title: Determination of the rate of true fertility in duck breeds by the combination of two in vitro methods.
abstract: Embryonic mortality is a significant problem plaguing the hatching success. Its early forms are especially hardly distinguishable from true infertility. Propidium iodide (PI) staining of the germinal disc combined with outer perivitelline layer (OPVL) sperm counting was used for the determination of 'true' fertility of duck eggs in two different experiments: fertility investigation on fresh, unincubated eggs of Hungarian ducks and on incubated eggs of a crossbred, selected as 'infertile' at the 7th day of incubation. Examination of the relationship between OPVL sperm count and fertility seems to be an adequate tool for checking the effectiveness of insemination programmes and the fertilising capacity of poultry spermatozoa. The proportion of fertile eggs was around 50% when the number of OPVL sperm was between 0.1 and 0.2 spermatozoa/mm2. Ninety-nine percent of the eggs containing > 0.3 OPVL sperm/mm2 were fertile and all of the eggs containing < 0.05 sperm/mm2 were infertile. To assure the accuracy of fertility prediction by OPVL sperm counting, PI staining of the germinal disc was used to determine fertility in uncertain cases. Identification of very early embryonic mortality, i.e. that occurring before oviposition, is very difficult. The use of a dissecting microscope for the assessment of real fertility is suitable in most of the cases, while PI staining of the germinal discs proved to be more reliable for detecting very early embryonic death. The combination of the two methods proved to be a useful tool for detecting the 'true' fertility of duck eggs of different breeds.
authors.affiliation: Institute for Small Animal Research, H-2100 Gödöllo, PO Box 417, Hungary. liptoi@katki.hu
authors.forename: Krisztina
authors.initials: K
authors.lastname: Liptói
authors.forename: A
authors.initials: A
authors.lastname: Varga
authors.forename: A
authors.initials: A
authors.lastname: Hidas
authors.forename: Judit
authors.initials: J
authors.lastname: Barna
mesh_terms: D000818:Animals; D001947:Breeding; D004372:Ducks; D005260:Female; D005298:Fertility; D008297:Male; D010063:Ovum / Q000502:physiology*; D011247:Pregnancy; D011419:Propidium; D013076:Sperm Count / Q000662:veterinary*; D013194:Staining and Labeling / Q000662:veterinary
chemical_list: D011419:Propidium