title: Effects of dietary selenium and vitamin E on immune response and biological blood parameters of broilers reared under thermoneutral or heat stress conditions.
abstract: A study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125 and 250 mg/kg), selenium (Se, 0, 0.5 and 1 mg/kg), or their different combinations on immune response and blood biological parameters of broilers raised under either thermoneutral (TN, 23.9 °C constant) or heat stress (HS, 23.9 to 37 °C cycling) conditions. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Heterophil to lymphocyte (H/L) ratio also determined as an indicator of stress. Furthermore, at the end of the experiment, birds were bled for determination of some biological parameters. There was a significant reduction in body weight and feed intake, but the feed conversion ratio increased when the birds were exposed to HS (P<0.05). Body weight and feed intake were not influenced significantly by dietary vitamin E and Se (P>0.05), whereas feed conversion was improved significantly by 125 mg/kg vitamin E (P<0.05). The liver and lymphoid organ weights as well as IgM and IgG, antibody titers for primary and secondary antibody responses to SRBC were reduced significantly under HS (P<0.05). Heat stress also resulted in a significant increase in H/L ratio (P<0.05). Dietary vitamin E resulted in improvement of primary and secondary antibody responses both in TN and HS broilers (P<0.05). The HS birds also showed an improved antibody titer in secondary response with high concentration of Se (P<0.05). Vitamin E and Se had interactive effects on anti-SRBC titers; however, no consistent differences were found between dietary levels during the study. The H/L ratio decreased by feeding vitamin E at both levels either under HS or TN conditions (P < 0.05). The serum concentrations of glucose, triglycerides, total cholesterol, and LDL-cholesterol were increased but serum HDL-cholesterol decreased in HS broilers (P<0.05).
authors.affiliation: Department of Animal Science, Faculty of Agriculture, Razi University, Kermanshah, Iran, mahmood_habibiyan@yahoo.com.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Habibian
authors.forename: Shahab
authors.initials: S
authors.lastname: Ghazi
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Moeini
authors.forename: Alireza
authors.initials: A
authors.lastname: Abdolmohammadi
mesh_terms: D000821:Animal Feed; D000818:Animals; D000906:Antibodies / Q000276:immunology; D000975:Antioxidants / Q000494:pharmacology*; D001786:Blood Glucose / Q000032:analysis; D002645:Chickens; D004032:Diet; D004435:Eating; D004912:Erythrocytes / Q000276:immunology; D018882:Heat Stress Disorders / Q000097:blood* / Q000276:immunology* / Q000662:veterinary; D056724:Immunity, Humoral / Q000187:drug effects; D008055:Lipids / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000254:growth & development; D008214:Lymphocytes / Q000276:immunology; D009929:Organ Size / Q000187:drug effects; D012643:Selenium / Q000494:pharmacology*; D012756:Sheep; D013154:Spleen / Q000187:drug effects / Q000254:growth & development; D013696:Temperature; D013950:Thymus Gland / Q000187:drug effects / Q000254:growth & development; D014810:Vitamin E / Q000494:pharmacology*
chemical_list: D000906:Antibodies; D000975:Antioxidants; D001786:Blood Glucose; D008055:Lipids; D014810:Vitamin E; D012643:Selenium