Placenta tissue may be a major source of lipid peroxidation products in pregnancy. It was proven that placental peroxidation activity increases with gestation. Selenium (Se), as an essential constituent of glutathione peroxidase (GSH-Px), takes part in the reduction of hydrogen peroxides and lipid peroxides. Malondialdehyde (MDA) is a major breakdown product split off from lipid peroxides. In this study, Se and MDA content and GSH-Px activity were measured in blood and plasma taken from 20 apparently healthy nonpregnant women between 19 and 38 yr of age and from 115 unselected pregnant women between 17 and 45 yr of age (35 in the first trimester, 22 in the second trimester, 38 in the third trimester, and 20 within 2 d of delivery). Samples of umbilical cord blood and amniotic fluid were taken from women in the second and third trimesters and at delivery. The Se content was measured by atomic absorption spectrometry (AAS), plasma MDA concentration by thiobarbituric acid reaction, and Se-dependent GSH-Px spectrometrically. Blood and plasma Se contents of nonpregnant women were below those considered adequate, indicating low selenium intake. In comparison to nonpregnant women, pregnant women had significantly decreased whole-blood and plasma Se levels in the second and third trimesters and at delivery. The significant drop of whole-blood SeGSH-Px activity was observed in the first trimester of pregnancy and its lower activity was maintained until delivery. A significant drop in plasma SeGSH-Px activity occurred in the second trimester and attained the minimal level at delivery. The Se level and SeGSH-Px activity in maternal and umbilical cord blood were at similar levels. Amniotic-fluid SeGSH-Px activity was nondetectable or exceptionally low and its Se content remained unchanged during pregnancy. Plasma levels of MDA were significantly decreased in the second and third trimesters and at delivery. The fetal blood plasma at birth had a lower MDA level compared to the levels of MDA of their mothers at delivery. A low, but significant inverse correlation existed between blood SeGSH-Px activity and plasma MDA content and between plasma Se and plasma MDA contents during pregnancy. A significant decrease of Se and SeGSH-Px activities (antioxidant enzyme) in both blood and plasma suggests a possible drop in total antioxidant status during pregnancy. Elevated MDA plasma levels might be the result of increased lipid peroxidation in placental tissue during pregnancy. Index Entries: Selenium; glutathione peroxidase; malondialdehyde; pregnancy; umbilical cord blood; amniotic fluid.

Serbia is a selenium (Se) deficient area. In the food chain animals accumulate Se in tissues, thus meat is a good source of this microelement. The aim of the research is to study the effects of different forms and doses of dietary Se in pigs and broilers on muscle and liver tissue Se concentrations, as well as to assess the possibility of using selenized meat as a Se source in the Belgrade area. Pigs (24) were randomly assigned in 4 groups: control and groups supplemented with Na-selenite: 0.10, 0.30 mgSe/kg feed and selenized yeast 0.30 mgSe/kg. Chicks (42) were assigned in 7 groups supplemented with 0.05, 0.10 and 0.30 mgSe/kg feed as Na-selenite or selenized yeast. Se content in muscle and liver samples was determined by AAS. Serum Se content in 54 healthy adult subjects (13 from Barajevo and 41 from inner city area) was determined by AAS. In all supplemented broilers Se-yeast was more effective in raising muscle Se content than Na-selenite. The most efficient increase in tissue Se content in pigs was obtained with 0.30 mg Se/kg feed supplemented as Se-yeast. Plasma Se levels in man were low, being significantly lower in subjects from Barajevo compared with the inner city residents (p<0.05). The use of Se-enriched pork and poultry meat in quantities according to dietary habits would have beneficial health effects specially in Se deficient rural areas where home grown feedstuffs are commonly used

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The aim of this study was to investigate the influence of organic and inorganic Fe supplementation on red blood picture, immune response and quantity of iron in organs of broiler chickens. The trial was conducted on 200 'Arbor Acres' chickens randomly alloted in four equal groups. Birds from all groups were fed standard broiler feed, supplemented with 40 mg/kg of Fe originating from different sources: Group I (FeSO4), Group II (Fe bounded to yeast), Group III (ferrous ascorbate) and Group IV (iron chelate). From each group, 10 birds were sacrificed on 21st, 35th and 42nd day and the following parameters were measured: erythrocyte count, hematocrite value, hemoglobin concentration, concentration of nonheme iron in spleen, liver and bone marrow (femur), degree of cutaneous hypersensitivity to PHA and titers of antibodies to Gumboro virus following vaccination. Addition of organic iron supplements resulted in increased erythrocyte count, hemoglobin concentration and hematocrite value on the 21st day. Different iron forms did not change the concentration of nonheme iron in the liver on the 21st and 42nd day. On the 35th day, the group supplemented with ferrous ascorbate had lower liver iron concentration. Also, concentrations of nonheme iron in the spleen were lower in groups supplemented with organic iron forms. The concentration of iron in the bone marrow decreased with age and the lowest values were recorded in the ferrous ascorbate supplemented group. The degree of cutaneous hypersensitivity to PHA was higher in groups supplemented with organic iron forms on the 21st and 35th day. Titers of anti-Gumboro antibodies were higher in the group supplemented with iron helate on the 35th day, but later (day 42) no significant differences were observed among groups.

The selenium and iodine status was determined in calves (3, 6 and 9 months old) and heifers (12 months) on two farms (A-Kovin, and B-Vrbas) in iodine and selenium deficient areas of Serbia. Selenium concentrations in feedstuffs on the territories surrounding farm A and B were lower than 0.1 ppm in more than 90% of the samples and lower than 0.05 ppm in more than 67% of the samples. Plasma selenium concentrations in calves and heifers from both farms were very low, ranging from 1.58 to 9.42 µg/L. Plasma GSH-Px activity was very low in 3 month old calves: 8.4 ± 5.2 and 16.1 ± 4.3 µkat/L on farm A and B, respectively, and significantly higher in 12 month old heifers: 39.0 ± 6.2 and 40.8 ± 9.8 µkat/L on farm A and B, respectively. Mean plasma T4 levels in all groups of calves and heifers were relatively high, ranging between 57.1 and 102.9 nmol/L. Mean plasma T3 levels in calves and heifers from both farms ranged from 2.72 to 3.51 nmol/L, and did not vary significantly, except for the 3-month-old calves on farm B, where the level was significantly higher than in the other groups. A significant correlation was found between plasma GSH-Px activity and T3:T4 ratio in the 6- month-old calves from farm A (r2 = 0.80), as well as in the combined groups of 6-and 9-month old calves from farm B (r2 = 0.68)