Lymphocytes and macrophages are the main white cells involved in fetal-maternal tolerance. Little is known about these leukocytes in bovine placenta, such as the quantity and location of these cells. Thus, the objective of this study was to identify lymphocyte and macrophage populations in bovine placenta using specific markers and flow cytometry. This study analyzed samples of placentomes and intercaruncular regions of cows in the three quarters of pregnancy. In the placentomes, during the first quarter of pregnancy, mean percentage of labeled CD3+ cells was 2.34%; CD8+, 1.28%; CD14+, 1.66%; and CD335+, 0.96%. For the intercaruncular region, percentage of CD3+ cells was 0.71%; CD8+, 1.63%; CD14+, 2.81%; and CD335+, 2.81%. In the second quarter, placentomes showed 0.94% CD3+ cells; 0.77% CD8+; 0.72% CD14+; and 0.51% CD335+. In the intercaruncular region, percentage of labeled CD3+ cells was 0.50%; CD8+, 1.81%; CD14+, 2.64%; and CD335+, 0.51%. In the third quarter, placentomes showed labeling of 0.88% CD3+; 0.66% CD8+; 1.06% CD14+; and 0.74% CD335+ cells. In the intercaruncular region, percentage of labeled CD3+ cells was 0.19%; CD8+, 2.23%; CD14+, 2.43%; and CD335+, 0.16%. The results showed that there was a greater immunomarking of leukocytes CD3+ and CD335+ in the placentome when compared to the intercaruncular region during the third trimester. It can be concluded that leukocytes populations in bovine placenta is reduced, probably because of the syndesmochorial characteristic of bovine placenta. This represents a significant barrier for the immunological system of the mother, sharply decreasing the exposure of the conceptus to the mother’s immune system.

This study was undertaken to investigate the ameliorative effect of sodium selenite and nano-selenium on chicks exposed to heat stress. Ninety one day-old broiler chicks were divided into six groups each of 15 birds. Birds in group one and four were fed on basal diet and served as a control group, while birds in group two and five were fed on basal diet treated with 0.15 mg/Kg diet prepared selenium nanoparticles and birds in group three and six were fed on basal diet treated with 0.15 mg/Kg sodium selenite. On day 37 of experiment birds in 4th, 5th and 6th group were exposed to artificial heat stress at 40°C for 12 hours. Based on the results of total body weight gain and FCR lower parameters of body weight, body weight gain, feed conversion rate and higher feed intake ratio were observed in heat stressed chicks. Nano-selenium and Na selenite supplementation decreased the serum AST, ALT, urea, creatinine and MDA while the serum total protein, SOD, LZM, IgG, IgM and C3 were increased, also nano-selenium has ameliorative effect on hematological and histopathological findings. In conclusion, both nano-selenium and sodium selenite have an essential role in treatment of adverse effect of heat stress on chicks, with superiority of nano-selenium in improving anti- oxidative status and boosting immune response.