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Lead increasingly contributes to pollution of the environment and may play a role in the development of adverse effects in the human and animal body. Data concerning its mutagenic, clastogenic, and carcinogenic properties have been conflicting. In this study, we evaluated the frequency of micronuclei in bone marrow erythrocytes of rats treated with lead acetate trihydrate. Outbred Wistar rats were exposed to a daily dose of 100 mg/L drinking water for 125 days. The mean value of the total number of micronuclei observed in polychromatic erythrocytes of female rats was significantly higher than that found in the control group (13.375 +/- 2.722 against 9.625 +/- 3.204 micronuclei/1000 cells; P = 0.024 in ANOVA). In exposed female animals, no significant reduction of the ratio of polychromatic to normochromatic erythrocytes was observed (0.990 +/- 0.228 against 1.208 +/- 0.195; P = 0.060 in ANOVA). The effects of lead acetate trihydrate in male rats are both cytotoxic and genotoxic because of a decrease in ratio of polychromatic to normochromatic erythrocytes (0.715 +/- 0.431 against 1.343 +/- 0.306; P = 0.023, ANOVA followed by Tukey test) and an increase in frequency of micronucleated polychromatic erythrocytes (24.167 +/- 7.859 against 4.0 +/- 4.528 micronuclei/1000 cells; P < or = 0.001, ANOVA followed by Tukey test), respectively.

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The immunotoxic and genotoxic effect of endosulfan, an organochlorine insecticide, on sheep peripheral blood leukocytes was examined in in vitro conditions. The immunotoxic effect was evaluated by assays of the metabolic activity of phagocytes and assays for lymphocyte activation--the leucocyte migration-inhibition assay (LMIA) and lympho-proliferation. The significant inhibitory effect of endosulfan on metabolic activity of peripheral blood phagocytes was registered at the actual concentrations of 10(-3)- 10(-4) M. At 10(-3) M the migration of leukocytes was inhibited, both in activated and non-activated with phytohemagglutinin (PHA) leukocyte suspensions (p < 0.01) in LMIA. This indicated the direct cytotoxic effect of endosulfan on the polymorphonuclears and monocytes of which the intensity of migration is an indicator of lymphocyte activation with mitogen. At the concentration of 10(-4) M an immunotoxic effect, ie significant decrease of lymphocyte activation with mitogen was recorded in LMIA. Lympho-proliferation test showed the significant inhibition of proliferation for PHA-stimulated lymphocytes at 10(-3) M and 10(-4) M. Micronucleus assay evaluated the genotoxic potential of endosulfan. Higher concentrations of insecticide (10(-5) M, 10(-6) M) resulted in a significant dose dependent increase in the number of micronuclei.

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DNA lesion induced by xenobiotics is implemented either through direct interaction of the chemical with DNA through covalent binding or intercalation, or indirectly, through interference with the processes of DNA replication and repair, interaction with proteins, nuclease release from lysosomes etc. The present study emphasizes that the assessment of genotoxic risk arising from xenogenous substances demands the development of sensitive, direct and more exact genotoxic testing methods. One of them is micronucleus assay. It is a simple and quick test for investigating of cytogenic damage with the advantage that exposure to both clastogens and aneugens may be detected.

