Gräns, Albin
- Institutionen för tillämpad husdjursvetenskap och välfärd, Sveriges lantbruksuniversitet
Sammanfattning
Ensuring humane slaughter is essential for ethical and high-quality fish production. Ikejime is widely regarded as rapid and quality-preserving, yet its manual application is labour-intensive and anatomy-dependent, limiting scalability. An automated, AI-guided ikejime system could overcome these constraints, but its welfare efficacy is unvalidated. We provide the first neurological evaluation of manual and automated ikejime for rendering rainbow trout (Oncorhynchus mykiss, similar to 0.3-0.5 kg) and hybrid striped bass (Morone chrysops female x M. saxatilis male, similar to 1.1-2.1 kg) insensible, using visually evoked responses (VERs) on the electroencephalogram (EEG). Results are compared with manual percussion and asphyxiation, together with exploratory product-quality analyses. Asphyxiation caused prolonged distress lasting up to 13-16 min in both species. In contrast, both ikejime methods rendered all trout irreversibly insensible within 2 min, although neither reliably achieved immediate insensibility. Efficacy declined in bass, with similar to 25-43 % of individuals remaining sensible after application. These findings demonstrate that ikejime, whether manual or automated, should be preceded by a stunning step ensuring immediate loss of sensibility. Reduced effectiveness in larger and more robust species underscores the need for species-specific refinements, including optimized spike dimensions and insertion techniques. While exploratory product-quality assessments indicated potential effects of slaughter method and effectiveness on rigor mortis and drip loss, these patterns should be validated in future studies using larger sample sizes and broader replication. Together, these data provide critical evidence to guide the refinement of slaughter methods aiming to enhance fish welfare while ensuring product quality.
Nyckelord
Spiking; Electroencephalography; Conscious; Unconscious; Stress
Publicerad i
Aquaculture
2026, volym: 613, artikelnummer: 743458
Utgivare: ELSEVIER
SLU författare
UKÄ forskningsämne
Fisk- och akvakulturforskning
Publikationens identifierare
- DOI: https://doi.org/10.1016/j.aquaculture.2025.743458
Permanent länk till denna sida (URI)
https://res.slu.se/id/publ/145249