Factors determining sensitivity of prepubertal gilts to hormonal influence of zearalenone.

Among large husbandry animals, swine are the most predisposed to zearalenone (ZEA) intoxication, mainly because cereal is an important component of their diet. Studies performed so far (in vivo, in vitro) suggest that ZEA and its metabolites, which may appear due to ZEA biotransformation (especially alpha-zearalenole; alpha-ZOL), can modify signaling cascades of endogenous sex steroids, through either receptor or non-receptor mechanisms. Of all age groups of swine, immature gilts are particularly predisposed to zearalenone intoxication, as manifested by the occurrence of genital tract tissue dysfunction on exposure to ZEA. The intensity of the adverse effects observed at either systemic or local level in gilts, when compared to sexually mature swine females, suggest that specific age-dependent physiological conditions may exist, which determine the high sensitivity of gilts to exogenous estrogen-like compounds, including ZEA.

Ultrastructural changes of ovarian follicle and corpus luteum after experimental zearalenone mycotoxicosis in bitch.

The aim of the study was to determine the influence of experimental zearalenone (ZEA) mycotoxicosis on the ultrastructure of ovaries in bitches receving zearalenone for 100 days per os in the anestrus phase. Experiment has been conducted on 9 sexually mature clinically healthy bitches. The sexually mature animals aged 1-3 years were in anestrus. The dogs have been divided into three groups: EI and EII, receiving ZEAper os in two dosages (25 microg/kg and 50 microg/kg b.w.) and control animals which received placebo per os. On the last day of experiment, ovariohysterectomy was performed in all the bitches and the uterine samples were submitted to ultrastructural analyses. The study has revealed that long lasting administration of higher dose of zearalenone causes ultrastructural changes in the granular layer of ovarian follicles, which showed due to their biological activity decrease. The changes in the granular layer, atrophy of intercellular connections and the appearance of intercellular spaces can stand for reduced activity of this layer. Changes in morphology of mitochondria, rough endoplasmic reticulum and Golgi apparatus sugest ZEA influence on cell metabolism and secretory processes. It seems therefore that in bitches and other monogastric animals, intoxications induced by this mycotoxin causes ultrastructural changes in granular cells of ovarian follicles.

Histopathological examination of ovaries in bitches after experimental zearalenone mycotoxicosis.

The present study deals with the influence of experimental ZEA mycotoxicosis on histopathological lesions in ovaries of bitches, which were administered zearalenone per os during anestrus phase for one hundred days. The experiment was performed on 9 sexually mature, clinically healthy bitches. The animals assigned into two experimental groups received zearalenone per os at two doses, 25 microg/kg b.w. and 50 microg/kg b.w., respectively: the bitches from control group received placebo per os. On the last day of zearalenone intoxication, the bitches were ovariohystorectomized. Histopathology and immunohistochemistry were performed. The study revealed that zearalenone and its metabolites caused profound regressive lesions: granular cells degeneration and atrophy. Numerous edemas and blood extravasations were also found. The intensity of these changes was significantly dose dependent. Furthermore, in ovarian cells and tissues of both experimental groups, no reaction for PCNA antigen was observed. In conclusion, zearalenone and its metabolites exerts unfavorable effects on the morphology of ovaries in bitches.

The impact of zearalenone on the level of the selected estrogens in blood serum of sexually immature gilts.

The aim of the study was to evaluate the influence of low dose (LOEL - lowest observed effect level) of zearalenone (200 microg/kg b.w.), applied per os for 7 days (short-term intoxication), on sexual behavior, concentration of the examined xenobiotic and its metabolite and selected estrogens in sexually immature gilts: ovariohysterectomised (group D1) and intact (group D2) animals. Clinical signs of oestrus (reddening, oedema and hyperaemia of the vulva and serorhoea from the reproductive tract--lack of standing reflex) were obserwed in group D1 on day 6 and in group D2 on day 4 of the experiment. Laboratory analyses of blood plasma were carried out determine the presence of zearalenone and alpha-zearalenole. They revealed an increase in the level of alpha-zearalenol before the oestrus, decrease in total amount of both examined substances on day when the oestrus appeared and increase in the level of both examined xenobiotics in the post oestrus period together with the higher share of zearalenone. Medium concentrations of estrone and estradiol within the borders of method determination in the majority of periods examined. Higher levels of estrone (32.0 pg/ml) were found on day 4, in the group D2 and estradiol (6.5 pg/ml) on day 6 in the D2 group. The presents study revealed that zearalenone applied per os at LOEL dose causes the incidence of apparent sexual readiness (without standing reflex) in sexually immature gilts with the somatically immature reproductive system.

