The effects of glycerol on the metabolism and ultrastructure of boar spermatozoa.

Cooling diluted boar semen to 5 degrees C and the addition of glycerol at 20 degrees C and 5 degrees C all depressed the subsequent metabolism of glucose, but had no effect on total oxygen uptake or lactate production. Ultrastructural studies showed that although glycerol had no effect on middle-piece cytology, it increased the incidence of acrosomal vesiculation at 5 degrees C. It is concluded that acrosomal vesiculation does not affect the metabolism of spermatozoa and it is suggested that the reported detrimental effect of glycerol on the fertilizing capacity of spermatozoa is related to its membrane activity.