The Effect of Diluted Doses of GnRHa (Ovulin) Supplemented with Buserelin Acetate- GnRHa (Suprecur) on Final Ova Maturation and Breeding of the African Catfish (Clarias gariepinus)

Abstract

Studies have shown that Ovulin® is a cost-effective hormone for inducing final oocyte maturation (FOM) in Clarias gariepinus, and further studies have shown that dilution of the hormone can also be effective. This study was designed to investigate the spawning response of C. gariepinus, with an average weight of 1110.0±91.2g, by the induction method utilising serially diluted Ovulin® combined with buserelin acetate (Suprecur®), a gonadotropin hormone-releasing hormone analogue (GnRHa). Treatments administered include 0.5ml/kg Ovulin® (T1), 0.4ml/kg Ovulin® + 32µg/kg Suprecur® (T2), 0.3ml/kg Ovulin + 32µg/kg Suprecur® (T3), 0.2ml/kg Ovulin® + 32µg/kg Suprecur® (T4) and 32µg/kg Suprecur® (T5) + 5mg/kg Domperidone®. We determined the fecundity (absolute egg numbers), latency period, fertilisation rate, hatching rates, and survival (post-yolk absorption stage) in eachtreatment. The results demonstrated that diluted Ovulin® + Suprecur® together successfully induced ovulation in the experimental C. gariepinus broodfish. There was no significant difference (p>0.05) in egg weights stripped from each treated group. The application of 0.5ml/kg Ovulin®, 0.3ml/kg Ovulin® + 32 µg/kg of Suprecur® and 0.2ml/kg Ovulin® + 32 µg/kg of Suprecur® resulted in a Latency period of 12 hours compared to 11 hours for the other treatments. Results of the fertilisation percentage indicated that hormone administration did not significantly affect the fertilisation rate (p>0.05). Similarly, the hatching rate was not dependent onhormone administration (p>0.05). Also, hormonal administration to female broodstock did not affect fry survival rate to first feeding (p>0.05).