. Fat was measured gravimetrically following 5 h extraction of dried samples in a mixture of equal volumes of sulfuric ether and petroleum ether, using a Twisselman apparatus. Fatty acid methyl esters (FAME) from muscle samples were prepared from aliquots of total lipid extracted by the Folch method (Folch et al., 1957) and quantified by gas chromatography with FID detector. Carbohydrates were calculated by the equation C = 100 − F − P − W − A; where C, F, P, W and A correspond respectively to carbohydrates, fat, protein, water and ash. Energy in kJ was calculated from the following equation: kJ/100 g = 37 × F + 17 × P + 17 × C; where F corresponds to fat, P corresponds to protein and C corresponds to carbohydrates.