Effects of the preservation medium and storage duration of domestic cat ovaries on the maturational and developmental competence of oocytes in vitro

Prolonged cold-preservation of domestic cat ovarian tissue is improved by extracellular solution but impaired by the fragmentation of ovary

For domestic cats ovaries, recommended cold-storage limit is 24 h in Phosphate Buffered Saline (PBS) or Dulbecco`s PBS (DPBS). Here, we attempted to verify wheatear cat ovaries may benefit from more complex solutions during prolonged cold-storage (>24 h). First, the preservation capabilities of extracellular (SP+), intracellular (UW) solutions and DPBS supplemented with glutathione (DPBS+GSH) were compared using ovary fragments from the same ovary (n=10). Intact ovary stored in DPBS served as a control. Ovaries were kept at 4 °C for 48 h, and 72 h. In the second experiment, first ovary was stored in DPBS, second in SP+ or UW solution for 48 h (n = 12). Ovaries pairs stored in DPBS for 24 h served as a control (n=8). Tissue samples were evaluated directly after cold-storage and after following 24 h in vitro culture. Ovarian follicle morphology, apoptosis rates (cleaved caspase-3, TUNEL), and follicular growth activation (Ki-67) were assessed. Ovary fragmentation impaired follicular morphology preservation upon cold-storage comparing to intact ovary. However, ovarian fragments stored in UW for 48 h and in SP+ for 72 h presented better morphology than DPBS+GSH group. Comparison of intact ovaries cold-storage for 48 h showed that SP+ provided superior follicular morphology over DPBS, and it was comparable to the outcome of 24-hour storage. No follicular activation after in vitro culture was observed. Nevertheless, tissue culture increased considerably caspase-3 cleavage and TUNEL detection. The ovary fragmentation prior to cold-storage is not recommended in domestic cats. Replacement of DPBS with SP+ solution for whole ovary and UW solution for ovarian tissue fragments improves follicular structure preservation during 48-hour cold-storage.

Effects of glucose and trehalose on tris-citric acid-egg yolk-fructose diluents for semen cryopreservation in goat

Objectives

This study aimed to examine the impacts of the wide range of concentrations of glucose and trehalose on the tris-citric acid-egg yolk-fructose (TCEF) extenders for cryopreservation of goat semen.

Materials and Methods

The sperm sample was pooled, washed, and diluted in control (TCEF without glucose and trehalose), TCEF + glucose (75, 150, 450, and 900 mm), and TCEF + trehalose (75, 150, 450, and 900 mm). After equilibrations, the semen straws were frozen under LN2 in the LN2 tank. After LN2 storage, the straws were thawed at 37°C for 30 seconds. The sperm parameters of all study groups were checked after equilibration and freezing.

Results

After equilibration, the progressive motility (PM), total motility (TM), and viability of sperm in G-75, G-150, G-450, T-75, T-150, and T-450 were not significantly different (p < 0.05) from those in control. After cryopreservation and thawing, the PM, TM, and plasma membrane integrity (PMI) of T-150 were significantly higher (p < 0.05) than in control, G-75, G-900, T-75, and T-900. The viability of sperm in T-150 was substantially higher (p < 0.05) than in the control, whereas there was no significant difference among the control, G-75, G-900, T-75, and T-900. However, the acrosome integrity (AI) of sperm in G-900 was significantly decreased (p < 0.05) compared to the control, G-75, G-150, G-450, T-75, T-150, and T-450.

Conclusion

According to the findings, the supplementation of 150 mm trehalose in the TCEF diluent was more efficient for sperm cryopreservation in the buck as reflected by PM, TM, viability, PMI, and AI.

Effects of tris (hydroxymethyl) aminomethane and egg yolk on the cryopreservation of buck semen

Objectives

This study was designed to examine the effects of various concentrations of tris (hydroxymethyl) aminomethane (tris) and egg yolk on the quality of cryopreserved buck sperm.

Materials and Methods

The collected semen samples were pooled, washed, and diluted into five different freezing extender groups, viz., extender I (tris 0% + egg yolk 0%), extender II (tris 1.41% + egg yolk 4%), extender III (tris 2.41% + egg yolk 8%), extender IV (tris 3.41% + egg yolk 16%), and extender V (tris 4.41% + egg yolk 24%). The sperm parameter of the five groups of extenders was evaluated after equilibration and cryopreservation.

Results

The results showed that extenders II-V provided significantly higher semen progressive motility and total motility percentages than extender I after equilibration (p < 0.05). The higher percentages of semen progressive motility, total motility, viability, and plasma membrane integrity (by both HOST under light microscopy and stain after HOST under light microscopy) were found in the sperm cryopreserved with extender IV than extender I, extender II, and extender III groups after thawing (p < 0.05). In addition, semen progressive motility, total motility, and viability were not further increased, or plasma membrane integrity (by both HOST tests) was decreased by the addition of tris and egg yolk (extender V) after cryopreservation (p < 0.05).

Conclusion

In conclusion, our result indicates that the following washing, the supplementation of tris (3.41% + egg yolk 16%) on the freezing extender are suitable for improving the semen quality of buck after freezing and thawing.