ABSTRACT
The different stunning methods for Atlantic salmon can still be improved with regard to animal welfare. Salmon exposed to carbon monoxide expressed no aversive reactions towards CO as such. CO exposed fish showed an earlier onset of rigour mortis and a faster decrease in muscle pH due to depletion of oxygen during the treatment. Exposure to CO did increase the level of cortisol compared to undisturbed control fish, but the increase was less than in the water only control group. Neuroglobin, a CO binding globin, was found in salmon brain and Saccus vasculosus, a richly vascularized sac connected to the fish brain. Binding of CO to neuroglobin during sedation might possibly improve animal welfare.
Subject(s)
Carbon Monoxide , Salmo salar , Animals , Behavior, Animal , Brain/metabolism , Globins/metabolism , Hydrocortisone/blood , Hydrogen-Ion Concentration , Muscles/chemistry , Nerve Tissue Proteins/metabolism , Neuroglobin , Rigor Mortis , Salmo salar/metabolismABSTRACT
Neuroglobin (Ngb) exists only in small amounts in salmon brain. In order to study the protein in more detail salmon neuroglobin (sNgb) was cloned, heterologously expressed in Escherichia coli and purified. The protein had red color and showed the characteristic peaks at 411nm (metNgb), 415nm (carboxyNgb) and 424nm (deoxyNgb). Western analysis showed that sNgb reacted weakly against a rabbit anti human neuroglobin (hNgb) and strongly to a sNgb specific antibody. Our 3D-homology model of the sNgb indicated modifications adjacent to and in the O(2)/CO binding site. This may correlate to differences in substrate affinities for the sNgb compared to the hNgb. Also sNgb contained shorter helixes and longer interhelical loops typical for psychrophilic proteins.
