Fat digestion, transport and effect on metabolism in salmonids

Dietary fat is a key factor in salmonid culture. Optimal protein utilzation requires optimal fat supply. In a recent experiment protein utilization was improved 14% units by using medium chain fatty acids in the diet. Effects on digestion and possibly on protein synthesis appeared to be mechanisms behind. However, depressing effects on feed intake restrict immediate exploitation of the results. The present project is planned to reveal mechanisms behind the beneficial and negative effects to make us able t o overcome the negative effects and to take advantage of the potential for improvements. The sstrategies involve studies of effects of lipids with different fatty acid profile on composition of secreta from pancreas and liver (enzymes and bile salts), on nutrient hydrolysis (protein and lipids), on lipid transport across the intestial wall (everted sleeve method) and routes of lipid transport from the intestine (portal cannulation, riddance and isotope markers). Effects of fatty acid composition on muscle protein synthesis (RNA, specific proteins) and on hormones affecting nutrient partitioning and feed intake will also be investigated (insulin, glucagon, GLP-1, CCK). The project will be a cooperation with AKVAFORSK, University of Osl o and Norwegian School of Veterinary Science.