Svetlana Milanović

Effects of Different Amounts of Supplemental Selenium and Vitamin E on the Incidence of Retained Placenta, Selenium, Malondialdehyde, and Thyronines Status in Cows Treated with Prostaglandin F2α for the Induction of Parturition

The incidence of retained placenta (RP) in cows increases in cases of parturition induced by prostaglandin F2α. We analyzed the effects of different doses of supplemental selenium and vitamin E on the incidence of RP, blood selenium, plasma thyronines, and malondialdehyde concentration. Thirty-three clinically healthy, multiparous Holstein-Frisian cows were assigned to 3 groups and supplemented with a single intramuscular injection of sodium selenite (SS) and tocopherol acetate (TAc) between days 250 to 255 of gestation: control—unsupplemented; group A—10 mg SS + 400 mg TAc; group B—20 mg SS + 800 mg TAc. Parturition was induced using PGF2α not before day 275 of gestation. The RP incidence was reduced from 66.7% in the control to 38.2 and 30.8% in groups A and B, respectively. Blood selenium and glutathione peroxidase activity in treated groups were significantly higher compared to control, with no significant difference between groups A and B. Plasma malondialdehyde in group B was significantly lower than that in control and group A, while thyronines levels were not affected. Comparison of RP and non-RP cows, independently of supplement treatment, revealed higher blood selenium and glutathione peroxidase activity and lower MDA and thyroxine in non-RP animals, while triiodothyronine level did not differ.

Supplemental Selenium Reduces the Levels of Biomarkers of Oxidative and General Stress in Peripartum Dairy Cows / Dodati Selen Snižava Nivoe Biomarkera Oksidativnog I Opšteg Stresa Kod Mlečnih Krava U Peripartalnom Periodu

The aim of this investigation was to determine the influence of oxidative stress upon general stress in dairy cows on parturition and whether the indicators of stress can be reduced by selenium (Se) supplementation. A total of 36 animals were divided into 3 groups 21 days prepartum and treated with a single-term intramuscular supplement of sodium selenite: Control group - 0 mg; group Se10 - 10 mg; group Se20 - 20 mg. Se supplementation significantly raised blood Se content and glutathione peroxidase (GPx) activity in groups Se10 and Se20, compared to Control, although there was no marked difference between supplemented groups. Plasma malondialdehyde (MDA) and cortisol concentrations were significantly reduced in supplemented groups Se10 and Se20, compared to Control. A negative correlation was detected between blood GPx activity and plasma MDA, while a positive correlation was determined between plasma MDA and cortisol concentrations. These results indicate that prepartum Se supplementation can be utilized for a partial relief of stress in cows during labor by augmenting the antioxidative action of GPx. Cilj ispitivanja je bio da se odredi obim uticaja oksidativnog stresa na opšti stres kod mlečnih krava u toku 24 sata oko porođaja, kao i da li on može biti ublažen primenom selena. Ukupno 36 krava je bilo podeljeno u tri grupe 21 dan pre porođaja i jednokratno tretirano natrijum selenitom aplikovanim intramuskularno u dozama: kontrolna grupa - 0 mg; grupa Se10 - 10 mg; grupa Se20 - 20mg. Grupe Se10 i Se20 su imale značajno višu koncentraciju selena i aktivnost glutation peroksidaze (GPx) u krvi u odnosu na kontrolnu grupu, iako nije uočena razlika između suplementiranih grupa. Koncentracije malondialdehida (MDA) i kortizola su bile značajno niže u grupama Se10 i Se20 u odnosu na kontrolnu grupu. Uočena je negativna korelacija između aktivnosti GPx u krvi i koncentracije MDA u plazmi, a pozitivna korelacija između koncentracije MDA i kortizola u plazmi. Rezultati ukazuju da prepartalna upotreba selena može biti korisna u smislu delimičnog smanjenja stresa u toku porođaja zbog povećanja antioksidativnog delovanja GPx.

Corrigendum to “The effects of dietary Selenium-yeast level on glutathione peroxidase activity, tissue Selenium content, growth performance, and carcass and meat quality of broilers”

