Excess nuclear DNA in spermatozoa of guinea fowl.
The proportion of spermatozoa with elongated nuclei in ejaculates from a strain of guinea fowl was estimated, subjectively, to range from approximately 1 to 6%. It was confirmed by image analysis that in an ejaculate from one male, the distribution of nuclear lengths was bimodal, with a distinct population comprising 10% of spermatozoa having a mean nuclear length that was 52% greater than that of the remaining 90%. Furthermore, the mean DNA content of the 'large-nuclei' population was 1.85 times (not significantly different from twice) that of the main sperm population. The proportion of large-nuclei spermatozoa that was motile was less than that of normal sperm (31% versus 59%) and the velocity of motile spermatozoa was also less (24 microm/s versus 72 microm/s). The poor motility of the large-nuclei spermatozoa in vitro was reflected in their limited performance in vivo, since only 1.1% were found associated with the egg outer perivitelline layer. This is the first report to quantify the occurrence of, presumed, polyploid spermatozoa in a domestic bird. The incidence of such spermatozoa in commercial guinea fowl and other domestic poultry and the genesis and effects on fertility of such spermatozoa may be significant.
Barna
Judit
J
Department of Avian Reproduction, Institute for Small Animal Research, P.O. Box 417, Gödöllo H-2101, Hungary.
Wishart
Graham J
GJ
D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D001717:Birds; D002467:Cell Nucleus / Q000737:chemistry* / Q000648:ultrastructure; D004247:DNA / Q000032:analysis*; D008297:Male; D011123:Polyploidy; D013081:Sperm Motility; D013082:Sperm Tail / Q000648:ultrastructure; D013094:Spermatozoa / Q000648:ultrastructure*
D004247:DNA