Morphometric parameters of alpaca spermatozoa (Vicugna pacos), obtained by three collection methods

Abstract

Sperm morphology is essential in evaluating seminal quality and important for fertility prediction in breeding males. The aim of this study was to compare the morphometric parameters of alpaca sperm, collected using three methods of semen extraction, recovery of the vas deferens (DCD), electro ejacula-tion (EE) and vaginal aspiration (VA). The collection was made of 3 animals by each method. The mobility, concentration, vitality, membrane functionality and sperm morphometry parameters were determined in a computerized semen analysis kit – ISAS® CASA - Morph. For morphometric parame-ters, semen samples were processed with a Hemacolor® staining kit and viewed under a phase-contrast microscope. For each sample, at least 200 sperm were captured at random, with an image resolution of 0.08 µm per pixel on the horizontal and vertical axes. The comparison of the morphometric parameters between the collection method and the animal was carried out using a random block design. Total motil-ity was 16.27±11.96%, 14.68±11.21% and 12.44±7.27%; the sperm concentration of 247±186.70x106EPZ/mL, 67.92±67.92x106EPZ/mL and 100.32±56.13x106EPZ/mL, the vitality was 62.86 ±15.92%, 63±15.21% and 70.16±14.33% in sperm collected by DCD, EE and AV respectively. Regarding the morphometric parameters, a length of 5.49±0.43µm, 5.53±0.41µm and 5.75±0.53µm was found, area 14.30±2.00 µm2, 15.05±1.77 µm2 and 15.88±2.00 µm2, perimeter of 16.10±1.31µm, 17.11±1.20µm and 17.41 ± 1.43, width of 3.22±0.27µm, 3.30±0.32µm and 3.33±0.25µm and the acrosome percentage of 52.22±7.82µm, 49.52±7.47µm and 47.44±5.77µm in sperm collected by DCD, EE and AV respectively. The morphometric parameters of the size and shape of the sperm head and the intermediate piece showed significant statistical differences (p <0.01) between the collection methods and between the animals. In conclusion, the morphometric parameters of alpaca spermatozoa were influenced by collection method, and show variations between animals.