The effect of feeding strategies on growth performance, hematological indices, and biochemical parameters in male rainbow trout (Oncorhynchus mykiss) broodstocks

This investigation was carried out to determine the effect of feeding strategies on growth performance, biochemical parameters, and hematological indices in male rainbow trout (Oncorhynchus mykiss) broodstocks. For this purpose, 45 broodstocks with 475.55 ± 54.24 g (mean ± S.D) were divided into three treatments and fed at satiation, restricted feeding (50% of satiation limit), and starvation levels in concrete ponds. The flow rate was 1 liter per second for each replicate and the broodstocks were fed for 8 weeks with extruded feed. According to the results, the final weight of the starvation treatment had a significant decrease compared to the restricted and satiated treatments (p<0.05). Moreover, the weight gain, body weight increase and specific growth rate showed significant differences among the treatments (p<0.05), but the condition factor was not significantly different (p>0.05). A significant difference was observed in feed conversion ratio between the restricted and satiated groups (p<0.05). Hematological indices did not show any significant difference between the treatments (p>0.05). In the blood biochemical parameters, plasma glucose level in the starvation treatment showed a significant difference with the restricted feeding and satiation treatments (p<0.05). In addition, blood globulin level of the starved fish was significantly different with the starvation treatment (p<0.05). In general, the present study showed that unpredictable stresses during the breeding season and the consequent reduction or interruption of feeding regimes could adversely affect the performance of male breeders, including growth indices and some physiological parameters.