner. Further work on the mechanisms underlying cross-talk between brown or white adipocytes and muscle fibres will help to achieve better understanding as a prerequisite to improving the control of body growth and composition in cattle.

“…The works of Gagniè re et al (1999) and Picard et al (2006) have demonstrated that the proportion of the developmental Myosin heavy chain isoforms (MyHC: embryonic, foetal, alpha-cardiac, etc.) decreased during this period as they are progressively replaced by the adult fast MyHCs.…”

Section: Introductionmentioning

confidence: 99%

Proteome dynamics during contractile and metabolic differentiation of bovine foetal muscle

Chaze

Meunier

Chambon³

et al. 2009

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Contractile and metabolic properties of bovine muscles play an important role in meat sensorial quality, particularly tenderness. Earlier studies based on Myosin heavy chain isoforms analyses and measurements of glycolytic and oxidative enzyme activities have demonstrated that the third trimester of foetal life in bovine is characterized by contractile and metabolic differentiation. In order to complete this data and to obtain a precise view of this phase and its regulation, we performed a proteomic analysis of Semitendinosus muscle from Charolais foetuses analysed at three stages of the third trimester of gestation (180, 210 and 260 days). The results complete the knowledge of important changes in the profiles of proteins from metabolic and contractile pathways. They provide new insights about proteins such as Aldehyde dehydrogenase family, Enolase, Dihydrolipoyl dehydrogenase, Troponin T or Myosin light chains isoforms. These data have agronomical applications not only for the management of beef sensorial quality but also in medical context, as bovine myogenesis appears very similar to human one.