Effect of Diluent Composition on Survival and Fertility of Bovine Spermatozoa Stored in Carbonated Diluents

Abstract

Attempts were made in this study to determine the concentration of each constituent of the carbonated Illini variable temperature diluent which would result in optimum sperm survival. Changes in the potassium chloride or the sulfanilamide concentration resulted in no substantial increases in spermatozoan survival. An increase in the glucose concentration from 0.017 m to 0.067 m resulted in an increase in sperm livability. Little difference was noted in sperm survival in diluents with 5, 10, and 20% egg yolk during storage at 26.5C, whereas, at 5C, 20% egg yolk permitted longer sperm life. The addition of catalase also prolonged sperm life at 26.5C and when used in conjunction with higher levels of egg yolk and glucose, greatly increased livability compared to semen extended with the original IVT diluent. A sodium bicarbonate concentration of 0.05 m in the buffer supported better sperm livability than the original 0.025 m concentration. When the sodium bicarbonate concentration was increased to 0.10 m in a diluent containing 0.067 m glucose and 15% egg yolk, and the ampules were flushed with CO2 immediately before filling, 47% live sperm were found after 60 days of storage at 5C. Two modifications of the IVT diluent tested for their effect on fertility resulted in an increase in the fertilizing capacity of sperm during storage for a week, as compared to fertility in one of two previous tests of the original IVT diluent.