Application of ovarian insemination method for the artificial reproduction of Caspian kutum (Rutilus frisii) under controlled conditions

The present study aims to compare the efficacy of the ovarian insemination technique with the traditional hormonal induction and artificial fertilization methods over the controlled reproduction of the Caspian kutum ( Rutilus frisii ). A total of 60 females, with a mean weight of 1484.9 ± 46.7 g, were randomly placed into six treatments (n = 10) as follows: intraperitoneal (IP) injection of saline (C1); injection of saline into the ovary with the catheter (C2); IP injection of sGnRHa+domperidone (T1); IP injection of sGnRHa+domperidone and injection of sperm to the ovary with the catheter (T2); injection of sGnRHa+domperidone into the ovary with the catheter (T3); injection the mixture of sGnRHa+domperidone and sperm into the ovary with the catheter (T4). Moreover, two subgroups [fertilization with additional (T2b, T4b) and no additional (T2a, T4a) fresh sperm] were considered to test ovarian inseminated sperm quality. The results indicated no fish ovulated in the control groups. Other reproductive parameters showed no considerable changes ( P > 0.05) among treated groups. The highest fertilization rate (96.9 ± 0.47 %) was observed in the T3 group and significantly differed ( P < 0.05) from the T2a (73.7 ± 1.52 %) and T4a (76.7 ± 1.90 %) treatments. The hatching rate, survival, and malformations were similar ( P > 0.05) across all treatments. According to the results, the ovarian injection technique can be recommended as a non-invasive practical approach for inducing Caspian kutum breeders, as it achieved 100 % ovulation success. Considering that fertilization with no additional fresh sperm following the injection of sperm into the ovary is not as effective as traditional fertilization, it is suggested that this method be applied only in situations where short-term sperm storage is necessary. In conclusion, our results emphasize the potential flexibility of hatcheries to implement customized protocols for their operational needs in the controlled reproduction of Caspian kutum. • The ovarian insemination technique was assessed for the first time on Rutilus frisii . • The effectiveness of hormonal induction via ovarian injection was evaluated for R. frisii . • Ovarian hormonal injection achieved 100 % ovulation success. • Fertilization success decreased by 20 % in groups that underwent ovarian insemination with sperm. • Ovarian injection can be a suggested alternative strategy for the induction of R. frisii .