Acta Vet. Brno 2010, 79: 3-12

Effect of Age and Sex on Histomorphometrical Characteristics of Two Muscles of Laticauda Lambs

Salvatore Velotto1, Ettore Varricchio2, Maria Rosa Di Prisco1, Tommaso Stasi1, Antonio Crasto1

1University of Study of Naples Federico II, Department of Soil, Plant, Environmental and Animal Production Sciences, Faculty of Agraria Via Università, Portici, Italy
2University of Study of Sannio, Department of Biological and Environmental Science, Faculty of Science MM.FF.NN., Benevento, Italy

Received January 15, 2009
Accepted June 30, 2009

The aim of the present experiment was to determine the effect of sex and age on histochemical and morphometric characteristics of muscle fibres (myocytes) in lambs born by single, twin, triplet and quadruplet birth. Thirty lambs were slaughtered at 60 days of age; thirty were weaned at 60 days and fed until 120 days with flakes (60%) and food supplements, and then slaughtered. Muscle tissues were obtained from two muscles, namely m. semitendinosus and m. longissimus dorsi of all lambs. For each fibre type, area perimeter and diameter (maximum and minimum) were measured and slow-twitch oxidative fibres, fast-twitch glycolytic fibres, fast-twitch oxidative-glycolytic fibres were histochemically differentiated. The muscles were stained for myosin ATPase, and succinic dehydrogenase. At 60 days, females had fibres larger than males, whereas the opposite was observed at 120 days. Besides, at 60 days, the lambs born by single birth had fibres larger than those born by multiple birth, whereas the opposite was observed at 120 days. Single lambs were heavier than twin lambs and multiple lambs. Fast-twitch glycolytic fibres had the largest size, followed by slow-twitch oxidative and fast-twitch oxidative glycolytic fibres. The dimensions of fibre types in m. longissimus dorsi were larger than in m. semitendinosus (P < 0.001).These muscle fibre characteristics are thought to be important factors influencing meat quality, which is often related to metabolic and contractile properties as determined by the muscle fibre type distribution.


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