Protein content of fish

The protein content does not vary greatly and is usually around 16% (although tuna is an exception with over 20%).

The protein content of fish muscle varies with season in some species and where this occurs the protein content varies inversely with the water content.

Plankton-feeding fishes appear to show higher protein values than fishes feeding otherwise. Hibernating carp show a decrease in both protein and free amino acids.

Higher levels of protein are found in the feeding season and less around the spawning season - there are obvious incentives in using fish who high protein content.

Wild fish contained more hemoglobin, greater total serum protein content and higher serum albumin concentration than did the cultivated ones.

The protein quality in terms of amino acid composition is very similar in most fishes though the molluscan and crustacean proteins appear to be rich sources of essential amino acids.

Actomyosin amounts to about 70% of the total protein content of fish muscle. G-actin from cod exists mainly in the form of a dimer of molecular weight of about 150,000, whilst cod myosin has a molecular weight of about 550 000.
Protein content of fish