Effects of magnetic fields on the freezing of boar spermatozoa

摘要

The perpose of this experiment was to investigate the effects of freezing in the magnetic fields on the viability, acrosorne integrity and GOT releasing of boar spermatozoa. Sperm rich fraction was extended by pre-extender and stood for 3 hours at room temperature. After centrifugation, precipitated spermatozoa were suspended in the first diluent and cooled to 5 deg C taking about 90 minutes prior to the second dilution. Finally diluted semen was filled into straws and frozen in liquid nitrogen vapour in magnetic fields. Each magnetic strengthes in three cases of magnetic fields prepared by 10,000 and 4,000 gauss of permanentmagnets were 7,450, 1,550 and 240 gauss, respectivly, by the gauss meter. The results obtained were as follows; 1. The exposing of magnetic fields in process of freezing were beneficial for the improvement of sperm viability after thawing. Acrosomal integrity and GOT release were not different between each exposing of magnetic fields. 2. The effect of magnet to sperm viability was obtained in maxi-straw (phi 5 mm) freezing, but not in mini-straw (phi 2 mm) freezing. 3. Sperm viability in maxi-straw after freezing in magnetic field was not inferior to that in mini-straw. It seemed that 1,550 G was little superior to 240 G. 4.Normal piglets were farrowed after insemination of frozen semen in 1,550 gauss of magnetic strength. From the above results, it was indicated that the freezing in magneticfield was beneficial for the improvement of sperm survival rate and the maintenance of sperm motility after thawing. And also more effective production of frozen semen and more economically storing will be possible.