Effect of zearalenone on circulating testosterone concentration, testicular and epididymal morphology and epididymal sperm characteristics in wild boars

Abstract This study investigated the effect of exposure to zearalenone (ZEN) and its metabolites on the characteristics of epididymal spermatozoa, testicular and epididymal biometry and histology, and the concentration of testosterone in blood plasma in male wild boars. The study was performed during more than one year on 18 clinically healthy male wild boars with initial and final body weight, of 39 ± 4 kg and 59 ± 3 kg, respectively. The animals were divided into two experimental groups (group I and group II) and one control group (group C) comprising 6 boars per group. Group I animals were administered per os pure zearalenone (ZEN) at 150 μg/kg BW for 7 consecutive days every two months, while group II animals received a dose of 50 μg/kg BW/day via feed that was naturally contaminated with ZEN. These male wild boars were exposed to ZEN over a period of 1 year. Control animals were fed a placebo. Testicles with epididymides of the boars were collected on the last day of the experiment within 3 min after slaughter. Blood samples were collected from each of the male wild boars. Testes and epididymides were measured and sampled for histological examination. Epididymides were dissected and epididymal spermatozoa were harvested. The spermatozoa were diluted with swine-specific BTS extender and stored at 17°C for 144 h. Sperm motility was analyzed with CASA, and other parameters including viability, acrosome integrity, DNA fragmentation index, lipid peroxidation and apoptosis were assessed with flow cytometry. In these wild boars, per os exposure to natural sources of ZEN or a combination of ZEN and its metabolites changed the testicular interstitium and led to modification of some epididymal sperm parameters. The interstitial glands in testes of experimental group I were markedly reduced and hyperemic with evident blood stasis in small capillaries. Also in group I were single degenerating seminiferous tubules. In both groups I and II, immediately after dilution of spermatozoa with BTS remarkable decreases in motility rate as well as in progressive motility and the subpopulation of cells with rapid movement were noted compared with the control group (P