Investigation of the effect of triiodothronine (T3) and thyroxine (T4) hormones on reproduction characteristics of the electric blue hap (Sciaenochromis ahli Trewavas, 1935)

In this study, the determination of the differences in reproduction characteristics of brood stock fed with triiodothronine (T3) and thyroxine (T4) supplemented diets was aimed. This research consisted of two seperate studies. Each study was performed as 6 groups in triplicates and different ratios of T3 and T4 were added into the diets contained 5 mg hormones in total. First and second experiments lasted 1 and 6 months, respectively. At the end of the first study, in terms of the growth parameters of electric blue haps, there were no significant difference between the groups (P>0.05). In females, amount of T3 increased in 15th day but decreased in 30th day. In female and male individuals lowest TSH (thyroid stimulating hormone) in 15 and 30th days were detected in the group fed with the diets contained high amount of T4. At the end of the second study, shortest hormone response time was detected in group C as 57 days. While least yolk sac consumed fry was determined in groups C and E with 32 fries, highest fries was obtained in group K with 43 fries. In 30th day, minimum and maximum fries were determined in group D (21 fries) and group K (41 fries). 30 days after the fries consumed their yolk sac, best survival rate was found in control group (95.69%) and the least survival rate was detected in group D (50.00%). Maximum and minimum weights of the fries consumed their yolk sac were found in group E as 0.028±0.000 g and group B as 0.020±0.000 g, respectively. The maximum fry weight was determined in group C (0.035±0.001 g) and the minimum weight was found in group D (0.023±0.000 g) in 30th day. As a result, both hormones showed negative and positive effects for this fish and using T4 hormone was found applicable in terms of response time to hormone, decreasing TSH secretion and growth performance of fry.