Establishment of a practical sperm penetration test for bovine semen

Abstract

Summary Objective: Several methods for evaluating semen quality have been developed in addition to traditional semen analysis. Most of these methods are very complex and require expensive technical equipment as well as special knowledge to be performed. The aim of this study was to establish an easy and cost-effective sperm penetration test for bovine semen using artificial media. Additionally a standard procedure for test performance should be figured out. Material and methods: In the first part of the study four different capillary tubes or pipettes were evaluated in order to determine the most appropriate one to use in the penetration test. In the second part of the study the tubes were filled with different compositions of polyacrylamide gel and subsequently incubated at 37.5 °C for 30 minutes. Sperm penetration was then evaluated using a phase contrast microscope, measuring the penetration distance of the first, the first motile and the five vanguard motile spermatozoa as well as determining the number of sperm cells cumulated per low power field (LPF) at three distinct distances in the tube. Results: Non-heparinised haematocrit capillary tubes were the most appropriate tubes for performance of sperm penetration test as 100% of used capillaries were evaluable after incubation and size of the capillaries allowed a simple handling and good visualisation of migrated spermatozoa. Best results were achieved with 1.9% polyacrylamide gel containing phosphate-buffered saline. Measuring the penetration distance of the vanguard motile sperm cell can be recommended for test evaluation. Conclusion: A sperm penetration test with 1.9% polyacrylamide using non-heparinised capillary tubes was established. Results showed high reproducibility, the procedure is simple to carry out and only requires a phase contrast microscope.