Effect of nutritional factors on biochemical, structural and metabolic characteristics of muscles in ruminants, consequences on dietetic value and sensorial qualities of meat.

Ruminant meat is an important source of nutrients and is also of high sensory value. However, the importance and nature of these characteristics depend on ruminant nutrition. The first part of this review is focused on biochemical and dietetic value of this meat.

Age-related changes and location of types I, III, XII and XIV collagen during development of skeletal muscles from genetically different animals.

The ontogenesis of total collagen and of different collagen types was studied in four muscle types from genetically different cattle. Hydroxyproline content was 1.2-fold higher in muscles from cross-bred foetuses with normal muscle growth compared to those of the other genetic types (pure bred with different growth rates, double-muscled breed).

Specificity of different anti-myosin heavy chain antibodies in bovine muscle.

Muscle fibre types play an important role in bovine meat tenderness, and conditions the speed of ageing. Two generations of myotubes appear during foetal life. Their differentiation results in several types of fibres differing in their contractile and metabolic properties, namely type I fibres and type II fibres (IIA and IIB).

Effects of muscle type, castration, age, and compensatory growth rate on androgen receptor mRNA expression in bovine skeletal muscle.

The effect of testosterone on sexual dimorphism is evident by differential growth of forelimb and neck muscles in bulls and steers. Divergent hormone sensitivites may account for the differential growth rates of individual muscles. Therefore, the objective of this study was to compare androgen receptor (AR) expression in three different muscles of bulls and steers at various ages and growth rates.

Regulation of bovine satellite cell proliferation and differentiation by insulin and triiodothyronine.

Satellite cells activity contributes to postnatal muscle growth. Herein, we have studied the respective influence of insulin and triiodothyronine (T3) on the proliferation and differentiation of primary bovine satellite cells isolated from Semitendinosus muscle of Montbéliard steers. Under basal conditions, satellite cells proliferated until the fifth day of culture, began to fuse into myotubes and expressed differentiation markers such as connectin, myogenin, and myosin heavy chain (MHC) isoforms.

Contractile differentiation of foetal cattle muscles: intermuscular variability.

off actile differentiation was studied in six foetal muscles exhibiting different contractile characteristics in adult cattle: the Masseter, Diaphragma, Biceps femoris, Longissimus thoracis, Semitendinosus and Cutaneus trunci. These muscles were excised from foetuses aged 60-260 days. Fibre types were identified by immunohistochemistry using three monoclonal antibodies raised against types 1, 2a, 2b (or 2x) and foetal myosin heavy chains.

Effect of the type of diet on muscle characteristics and meat palatability of growing Salers bulls.

The effect of the type of diet (hay vs grass silage) on body composition and characteristics and palatability of semitendinosus (ST) and longissimus thoracis (LT) muscles of 16 month old Salers bulls fed at the same energy levels were studied. Animals fed hay had a lower daily weight gain and carcass weight and were leaner. There were no significant differences in the proportions of fibre types in the ST or LT due to diet.

Characterisation and location of insulin-like-growth factor (IGF) receptors in the foetal bovine Semitendinosus muscle.

We characterised IGFI and IGFII receptors and located them in bovine muscle during foetal growth. Semitendinosus muscle samples were taken from foetuses ranging from 80 to 270 days post-conception. The relative affinities of 125I-IGFII and 125I-IGFI mark the presence of typical type II and type I receptors in foetal muscle membranes.

Electrophoretic separation of bovine muscle myosin heavy chain isoforms.

This study concerns the definition of the optimum conditions for separation of adult and developmental myosin heavy chain (MHC) isoforms in bovine muscle. The various techniques published do not result in good separation of the MHC in this species. The trials carried out concerned the concentration of acrylamide and N, N'-methylene-bis-acrylamide, and more particularly the concentration of Tris in the separating gel.

Changes in the metabolic and contractile characteristics of muscle in male cattle between 10 and 16 months of age.

Samples of semitendinosus muscle from 28 male cattle (18 Salers and 10 Limousins) were taken at 10 months (biopsy) and at 16 months of age (at slaughter). The animals had received the same diet and were slaughtered after the same duration of fattening. The activities of isocitrate dehydrogenase and lactate dehydrogenase were measured in the muscle samples.

Age-related changes and location of type I, III, IV, V and VI collagens during development of four foetal skeletal muscles of double-muscled and normal bovine animals.

The aim of this work was to study the variability in the quantities of hydroxyproline, of type I and III collagens and in the location of types, I, III, IV, V, VI in four muscles of normal and double-muscled (DM) cattle. Samples were collected from foetuses at different ages post-conception. Both in the two genetic types and in muscles, from 110 days, types I, III, V, VI were located in perymisium and types I, IV, V, VI in endomysium.

Insulin-like growth factor II (IGF-II) mRNA expression during skeletal muscle development of double-muscled and normal bovine foetuses.

We investigated the IGF-II gene expression in developing Semitendinosus muscle in foetal normal and double-muscled cattle. Samples from normal and double-muscled foetuses ranging from 90 to 210 d post-conception were collected and total RNA extracted. Northern blot analysis was performed using the human IGF-II cDNA probe.

Comparison of foetal metabolic differentiation in three cattle muscles.

Metabolic differentiation of Semitendinosus (ST), Cutaneus trunci (CT) and Masseter (MA) in cattle foetuses aged from 110 to 260 days was studied by measuring isocitrate dehydrogenase (ICDH, oxidative) and lactate dehydrogenase (LDH, glycolytic) activities. The five LDH isoenzymes were separated by electrophoresis and assayed by densitometry. ICDH activity increased from 210 days onwards in the three muscles but more intensively in MA (oxidative).

