Chromatin integrity of ram spermatozoa. Relationships to annual fluctuations of scrotal surface temperature and temperature-humidity index

摘要: The objective of the present study was to explore potential relationships ovine sperm chromatin integrity, quantified using structure assay (SCSA), heat load scrotum and discomfort felt by animals because fluctuations microclimatic factors at different time periods before ejaculation. Ejaculates were collected once per week from five Chios rams four East Friesian for 12 months stored in liquid nitrogen. Frozen-thawed semen samples analyzed SCSA, determine DNA fragmentation index (DFI) percentage cells outside main population (%DFI) each one samples. Scrotal surface temperature (SST) ram measured an infrared thermometer on a daily basis. Ambient air relative humidity recorded hourly intervals throughout experimental period temperature-humidity (THI) used assess rams. Mean values SST (SSTmean) THI (THImean) computed eight (up 61 days) preceding ejaculation day (Day 0). A linear mixed-effect model analysis performed describe relation SCSA parameters collection month, SSTmean, THImean results statistical revealed %DFI SSTmean last days ejaculation, namely that resembled phase epididymal maturation. On contrary, variation DFI most adequately described applied Days 54 48 which spermatogonial mitoses. effect month significant %DFI, with September February exhibiting lowest values; less profound seasonal pattern detected %DFI. proven nonsignificant regard all periods. In conclusion, shown study, implying scrotal microenvironment intratesticular population. contrast, we failed detect any microclimate-induced integrity frozen-thawed spermatozoa.