Lipids in common carp (Cyprinus carpio) and effects on human health

There is evidence that n-3 fatty acids (FA), especially EPA and DHA, are beneficial for human health. This thesis examined factors influencing FA composition in common carp flesh, sought to develop a procedure for long-term sustainable culture of common carp with improved muscle lipid quality (omega 3 carp) and studied the health benefits of eating such carp in the secondary prevention of cardiovascular disease. An approach using the bioactive compound sesamin to increase biosynthesis of EPA and DHA from alpha linolenic acid showed that addition of sesamin did not alter muscle lipid composition in common carp. Investigations of the response of carp to finishing feeding and prediction of FA changes by a dilution model revealed that fillet FA composition reflected the FA composition of the diet and was correlated to the length of the feeding period. The simple dilution model accurately predicted changes in the fillet FA composition. A procedure for long-term sustainable culture of omega 3 carp based on supplementation by pellets containing rapeseed cake and extruded linseed as a lipid source was developed and the carp were compared with fish supplemented by cereals and fish kept on natural feed (plankton and benthos) only. Carp supplemented by cereals were characterised by a high level of monounsaturated FA (MUFA) and low level of n-3 FA, whereas carp supplemented by the rapeseed/linseed pellets had a favourable FA profile close to that of fish kept on natural feed only. Studies on the effects of purging on carp flesh lipid content and composition showed that lipid quality changed during the purging period, with increasing levels of n-3 FA and decreasing levels of MUFA. Supplementation with rapeseed/linseed pellets in the growing period and purging for no longer than 14 days resulted in a nutritionally beneficial FA composition combined with an economically acceptable weight loss. In studies on the health benefits of carp in the prevention and treatment of cardiovascular disease, consumption of carp improved plasma lipid parameters in patients after major cardiac revascularisation surgery. Overall, these results suggest that culture of carp should be recognised as long-term sustainable and carp should be promoted as a healthy and local product