Abstract The present study was conducted to assess effects of selenium (Se)‐yeast supplementation on glutathione peroxidase activity, Se levels in tissues, growth performance, carcass, and meat composition in broilers. A total of 275 one‐d‐old Cobb 500 broilers of both sexes were randomly allotted to 1 of 5 treatments during a 42‐d period. The 5 treatments differed only in Se content: group 1 had no additional Se (background only); groups 2, 3, and 4 received 0.3 mg/kg of added Se from the beginning of the trial until d 21, whereas in the second half of the study (from d 22 to 42), these groups received 0.3, 0.6, and 0.9 mg/kg of added Se, respectively; and group 5 received 0.9 mg/kg of Se for the entire experimental period. At the end of the study, the control group showed significantly lower (P < 0.01) glutathione peroxidase activity in blood plasma compared to Se‐supplemented groups. Regarding Se concentration in various tissues, the groups receiving Se yeast showed higher plasma, feces, and meat Se contents than the control group (P < 0.01). Supplementation of Se improved broilers’ body weight, weight gain and feed conversion ratio (P < 0.01). Dressing percentage was lower in the control group and the group with 0.3 mg/kg of added Se compared to other experimental groups (0.6 and 0.9 mg/kg of dietary Se). The proportion of less valuable carcass parts (wings and legs) was higher (P < 0.01) in the group fed the basal diet compared to groups supplemented with 0.9 mg/kg of Se. Initial and ultimate pH values differed among experimental groups (P < 0.05). Supplementation of Se improved the broilers antioxidative resistance, growth performance, carcass quality, and chemical composition of meat.

Effects of Selenium and Thyroid Hormone Deficiency on Peritoneal Macrophages Adhesion and Occurrence of Natural IGM Antibodies in Juvenile Rats

Abstract Both selenium, as an effector and regulator of antioxidative enzymes activity, and thyroid hormones are potent immunomodulators. Besides, selenium incorporated into iodothyronine deiodinases is involved in the thyroid function and thus indirectly regulates the immune response. Studies of the mutual influence of selenium and thyroid hormones on the immune response are scarce, hence we analyzed the effects of an iodothyronine deiodinases blocker, propylthiouracil (PTU), and selenium deficiency on the function of peritoneal macrophages, and titer of naturally occurring anti-sheep red blood cells (SRBC) IgM antibodies in juvenile rats. The experiment was carried out on 64 Wistar male rats allotted to 4 groups: controlselenium adequate PTU- group; selenium adequate, PTU+ group; selenium defi cient, PTU- group; and selenium defi cient, PTU+. The selenium adequate and selenium defi cient groups were fed a diet containing 0.334 and 0.031 mg Se/kg, respectively. PTU+ groups received PTU (150 mg/L) in drinking water. After 3 weeks, thyroxine (T4), triiodothyronine (T3), and thyroid stimulating hormone (TSH) were determined. The animals having “intermediate” concentrations of T3 (1.56-1.69 nmol/L) and T4 (41-50 nmol/L) were excluded from further analysis. Thus, PTU+ groups included hypothyroid animals (T3≤1.55 nmol/L; T4≤40 nmol/L), while PTU- groups included euthyroid rats (T3≥1.70 nmol/L; T4≥50 nmol/L). Both groups of selenium deficient rats had, when compared to the control group, a significantly lower activity of glutathione peroxidase GPx1 and GPx3. Neither selenium deficiency nor PTU influenced the adherence of peritoneal macrophages. Selenium deficiency significantly decreased the peroxide synthesis in macrophages and significantly increased the titer of anti-SRBC IgM. Hypotyroidism alone or in combination with selenium deficiency had no influence on these parameters.

Progesterone concentration, pregnancy and calving rate in Simmental dairy cows after oestrus synchronisation and hCG treatment during the early luteal phase

Early embryonic development may be negatively affected by insufficient progesterone (P4) production. Therefore, the aim of our study was to increase P4 by gonadotropin-releasing hormone (GnRH) and/or human chorionic gonadotropin (hCG) treatments after inducing oestrus by prostaglandin (PG) treatment. Lactating Simmental dairy cows (n = 110), between 1 to 5 lactations, with an average milk production of 6,500 1/305 days, at 40-80 days postpartum were used and grouped as follows: (1) PG + GnRH treatment at AI (GnRH group), (2) PG + hCG treatment at day 7 after AI (hCG group), (3) PG + GnRH at AI + hCG treatment at day 7 after AI (GnRH/hCG group), and (4) spontaneous oestrus (C: control group). All animals were double inseminated (at the time of oestrus detection and 12 ± 2 h thereafter). Blood serum and milk samples were collected at the day of observed oestrus (day 0), and 14, 21 and 28 days after AI. Serum P4 was determined using a commercial radioimmunoassay (RIA) test (INEP, Zemun), and milk P4 was determined using enzyme-linked immunoassay (ELISA) test (NIV Novi Sad). Pregnancy status was confirmed by ultrasonography between days 28 and 35 after AI. Differences of serum or milk P4 medians, pregnancy (and calving) rate were determined using Dunns Multiple Comparison Tests and Z test, respectively. Serum P4 medians were significantly higher at days 14, 21 and 28 after AI in the hCG-treated animals, indicating increased luteal activity, with a similar tendency in whole milk P4 values. Treatment with hCG during the early luteal phase significantly contributed to the maintenance of gestation at days 28-35 after AI, and also increased the calving rate in Simmental dairy cows.