Joint action of carp ( Cyprinus carpio L.) pituitary homogenate and human chorionic gonadotropin (HCG) in carp oocyte maturation and ovulation: In vitro and in vivo studies

Abstract

In an in vitro study it has been shown that HCG at a dose of 100 i.u./ml does not cause an increase in the percentage of mature oocytes (follicles) compared to a control incubation. However, HCG together with carp pituitary homogenate (c.p.h.) at ratios of 6:4, 5:5, 4:6 (dosages of 60, 50, 40 i.u./ml of HCG and 40, 50, 60 μg/ml of c.p.h.) gave a higher mean percentage of mature follicles than did c.p.h. alone at a dose of 100 μg/ml. Based on the in vitro results, in vivo experiments with HCG and c.p.h. were conducted in order to decrease the amount of c.p.h. used in the induction of artificial spawning in carp. Experiments were carried out on 200 adult female carp. The use of HCG and c.p.h. in two injections (ratios 6:4, 5:5 and 4:6) at a dose 10 times higher than in the in vitro experiment did not increase either the percentage of mature oocytes or the number of ovulated females compared to groups injected with c.p.h. alone at the same dose. Classical hypophysation induced ovulation in the majority of injected females (60–80%). The results indicate that HCG with c.p.h. is ineffective in reducing the amount of c.p.h. required for artificial spawning of carp.