Induction of Ovulation by RCG Injection in the Tropical Walking Catfish Clarias batrachus Reared under 23-25°C

Abstract

A series of trials on induced ovulation were conducted using female walking catfish to examine conditions of maturity under warm water conditions. For this purpose, females were maintained at 23-25°C for a long period, either under 12L12D or natural photoperiod. Using 12-37 month-old females, induction of ovulation was achieved with a single injection of RCG (0.2, 0.4, 0.8, 1.6, or or 3.2 IUjg BW). In all the trials, RCG treatment succeeded in inducing ovulation at dosages of 0.4 IU/g BW or higher. Oocytes larger than 770 pm responded to RCG and ovulated. These results indicate that female walking catfish can maintain conditions of maturity for an extended time under warm water conditions, and can respond to RCG irrespective of photoperiod.