The Effects of Organic, Inorganic, and Nano-Selenium on Blood Attributes in Broiler Chickens Exposed to Oxidative Stress

Abstract

"Background: Physiological stress is one of many concerns facing the modern broiler producer. In this study, tert-butyl hydroperoxide (tert-BHP) was used to induce oxidative stress. When birds exposed to stress, selenium is used in antioxidant enzymes to decrease the harmful effects of free radicals. In this regard, the source of selenium is important to provide enough protection. There are three forms of selenium as inorganic, organic and nano-selenium (Nano-Se). Recently, the latter has attracted widespread attention because of large surface area, high surface activity, high catalytic efficiency, strong adsorbing ability and low toxicity. The present study aimed to compare different sources of selenium on blood attributes of male broilers subjected to oxidative stress. Materials, Methods & Results: Corn grain and soybean meal-base diets were formulated to meet the nutritional requirements of Cobb 500 broiler chickens. Three hundred twenty chicks were randomly assigned to receive diet without selenium supplementation (CON) or diets supplemented with 0.3 mg/kg nano-Se (NAN), organic Se (ORG), and inorganic Se (INO). The study was conducted as a completely randomized designed with a 2×4 factorial arrangement comprising four replicates of 10 birds per each. Circulatory concentration of cholesterol and glucose were not influenced by the source of selenium. Experimental groups under the oxidative stress, however, recorded and increase in blood cholesterol and glucose. A higher heterophil to lymphocyte (H:L) ratio was found at oxidative condition. Furthermore, Se-supplemented groups were kept under non-oxidative condition had a lower H:L ratio as compared to CON group, where the lower value was recorded for NAN birds (P < 0.05). The percentage of peripheral basophil in oxidatively-stressed experimental groups was significantly higher than their counterparts (P < 0.05). However, no differences were found for the number of red blood cells, hemoglobin concentration (Hb), hematocrit, Mean corpuscular hemoglobin (MCH), Mean corpuscular hemoglobin concentration (MCHC), and platelet number (P > 0.05). A significant difference was found for total white blood cells (WBC) number and Mean corpuscular volume (MCV) among the experimental groups (P < 0.05). Discussion: In the present study, the sources of Se did not affect the total leukocyte and erythrocyte number as well as the Hb concentration within each rearing condition. Higher record of H:L ratio for oxidative stress condition. The lowest value was recorded for stressed chicks fed nano selenium. Higher H:L ratio is an indicative of a stressful condition. Although no difference in monocyte number were recorded among the experiment groups, decreased lymphocyte and monocyte numbers and increased heterophil number which, in turn, results in a higher H:L ratio are used as stress indices in animals. The number of lymphocytes in chicken blood samples decreased and the number of heterophils increased in response to o"