DEVELOPMENT OF DNA FRAGMENTATION IN SEMEN CRIOPRESERVATION OF FIGHTING BULL

摘要

SummaryThe objective of the present study was to analyze the curve of sperm DNA fragmentation and its development during a pre-established period of time, in cryopreserved semen of 10 bulls from Lidia"s breed. Semen samples were thawed at 37oC and were preserved in incubation up to 10 days at 38.6oC, to emulate the corporal temperature in the female. Analysis of DNA fragmentation was assessed after 4, 24, 48, 72 hours and at 4, 5, 6, 7, 8, 9 and 10 days of incubation from each sample. Sperm-Halomax?-Bos-FF kit (ChromaCell SL, Madrid, Spain) was used to determine this parameter, by fluorescence microscopy. The results obtained indicated that: (i) Basal levels of fragmentation, and the velocity of sperm DNA degradation between different times, presented variation among individuals. (ii) We can consider that in these breed, the nuclear chromatin integrity gets degraded when it is incubated at a temperature of 38.6oC and can remain stable for long periods of time. Those bulls that present high percents of fragmentation index and a high speed of damage accumulation have a low potential to achieve fertilization. Therefore, it would be interesting to determinate the curve of DNA fragmentation in each cryopreserved sample, because it would supply information when establishing the best strategy for use to assisted reproduction techniques and it could clarify infertility or embryonic development problems for artificial insemination protocols.