Saccus vasculosus, neuroglobin, stress and welfare during slaughter of salmon

Slaughter of fish is not optimal from a welfare point of view. We lack understanding of the oxygen storage protein neuroglobin in the fish brain and the heme red proteins in the Saccus vasculosus. Present methods used to stun and slaughter fish: electrici ty, percussion, chilling and carbon dioxide (CO2) are stressful. Sedation followed by anaesthetisation and slaughter that does not evoke stress responses would be very beneficial. We have found that CO has sedation and anaesthetic effects in fish. We beli eve that CO binds to oxygen storage proteins in the Saccus vasculosus and neuroglobin in the brain and cause sedation and anaesthetisation of fish/animals. From a welfare point this is very favourable, and the aim is to gain basic knowledge on how heme re d proteins in the Saccus vasculosus and neuroglobin function as an O2 storage component in brain and how stress regulates transcription and translation of Atlantic salmon neuroglobin. The heme red proteins of the Saccus vasculosus will be quantified, and neuroglobin will be isolated and characterized using classical analytical methods. Experiments using hypoxic conditions have shown that the amount of globins mRNAs change in salmon. The sequence of both neuroglobin and its genetic origin in salmon will be determined. Spectra of extracts from the Saccus vasculosus and gel chromatography indicate the presence of a high molecular hemoglobin component and a low molecular myoglobin component that is likely to be neuroglobin. CO will be used for sedation, anaes thetisation and slaughtering of salmon. Animal welfare, i.e. stress, will be measured using cortisol, brain and heart waves and behaviour responses. CO binds to the heme group of proteins and oxidation and rancidity are reduced. CO functions as a bacterio static agent, improving storage properties of fish fillets. Red colour of the product, due to CO binding, promotes fish and meat products in the market.