Please cite this article as Hossein Zadeh M, Kermanshahi H, Sanjabi MR, Golian A, Azin M & Majidzadeh-Heravi R. 2018. Comparison of Different selenium Sources on Performance, Serum Attributes and Cellular Immunity in Broiler Cchickens. Poult. Sci. J. 6(2): 191-203. © 2018 PSJ. All Rights Reserved Poultry Science Journal ISSN: 2345-6604 (Print), 2345-6566 (Online) http://psj.gau.ac.ir DOI: 10.22069/psj.2018.15232.1341 Comparison of Different selenium Sources on Performance, Serum Attributes and Cellular Immunity in Broiler Chickens Hossein Zadeh M 1 , Kermanshahi H 1 , Sanjabi MR 2 , Golian A 1 , Azin M 2 & Majidzadeh-Heravi R 1 1 Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran 2 Iranian Research Organization for Science and Technology, Tehran, Iran Poultry Science Journal 2018, 6(2): 191-203 Introduction Selenium (Se) has been defined as an essential element for growth (Yoon et al., 2007; Wang and Xu, 2008), immune competence (Cai et al., 2012; Liao et al., 2012), antioxidant (Peng et al., 2007; Zhou and Wang, 2011) and reproductive functions, immunocompetence, and ageing (Sevescova et al., 2006; Leeson et al., 2008) of broilers. Selenium as an essential trace mineral is crucial in human health (Rayman, 2004), and improving performance and health of the birds (Haug et al., 2007; Yoon et al., 2007). Commercial organic and inorganic forms of Se are available in the market. Organic forms are selenomethionine, Se enriched yeast, and Se enriched alga, while inorganic forms of Se are available as selenite, selenate, and selenide (Sevescova et al., 2006). The main used Se source in poultry diets is sodium selenite. However, research has shown Se yeast and other sources of Se, have been examined as alternatives to inorganic Se supplementation (Payne and Abstract Keywords Broilers Immunity Performance Blood indices Selenium source The effects of organic and inorganic sources and concentration (0 and 0.3 mg per kg of diet) of Selenium (Se) on growth performance, blood biochemical and immune system were evaluated in broiler chickens. Chickens were fed corn-soy-based diets formulated to 8 dietary treatments containing no added Se (negative control), negative control plus yeast (positive control), and 6 diets had 0.3 mg/kg of diet supplemented with Se from Availa Se, Sel-plex, SeleMax, Se enriched yeast, sodium selenite and sodium selenate. Four hundred Ross 308 male chickens were randomly divided into 8 treatments and 5 replicates of 10 birds each. Feed intake, body weight gain, and feed conversion ratio were measured at starter (0-10 d), grower (11-24 d), and finisher (25-42 d) periods. On d 24 and 42, one bird from each replicate was killed by cervical dislocation and blood samples were collected to determine blood chemicals, glutathione peroxidase (GPx) activity and heterophile to lymphocyte ratio. Results showed that Se supplementation had no effect on feed intake, body weight gain, and feed conversion ratio of the chickens (P < 0.05). However, blood triglycerides, GPx activity and heterophile to lymphocyte ratio were significantly affected by organic and inorganic Se sources (P < 0.05). Results showed that selenium in organic and inorganic forms didn't have any effect on growth performance and blood parameters but they could improve immune system through increase in GPx activity. Corresponding author Hassan Kermanshahi kermansh@um.ac.ir Article history Received: September 26, 2018 Revised: November 9, 2018 Accepted: November 14, 2018