Effect of uncontrolled warming on supercooled chicken sperm

Description

Preliminary studies by our group showed that the % intact acrosomes of chicken sperm had declined from 87.3 ± 1.42 to 41.7±7.7 after 2 min of supercooling at -10°C. The present study investigated whether the negative effect was due to supercooling per se or to the subsequent warming of the supercooled sperm. The experiment was replicated six times. Per replicate, pooled semen from 5 randomly selected roosters was prediluted with ASG diluent, and after cooling to 5°C, it was mixed with diluent + DMA to a final concentration of 0.6M DMA. The semen was held at 5°C during 1h. Aliquots (0.22 mL) were transferred into glass tubes and placed in an ethanol bath at -10.5ᵒC. After 2 min (sample temperature -8 ± 0.5ᵒC) the semen in one tube was fixed by adding 0.22 mL of cold formaldehyde and placed on ice. Simultaneously, another tube was removed from the bath to warm at room temperature for 5 min prior to fixation. The same procedure was performed after 4, 6 and 10 minutes. Smears were prepared from the fixed samples and stained with methyl blue to visualize the acrosome. The results obtained were compared with those obtained from the same semen+DMA that had remained at 5ᵒC. The data were analyzed by Wilcoxon test. There was no appreciable decline in acrosome integrity of semen that had been supercooled and fixed at -8 ᵒC, compared with the semen that remained at
5ᵒC. In samples that were warmed prior to fixation, acrosome integrity decreased from 87.8±1.0 (semen held at 5ᵒC) to 45.6±1.6 (supercooled). This showed that uncontrolled warming from −8 to −10°C to room temperature was deleterious to the acrosome integrity of chicken sperm, while the supercooling per se had no appreciable effect.

Period	23 Jul 2024
Event title	CRYO 2024
Event type	Conference/symposium
Location	Washington DC, United StatesShow on map
Degree of Recognition	International