The Traits of Protein Metabolism in the Skeletal Muscle of Teleost Fish

The review summarizes the literature and our own experimental data on the features of the structure, function, and protein metabolism in skeletal muscles of teleost fish (Teleostei). Despite the conserved basic mechanisms of muscle growth (myogenesis) and degradation in vertebrates, fish are characterized by unique features related to their poikilothermy, indeterminate growth, and a special role of skeletal muscle as a depot of plastic and energy substrates. Fish skeletal muscles show high plasticity in terms of their ability to undergo substantial anabolic or catabolic changes in response to environmental variables, such as temperature, photoperiod, and food availability. Under optimal (anabolic) conditions, fish muscle tissue grows by hypertrophy and hyperplasia at an extremely high rate, while during the periods of high energy demand, including migration, starvation, and gonad maturation, catabolism of skeletal muscle proteins temporarily dominates. However, degradation of fish muscle tissue can be profound enough to exceed its regenerative capacity: both genetic programs and responses to exogenous signals of excessive strength and duration can be implemented via this scenario. An extreme and demonstrative example of the mobilization of muscle protein reserves and utilization of resulting amino acids for energy production and synthesis of stage-specific gonadal proteins are Pacific salmonids whose exhaustion during spawning is so great that results in their death. Fish myopathies and the potential of fish as objects for human disease modeling are also considered.

Automated summary

Fish skeletal muscles exhibit high plasticity in response to environmental variables, showing the ability for substantial anabolic or catabolic changes. Under optimal conditions, fish muscle tissue grows rapidly through hypertrophy and hyperplasia, while periods of high energy demand may lead to temporary dominance of protein catabolism.