mGnRHa and Domperidone in separated PLGA microspheres enhance spermiation in Goldfish (Carassius auratus)

Artificial reproduction in fish species with strong dopaminergic inhibition typically relies on acute hormone injections, while controlled-release strategies remain underutilized. This study aimed to develop, for the first time, separately encapsulated microspheres of mGnRHa and domperidone using a PLGA polymer matrix for spermiation induction in male goldfish ( Carassius auratus ), serving as a dopaminergic species model. Microspheres were synthesized via single and double emulsion techniques. The entrapment efficiencies of mGnRHa and DOM microspheres were 94.48% and 98.21%, respectively. Forty adult males were randomly divided into four groups: negative control (empty microspheres), positive control (acute injection of 5 µg/kg b.w. mGnRHa + 2.5 mg/kg b.w. DOM), M10 and M20; microspheres containing 10 µg/kg b.w. mGnRHa + 5 mg/kg b.w. DOM, and 20 µg/kg b.w. + 10 mg/kg b.w. DOM, respectively. Spermatogenic parameters were evaluated at 24, 72 h, and 10 days post-injection. Sustained-release treatments (M10 and M20) significantly enhanced sperm volume, spermatocrit, density, motility, and viability compared to control groups ( P  < 0.05). Improvements were most pronounced in M20, particularly at 10 days. These results demonstrate that PLGA-based microspheres containing mGnRHa and DOM, when encapsulated separately, are a promising alternative to conventional hormone therapies, offering enhanced and prolonged spermiation in species with dopaminergic inhibition.