Effect of seminal plasma components on the stallion semen quality

The importance of seminal plasma (SP) components for stallion semen quality is little known. Among the components of stallion SP some enzymatic and non-enzymatic antioxidants which protect sperm from the injurious effects of reactive oxygen species (ROS) have been identified. This study aimed to evaluate the relationship between SP components and stallion semen quality. Semen of 30 stallions was collected, and then, SP was recovered and lyophilized. In SP total protein (TP) was assessed by Bradford method; vitamin C (CVIT), vitamin E (EVIT) and vitamin A (AVIT) were evaluated by high-performance liquid chromatography (HPLC) method; iron (Fe), copper (Cu), magnesium (Mg), and zinc (Zn) were assessed by flame atomic absorption spectroscopy. Semen motility (MOT), abnormal morphology (AM), sperm vitality (SV), and plasma membrane integrity (PMI) were evaluated. Levels of component of SP were established by a distribution analysis. Generalized linear models were fitted. Comparisons of means were done with Tukey's test. A high level of EVIT, Cu, Fe, and Zn in SP resulted in higher PMI while high level of Cu and Fe resulted in better SV. A high level of CVIT, had a deleterious effect on SV and the normal morphology of semen. Likewise, a low level of AVIT showed better results for SV and PMI. For TP, the results were less consistent because while a medium level of TP showed higher percentages for MOT, a high level of it had better results for the SV and PMI of semen. In conclusion, the level in which ions, vitamins and proteins are present in the seminal plasma influences the quality of stallion semen.