Effects of different levels of organic acids on growth performance, body composition and hematological parameters of rainbow trout fry (Oncorhynchus mykiss)

A 12-week feeding trial was carried out with rainbow trout fry (3.45±0.05) by application of four diets including commercial diet (control), commercial diet with 0.1% organic acids (T1), commercial diet with 0.2% organic acids (T2) and commercial diet with 0.3% organic acids (T3) to investigate the proper dose and study the effect of organic acids on growth performance, survival, body composition and some hematological parameters. Experiment was done in completely random design and the data analysis was performed by Excel and SPSS. Finally, significant difference was not observed in final weight, SGR, FCR, PER and feed intake (P>0.05). Also, a significant difference (P<0.05) was observed between T1 and control in survival rate, while there is no significant difference among these two groups and T2, T3 (P>0.05). As far as body composition is concerned, no remarkable difference was found among treatments (P>0.05). WBC was significantly higher (P<0.05) in T1 compared with other groups. However, no significant difference was obtained among treatments (P>0.05) with regard to RBC and Hb. The highest (P<0.05) HCT was observed in T1 which had a significant difference comparing with control, nevertheless, there is no significant difference among these two groups and T2, T3 (P>0.05). To sum up, As far as results of this study are concerned, the addition of 0.1% of organic acids to rainbow trout fry diet is suggested.