Hormonal (sGRnH) Doses Optimization with the Ages of Brood Fish in Induced Breeding of Mystus tengara (Hamilton, 1822)

Abstract

The age of brood fish is an inevitable factor in induced breeding technology worldwide. This study aimed to determine the optimal age for M. tengara for induced breeding and identify the most suitable age based on hormonal doses. Three age groups (1, 1.5, and 2-year-old) of brood fishes were used as three different treatments (T1, T2, and T3), with 0.8 ml kg-1, 1 ml.kg-1, and 1.2 ml kg-1 body doses of Ovasis (sGRnH) as the replications (R1, R2, and R3) of each treatment. Results showed that the highest mean fertilization rate (77.5 ± 1.73 %) was achieved in T1R2 for 1-year-old fish, while 1 ml kg-1 dose was ideal for them. For 1.5-year-old M. tengara, the highest mean fertilization rate was observed in T2R1 (79.25 ± 2.99 %) with 0.8 ml kg-1 dose being the most suitable. Two-year-old fish had the highest mean fertilization rate in T3R1 and T3R2 (76.25 ± 5.5 %) in June. Based on the fertilization rate and hatching rate, 1 ml kg-1 dose was identified as ideal for 1-year-old, and 0.8 ml kg-1 was suitable for 1.5-year-old M. tengara. Among all the treatments, T2R1 (1.5 year age, 0.8 ml kg-1) showed the highest hatching rate (78.25 ± 2.36 %) and most successful breeding performance over the study period, and June was identified as the best time for induced breeding. This scientific evidence provides valuable insight into the optimal age and hormonal doses for M. tengara in induced breeding technology