Effect of thyroxine injection on female growth performance and hematological parameters of sterlet sturgeon (Acipenser ruthenus)

Thyroid hormones [triiodothyronine (T3) and thyroxine (T4)] are also known to play an important function in other biological processes such as growth, sexual development and metabolism in different fish species. Therefore, the objective of this study was to examine the effects of T4 injection on growth performance and hematological indices in sterlet sturgeon (Acipenser ruthenus) broodstock. Three treatments with two replicates and 5 fish for each group were considered. The experimental treatments included: control (coconut oil alone), low dose of T4 (T1; 1 mg T4/kg body weight + coconut oil) and high dose of T4 (T10; 10 mg T4/kg body weight + coconut oil). Four intraperitoneally injections were made in female sterlet sturgeon (initial weight 707.97 ± 37.15 g) every 2 months over a 170-day period. At the end of study growth performances and hematological indices were determined. The results showed that fish treated with high doses of thyroxine were noted higher growth performance from other group. The fish in T10 group showed significantly higher red blood cells, hematocrit, hemoglobin, white blood cells, neutrophil and lymphocyte percentage than the other groups. Based on the current study, 10 mg thyroxine hormone /kg body weight in sterlet sturgeon broodstock can perform positive effects on growth and physiological performance.