Effect of Hormonal Stimulation on Egg Production andThermal Accumulation Period in Grass Carp

Three types of hormonal stimulation were tried using HCG, PG extract and Ovaprimto induce egg production and accelerate thermal accumulation period (TAP). Resultsshowed that there is a direct relationship between the type of hormones and TAP. Fishreceiving PG-extract had the shortest TAP which was significantly different thanthose receiving HCG and Ovaprim treatments. Values ranged between ۲۵۸.۹۷, ۳۴۴.۶۷and ۳۲۲.۷۸ (C ◌ -hour) in fish injected with PG extract, HCG and Ovaprimrespectively. Results also showed noticeable variation in egg production in fishreceiving various hormones with clear superiority for fish injected with PG-extractcompared with those receiving HCG and Ovaprim. The lowest weight of extractedeggs (۷.۳ g/kg) was in fish injected with HCG and the highest (۱۳۹.۷ g/kg) in fishreceiving the PG hormonal extract.

Keywords:

Grass carp , Hormonal-induced spawning , Egg production , Thermalaccumulation period.