Comparative analysis of the effects of HCG and CPE combinations on the sexual maturation of common Japanese conger Conger myriaster

Abstract:

By analyzing the relationship between gonadal development and sex steroid hormone content during artificial ripening process, the aim of this study is to provide knowledge of artificial induction of maturation in Conger myriaster. A total of 100[body mass:(288.30±62.34) g] wild Japanese conger were collected and divided into four groups:group A (CPE:2 mg/kg), group B (HCG:200 IU/kg), group C (CPE:1 mg/kg and HCG:100 IU/kg) and control group without any hormone injection. The injection was given once a week and lasted for 12 weeks. The results showed that hormones can significantly promote the development of oocytes and induced the development of oocytes to the stage of nuclear transplantation successfully. The gonad of fish from Group C had the best development that about 32% eels' oocytes developed into Ⅳ stage. Moreover, all the fish induced by treatment had developed the oocyte into Ⅲ stage compared to the control group which was still stagnant in the stage Ⅱ. The content of testosterone[(217.00±31.76) ng/g] in the gonads of conger eels from treatment group C was significantly higher than that from the control group[(123.24±21.05) ng/g]. This study revealed that the CPE combined with HCG plays a better role in inducing gonad maturation of Conger myriaster.