Sperm quality and morphometry characterization of cryopreserved canine sperm in ACP-106c or TRIS

Abstract

Morphological sperm evaluation supported by the morphometry can be used in the determination of the seminal quality and in the investigation of potential extenders. Although there are studies comparing TRIS and ACP extenders, there are no comparative studies between them for the computerized assisted semen analysis (CASA), sperm viability, membrane functionality and sperm morphometry parameters of cryopreserved canine semen. Hence, we aimed to evaluate the effects of ACP-106c and TRIS on post-freezing canine sperm quality. Five dogs were submitted to semen collection twice with one-week interval. The semen was evaluated within the parameters: total motility, vigor, concentration, viability, plasma membrane functionality, morphology and morphometry. In the morphometric evaluation, the morphologically normal sperm was measured as: length, width, area and perimeter of the head and the midpiece, tail length and total length. The parameters of ellipticity, elongation, regularity and roughness were determined. Then, the semen was divided into two aliquots that were diluted in TRIS or ACP-106c, with the addition of egg yolk and glycerol. The diluted semen was refrigerated and frozen. The thawed samples were evaluated. Total motility, viability, sperm membrane functionality and normal morphology reduced after thawing in both extenders (morphology reduced from 89.60 ± 1.3% to 84.40 ± 1.8 and 84.60 ± 1.1% in TRIS and ACP-106c, respectively). However, it did not differ between TRIS and ACP-106c. In the ACP-106c the sperm head defects in cryopreserved semen were higher compared to fresh semen (P < 0.05). For all the morphometric parameters evaluated, there were no differences between fresh and cryopreserved samples (3.70 ± 0.4% vs. 2.30 ± 0.5%). In kinetics, with an interval of one week statistical differences between the extenders were found only in the parameters ALH and LIN (P < 0.05). Regardless of the extender, there were no changes in the morphometric parameters of sperm after thawing.

Short‐term preservation of canine sperm‐binding ability and other metrics using the INRA‐96 in comparison to Tris‐egg yolk extender

“…The high rate of morphologically normal spermatozoa obtained in this study suggests that INRA-96 extender is suitable for maintaining the form and structure of spermatozoa during refrigeration. This can be attributed to the composition of the diluent, which includes monosaccharides and disaccharides such as glucose and lactose, which play an important role in energy supply, osmotic maintenance and protection of the sperm acrosome, thereby contributing to the maintenance of sperm functional and structural metrics (Teixeira et al, 2022).…”

“…As the control group, we used a Tris-based extender composed of 3.028 g Tris-hydroxymethyl aminomethane, 1.78 g monohydrated citric acid and 1.25 g D-fructose dissolved in 100 mL ultrapure water (Teixeira et al, 2022), plus the addition of 20% egg yolk and gentamicin (1.75 μL/mL). The extender had an osmolarity of 305 mOsm/L, and a pH of 6.6.…”