Comparison of Different Glycerol and Egg Yolk Concentrations Added toTris‐based Extender for the Collared Peccaries (Tayassu tajacu) Semen Freezing

Abstract

This study aimed to evaluate various concentrations of egg yolk (5, 10, or 20%) in combination with different concentrations of glycerol (3% or 6%) added to a Tris-based extender on the post-thaw characteristics of sperm obtained from Tayassu tajacu. For this purpose, semen from 10 sexually male mature collared peccaries was collected by electroejaculation and evaluated for sperm motility, vigour, viability, morphology and functional membrane integrity. The ejaculates were initially extended in Tris-fructose plus egg yolk (5%, 10% or 20%). After cooling, the semen was added to Tris-egg yolk plus glycerol (6% or 12%), resulting in a final concentration of 3% or 6% glycerol of the extender. Straws were frozen using liquid nitrogen and thawed in a water bath at 37°C for 30 s. The frozen-thawed semen was evaluated as reported for fresh semen. After thawing, a significant decrease was verified for sperm motility and vigour, for all the samples in comparison with fresh semen. However, no differences were evidenced among treatments for any sperm characteristics evaluated (p > 0.05), except for the combination between 10% egg yolk and 6% glycerol, which provided the worst preservation of functional membrane integrity (p < 0.05). The interactions between higher concentrations of egg yolk (20%) and glycerol (6%) and also between lower concentrations of the same substances (5% egg yolk and 3% glycerol) added to the Tris-based extender negatively affected the preservation of the normal sperm morphology after thawing (p < 0.05). In conclusion, the use of Tris-based extender added to 10% or 20% egg yolk plus 3% glycerol is recommended for effective sperm cryopreservation in collared peccaries.

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

“…These modifications could had interfered with the sperm motility, which decreased from 72.3 ± 9.9% in fresh samples to 25.0 ± 15.0% in frozen/thawed samples. In fact, a reduction in sperm motility after thawing/freezing procedures has been described not only in collared peccaries (Alves et al, , Souza et al, ) but also in various other wild animals as bears ( Ursus thibetanus japonicus ) (Okano, Murase, & Tsubota, ), white rhinoceroses ( Ceratotherium simum simum , C.s. cottoni ) (Hermes et al, ), deer ( Cervus elaphus hispanicus ) (Martínez‐Pastor et al, ), and Asian elephants ( Elephas maximus ) (Saragusty et al, ).…”

Cryopreservation of collared peccary (Pecari tajacu L., 1758) epididymal sperm using extenders based on Tris and powdered coconut water (ACP®-116c)

“…In fact, this quality loss is somewhat expected because of the biochemical, functional, and ultrastructural damages that are induced by cryopreservation (Hamilton et al ., 2016). Comparing our post-thawing results to those previously reported for ejaculates (Silva et al ., 2012; Alves et al ., 2013; Silva et al ., 2013), peccaries’ sperm derived from both cauda epididymis and ejaculation apparently can be efficiently preserved using the same freezing–thawing procedures.…”

“…To reduce these problems, several factors, including the choice of an adequate semen extender, are critical for the effectiveness of sperm preservation during the freezing process. For peccaries’ ejaculated sperm, various studies have shown the effectiveness of a Tris-based extender for sperm freezing (Castelo et al ., 2010a; Silva et al ., 2012; Alves et al ., 2013). Other studies, however, have demonstrated that a coconut water-based extender, ACP-116c, better preserved ejaculated sperm of peccaries than did Tris (Silva et al ., 2012).…”

Relationship of extender and packaging system an the length of preservation and the quality of chilled semen of Boer goat

“…Addition of extender might protect spermatozoa from cold stock. Tris Egg Yolk was able to protect spermatozoa from cold sock, so that was used as basic material of extender (Alves et al 2013). Low density lipoprotein (LDL) in Tris Egg Yolk consisted of 79% lipid and 21% protein with the main component was cholesterol.…”