Abstract
It has been well known that boar sperm are liable to fall into a state so-called "anabiosis", and that it takes 15 minutes to 2 hours warming and shaking to demonstrate their motility.
This study was conducted to examine the effect of the caffeine-slide (glass slide which was smeared with caffeine anhydrous) on the restoration of boar sperm motility. The preparation procedure of the caffeine-slide is shown in Figure 1. Undiluted boar semen was subjected to motility evaluation after 3 days' preservation in a test tube at 15°C.
Evaluation of motility was made microscopically at 38°C by placing 10 μl of semen between the pre-warmed slide and coverslip (1.8×1.8 cm).
Experiment 1. Using caffeine-slides which were smeared with various amounts of caffeine, motility evaluations were made at 15, 30, 60, 120 and 180 seconds after incubation on the microscopic stage at 38°C (Table 1). Caffeine-slides (0.52.0%) markedly stimulated sperm motility. Motility was increased as the amount of smeared caffeine was increased. However, the state of caffeine smeared on the slide was ununiform in the 2.0% slide. From these results, the use of a caffeine-slide which was smeared with 1.0% caffeine-ethanol solution appears to be adequate for the restoration of boar sperm motility.
Experiment 2. Semen samples were diluted with an equal volume of Ca++-free KRP containing fructose (0.2%) or both fructose (0.2%) and caffeine anhydrous (0.1%). Three ml diluted and undiluted semen samples in glass tubes (φ: 15 mm, depth: 90 mm) were incubated in a water bath at 38°C without shaking. Motility evaluations were made on the semen samples at 0, 10, 20, 30, 60, 90 and 120 minutes after incubation using either caffeine-slides (1.0%) or untreated slides (Table 2). Regard-less of the dilution treatments, motility percentage was higher for caffeine-slides than untreated slides. In undiluted semen samples, tail to tail agglutination of sperm was characteristically induced by caffeine-slides (Figure 2).
Because of the simplicity of use and effectiveness for the restoration of motility, caffeine-slides may be applied to the evaluation of boar sperm motility in the laboratory and field.