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The oxidative processes in the organism are activated by hormones of the thyroid gland. The pyruvate-lactate component catalyzed by lactate dehydrogenase presents one of the important oxidic-reductive systems in the animal organism of biochemical importance (EC. 1.1.1.27). In certain cases of the thyroid gland disturbances antithyroid drugs, such as derivatives of thiouracil, mercaptoimidazole and some others may be used for the treatment of men and animals (Marchant et al., 1979; Negwer, 1987). In the present study, the activity changes of lactate dehydrogenase isoenzymes in the blood plasma of young rams and ewe hoggets in experiments with carbimasole [carbimasolum(1-carbaethoxy-3-methyl-2-thioimidazolum) ] have been studied. The dose of carbimasole at the time of sampling (May, 1993) was 7O mg per animals and day. In May, no significant differences in T3 and T4 concentrations in the serum of experimental and control animals in males and females were found (Tab. 1). The T3 concentrations in the experimental group of young rams were 0.56 +/- 0.21 nmol/l (n = 3), in ewe hoggets 0.70 +/- 0.19 nmol/l (n = 6). The T4 concentrations in young rams were 39.15 +/- 24.15 nmol/l (n = 3), in ewe hoggets 48.6 +/- 15.3 nmol/l (n = 6). Out of lactate dehydrogenase isoenzymes, only LD4 exhibited significant differences (P < 0.02) in the blood plasma of ewe hoggets (Tab. I). In the course of these months, no clinical signs of hypothyrosis were observed in experimental animals.

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Robertsonian translocation (centric fusion) is one of the most frequent types of chromosome aberrations found in cattle. Observing the health state of a group of dairy cows in the fallout region of a metallurgical plant, centric fusion of chromosomes was discovered in one animal. Chromosome fusion is supposed within pairs 13-24 (dicentric translocation). Although the finding was started in a commercial flock, it is rather interesting from the viewpoint of the R. translocation type and because of the fact that the father of this dairy cow (bull NOM-37) had been used in insemination for several years and his semen is still preserved for further use.

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The health of animals depends not only on the level of hygiene on the farms but also on the ability of the individual to withstand diseases and to face various unfavourable effects of the environment. On the cellular level, chromosome analysis in the peripheral lymphocytes of farm animals is used to determine the effects of various environmental factors. According to present knowledge the frequency of chromosome aberrations is considered to be a quantitative index of genetic damage. The present work reports on in-vitro observations of structural aberrations in the peripheral lymphocytes of Merino and crossbred sheep kept under good hygienic conditions. Comparison of the incidence of aberrant cells (AB.C.) was carried out in two seasons of the year (Tab. I). There was not a significant difference (P > 0.05) between the spring (0.96%-AB.C.) and autumn findings (1.59% AB.C.). In these seasons, chromatid breaks (B1) were the most frequently recorded structural aberrations. Comparison of the three age groups (comprising animals aged 1-2, 3-4 or 5-9 years) did not reveal any significant differences in the AB.C. percentage (P > 0.05, Tab. II).

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In farm animals the questions of clinical and mainly heritable health receive increased attention. In this work the activity of the polymorphous system of lactate dehydrogenase was observed in some pure- and crossbred ewes and rams under field conditions. The isoenzyme of lactate dehydrogenase were separated on 5.5% polyacrylamide gel as reported Dietz, Lubrano (1967). Age- and sex-related determinations of the isoenzyme spectrum of lactate dehydrogenase revealed increased LD3 activity in yearling ewes, and increased LD4 and LD5 activity in yearling rams (Tab. I). Significant differences of LD4 isoenzyme activity (P < 0.05) were observed between the Stavropol Merino and the Stavropol Merino x Merino x Corriedale crossbreds (Tabs II and III). In the blood plasma of Stavropol Merino rams the following quantities of LD isoenzymes were determined: LD1 = 48.0 +/- 10.6%, LD2 = 12.1 +/- 5.2%, LD3 = 25.9 +/- 7.02%, LD4 = 4.0 +/- 2.2% and LD5 = 10.0 +/- 3.5%. In the activity of some isoenzymes breed differences were recorded in 2-5-year-old ewes (Tabs IV and V). For LD1, significant differences (P < 0.01) were found between the Merino and Ascan Merino x Merino sheep breeds as well as between the Merino x Corriedale sheep and the crossbreds of Merino with a certain share of Lincoln. Differences in LD1 activity between Merino and Merino x Corriedale sheep as well as between the Ascan Merino and Merino crossbreds with a certain share of Lincoln were significant at the level of P < 0.02. For LD2, no significant differences were stated in the pure- and crossbred animals under examination.(ABSTRACT TRUNCATED AT 250 WORDS)

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