Evaluation of different levels of feeding and their effects on growth and FCR in grower rainbow trout in fiberglass tanks under the condition of brackish water in Bafgh station

The objective of this study was to evaluate 4 levels of feeding defined as 1.ad libitum to satiation, 2.Standard feeding (based on fish size and water temperature), 3.10% less than that of standard feeding and 4.10% more than that of standard feeding on growth, feed conversion rate (FCR) and carcass quality of rainbow trout (Oncorhynchus mykiss) reared in 12 aerated flow-through fiber glass tanks (2500l rearing volume, n=150 fish per tank, body weight average 45 g) comprised of 3 replicates under the condition of brackish water (salinity 8.4 g/l) in Bafgh Fisheries Research Station in center of Iran. The increase in average body weight (BW) and size of fish in different feeding groups was significantly different (P<0.01) during the experiment (101 days) and the highest average BW and size increase occurred in the group fed ad libitum to satiation. On the contrary, FCR (average ±SE: 1.27±0.09) in this group was statistically lower than that of the other groups (P<0.01). The chemical composition of carcass was significantly influenced by the level of feeding (P