The effect of feeding frequency on growth performance and body composition in juvenile rainbow trout (Oncorhynchus mykiss) reared in cold seawater
This study was done to investigate the effects of different feeding frequencies on the growth, feed efficiency and specific growth rate (%) of juvenile of rainbow trout (Oncorhynchus mykiss, weight 16.44±0.22 g) rearing in cold sea water conditions (5.8 to 9.3°C; 17 to 18 ppt). Fish were fed on a commercial feed to the apparent satiation twice a day (Control), six times every day (TD6), four times every day (TD4) and three times every day (TD3) for 8 weeks of the trial. The fish fed to satiation in all the experimental groups. Weight gain, growth rate, feed intake and final body weight decreased with reduction of feeding frequency from six times daily to two times daily. The fish fed at TD6 had relatively high apparent net protein retention and better feed conversion efficiency compared with the fish fed at the control, TD4 and TD3. The feeding frequency had significant effect on the crude lipid, crude protein but not moisture and crude ash proximate composition of rainbow trout. It was recommended that six meals per day was the optimal feeding frequency for juvenile rainbow trout reared in cold sea water at 5.8 to 9.3°C, 17 to 18 ppt.
Key words: Feeding frequencies, growth, body composition, sea water, Oncorhynchus mykiss.