Regional differences in micro-structural and biochemical characteristics of growth and metabolism in semitendinosus muscle of 28-day old piglets

Micro-structural and biochemical characteristics of myofibre growth and metabolism were compared among three regions (dark [near bone], central, and superficial bright) of the semitendinosus muscle mid-belly of 28-day old piglets. The total fibre number as estimated from the dark, central, and bright region, as well as mean fibre area did not differ among regions. Compared with the bright region, the dark region exhibited a larger proportion of red oxidative fibres, a greater capillary density, smaller protein concentration, greater DNA concentration, a lower lactate dehydrogenase (LDH) activity, and a higher isocitrate dehydrogenase (ICDH) activity. High concordance correlation coefficients were found between the central region and the mean of the three regions in terms of micro-structural properties (except fibre type distribution), LDH and ICDH activities per g tissue, which would allow restricting the analyses to the central region for these traits.