Hypophysation is one of effort to stimulate matured broodstock to ovulate and ready to spawn, with hypophysa gland extract injection (Fujaya, 2004). It means to make hypophysation or make hypophysa extract, needs another fish which is called donor. Eventhough hypophysation is not populer than using an artificial hormone which is called ovaprim, many farmer still using hypophysa to stimulate dumbo catfish to spawn in certain case.
As natural hormone, the power of it as stimulator is depend on many things such as: age of donor and the concentrate of donor’s gonadothropine. Most of farmer usually use male carp for this process. They choose it because male’s hypophysa releases gonadothropine in seven months for the first time but not with female. As we know that female’s gonad (ovarium) is bigger than male’s, so it takes more times to ripen female’s gonad. For female’s carp, its gonad reach the peak of maturation level (ready to spawn) in 12 months for the first time. So, they believe if using male carp would give more advantageous than female, at least male would be cheaper so farmer could save their money.
In fact, there’s no strict rule or fact that can support farmer’s opinion. That’s why this research is concentrated in using of different donor fish based on sex to stimulate spawning process in Clarias gariepenus.
Sumber : Laporan Penelitian M.Ridwan XI TBP SMKN 36 Jakarta
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