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The objective of this study was to determine the effect of long-term (48 d), per os animal administration of low zearalenone (ZEA) doses (50% and 100% NOAEL values) on the dynamics of changes in the morphometric parameters of the reproductive organs in sexually-immature gilts. The experiment involved 12 clinically-healthy gilts aged 2 months with initial body weight of ± 40 kg and a determined immune status. The animals were randomly divided into two experimental groups (El, n=4; E2, n=4) and a control group (C, n=4). Group El was administered per os 20 µg of ZEA/kg b.w. for 48 d, group E2 received per os 40 µg of ZEA/kg b.w. for 48 d, and group C was administered per os placebo for 48 d. The mycotoxin was administered daily per os animal in gelatin capsules before morning feeding. The animals were slaughtered at the end of the experiment. No significant morphometric changes were noted in the reproductive system of the gilts, except for an increase in the number of medium-sized ovarian follicles in group El. This suggests that ZEA at low concentrations may cause hormonal effects (hyperoestrogenism) but it does not exhibit xenobiotic activity.
The purpose of this study was to determine whether inflammatory changes in uterus caused by Escherichia coli are associated with changes in nitric oxide (NO) production. Therefore, the activity of NADPH-diaphorase (NADPH-d), a histochemical marker for nitric oxide synthase (NOS), localization of inducible isoform of NOS (iNOS) and tissue content of nitrite were studied in the uterine structures after inoculation of Escherichia coli into the uterus in gilts. Twelve sexually matured gilts with controlled estrous cycle were used. The animals were laparotomized on the 2nd day of the estrous cycle and polyvinyl cannulas were inserted into the uterine horns to infuse saline or Escherichia coli. In the group I (control; n=6), 25 ml of saline was infused into each uterine horn on the 4,h day of the estrous cycle. At the same time, 25 ml of Escherichia coli (strain 025:K23/α/:Hl) suspension, containing 107 colony forming units/ml was inoculated into each uterine horn of the treated gilts (group II; n=6). The middle part of the uterine horn was collected on the 14th day of the next estrous cycle immediately after slaughter. Cryostat sections from paraformaldehyde fixed tissues were stained histochemically to study the activity of NADPH-d and immunohistochemi- cally to investigate the distribution of iNOS. Optical density was assessed to evaluate the intensity of the histochemical reaction. Nitrite content was measured spectrophotometrically. In the Escherichia coli-treated gilts, the activitý of NADPH-d in the luminal epithelium and in external parts of excretory ducts of uterine glands was higher (P < 0.001) as compared to that in the control animals. In the secretory part of the uterine glands the activity of this enzyme was similar in both groups of the gilts. In the gilts that received Escherichia coli, the histochemical reaction of NADPH-d in endometrial blood vessels was stronger than that found in the control animals. Immunoreactivity for iNOS in the luminal epithelium, in external parts of excretory ducts of uterine glands and in vascular endothelial cells was stronger in the Escherichia coli-treated gilts as compared to that observed in the control animals. Only weak or no immunoreactivity was found in the secretory part of the uterine glands in both groups of the gilts. After Escherichia coli inoculation, nitrite content in the uterine tissues was higher (P < 0.05) than that determined in the controls. Our study has revealed that infusion of Escherichia coli into the porcine uterus induces the activity of NADPH-d, iNOS and increases the tissue content of nitrite in this organ. The data obtained indicate that NO can mediate an inflammatory effect of Escherichia coli in the uterus.
In gilts, the period of early pregnancy occurring from the time of fertilization to the beginning of implantation is sensitive to any environmental disruptions, including an unbalanced diet of a future mother. Previously, we found that due to the undernutrition in gilts during this period, the endocrine intrauterine microenvironment and DNA methylation in the uterus have been changed. These distortions may diminish the success of pregnancy. In this study we focused on the influence of a restricted diet used in gilts during the first days of pregnancy on their biochemical and haematological parameters in peripheral blood. The applied restrictive diet vs. normal diet covered only 70% of the nutritional demands of early pregnant gilts. Normal (n = 4 gilts) or restrictive (n = 5 gilts) diets were used from the day of the first signs of the estrus until day 9 of pregnancy and biochemical and haematological parameters in blood plasma were determined during peri-implantation period, e.g. on days 15 to16 of pregnancy. In restrictive vs. normal fed gilts significantly lower plasma phosphorus, calcium and total cholesterol as well as the tendency to increasing concentrations of triglicerydes and asparate aminotranserase were found. Haematological parameters did not differ between the studied gilts. Thus, it seems that the availability of nutritional factors became suboptimal in restrictively fed early pregnant gilts. Even short-lasting undernutrition of females during the peri-conceptional period may cause a disruption of biochemical homeostasis during the peri-implantation period and probably affect the success of pregnancy.
The paper presents the statistical calculations of correlation coefficients (r) between the concentrations of various hormones in peripheral and ovarian venous plasma of hypo- and hyperthyroid, experimental cyst-bearing gilts. The experiment was carried out on 70 gilts randomly divided into the following six groups (10-16 heads in each): control, hypo- and hyperthyroid gilts (oral application of methylthiouracyl and injections of L-thyroxine) and gonadotropine (PMSG and hCG) treated eu- hypo- and hyperthyroid animals. The experiment started on the 2nd day of estrous cycle. Gonadotropins were applied starting from the 15th day of the cycle for 10 consequtive days. Peripheral venous blood samples were collected several times during the experiment by cannulation of the v. jugularis. On the 25th day of the experiment ovarian blood was collected after laparotomy by cannulation of uterovarian veins and again 2-3 days later (cannulae exposed on back of animals). The gilts were slaughtered on the 2nd - 3rd day after laparotomy. Ovaries were excised, inspected and the number of cysts, follicles and corpora lutea was counted. In several samples of peripheral and ovarian plasma of each gilt, the concentrations of luteinizing hormone (LH), prolactin (PRL), estrone (E,), estradiol- 17p (E2), progesterone (P4), androstenedione (A4), testosterone (T) and Cortisol (CI) were analysed by RIA procedures. The correlation coefficients (r) were calculated between concentrations of various hormones in both kinds of plasma in suitable pairs of individual animals of all groups as well as between their relations to the number of ovarian structures. Hypothyroid gilts evidenced correlation of the level of T to E1 and E2 but hyperthyroid animals - correlation of the level of A4 to P4, LH, PRL, Cl and PRL to P4 and LH. The euthyroid gilts after gonadotropine treatment showed interrelation of the concentration of PRL to LH and E, to E2, T and PRL. Hypothyroid and gonadotropine treated gilts evidenced numerous correlations, namely: the level of E1 to E2 and T and A4 to CI, E2, P4, P4 to PRL and T to LH. Hyperthyroid gilts treated with gonadotropins exhibited correlation of E, to T and A4 to CI. The number of cysts correlated mostly with the concentration of E1, E2, P4 and CI. The follicles showed only singular interrelations with the level of E1, P4, T, LH, PRL and Cl. The number of corpora lutea correlated only with the level of E1 and LH.
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