Nitric oxide euthanasia: a potential procedure for improving animal welfare and fillet color of tilapia (Oreochromis niloticus)

Abstract

Tilapia (Oreochromis niloticus) were euthanized with saturated nitric oxide (NO) solution prior to slaughter. The behavior, heart rate, plasma cortisol, and color values were used to evaluate the welfare and fillet color of the fish. Tilapia were unconscious after 20 min of NO euthanasia which was much shorter than with carbon monoxide (CO) treatment. Tilapia remained quiet during the euthanasia process. The heart rate reduced from 41 to 7 beats/min after 20 min of NO euthanasia, and the cortisol level in the NO-euthanized fish plasma was significantly lower than that of the percussively stunned fish sample. Moreover, both the red and white muscles of NO-euthanized tilapia fillets had a brig..