Fast growth and welfare in Atlantic Salmon and Rainbow Trout

The continued increase in productivity in salmonid farming is closely related to shortening of the production cycles, and the key factor is increased growth rates. In the early days of salmon farming, fish needed 4-5 years from hatching to harvest, wherea s today, market size can easily be reached in half that time. This progress has been achieved through a combination of genetic improvement, better feeds and feeding systems, environmental management and improved production techniques, health control and f arming systems. There is a growing public concern about modern farming methods, related to the welfare of the animals. The markets have a definite prerequisite to food producing animals being normal and healthy. The challenge of obtaining normal developm ent in periods ofextremely fast growth is well known from animal husbandry. Animal growth represents the concerted action of numerous biological processes, and in order to produce a healthy animal, these processes must keep its synchronization even when s peed of each si ngle process is increased. This strategic program aims at increasing fundamental knowledge about the process of growth in Atlantic salmon (Salmo salar L.) and rainbow trout (Oncorhynchus mykiss). We will perform integrated studies of growt h of muscle, connective tissues, cartilage and bone, at the whole animal level as well as in tissues, cells and the molecular level. Different models aimed at promoting fast growth and/or abnormal development will be used. Key factors and markers for norm al vs. abnormal development will be identi fied.