The Possibility of using locusts (Schistocerca gregaria) as a protein source in the diet of rainbow trout fingerling (Oncorhynchus mykiss): growth performance and blood biochemical parameters

In this study, the possibility of using locusts as a source of protein in the diet of rainbow trout and its effect on growth performance and blood biochemical parameters were investigated. 300 fish with average weight (5.08 ± 0.33g) with diets of 0% (control), 15% (SG15), 30% (SG30) and 60% (SG60) locust meal were formulated, with equal protein energy contents. Diet was distributed in a completely randomized design in three replications for eight weeks and twenty-five pieces of fish with the same conditions, in each tank. At the end of the experiment, growth, biochemical and safety indices were calculated based on standard formulas and the analysis was performed using Tukey test. The results showed that the highest final weight was observed in 30% treatment )89.34 ± 20.61%) and the difference between 0, 15 and 60% treatments was significant (p <0.05). In 60% treatment, a significant increase in feed conversion ratio was observed compared to the control treatment (p <0.05). In feeding fish with locust meal diet, glucose, cortisol, albumin, globin and IgM levels did not show significant differences between different experimental treatments (p <0.05). However, the amount of total protein, triglyceride and blood cholesterol showed a significant difference in experimental treatments compared to the control treatment (p <0.05). Therefore, it can be concluded that the use of 30% locust meal in the commercial diet of rainbow trout fingerling, in addition to adversely affecting blood and safety parameters, can improve growth performance.