Effects of dietary vitamin E on the immune system in broilers: altered proportions of CD4 T cells in the thymus and spleen.
To gain insight into the immunomodulatory effects of vitamin E (VE), immune cell population analyses were conducted using thymus and spleen from male broilers fed diets with various levels of VE supplementation (0, 17, 46, and 87 mg dl-alpha-tocopherol acetate/kg of feed). At 2 and 7 wk of age, the percentages of B cells, macrophages, and T cell subsets, delineated by the expression of CD4, CD8, and T cell receptor (TCR) isotype, in thymus and spleen were determined by flow cytometry. The percentages of thymic and splenic B cells and macrophages from 2- and 7-wk-old chickens, as well as the percentage of thymic T cells in 2-wk-old chickens, were unaffected by VE treatment. However, 7-wk-old broilers maintained on 87 mg VE/kg feed had a higher percentage of CD4+CD8- thymocytes, a higher CD4+CD8- to CD4-CD8+ thymocyte ratio, and a lower percentage of CD4+CD8+ thymocytes than chickens receiving no dietary VE supplementation. The VE-induced increase in the percentage of CD4+CD8- thymocytes was due to an increase in the TCR2+CD4+CD8- thymocyte subset, whereas the decrease in the percentage of CD4+CD8+ thymocytes involved all TCR defined T cell subsets. In the spleen, the percentage of CD4+CD8- T cells was lower in 2-wk-old chickens and higher in 7-wk-old chickens maintained on 87 mg/kg feed than in chickens receiving no dietary VE supplementation. The decrease in CD4+CD8- splenocytes at 2 wk of age was due to a decline in the percentage of TCR2+CD4+CD8- splenocytes, whereas the increase in CD4+CD8- splenocytes in 7-wk-old chicks was due to an increase in the percentages of all TCR defined CD4+CD8- T cell subsets. These data support an immunomodulatory effect of VE on CD4+CD8- T cells.
Erf
G F
GF
Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville 72701, USA. gferf@comp.uark.edu
Bottje
W G
WG
Bersi
T K
TK
Headrick
M D
MD
Fritts
C A
CA
D000284:Administration, Oral; D000375:Aging / Q000187:drug effects / Q000276:immunology; D000821:Animal Feed; D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology; D016516:CD4-CD8 Ratio / Q000187:drug effects; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002645:Chickens / Q000276:immunology*; D015331:Cohort Studies; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008297:Male; D011948:Receptors, Antigen, T-Cell / Q000187:drug effects / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D014810:Vitamin E / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use
D011948:Receptors, Antigen, T-Cell; D014810:Vitamin E