Stunning and slaughter methods in gilthead seabream: animal welfare and muscle quality

European Union directives and international guidelines emphasise the need for humane slaughter practices, with particular attention to the proper stunning of fish prior to slaughter. This study investigates the impact of various combinations of stunning and slaughter methods on the welfare of gilthead seabream (Sparus aurata), a widely farmed species in the Mediterranean and Black Sea regions. Specifically, the study explores electrical stunning, anaesthesia, and no stunning, followed by slaughter using either ice-slurry or the ikejime (hand-held spike tool) technique. Fish were monitored for visual signs of consciousness, heart rate, internal temperature, plasma stress and osmotic parameters, and muscle quality parameters. The findings revealed that electrical stunning, although inducing brief unconsciousness, did not sustain it long enough to be effectively combined with ice-slurry, resulting in stress responses and muscle quality parameters comparable to those observed in unstunned fish. In contrast, anaesthesia effectively reduced stress and improved meat quality. The ikejime technique, despite its labour-intensive nature, demonstrated significant advantages, including reduced physiological stress and superior muscle quality outcomes. These results suggest that the viability of electrical stunning as a humane option for industry implementation has important limitations, while ikejime, with further refinement and automation, could offer a humane and effective solution to optimise both animal welfare and meat quality in industrial settings.