The effect of short-term growth hormone bath on hatching, absorption of yolk sacs and some blood parameters of egg, Alvin and fry of rainbow trout (Oncorhynchus mykiss) permeable to sodium hypochlorite

This study investigated the effects of different levels of growth hormone on hatching rate, yolk sac absorption and some blood parameters in egg, Alvin and fry stages of rainbow trout (Oncorhynchus mykiss). The experiment consisted of 4 treatments 0 (control) 0.1, 0.5 and 1 mg/l of growth hormone in 3 groups, each group at 3 stages of fish life (egg, Alvin and fry) permeabeled with sodium hypochlorite (0.005%) for 15 seconds and then Immersed in the concentrations of growth hormone for 5 minutes. Results showed that the percentage and duration of hatching time in all treatments were not significantly different with control (p>0.05). The length of absorption period of yolk sac in 0.1 mg/l was lower than 0.5 and 1 mg/l. Moreover, it was significantly lower than control group (p < 0.05). The highest amount of white and red blood cells was in egg stage with 1 and 0.1 mg/l respectively, which was significantly different from control (p < 0.05). Hemoglobin levels were also highest in 1 mg/l in egg stage. Hematocrit levels were significantly higher in all experimental groups (except in 1 mg/l in fry stage) compared to control. The highest levels of glucose were respectively observed in the fry, Alvin and egg stage. The highest amount of albumin and total protein were observed in 1 mg/l in egg stage which significantly were higher than other experimental and control group in different stages (p < 0.05). in conclusion, in egg stage, 1 mg/l of growth hormone had the best performance compared to other stages