Oxidative stress is a state related to increased cellular damage caused by oxygen and oxygen-derived free radicals known as reactive oxygen species (ROS). It is a serious condition, as ROS and their metabolites attack DNA, lipids and proteins, alter enzymatic systems and cell signalling pathways, producing irreparable alterations, cell death and necrosis. While small amounts of ROS have been shown to be required for several functions of spermatozoa, their excessive levels can negatively impact the quality of spermatozoa and impair their overall fertilising capacity. These questions have recently attracted the attention of the scientific community; however, research aimed at exploring the role of oxidative stress and antioxidants associated with male fertility is still at its initial stages. This review summarises the current facts available in this field and intends to stimulate interest in basic and clinical research, especially in the development of effective methods for the diagnosis and therapy of semen damage caused by oxidative stress.
The purpose of this study was to evaluate the dose- and time-dependent effect of caffeine treatment on the motility and viability of stallion spermatozoa at different temperatures. Six dose groups (A to F) were established with changing caffeine concentrations (from 0.625 to 10 mg/mL). The control samples were prepared by diluting the ejaculate only with physiological salt solution. The samples were examined after 0, 1, 2 and 3 h of incubation at 5 °C and 37 °C. The motility parameters were evaluated by Computer Assisted Semen Analyzer (CASA) system, and the viability was assessed by the mitochondrial toxicity test at the end of the incubation. A positive effect of the lowest tested caffeine concentration on the motility parameters was observed throughout the incubation period at 5 °C. At the end of the 3h incubation, the viability in every sample in these groups, treated with any caffeine concentration, showed lower values compared to the control. At the higher incubation temperature (37 °C), caffeine positively affected the motility in samples B (P < 0.05) and D, E, F (P < 0.001) after 3 h of incubation; however, the viability showed a slightly decreasing tendency. Our results suggest that caffeine, in an optimal concentration, may be used as a component of stallion semen extenders.
The purpose of this study was to evaluate the impact of caffeine on turkey spermatozoa during in vitro incubation. Experimental samples were prepared by diluting the raw semen with nine different concentrations of caffeine – from 0.078125 mg/mL to 10 mg/mL. The individual motility parameters were evaluated by the Computer Assisted Semen Analyser (CASA) system, and the viability of spermatozoa was evaluated using eosin-nigrosin staining. Selected parameters were recorded at six time periods: 0, 1, 2, 3, 4 and 5 h at 5 °C and 41 °C. A significantly higher motility and progressive motility of spermatozoa (P < 0.01 and P < 0.001, respectively) was detected in the samples containing caffeine ranging from 0.15625 to 7.5 mg/mL as compared to the control sample at 5 °C. At an incubation temperature of 41 °C the positive effect of caffeine on motility parameters was observed only at the beginning of incubation (at times 0 and 1). The tested caffeine concentrations showed no significant effect on the viability of turkey spermatozoa at any time period of incubation. A higher percentage of dead spermatozoa was observed for incubation at 41 °C (from 5.96% to 11.1%) in comparison to 5 °C (from 1.62% to 5.79%). The results suggest that caffeine can be used as a suitable component of turkey semen extenders and has the potential to improve fertility.
Genetic variability and relationships among five cattle breeds (Holstein, Pinzgau, Limousin, Slovak Spotted and Charolais) bred in the Slovak Republic were investigated separately using 11 microsatellite markers and 61 blood group systems. Allele frequency, heterozygosity (H
) and PIC values were investigated. F-statistics were computed separately. For microsatellite markers F
and for blood groups H
parameters were calculated. Microsatellite and blood group comparison showed similar results by F-statistics but some differences were marked using the other methods. Both methods were able to detect close relation between Slovak Pinzgau and Slovak Spotted cattle breeds. Their relation was confirmed by genetic distance, principal component analysis (PCA) and coefficient of admixture (mY). Important divergences between different markers used in the study were observed by the characterisation of Limousin and Charolais breeds.