Use of Carbopol resin for carp pituitary administration improves the fertilization percentage of northern pike (Esox lucius Linnaeus) eggs in commercial hatcheries

摘要

The efficiency of northern pike (Esox lucius Linnaeus) fry production via hormonal treatment of wintered broodstock is, in general, relatively low due to low egg fertilization percentage. It has been experimentally demonstrated that administration of acetone-dried carp pituitary extract in a slow-release vehicle of aqueous dispersion of Carbopol 971 P resin (CP) resulted in a higher mean fertilization percentage, possibly because the gradual hormone action could optimally control ovarian follicle maturation and ovulation. This new method of hormonal induction of ovulation was tested in a large-scale hatchery production of northern pike fry. In the present study, data on fertilization percentage collected between 2002 and 2006 at two prominent hatcheries in Hungary were analyzed. Administration of acetone-dried carp pituitary in a 2.5% CP vehicle resulted in higher fertilization (76.4 ± 7.7%; mean ± SD) compared to the saline vehicle group (59.3 ± 10.8%). The vehicle used did not affect the ovulation ratio. According to these results from large-scale production, the new method could be suitable to have wide application for induced breeding of northern pike.