Effects of adding various oils to the diet on growth, feed conversion and chemical composition of carp (Cyprinus...

The suitability of various vegetable and fish oils was tested as feed components for one-summer-old carp fingerlings. Five diets were used: a basal diet, which served as control feed, was supplemented with 10% corn-germ oil, 10% sunflower oil, 10% fish oil or 10% rapeseed oil, respectively. By means of the lipid supplementation the crude protein content decreased from 35.5% in the basal diet to 31.9% in the test diets, whereas the gross energy level increased from 16.3 to 18.9 MJ/kg. The diets were fed over a period of 84 feeding days and water temperature was 23 degrees C. Weight gain, feed conversion ratio and protein utilization were superior in all groups of carp which received the fat-enriched high energy diets. Considering the gain in % of the initial weight, the control fish reached less than 400% whereas all carp in the test groups, which consumed the oil-enriched diets, reached 455 to 485%. A significant influence of the kind of lipid on growth and feed conversion could not be recognized. The lipid-enriched diets with higher energy content resulted in increased fat levels of the carp. Fatty acid composition of the carp reflected that of the diets. In the control group and the fish oil group the levels of palmitic, palmitoleic, eicosapentaenoic and docosahexaenoic acid were especially high corresponding to the fatty acid profile of the diets. In carp fed the diets supplied with corn-germ oil and sunflower oil linoleic acid was dominant whereas the carp fed the rapeseed diet were characterized by a high level of oleic acid.