Study of boar sperm interaction with ce:italic>Escherichia coli/ce:italic> and ce:italic>Clostridium perfringens/ce:italic> in refrigerated semen

摘要

The present study analyses the interaction of boar spermatozoa withEscherichia coliand Clostridium perfringens, in 9-day refrigerated semen samples. Ejaculates from 10 sexually mature boars were inoculated with eitherE. coliorC. perfringens, at infective titer from 101to 107CFU/mL. The sperm-bacteria interaction was evaluated by optical and scanning electron microscopy (SEM), through: a) determining the proportion of spermatozoa with eitherE. coliorC. perfringensadhered and the number and localization of bacteria adhered on the sperm surface; and b) analyzing the effects of bacterial contamination on sperm membrane integrity. While proportions of spermatozoa with bacteria adhered did not differ betweenE. coliandC. perfringensduring the first 3 days of storage, proportions of spermatozoa withE. coliadhered were greater than those withC. perfringenson and subsequent to Day 4 of storage. Both bacterial types adhered non-specifically over the sperm surface; nevertheless, the proportion of spermatozoa with bacteria adhered to the mid-piece was greater withE. coliinfection, and of spermatozoa with bacteria adhered to the principal piece greater withC. perfringensinfections. Alterations in the sperm plasma membrane induced byC. perfringensaffected the acrosomal end and appeared at Day 4 of storage, those induced byE. coliwere apparent from Day 7 of storage and affected the acrosomal region and mid-piece. In conclusion,E. colihas a greater capacity to adhere to the sperm surface thanC. perfringensduring liquid storage at 17?°C, but damage on sperm membrane integrity induced byC. perfringensoccurred in a shorter period of time.