Effects of stocking density on performance, proximate composition and pigmentation of cultured arctic charr (Salvelinus alpinus)

The effects of stocking density on performance, proximate composition and pigmentation of cultured Arctic charr (Salvelinus alpinus) were studied. Performance parameters of fish correlated inversely with stocking density at 40, 50 and 75 kg/m;Results also indicated that while the moisture content decreased, protein and lipid content increased as fish grew; the mineral content remained relatively unchanged over this period. Analysis indicated that moisture, protein and lipid content varied significantly among density groups while ash content did not. Regression analysis showed that moisture and ash content were directly related to stocking density, whereas protein and lipid content were not.;The total amino acid content of fish varied significantly according to stocking density and sampling dates. The free amino acid content of the fish also varied significantly and inversely with stocking density and sampling dates. The major free amino acids were anserine, taurine, glycine and alanine.;Lipid fatty acid composition of charr flesh was relatively unchanged over the course of the experiments.;The Hunter L* values of fillets and homogenized tissues were inversely correlated with their carotenoid contents, whereas their Hunter a* and b* values were directly correlated with total carotenoid contents.;The content of carotenoid pigments in flesh and skin of charr increased with duration of feeding on pigmented diets. After 11 to 16 weeks of feeding on a canthaxanthin-pigmented diet, fish flesh attained the required level of carotenoids (3-4 mg/kg wet tissue) considered sufficient for providing a satisfactory colour impression. However, stocking density did not correlate with flesh carotenoid concentration. (Abstract shortened by UMI.)...