title: Lesions of thymus and decreased percentages of the peripheral blood T-cell subsets in chickens fed on diets excess in selenium.
abstract: Selenium is an essential trace element possessing immune-stimulatory properties. The purpose of this 42-day study was to investigate the effects of excess dietary selenium on cellular immune function by determining morphological changes of thymus and peripheral blood T-cell subset. Three hundred 1-day-old avian broilers were fed on a basic diet (0.2 mg/kg selenium) or the same diet amended to contain 1, 5, 10, 15 mg/kg selenium supplied as sodium selenite (n = 60/group). Pathological lesions were progressed with the dietary Se level increased. Grossly, the volume of thymus was decreased. Histopathologically, lymphopenia and congestion were observed. Ultrastructurally, mitochondria injury was observed. In comparison with that of control group, 5, 10 and 15 mg/kg dietary Se decreased the percentage of CD3(+), CD3(+)CD4(+) and CD3(+)CD8(+) T cells of the peripheral blood, as measured by flow cytometry. The results showed that excess selenium (more than 5 mg/kg) intake could cause lesions of thymus and decrease of T-cell subsets. The cellular immune function was finally impaired in broilers.
authors.affiliation: College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Peng
authors.forename: Hengmin
authors.initials: H
authors.lastname: Cui
authors.forename: Yun
authors.initials: Y
authors.lastname: Cui
authors.forename: Junliang
authors.initials: J
authors.lastname: Deng
authors.forename: Zhicai
authors.initials: Z
authors.lastname: Zuo
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
mesh_terms: D000821:Animal Feed; D000818:Animals; D000975:Antioxidants / Q000506:poisoning*; D017252:CD3 Complex / Q000276:immunology; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000473:pathology; D002452:Cell Count; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D007111:Immunity, Cellular / Q000187:drug effects; D008231:Lymphopenia / Q000139:chemically induced* / Q000473:pathology; D018038:Sodium Selenite / Q000506:poisoning*; D016176:T-Lymphocyte Subsets / Q000187:drug effects* / Q000473:pathology; D013950:Thymus Gland / Q000187:drug effects* / Q000473:pathology
chemical_list: D000975:Antioxidants; D017252:CD3 Complex; D018038:Sodium Selenite