Effects of different feed restriction periods on the growth and fatty acid compositions in juvenile rainbow trout (Oncorhynchus mykiss)

The aim of this study was to determine the effect of different feed restriction periods on the growth performance as well as the biochemical and fatty acid compositions of fillet in rainbow trout (Oncorhynchus mykiss). Fish with an average initial weight of 64.80±7.41g were used in the study. The trial lasted 60 days and 4 different feeding diets were alternately applied to the fish. The control group (C) was fed continuously throughout the trial while the other groups were fed 2 days starvation 1 day-1 feeding (2D), 4 days starvation 1 day-1 feeding (4D), and 6 days starvation 1 day-1 feeding (6D). The average weight of the fish at the end of the trial was 219.78±31.32g (C), 168.41±21.44g (2D), 116.60±12.28g (4D), and 87.64±12.99g (6D), respectively. The fillet protein values were determined as 20.85±0.69 (C), 19.82±0.68 (2D), 18.19±0.79 (4D), and 18.42±1.21 (6D), respectively. The lipid values were 6.18±0.40 (C), 3.35±0.41 (2D), 2.26±1.63 (4D), and 1.94±0.63 (6D), respectively. The lipid lean-1 body mass values were 0.27±0.05 (C), 0.16±0.03 (2D), 0.08±0.05 (4D), and 0.11±0.03 (6D), respectively. Regarding the analyses conducted on fish muscle tissues, the differences between the control group and feed restriction groups were statistically significant in terms of saturated fatty acids, monounsaturated fatty acid, polyunsaturated fatty acid, Omega-3, Omega-6, and Omega-9 values. In conclusion, it has been determined that the different feed restriction periods in the feeding of rainbow trout had an effect on the duration of reaching the marketable weight, feed conversion rates, meat yield, fillet protein, and fat ratio values and increased reaction to feed.