Chromatin status as the index of spermatozoa valuable: the tests for estimation (review)

Improvement of reproduction level in the modern animal husbandry is a reserve of a considerable rise of its effectiveness. That is the extreme necessity in a dairy farming as low calf income can produce the depression of this intensive subindustry. Basically reproduction level is determined by reproductive potential of female and male equally. However in case of a female the infertility causes loss only from one itself but the subfertility of a male determines the loss that multiplied by number of females inseminated without success. Therefore, the priority of the problem decision should prefer the work with the sires. The last studies shown a sire subfertility can be caused by pathological state of spermatozoa chromatin as a genetic information carrier that determines the fertilization and the embryo development. Frequent a spermatozoa anomalies are the chromatin fragmentation, insufficient condensation and other violations that can decrease fertilization and embryo survival. For assessment of spermatozoa chromatin and accordingly sires reproductive potential the tests were developed. In particular, SCSA (Sperm Chromatin Structure Assay) reveals stability of chromatin to denaturation, TUNEL (Terminal deoxynucleotidyl transferase-mediated dUtp Nick End Labeling) realizes visualization of DNA fragmentation by marking nicks, Comet Assay method reveals fragments by microelectrophoresis of separate spermatozoa, content ratio -S-S- и -S-Н groups and other.