Fat partitioning and biochemical characteristics of fatty tissues in relation to plasma metabolites and hormones in normal and double-muscled young growing bulls.

Plasma metabolites and hormones, and the biochemical characteristics of four fatty tissues (FT) were studied in two groups of six normal (N) or six double-muscled (DM) Belgian Blue young growing bulls fed the same net energy amount at the same live weight and slaughtered at 10 months of age. Average daily gain and feed efficiency did not significantly differ between the two groups. However, the DM bulls exhibited a higher proportion of muscles (+22%, P < 0.

Influences of the method of housing bulls on their body composition and muscle fibre types.

The influence of the type of housing (loose or tying-type) was studied in relation to body composition and muscular characteristics of bulls. 34 young bulls (18 Salers and 16 Limousins) were divided into two groups with equal breed representation and equal mean growth rates, to 10 months of age. One group was housed in tying-type housing (short stalls 1·8m(2) per animal) and the other in loose housing (6·5m(2) per animal).

Age-related changes and location of type I, III and IV collagens during skeletal muscle development of double-muscled and normal bovine foetuses.

The aim of this study was to investigate age-related changes in collagen content in muscles of normal and double-muscled (DM) bovine foetuses. Psoas major (PM) and triceps brachii (TB) muscles were collected from foetuses at 110 to 260 days post-conception (p.c.

Comparative study of metabolic differentiation of foetal muscle in normal and double-muscled cattle.

Studies of the contractile differentiation of foetal muscles in normal and double-muscled cattle have shown that double-muscled foetal muscles display comparative delayed contractile differentiation. We compared the metabolic differentiation of foetal muscles in normal and double-muscled cattle, for which no data were available. The semitendinosus (ST) muscle was excised from normal and double-muscled cattle foetuses aged 110-260 days.

Regional variations of muscle fibre characteristic in m. semitendinosus of growing cattle.

The objectives of the present study were to elaborate an intra-muscular profile of metabolic enzyme equipment, contractile and morphometric features along the longitudinal axis of m. semitendinosus at various ages throughout the growth phase. Thirty-seven male Montbéliard cattle, about half of them castrated, were representatively allocated to various slaughter dates, scheduled at 4, 8, 12 and 16 months of age.

Comparison of the foetal development of muscle in normal and double-muscled cattle.

Muscle differentiation was studied in foetal Semitendinosus muscle from normal cattle and those with the 'culard' gene of muscular hypertrophy sampled at 90, 130, 170 and 210 days of foetal life. The different fibre types were characterized by immunohistochemistry with antibodies specific to different isoforms of myosin heavy chains. The isoforms were separated by electrophoresis, identified by immunoblotting and quantified by ELISA.

Presence of an unidentified myosin isoform in certain bovine foetal muscles.

Genetic variation in the establishment of bovine muscle fibre types was studied by comparing muscle differentiation at 210 days of foetal life in normal cattle and in 'culard' animals, which have muscular hypertrophy. The different fibre types were determined by histochemical and immunohistochemical analyses with monoclonal antibodies specific to different myosin heavy chain isoforms. The isoforms were separated by electrophoresis and quantified by the ELISA method.

Post-natal changes in the biological characteristics of Semitendinosus muscle in male Limousin cattle.

Samples of semitendinosus muscle from 45 male Limousin cattle reared under similar conditions were taken at 1, 6 and 12 months of age (biopsy) and at 16 months (at slaughter). The development of biochemical (DNA, protein/DNA), enzymic (lactic dehydrogenase, isocitric dehydrogenase), and histochemical (ATPase, succunic dehydrogenase) characteristics was studied. Muscle fibres were classified according to their contractile and metabolic properties (SO = slow oxidative; FOG = fast oxidative glycolytic; FG = fast glycolytic).

Inter-animal variation in the biological characteristics of muscle tissue in male limousin cattle.

The biochemical, metabolic and contractile characteristics of semitendinosus (ST) and longissimus thoracicus (LT) muscles were studied in 147 male Limousin cattle. The animals, which were slaughtered at 16 months, were the offspring of 15 different sires. Weight gain and carcass tissue composition (proportion of muscle and adipose tissue) were also measured.

Enzyme-linked immunosorbent assay for myosin heavy chains in the horse.

The content in slow and fast myosin heavy chains (MHC 1 and MHC 2) of 5 equine muscles was determined using an enzyme-linked immunosorbent assay. The results obtained with this immunoenzymatic method were compared with complementary techniques: electrophoresis and immunohistochemistry. Slices of masseter, diaphragm, tensor faciae latae, semitendinosus and cutaneus trunci were obtained from a 12-year-old saddle horse after slaughter.

Study of the influence of age and weaning on the contractile and metabolic characteristics of bovine muscle.

Weaning is an interesting period for the study of the nutritional regulation of muscle energy metabolism, since during this stage the nature of the substrates supplied to the muscle and their energy balance are profoundly changed. The aim of this study was to determine the effect of these modifications on the contractile and metabolic characteristics of bovine muscle. Two similar groups of 7 male Montbéliard calves were used with the same age and weight, and with the same energy intake.

Comparison of the foetal development of fibre types in four bovine muscles.

The pattern of expression of different types of myosin heavy chains and the development of different generations of muscle cells during foetal life were studied in four bovine muscles with widely varying characteristics, the Masseter, Longissimus thoracis, Cutaneus trunci and Diaphragma. Different complementary techniques were performed: immunocytochemistry, electrophoresis, immunoblotting and ELISA. Monoclonal antibodies against different myosin heavy chain isoforms were used.