The Effects of Different Feeding Rates on Growth Performance and Stomach Volume in Rainbow Trout (Oncorhynchus mykiss)

In this study, the effects of various daily feeding ratios on the growth, stomach volume and meat composition in rainbow trout (Oncorhynchus mykiss) were investigated. The feeding experiment was conducted in 450 L volume fiberglass tanks with 3 × 3 factorial patterns. During the experiment, while food were given to the fish at the first group in the 0.5% (I) of ratio of their live weight, the second group at the level of 2% (II) food were given to the fish, at the third group at the level of 6% (III) food. The initial weight and size values of the groups were 76.16±0.41 g and 19.11±1.63 cm, respectively. The final weight and size values reached up to 128.89±34.21 g, 25.09±2.37 cm; 236.05±89.32 g, 24.78±2.22 cm; and 238.91±86.67 g, 21.65±1.64 cm, for groups I, II, and III respectively. The best growth performance in terms of weight was obtained in group III, while the best growth performance in terms of size was obtained in groups I and II (P < 0.05). The best feed conversion ratio was determined in the low feeding group I (P < 0.05). At the end of experiment, three of the experimental groups were different from each other. The highest stomach volume was measured in group III (P < 0.05). In conclusion, the 6% feeding ratio increased the growth and significantly increased the stomach volume, however decreased the feed conversion ratio.