Level of zearalenone in blood serum and lesions in ovarian follicles of sexually immature gilts in the course of zearalenone micotoxicosis.

The aim of the study was to determine how a low dose of zearalenone applied orally for eight days influences the level of zearalenone (ZEN) and alpha-zearalenole in blood plasma and causes the occurrence of histopathological changes in the cells of the ovarian follicles in sexually immature gilts. The animals were divided into 2 groups (control, C; n = 4 and experimental, E; n = 4). The gilts from group E were treated daily with zearalenone at a dose of 200 microg/kg b.w. The level of zearalenone and alpha-zearalenole (ZON as the sum of the levels of both zearalenone and alpha-zearalenole) was measured daily. On day eight of the experiment the animals were sacrificed and their ovaries were taken for histopathological examination. The tissue sections obtained were HE- and PAS-stained according to McManus. The presence of PCNA antigen was also estimated. The highest concentration of ZON was noted on day 5 in group E (8.16 +/- 2.49 ng/ml). External estrus symptoms without standing reflex were observed in group E on day 4. In group C there were no pathological changes in the ovaries. In group E, a few ovarian follicles were found, but they were located in the cortical layer. They were filled with a liquid substance rich in protein and without the granulosa layer. There was disintegration with apoptotic-like changes of the PCNA-negative cells in the granulosa layer of single mature follicles. On day 4 the dose of zearalenone caused disturbances in the process of development and maturation of some of the best developed ovarian follicles. This probably occurred through the activation of on apoptosis-like process of the granulosa cells with simultaneous manifestation of estrus without standing reflex.

Influence of zearalenone micotoxicosis on selected immunological, haematological and biochemical indexes of blood plasma in bitches.

The immunological, haematological and biochemical analyses of blood plasma in bitches with 50 days lasting induced zearalenone micotoxicosis were carried out. It can be indirectly suggested that the inhibition of the humoral reaction of the organism, stimulation of detoxification effect in the liver and decreased cellular answer took place.

Preliminary results of monitoring research on zearalenone presence in blood of women with neoplastic lesions in reproductive system.

The aim of the monitoring of zearalenone presence in the blood plasma of women with neoplastic lesions in the reproductive tract was to asses whether the phytosteride is noted in the patients blood and whether the correlation exists between its presence and the incidence of particular neoplasm. The presence of zearalenone or its metabolite--alpha-zearalenole, was noted in 13.51% of the examined women. In 60% of the patients with the confirmed presence of the xenobiotic it was noted in the lowest concentrations. These patients had neoplastic lesions of Carcinoma corpus uteri type.

Preliminary evaluation of influence of zearalenone on cocultures of granulosa and internal theca cells of ovarian follicles in bitches in in vitro culture.

Zearalenone (ZEA) is an undesirable substance in feed materials and feed of plant origin. It is an example of the micotoxin that causes disturbances in the functioning of the reproductive system. The wide range of plant compounds in pet food means that ZEA may frequently have a negative effect on pet reproduction. An assessment of the influence of ZEA on the granulosa and theca cells of the ovarian follicle in bitches in vitro was carried out. The co-culture of the ovarian follicles was incubated for 72 hours with the addition of 12.5 ng/ml and 25.0 ng/ml of ZEA. Numerous vacuoles in the cytoplasm of the granulosa cells were noted in the culture with the addition of 25.0 ng/ml of ZEA. Preliminary investigations suggest negative effect of ZEA on the granulosa cells in bitches in vitro.

[Formation of erythroid colonies of bone marrow cells and their sensitivity to erythropoietin (EP) (in vitro) in piglets during the early postnatal period]. / Tworzenie kolonii erytroidalnych szpiku kostnego oraz ich wrazliwosc na egzogenna erytropoetyne (Ep) (in vitro) u prosiat we wczesnym okresie postnatalnym.

Collected at the first hours (0, 6, 12, 24, 48) and days (3 and 5) of piglets life bone marrow was cultured (in vitro) during 48 and 72 hours in order to assess the efficiency of development and ability of isolated marrow cells to form erythroid colonies (CFU-E-Colony Forming Unit) and also to examine the erythroidal sensitivity to Ep addition. It was found that bone marrow of new born piglets shows high ability to form erythroid colonies (CFU-E), but low sensitivity to Ep (erythropoietin). The limited efficiency to form immature erythroid colonies following 12h as well as matured ones after 24h, has been also shown. Observed changes could be caused by the limited erythroidal cells sensitivity to Ep.