The Effects of adding different ratios of synthetic essential amino acids to rainbow trout (Oncorhynchus mykiss, W.) rations on growth performance

In this study, it was aimed to determine the effects of adding different ratios of synthetic essential amino acids to rainbow trout, Oncorhynchus mykiss rations on the live weight, total length, live weight gain, relative growth rate, spesific growth rate, condition factor, monthly food intake, daily food intake, feed conversion ratio, protein efficiency ratio, protein productive value, carcass yield, fillet yield, proximate structure (crude protein, crude fat, crude ash, nitrogen free extract, moisture, essential and non-essential amino acids) offish meat and duration until reaching marketing weight offish. For this purpose, one control and two experimental rations were prepared. Some amino acid levels (as a percentage of the ration; 3.1 % lysine, 1.9 % iso leucine, 2.3 % arginine, 1.9 % phenylalanine, 2.0 % valine, 1.4 % threonine and 0.9 % methionine) of the control ration were increased 10 % for the first experimental ration, and 20 % for the second experimental ration. This study was replicated twice. The food calculated as a percentage of the live weight was given for fishes three times in a day.V In conclusion, it was a significant difference between the fishes fed with the second ration and the fishes fed with control in the live weight, live weight gain, relative growth rate and monthly food intake (p<0.001, p<0.01, p<0.01 and p<0.001 respectively) in the favour of former. In addition to these, it was also found that the live weight, live weight gain and monthly food intake values of fishes fed with the second ration were significantly higher than those of the fishes fed with the first ration (p<0.01, p<0.05 and p<0.01 respectively). There was no significant difference in the other parameters between the first, second rations and control (p>0.05 for each case). The fishes fed with control, first and second rations reached marketable weight in 9, 8 and 7 month respectively. As it can be seen from the investigated parameters, the best result was obtained from the second ration. Therefore the growth food of rainbow trout should contain 3.72 % lysine, 2.28 % izo leucine, 2.76 % arginine, 2.28 % phenylalanine, 2.40 % valine, 1.68 % threonine, 1.08 % methionine, 1.09 % histidine, 1.80 % leucine and 0.54 % triptophan. Key Words: Rainbow trout, Oncorhynchus mykiss, essential amino acid, requirement, growth performance.