General requirement and cataract preventative effect of dietary histidine relative to dietary lipid sources in Atlantic salmon growers

The amino acid histidine has been identified as a key preventative factor in the development of cataract in Atlantic salmon. The exact mechanism for the cataract mitigation by elevated His is not clear. Histidine covers many important biochemical roles in the salmon lens, such as a component in protein synthesis, pH buffering, osmoregulation, antioxidation and detoxification. Since we in several experiments have experienced significant cataract development in salmon fed diets with vegetable oils compared to fish fed marine oils, there is an urgent need for further research on the relationship between dietary lipids and His. The exact requirement for His in Atlantic salmon growers under practical conditions is not known. Thus, this project will apply an ex perimental design suitable to assess His requirement for growth, as well as possible “beyond deficiency” requirements for cataract prevention. Requirements will be assessed in fish groups receiving diets based on either vegetable or marine oil sources. He nce possible influence of vegetable oils on the His requirement and cataractogenesis will be investigated.