title: Immunomodulation in young laying hens by dietary folic acid and acute immune responses after challenge with Escherichia coli lipopolysaccharide.
abstract: We investigated the effects of dietary folic acid (FA) supplementation on immunological parameters in young laying hens under acute conditions of lipopolysaccharide (LPS) challenge. Twenty-four Shaver White laying hens at 24 wk were fed 2 diets in a completely randomized design. The diets were wheat-soybean based, with either 0 or 4 mg of supplemental FA per kilogram of diet. At 32 wk of age, 6 hens from each dietary treatment were injected intravenously with 8 mg/kg of BW of either LPS or saline. Four hours after injection, blood was collected and the hens were euthanized to obtain spleen and cecal tonsils. Heterophil:lymphocyte ratio, CD3+, CD4+, CD8+ T cells, and CD4+:CD8+ cells in the blood and spleen were not affected by dietary FA. Relative to saline-injected hens, LPS-injected hens had fewer (P < 0.05) CD3+, CD4+, CD8+, and CD4+:CD8+ cells in the blood, and no difference was found in the spleen. Total protein, albumin, and globulin were found to be higher (P < 0.05) in FA-supplemented hens compared with the control. However, total protein, albumin, and globulins decreased (P < 0.05) in the LPS-injected hens compared with the saline control. Expression of interleukin (IL)-1β in cecal tonsils decreased (P < 0.05) in FA-supplemented hens, but no dietary influence was found on the expression of other genes in both the spleen and cecal tonsils. Lipopolysaccharide upregulated (P < 0.05) expression of IL-10 and interferon (IFN)-γ in the spleen, and IL-1β, IL-10, and IFN-γ in the cecal tonsils, whereas the expression of Toll-like receptor (TLR)-4 and IL-8 was not influenced by LPS in the spleen and cecal tonsils. There was a diet × challenge interaction for total IgG, and cytokines IL-1β and IL-18 in the spleen as well as IL-18 in the cecal tonsils. In conclusion, there were few interactions of dietary FA and LPS; however, FA increased biochemical constituents, enhanced generation of total IgG, as well as exhibiting pleoitropic effects in inflammatory responses.
authors.affiliation: Department of Animal Science, University of Manitoba, Manitoba, Canada.
authors.forename: P M
authors.initials: PM
authors.lastname: Munyaka
authors.forename: G
authors.initials: G
authors.lastname: Tactacan
authors.forename: M
authors.initials: M
authors.lastname: Jing
authors.forename: K
authors.initials: K
authors.lastname: O
authors.forename: J D
authors.initials: JD
authors.lastname: House
authors.forename: J C
authors.initials: JC
authors.lastname: Rodriguez-Lecompte
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002432:Cecum / Q000166:cytology; D002645:Chickens; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004926:Escherichia coli / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D005492:Folic Acid / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D056747:Immunomodulation; D008070:Lipopolysaccharides / Q000276:immunology* / Q000378:metabolism; D008214:Lymphocytes / Q000502:physiology; D010058:Oviposition; D014066:Palatine Tonsil / Q000276:immunology; D013154:Spleen / Q000166:cytology
chemical_list: D016207:Cytokines; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D005492:Folic Acid