Sperm morphological and morphometric evaluation in captive collared peccaries (Pecari tajacu)

Abstract

Pesq. Vet. Bras. 33 (7) The aim of this study was to compare different staining methods for the evaluation of sperm morphology by light microscopy and also to describe the morphometry of the entire sperm in collared peccaries (Pecari tajacu). Semen from 10 males was obtained by electroejaculation and evaluated for sperm motility, vigor, and concentration. Semen smears were prepared through three different staining methods: Bengal rose, brome-phenol blue, and eosin-nigrosin. Smears were evaluated under light microscopy and sperm morphologic alterations were determined in percentage. In addition, sperm morphometric analysis was conducted by light microscopy coupled to image analyzer software. The smears stained with Bengal Rose provide the best results for the visualization of the sperm tail, midpiece, and head. The use of eosin-nigrosin stain did not allow an adequate impregnation, and some sperm presented a few contrasts with the background. A higher incidence of bent coiled tails was verified in the use of brome-phenol blue staining (P<0.05). Through morphometric evaluation, it was observed that the tail occupies the greatest proportion (89%) of the sperm which presents a discretely elongated head. According to the results, the use of the Bengal Rose stain is recommended for the morphologic evaluation of the collared peccary sperm.

Morphometry and abnormality evaluation of sex-sorted sperm of spotted buffalo (Tedong bonga)

“…Sperm body abnormalities include abaxial, proximal droplet, and sperm body defect. Tail abnormalities include folded tail and a distal droplet (Sousa et al 2013). The observation was done in triplicate of 200 sperm cells.…”

Ultrastructural description of fresh and frozen/thawed sperm derived from collared peccaries (Pecari tajacu Linnaeus, 1,758)

“…In collared peccaries, however, a peculiar feature is the presence of a well‐marked demarcation between the acrosome and the postacrosomal region. We emphasize that a previous study conducted by our team had explored the collared peccaries’ sperm morphometry (Sousa et al, ) using light microscopy. However, information regarding details of the acrosome and the presence of marginal thickening were only now possible with the use of SEM.…”

“…Before this study, morphological evaluation of peccaries’ sperm had been usually conducted by light microscopy (Sousa et al, ), which is a fast, easy, and low‐cost technique that allows the visualization of the contour and divisions of the sperm, allowing the identification of changes in morphology, and may also be applicable to the field (Silva, Silva, Cavalcante, Ferreira & Souz, ). In peccaries, light microscopy allows us to identify a series of secondary defects, probably provoked by sperm manipulation and the freezing/thawing process.…”

“…Rose bengal‐stained smears were prepared to evaluate the sperm morphology using light microscopy (1,000×), counting 200 cells per slide (Sousa et al, ). The functional integrity of the sperm membrane was verified by evaluating the sperm osmotic response under a hypo‐osmotic swelling test, using distilled water (0 mOsm/L) as the hypo‐osmotic solution.…”

“…Currently, it is well known that the ejaculate can be easily obtained by electroejaculation (Souza et al, ), and then evaluated by conventional analysis of sperm concentration, motility, and viability (Peixoto et al, ). Regarding morphological analysis, peccaries’ sperm are usually evaluated through stained semen smears under light microscopy (Sousa et al, ).…”