Freezing of equine semen is influenced by exposure time and concentration of the cryoprotectant glycerol

BACKGROUND

Glycerol is a cryoprotectant widely used in the freezing of mammalian semen, but no study has demonstrated its optimum concentration and the appropriate exposure time for equine species.

OBJECTIVE

To demonstrate that the exposure time (15, 30, 45, 60, 75 and 90 min) versus concentration (2, 3, 4 and 5%) of the cryoprotectant glycerol influences the freezing success of equine semen.

MATERIALS AND METHODS

The ejaculate of 12 stallions were frozen in different glycerol concentrations following different exposure times. The thawed sperm was evaluated for kinetic parameters using a Computer Assisted Semen Analysis (CASA) system and cell feature parameters were assessed by flow cytometry.

RESULTS

Considering the total and progressive motility of the spermatozoa, we concluded that protocols using 5% glycerol for 15 and 30 min exposure, 4% glycerol for 45 min exposure and 3% glycerol for 90 min exposure generated the best results.

CONCLUSION

We suggest the use of any of these protocols for a better cryopreservation of equine semen. Doi: 10.54680/fr23410110412.

Dimethylacetamide in Rooster Semen Cryopreservation

BACKGROUND

Sperm cryopreservation of cockerels is a major challenge, and so far there is no adequate information to enable commercial use of frozen semen.

OBJECTIVE

To test the toxicity of dimethylacetamide (DMA).

MATERIALS AND METHODS

DMA was added at 3%, 6%, 9% and 12% to the freezing diluent, and maintained for equilibration with the semen sample for 1 min, 3 min, 5 min, 7 min and 9 min prior to freezing. Thawed semen was evaluated for kinetic characteristics by computer-assisted semen analysis (CASA) and for structural and functional properties by flow cytometry (plasma membrane rupture, mitochondrial functionality and plasma membrane functionality).

RESULTS AND CONCLUSION

The addition of 6% DMA for 3-min equilibration resulted in the highest total and progressive motility, 42.0% and 36.9%, respectively. The point of intersection between a good protection and low plasma membrane rupture was obtained with the addition of 6% of DMA for 3-min equilibration with the rooster semen.

Epidemiology, risk factors and outcomes of multi-drug-resistant bloodstream infections in haematopoietic stem cell transplant recipients: importance of previous gut colonization

BACKGROUND

Bloodstream infections (BSI) are a major complication in the early phase of a haematopoietic stem cell transplant (HSCT).

AIM

To describe the incidence and risk factors for BSI occurring in the pre-engraftment phase of HSCT, and its impact on mortality.

METHODS

Clinical variables of 232 HSCT patients were analysed retrospectively between 2014 and 2015. Univariate Cox regression analyses were performed to test the association between each covariate and the outcome. Covariates with P < 0.10 on univariate analysis were included in a multiple Cox regression analysis using a backward elimination method.

FINDINGS

The cumulative incidence of BSI was 25.4%, mainly caused by Gram-negative bacteria (GNB) (55.2%). Approximately 40.5% of the patients had gut colonization by multi-drug-resistant (MDR) bacteria (vancomycin-resistant enterococcus and carbapenem-resistant GNB). Among patients colonized by MDR GNB, 20% developed an overt BSI due to MDR bacteria with the same pattern of sensitivity. Of the 13 deaths related to infection, 10 were patients with BSI caused by MDR GNB. The independent risk factors for BSI were gut colonization by MDR bacteria including GNB (P < 0.001) and duration of neutropenia >10 days (P = 0.005), and those associated with BSI caused by MDR bacteria were age >62 years (P = 0.03), use of total parenteral nutrition (TPN) (P < 0.001) and previous gut colonization by MDR GNB (P = 0.002).

CONCLUSIONS

Previous gut colonization by MDR was an independent risk factor for BSI, together with TPN and age, and had an impact on outcome. These findings suggest that gut decolonization may be a potential strategy to prevent BSI.

Quercetin in equine frozen semen

　　BACKGROUND: Supplementation of sperm diluents to reduce the damage caused by the freeze-thaw cycle is broadly used in equine semen cryopreservation.

OBJECTIVE

The present study aimed at determining the most appropriate quercetin supplementation in equine freezing extender.

MATERIALS AND METHODS

Quercetin at four different concentrations (0.25, 0.5, 0.75 or 1 mM) was added in the sperm freezing diluent before the freeze-thaw cycle. The spermatozoa population was analyzed by flow cytometry and a statistical analysis was conducted to detect significant differences between control and treated samples.

RESULTS

The statistical analysis did not reveal any significant modification of seminal parameters.

CONCLUSION

Within the concentrations tested, quercetin supplementation in equine freezing extender did not affect progressive motility, mitochondrial functionality, acrosome reaction, membrane integrity or DNA fragmentation index in post-thaw equine semen.