The requirement of a trypsin-like acrosomal enzyme for fertilization in the domestic fowl.

Abstract

Summary. The effect of a synthetic, irreversible trypsin inhibitor (TLCK: tosyl-l-lysine chloromethyl ketone) upon the fertilizing capacity of spermatozoa from four individual cocks was evaluated. Recently ejaculated spermatozoa were incubated with TLCK for 20 min at 37° C before insemination. The inhibitor was used at two concentrations that did not affect sperm motility. The mean fertility for the unincubated control, non-TLCK-incubated control and 50 μg TLCK-incubated semen groups was 91·8, 85·4 and 51·9%, respectively. Using 75 μg TLCK, the mean fertility for the unincubated control, incubated control and treated semen groups was 93·1, 74·1 and 24·4%, respectively. These results demonstrate the effectiveness of a synthetic trypsin inhibitor in successfully reducing fertilization in vivo and thus suggest the need for an active acrosomal trypsin-like enzyme for fertilization of the hen's ovum.