Temperature Shock in Chicken Spermatozoa

Abstract

Semen used in this study was collected from eighteen White Leghorn males. After the collected semen was thoroughly mixed with a glass rod, it was placed in a water bath at 25°C. Samples of undiluted semen (1.5ml) or diluted semen (1.6ml, 4-fold dilution with a Wilcox's buffer) were cooled at different cooling rates in order to determine whether chicken spermatozoa are subject to temperature shock produced by placing the samples at 25°C into cooling baths at 5.0 and -2°C. After the shock treatments, the diluted semen was centrifuged at 1, 200 R.C.F. for 5 minutes, supernatant discarded and resuspended to the original volume in the buffer just before insemination. In fertility tests White Leghorn hens were inseminated with 0.1ml of the undiluted semen or the reconcentrated semen. All precautions were taken against temperature shock during the collection and insemination of the semen. Results obtained are as follows.1) When the undiluted semen was cooled rapidly to 5°C as described above and stored for 60 minutes at that temperature, there was no change in fertility (94.2%), whereas a rapid cooling to 0 and -2°C resulted in lowered fertility (74.2 and 45.5%, respectively: P<0.01). When the undiluted semen was cooled slowly to -2°C at a rate of 0.5°C per minute and stored for 0, 30 and 60 minutes at the temperature, a slight decrease with the lapse of time with no significant decrease in fertility was observed through the storage periods (93.9, 85.0 and 82.5%, respectively). It was concluded, therefore, that chicken spermatozoa are subject to temperature shock.2) The effect of temperature shock on fertility was completely prevented by the 4-fold dilution of semen with the buffer.3) There was little change in motility of spermatozoa in any of the semen samples cooled rapidly to -2°C, whereas a significant increase (P<0.05) in the proportion of abnormal spermatozoa after the shock treatment was observed with the undiluted semen as compared to the diluted semen.