C. Jurie et al., Changes in the metabolic and contractile characteristics of muscle in malecattle between 10 and 16 months of age, HISTOCHEM J, 31(2), 1999, pp. 117-122
Samples of semitendinosus muscle from 28 male cattle (18 Salers and 10 Limo
usins) were taken at 10 months (biopsy) and at 16 months of age (at slaught
er). 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. The five lactate
dehydrogenase isoenzymes were separated by electrophoresis under non-denat
uring conditions and assayed by densitometry. Fibres were identified by his
tochemistry by myofibrillar ATPase and succinate dehydrogenase activities a
s SO (slow oxidative), FOG (fast oxidative glycolytic) or FG (fast glycolyt
ic), and by immunohistochemistry by their reaction to monoclonal antibodies
specific to slow and fast myosin heavy chain reactions in I, IIC, IIA, IIA
B and IIB type fibres. The isocitrate dehydrogenase activity was not modifi
ed between 10 and 16 months of age; the lactate dehydrogenase activity decr
eased and was correlated with an increase in the proportion of the H isozym
e to the detriment of the proportion of the M form. This period was charact
erized by an increase in fibre size, increased expression of MHC IIa, resul
ting in more IIA fibres, less IIB fibres, and an increase in the percentage
of type IIAB fibres, however the proportions of SO, FOG and FG, when analy
sed statistically, were not modified between 10 and 16 months of age.