Silica-based colloid centrifugation enhances sperm quality in cockerel semen.

1. PercollTM is one of the most widely used colloid for animal sperm preparation. The aim of this study was to evaluate whether PercollTM colloid centrifugation could be practical to improve cockerel sperm quality, and to compare the effects of PercollTM single layer centrifugation (SLC) and density gradient centrifugation (DGC) in order to obtain the most optimal protocol for cockerel semen.2. In the experiment with PercollTM SLC for fresh semen, an increase of motile sperm was seen after PercollTM 80% SLC and 90% SLC was conducted, at levels of 28.8% and 30.2% respectively (P < 0.01). The increase of progressively motile sperm after PercollTM 80% SLC and 90% SLC was 177.2% and 202.4% respectively (P < 0.01). Meanwhile, for semen stored at 4°C for 24 h, the increase of motile sperm after PercollTM 70% SLC and 80% SLC was 41.2% and 44.0% (P < 0.01), and the increase of progressive sperm after PercollTM 70% SLC and 80% SLC was 71.3% and 83.1% respectively (P < 0.01). Both the percentage of motile sperm and progressive sperm of the fresh and stored cockerel semen after appropriate PercollTM SLC was significantly enhanced.3. Sperm membrane integrity did not show any decrease after PercollTM centrifugation compared with non-centrifuged semen, which suggested that the PercollTM centrifugation treatment in this study did not cause damage to cockerel sperm membranes.4. In the experiment regarding the comparison of PercollTM SLC and DGC with fresh semen, the increase of motile sperm after PercollTM 80% SLC, 90% SLC and 40%/80% DGC was 29.5%, 36.4%, and 25.0% respectively; and the increase of progressive sperm was 44.7%, 58.5%, and 54.7%, respectively. For semen stored at 4°C for 24 h, the increase of motile sperm after PercollTM 70% SLC, 80% SLC and 35%/70% DGC were 41.2%, 44.0%, and 26.4%; and the increase of progressive sperm was 71.3%, 83.1%, and 43.7%, respectively. There were no significant differences between the increase of sperm motility after PercollTM 80%, 90% SLC or PercollTM 40%/80% DGC in fresh cockerel semen. There was no significant difference between PercollTM 70%, 80% SLC and PercollTM 35%/70% in stored cockerel semen. There was a tendency for sperm recovery rates with PercollTM SLC to be higher than PercollTM DGC, although this did not reach statistical significance in this study.5. It was concluded that PercollTM SLC was more suitable for cockerel sperm separation than PercollTM DGC. The results suggested that PercollTM 80% SLC was the most optimal procedure to separate fresh cockerel sperm and PercollTM 70% SLC was the most optimal procedure to separate stored cockerel sperm. PercollTM SLC is more simple, user-friendly and economical and less time-consuming than DGC for cockerel semen processing.

Colloid centrifugation reduces bacterial load in chilled dog semen.

Conventional semen extenders contain antibiotics to prevent bacterial growth. Finding alternatives would be beneficial to minimize the development of bacterial resistance mechanisms. The aim of this study was to determine the effect of Single Layer Centrifugation (SLC) with Canicoll of dog semen on microbial load and sperm quality during cooled storage. Twenty-four ejaculates were obtained from healthy dogs by digital manipulation. Samples were diluted in Tris-citrate-fructose extender without antibiotics and divided into two treatment groups: SLC-selected samples and unselected samples. Sperm motility (CASA), viability and acrosome integrity (PI/FITC-PNA) as well as bacterial load of each microorganism species (colony-forming units/mL) were assessed at 0 and 48 h of storage at 4 °C. Results indicate SLC-selected dog spermatozoa have greater percentages of motility, viability and acrosome integrity (P < 0.05). Bacterial growth in SLC sperm samples was less (P < 0.05) than unselected samples. Removal of individual bacterial species varied from 91 % to 98 % for Escherichia coli (91.62 %), Streptococcus spp. (98.18 %), Staphylococcus spp.(95.33 %) and Pseudomonas spp. (92.50 %). In conclusion, the use of SLC with Canicoll has the potential to decrease bacterial load in chilled dog semen.