Sodium hypochlorite solution has a good bacterial reduction effect. Thus, in order to understand the effect of sodium hypochlorite on tilapia storage, in this study, tilapia fillets were treated with sodium hypochlorite and Proclin 300 rinsing, the activity of histatinase protease was measured, and the muscle quality was assessed by the texture, colour, pH, myofibrillar fibril fragmentation index (MFI) and its structural changes. The results showed that sodium hypochlorite rinsing could significantly reduce the activities of histatinase enzymes B, L and D. Meanwhile, the sodium hypochlorite-treated group showed less degradation of myosin heavy chain, pro-myosin and myosin light chain, less degradation of texture and colour, better integrity in the fish myocytes, and a lower myofibrillar fragmentation index (MFI). In conclusion, sodium hypochlorite improved the storage quality of tilapia in several ways. Firstly, it inhibited protease activity, thereby maintaining the structural integrity of fish muscle fibres. Secondly, it reduced the rate of deterioration during storage.

Oregano essential oil (OEO) was tested as a natural botanical anesthetic for spotted sea bass (Lateolabrax maculatus) through a comprehensive evaluation of anesthetic efficacy, physiological homeostasis, tissue integrity, flesh texture and carvacrol residual dynamics. Gradient treatments (100–300 µL/L) revealed dose-dependent anesthetic performance, and 200 µL/L was validated as the optimal dosage, under which fish reached deep anesthesia within 3 min and regained normal swimming within 5 min, with zero mortality recorded 12 h post-anesthesia. Temporary stress and oxidative stress fluctuations occurred in serum biochemistry and antioxidant enzyme profiles, which approached control levels after 12 h depuration. Only slight histological changes appeared in liver and gill tissues without permanent pathological damage. Minor declines in partial texture attributes recovered completely within 12 h, whereas other muscle quality indicators remained unaffected. Carvacrol was detected in muscle immediately after OEO anesthesia but was below the detection limit at all subsequent sampling times. Functioning as an efficient natural anesthetic with minimal physiological disturbance, OEO shows potential as an alternative to synthetic anesthetics for spotted sea bass live transportation and delivers dependable technical guidance for aquaculture production.