Effects of Stocking Density on Composition and Performance of Reared Arctic Charr<i>(Salvelinus alpinus)</i>

Abstract

Abstract Proximate composition and performance of Arctic charr (Salvelinus alpinus) stocked at 40, 50, and 75 kg/m3, were determined. Moisture content of fish fillets decreased while their protein and lipid contents increased during the 24 weeks of rearing period. Statistical analyses indicated that moisture, protein and lipid contents of charr flesh varied significantly among density groups while ash contents did not. While the moisture and ash contents of fish fillets were directly related to stocking density (r = +0.9435 and r = +0.9918, respectively), contents of protein and lipid did not (r = −0.5251 and r = −0.7038, respectively). The level of carotenoids in the flesh and skin of Arctic charr increased with duration of feeding on pigmented diets. However, no correlation (r = −0.6053) existed between stocking density and concentration of carotenoids. The specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER) were significantly influenced by stocking densities but the hepatosomatic index (HSI) of fish did not. These performance parameters of fish were well correlated with stocking density (r = −0.9368, −0.9975, −0.9899, and −0.9920, respectively). Although SGR, FCR and PER of fish from different stocking densities varied significantly (p < 0.05), their final weights did not.