Recent understanding of stress response on muscle quality of fish: From the perspective of industrial chain

Fish is an important source of food that provides nutrition (particularly protein) for humans. Muscle quality is the key determinant of the economic value of fish. Throughout the industrial chain, live fish is exposed to a range of environmental stressors (e. g., temperature, oxygen, density, etc.) that may elicit the stress response, affecting muscle quality. From the perspective of industrial chain, we have comprehensively reviewed the effects of various stressors on fish muscle quality (e. g., nutrition, tissue structure, physical features, flavor, and sensory quality) in different primary chain nodes including farming/growing, catching, transportation, fasting, and slaughtering/stunning. This review also describes studies examining the potential mechanisms on alterations in muscle quality as induced by the stressors and their corresponding stress response. Owing to the variations on intensity, lasting duration, and mode of action, the same or different stressors in different chain nodes have varied effects on the muscle quality of fish. Generally, an intense stress response leads to the deterioration of fish muscle quality, such as fat oxidation, muscular fiber disruption, texture softening, decline of water holding capacity, and inferior sensory quality, etc. On the other hand, stress can also be artificially manipulated to improve the flavor of fish muscle or form crisp texture. Under stress, the changes on muscle quality may be the results of the fish's spontaneous regulatory strategy, which mobilizes energy to resist environment changes and maintain basic life activities, involving gene expression, metabolism, and immunity, etc.