Ovaprim Dosage Optimization for Spawning Induction of G6 Transgenic Mutiara Catfish

Abstract

Background: Optimization of Ovaprim dosage is necessary to improve spawning success in sixth-generation (G6) transgenic Mutiara catfish carrying the Clarias gariepinus growth hormone (CgGH) gene, whose reproductive performance has not yet been comprehensively evaluated despite stable transgene inheritance and superior growth traits. Aims: This study aims to determine the optimal dose of Ovaprim hormone for the success of semi-artificial spawning induction of sixth generation (G6) transgenic Mutiara catfish broodstock based on reproductive parameters including relative fecundity, egg diameter, fertilization rate (FR), hatching rate (HR), and survival rate (SR). Study Design: The study used an experimental method with a Completely Randomized Design (CRD) consisting of four treatments and three replications. Place and Duration of Study: The study was conducted at Hatchery Building 4, Faculty of Fisheries and Marine Sciences, Padjadjaran University, from July 2025 to March 2026. Methodology: The study used 32 G6 transgenic Mutiara catfish broodstock, consisting of 16 males and 16 females. The treatments consisted of varying doses of the Ovaprim hormone: Treatment A (0.2 mL/kg male broodstock + 0.6 mL/kg female broodstock), B (0.3 mL/kg + 0.3 mL/kg), C (0.4 mL/kg + 0.4 mL/kg), and D (0.5 mL/kg + 0.5 mL/kg). Observed parameters included relative fecundity, egg diameter, FR, HR, and SR. Data were analyzed using one-way ANOVA followed by Duncan's test using SigmaPlot 16.0 software. Results: The results showed that the treatments had a highly significant effect (P<0.05) on all reproductive parameters. The highest relative fecundity value was obtained in Treatment D, at 130,303 eggs/kg broodstock, but no improvement was observed in other parameters. Meanwhile, treatment C produced a fecundity of 85.00 eggs/kg, an egg diameter of 1.36 ± 0.14 mm, the highest fertilization rate of 92.39%, a hatching rate of 90.75%, and a survival rate of 85.32%. Duncan's test results showed that treatment C produced higher spawning parameter test results than the other treatments. Conclusion: The Ovaprim dose of 0.4 mL/kg male broodstock weight and 0.4 mL/kg female broodstock weight is the most optimal dose for semi-artificial spawning induction in G6 transgenic mutiara catfish because it produces the highest fertilization rate, hatching rate, and survival rate. Excessive Ovaprim doses (more than 0.5 ml/kg) cause excessive egg maturation resulting in micropylar blockage and reducing the ability of sperm to fertilize eggs, while low doses (suboptimal) are considered unable to stimulate gonadotropin release optimally so that the final oocyte maturation process does not occur perfectly.