Variations in the Contents of Crude Protein, Total and Free Amino Acids of Arctic Charr (Salvelinus alpinus) Reared at Different Stocking Densities

Abstract

The contents of crude protein and total and free amino acids of fillets of Arctic charr (Salvelinus alpinus) stocked at 40, 50, and 75 kg/m³, were determined. Results indicate that as the fish grew their protein content increased. Statistical analyses indicated that protein contents of fish varied significantly (p < 0.05) among density groups, but no relationship existed between stocking density and protein contents of fish (r = −0.5394).

The contents of total amino acids of fish varied significantly (p < 0.05) according to stocking density and sampling dates. Aspartic acid, glutamic acid, leucine and lysine were most abundant, whereas hydroxyproline was the least abundant amino acid present. The content of free amino acids of fish also varied significantly with stocking density (r = −0.9441) and sampling date. The major free amino acids and related compounds present in the fillets were glycine, alanine, anserine and taurine.

Key Words:

• Charr
• stocking densities
• amino acids
• fillets