Post-Ovulatory Oocyte Ageing in Pikeperch (Sander lucioperca L.) and its Effect on Egg Viability Rates and the Occurrence of Larval Malformations and Ploidy Anomalies

摘要

The effect of post-ovulatory oocyte ageing on egg quality was assessed in pikeperch Sander lucioperca to identify the reliable and the best post-ovulatory stripping time. Ovulated eggs were retained in the ovarian cavity for 0-3, 3-9, 6-12 and 12-18 hours post-ovulation (HPO) prior to fertilization. Fertilization, hatching and embryo mortality rates as well as the occurrence of larval malformations and ploidy anomalies were considered as indices for egg quality. The results indicated that the fertilization and hatching rates remained nearly constant, at approximately 80%, for the eggs retained in the ovarian cavity between 0-18 hours after ovulation. Post-ovulatory oocyte ageing did not affect the embryo mortality or the occurrence of larval malformations at least during the 12-hour experimental period. However, the incidence of triploidization in the larvae increased over time from 1.6% at 0-3 HPO to 5% in more aged oocytes at 6-18 HPO. Egg quality retention for at least 12 hours after ovulation appears to be helpful for pikeperch breeding programs by providing synchronous artificial egg insemination and thereby easing hatchery management.