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

• Main Author: Metusalach, 1960-
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1995
• Subjects: Arctic; Arctic charr; Salvelinus alpinus
• Online Access: https://research.library.mun.ca/4139/; https://research.library.mun.ca/4139/1/Metusalach.pdf; https://research.library.mun.ca/4139/3/Metusalach.pdf

The effects of stocking density on performance, proximate composition and pigmentation of cultured Arctic charr (Salvelinus alpinus) were studied. Results indicated that specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER) of fish were significantly (p<0.05) influenced by stocking densities, but no significant (p>0.05) effects were evident in the hepatosomatic index (HSI) of fish. These performance parameters of fish correlated inversely with stocking density at 40, 50 and 75 kg/m³ (r = -0.9522 for SGR, -0.9696 for FCR, -0.9886 for PER, and -0.9059 for HSI). Although SGR, FCR and PER of fish from different stocking densities varied significantly (p<0.05), their final weights did not. -- 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. Analyses indicated that moisture, protein and lipid content varied significantly (p<0.05) among density groups while ash content did not. Regression analysis showed that moisture and ash content were directly related to stocking density (r = 0.9440 and 0.9994, respectively), whereas protein and lipid content were not (r = -0.5394 and -0.7030, respectively). -- The total amino acid content of fish varied significantly (p<0.05) according to stocking density and sampling dates. Aspartic acid, glutamic acid, leucine and lysine were the most abundant amino acids present, whereas hydroxyproline was the least abundant. The free amino acid content of the fish also varied significantly (p<0.05) and inversely with stocking density (r = -0.9441) 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. Among density groups, fatty acid contents of fish flesh were also relatively similar. Unsaturated fatty acids were the dominant fatty acids, accounting for up to 75% ...