STIMULATING DISEASE RESISTANCE FOR COMMON CARP (CYPRINUS CARPIO) REARED IN RECIRCULATING SYSTEM, BY UTILISING FEEDING DIETS SUPPLEMENTED WITH FATTY ACIDS

Elena Mocanu, N. Patriche, Magdalena Tenciu, Viorica Savin, M.D. Popa

Abstract
   Fish production carries risks due to infectious diseases, unbalanced diet and environmental challenges which compromise fish welfare. Consumers demand a healthier and safer food and nutritionists recommend a diet low in saturated fat and rich in polyunsaturated fatty acids. The aim of this research is to investigate how diets supplemented with fatty acids affect the disease resistance of the carp species (Cyprinus carpio) 1 year of age, reared in a recirculating system. The experiment was performed in the recirculating pilot system, over a period of 2 months, using 120 specimens of carp (Cyprinus carpio) and three experimental feeding diets, supplemented with oils from various sources, rich in unsaturated fatty acids. In the experimental groups there were no mortality due to the use of oils rich in fatty acids that have the property to increase the immune system of the fish, compared to the control group where the survival was 86.66%. In the three experimental groups, at the end, a slightly higher level of proteins is observed in group T3 (18.18 g%), compared to group T2 (17.7 g%) and T1 (17.75 g%), the difference being proportional to the weight gain, but the difference is insignificant (p>0.05) which suggests the almost similar evolution of biological material in protein retention, regardless of the source of fatty acids. The feed conversion ratio and protein efficiency improved with the addition of lipids in the feeding diets. The addition of oils to feeding diets resulted in an increase in blood parameters measured in the experimental groups (PCV, Hb, Erythrocyte, MCV, MCH and MCHC), compared to parameters monitored at the beginning of the experiment and at the end of the experiment in the control group fed without oil supplements.