Bioeconomic analysis of some commercial trout feeds used at rainbow trout (Oncorhynchus mykiss) farms in Eastern Black Sea Region of Turkey

SUMMARY In this study, daily consumption rates, conversion ratios, growth performance and economy of three commercial palletised trout feeds widely used in rainbow trout farms in Eastern Black Sea region have been compared. Six groups, two replicates for each feed type, offish each comprising 75 fingerlings with mean initial weights of 16.54±3.48 (A), 16.51±3.24 (B) and 16.50±2.70 g (C) were established in 0.3 m3 fiberglas tanks. Monthly and daily mean values of growth and feed consumption rates, feed conversion ratios and condition factor were determined during 155 day study period and using these data bio-economical analysis of feeds has been conducted. Mean weights of fish at harvest reached 383.57±96.30, 359.60+93.27 and 366.97±84.21 g for groups A, B and C, while the final stocking densities were 90.47, 84.81 and 86.55 kg/ m3, respectively. Specific growth, feed consumption and conversion rates ranged between 1.17-4.06%, 1.09-4.46% and 0.88-1.37. As percentage of net income the mean feed cost was lowest for feed B, 36.1% followed by A, 39.7% and C,41.5%. It has been concluded that feed B which containing more plant material appears to more economical than the others, stock densities of 80-90 kg/ m3 at harvest are quite suitable for tank culture and daily feed consumption rates from 1.09% to 4.46% depending on fish size, feed type and water temperature. Key words : Rainbow trout culture, Oncorhynchus mykis, Pelletised feed, Daily feed consumption, Feed conversion ratio, Growth performance, Bio-economic analysis VI