Stimulation of ovarian development and spawning in the giant freshwater prawn, Macrobrachium rosenbergii (de Man).

摘要

The effect of 5-hydroxytryptamine (5-HT) and octopamine (OA) on the ovarian development and spawning of M. rosenbergii was investigated. 5-HT or OA was injected at 0.1 ml of 20 or 40 micro g/g and 20 or 40 micro g/g body weight, respectively, after spawning. Triple injections used one-third of the single injection dosage on the first, third and fifth days after spawning. The females were allowed to mate after the treatments, and embryo survival was monitored until hatching. The study lasted for 10 days. It was shown that 5-HT stimulated ovarian development but OA did not induce any changes. A single injection of 5-HT at 20 micro /g stimulated development in immature ovaries within 10 days and significantly increased ovarian index, while triple injections were not as effective. Both 5-HT and OA were equally effective in inducing spawning within a few hours after mating compared to untreated controls. The controls spawned at night (18:00-06:00 h), while 40% of the treated prawns spawned during the daytime (12:00-18:00 h). Spawned embryos were normal and survived to hatching. In conclusion, 5-HT and OA can induce spawning in prawns..