Effects of microwave irradiated canola meal on growth, nutrition performance, carcass characteristics and digestibility of nutrients in Huso huso fry

Effects of diets containing microwave-irradiated canola meal were evaluated on growth, nutrition performance, carcass composition and digestibility of nutrients in Huso huso fry with 31.18 ± 1.43 g in initial weight during 8-week experiment in a factorial design 4 × 2 with 8 treatments, each with 3 replications. Treatments included T1: %20 canola meal without irradiation; T2, T3 and T4: 20% irradiated-canola meal at 800 watts for 5, 10 and 15 min respectively; T5: 40% canola meal without irradiation; T6, T7, and T8: %40 800 watt – radiated canola meal at 5, 10 and 15 min respectively. At the end of the experiment, according to the results, the effects of diet containing microwave-irradiated canola meal on the final weight, weight gain, specific growth factor, feed conversion ratio and daily growth in H. huso fry were significant (p<0.05). The highest final weight, percentage of weight gain, daily growth and specific growth rate were found in T4, while the lowest ones in T5 (p<0.05). Food conversion ratio increased significantly in T5 compared to the other treatments (p<0.05). The results of analysis of variance exhibited that the effects of both canola meal rate (%) and irradiation time and also their interactions caused significant differences in the growth indices except for the coefficient of conversion (p<0.05), but only irradiation time displayed significant effect on food conversion ratio (p <0.05). During the experiment, survival rate was 100%. Microwave-irradiated canola meal diet did not significantly affect the protein and fat contents of the fish carcasses (p>0.05), but showed significant effect on the carcass ash content (p<0.05). According to these results, by increasing irradiation time, the protein digestibility increased (p<0.05). Microwave-irradiated canola meal exhibited no significant effects on fat digestibility and dry matter content (p>0.05). So, it can be added to the diet up to 40% without any unfavorable effect on protein digestibility and growth rate.