267 EFFECT OF SEMINAL PLASMA IN LAMA GLAMA SPERM

Abstract

In South American camelids, raw semen only presents sperm with oscillatory movements. Therefore, it is necessary to treat these cells to enable them to acquire progressive motility. The effects of raw seminal plasma (SP) on sperm movement patterns (oscillatory, progressive, and hyperactive) have apparently not yet been reported. The objective of this study was to determine effects of raw seminal plasma on sperm motility, viability, and acrosomal status in fresh llama semen. A total of 15 ejaculates were collected (electroejaculation) from 5 llamas (n = 5, r = 3). Each ejaculate was diluted 4 : 1 in 0.1% collagenase in HEPES-TALP (HT) medium and incubated 4 min at 37°C, with the objective of separating spermatozoa from SP. Immediately after incubation, each ejaculate was divided into 2 and centrifuged for 8 min at 800 × g. Pellets were resuspended in either HT or raw SP and maintained at 37°C until evaluation (at 0, 1.5, and 3 h). Sperm motility was evaluated using a phase contrast microscope and a warm stage. Propidium iodide and carboxyfluorescein diacetate were used for assessing membrane integrity (viability). Acrosomal status was evaluated with the Coomassie blue stain. A split-plot design was used with treatment as a factor, with 2 levels (HT and SP) and time as the other factor, with 3 levels (0, 1.5, and 3 h), and blocked by males. There was no significant interaction between treatments (HT and SP) and times (0, 1.5, and 3 h) for each of the seminal characteristics evaluated. Progressive sperm motility was observed after collagenase treatment in all samples. Progressive motility disappeared immediately after the addition of raw SP and showed only oscillatory movements. In contrast, samples incubated in HT maintained progressive motility and became hyperactive. There were no differences (P > 0.05) in total motility of sperm incubated in HT among incubation times (0 h: 30.8 ± 18.9%; 1.5 h: 26.5 ± 11.5%; and 3 h: 21.5 ± 13.5%). However, in samples incubated with SP, a decrease (P < 0.05) in total sperm motility was detected after 3 h of incubation (0 h: 16.5 ± 12.6%, 3 h: 2.3 ± 3.2%). Sperm viability was not different (P > 0.05) between treatments (HT and SP); samples incubated in HT retained 78.4% of the initial viability (32.8/41.8, 3 h/0 h), and samples incubated in SP retained 69.7% of their initial viability (24.4/35.0, 3 h/0 h). The percentage of spermatozoa with intact acrosomes was not different (P > 0.05) between treatments (HT and SP); however, the percentage of sperm with intact acrosomes decreased after 3 h of incubation in both samples (HT and SP). Due to the presence of a high percentage of progressive and hyperactive motile sperm in samples incubated in HT and their absence in samples incubated in SP, we concluded that raw seminal plasma preserved oscillatory sperm motility. Further studies are needed to understand the effects of SP on South American camelid spermatozoa.