Effect of linseed and sunflower oil supplementation in the diet on the growth performance in carp (Cyprinus carpio L.), cultivated in a recirculating system

Abstract. The aim of this study was to determine the influence of linseed and sunflower oil supplementation on the survival rate, weight gain and feed conversion ratio in carp (CyprinuscarpioL.), raised inarecirculating system. The fish in the experiment were reared in concrete tanks that were part of the recirculating system and had a capacity of 0.8 m3. The carps received extruded pellets (6 mm) obtained by “Aqua garant”. For a period of 60 days the feed of the fish of the experimental group (EL) was supplemented with 5 % linseed oil, while the carps of the group (ES) received additionally 5 % sunflower oil with the diet. The fish of the control group (C) received feed without any of the above mentioned vegetable oils. The weight gain of the carps was controlled at 15-days intervals. The live weight (g) and the linear growth (mm) were determined as the fish were weighed and measured individually. The final live weight of the carps of the experimental and control groups was as follows: EL–871.45±240.39 g, ES–849.00±223.22 g and C–819.55±269.91 g. The value of this parameter in the fish of EL groups was by 2.58% and 5.96% higher than those of the individuals of ES and C groups, respectively, but the differences were not significant (P>0.05). This tendency was similar for the linear measurements, as in the carps receiving linseed oil they were the highest. The EL group displayed the lowest feed consumption. The value of this parameter was lower than those of the ES and C groups by 13.90% and 25.74%, respectively. The differences were significant between the control group and the carps supplemented with linseed oil (P<0.05). The survival rate in the fish of the three groups did not differ significantly.