Effect of different levels of feed restriction on growth performance and body composition of rainbow trout (Oncorhynchus mykiss) larvae cultured in two different water circumstances

The aim of this study was to investigate the effects of short term starvation periods on growth, feed efficiency and chemical composition of rainbow trout (Oncorhynchus mykiss) larvae cultured at two salinity levels; 0.5 ppt (fresh water) and 1.95 ppt (brackish water). Fish larvae averaged 300 ± 10 mg in weight were exposed to three different feeding regimes for 40 days: one group (control) which continuously fed and the two other groups including T1 (5 days feed + 2 days starvation) and T2 (2 days feed + 2 days starvation). The growth performance results indicated that there are significant differences (P<0.05) between the treatments. The maximum body weight (1935.47 mg) was obtained in control group. These results indicate that protein, lipid and energy efficiency ratio in control group were significantly enhanced in comparison with T1 and T2 (P<0.05). The highest PER, LER and EER amounts (1.70, 5.26 and 0.56, respectively) were also obtained in control. Body composition was also analyzed at the end of the experiment. The highest and lowest crude protein levels were obtained in control (74.65%) and T2 (59.72%), respectively. The results showed that food deprivation has a negative impact on the growth performance and body composition in the fish larval stage