Study on feasibility of sperm injection in ovarian for induced propagation of Koi carp (Cyprinus carpio var. Koi)

One of the limitations in fish reproduction is the duration of sperm motility. One of the hypotheses related is the possibility that sperm survive relatively long in the female body. Therefore, in this study, the reproductive ability of koi carp (Cyprinus carpio var. Koi fish) was investigated by direct injection of sperm into the female ovaries. Three experimental groups were investigated in this study. In the control group, fertilization was performed by the conventional method. In the second group, sperm was injected directly into the ovaries 12 hours before ovulation, and in the third group, sperm were injected 2 hours before ovulation. In each group, 2 males and 3 females were used. Fertilization was performed by the dry fertilization method, using a mixture of cow's milk and water in a 1:10 ratio to eliminate adhesion. The results showed that in groups 2 and 3, which were injected directly into the ovary 2 and 12 hours before ovulation, respectively, the percentage of fertilization did not show a significant difference (p<0.05), but the percentage of fertilization in the control group was significantly (p<0.05) higher than groups 2 and 3. The percentage of hatching and survival showed no significant difference between control group and groups 2 and 3 (p<0.05). The results showed that ovarian fluid in carp could not activate sperm for motility. In general, it can be said koi carp sperm can maintain their fertilization ability in the ovaries of female for at least 12 hours.