Summary. This paper describes the effects of whole seminal plasma and of dialysed seminal plasma on the fertilizing ability of fowl spermatozoa stored for 24 h at 4°C. The fertilizing ability of fowl semen diluted 1:1 with Beltsville Poultry Semen Extender and stored for 24 h at 4°C was enhanced after replacement of the homologous seminal plasma by the diluent (89 versus 77% fertilization rate). Better results were obtained with seminal plasma dialysed against water before sperm storage to discard the < 1 kDa or the < 50 kDa fractions. It was concluded that low molecular weight seminal plasma fractions could damage the fertilizing ability of spermatozoa during storage at 4°C, whereas high molecular weight fractions appeared to enhance fertilizing ability.
Keywords: seminal plasma; fertilizing ability; fowl