The level of acute phase blood proteins as a predictive criterion of the cryo resistance of stallion sperm

The indicators of the biochemical analysis of the blood of horses reflect the state of metabolism of the animal and at the same time are potential predictors of the qualitative characteristics of spermatozoa, the freezing of which is one of the most important ways to preserve and further use the genetic material. The aim of this study was to identify correlations between the level of such acute phase blood proteins, as C-reactive protein and fibrinogen, and the qualitative and quantitative characteristics of the native and thawed sperm of stallions. The object of the study was blood and sperm samples from 87 stallions of various breeds, the average age of which was 10.5±0.5 years. To assess the protein status of the blood, in addition to the aforementioned acute phase proteins, the total protein content, the levels of albumin, globulins, and the albumin / globulin ratio were determined. Stallion sperm samples were assessed according to the following indicators: ejaculate volume, concentration, the total number of spermatozoa in the ejaculate, progressive motility and survival at +4°C. When analyzing the correlations between the studied parameters, a statistically significant negative inverse relationship was revealed between the level of fibrinogen in the blood serum and such parameters as the content of progressively motile sperm in native and thawed cryopreserved sperm (r=-0.22, p<0.05 and r=-0.29, p<0.01, respectively), as well as sperm survival in native and thawed sperm (r=-0.48, p<0.001 and r=-0.22, p<0.05, respectively).There was no statistically significant relationship between the level of C-reactive protein and the studied characteristics of the spermogram. The revealed negative correlation between the level of fibrinogen and the characteristics of the stallions’ sperm can be considered as one of the prognostic important indicators that must be taken into account when selecting stallions with the highest indicators of the quality of cryopreserved sperm.