Location: Livestock Behavior Research
Title: Dietary L-arginine supplementation attenuates lipopolysaccharide-induced inflammation and affects the extracellular recognition of lipopolysaccharide in broiler chickens Authors
|Tan, J -|
|Guo, Y -|
|Applegate, T -|
Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 14, 2013
Publication Date: N/A
Interpretive Summary: Over expression of immune responses can be detrimental to an animal during an infection. Methods to maintain a good immune response, but decrease the over production of immune products that can reduce growth or may even be lethal are necessary. Effects of the concentration of arginine (an essential amino acid for chickens) on immune responses to a part of the bacterial cell (lipopolysaccharide, LPS) were determined. The LPS injection decreased feed intake and gain (body weight, and reduced feed conversion) as expected. Additionally, LPS reduced molecules that are important to cell movement to the site of infection, antibody producing cells, and cells that identify pathogens (disease producing bacteria). The arginine supplement reduced immune responses in the spleen including inflammatory proteins, cell signals, and pathogen recognition molecules. Therefore, arginine attenuated the expression and damage by immune responses to the LPS injection, without abrogating the necessary immune response.
Technical Abstract: Two experiments were conducted to investigate the effect of dietary L-arginine (Arg) supplementation on inflammatory response and innate immunity of broilers. Experiment 1 was designed as a 2 × 3 factorial arrangement (n = 8 cages/treatment; 6 birds/cage) with 3 dietary Arg concentrations (1.05, 1.42, and 1.90%) and 2 immune treatments (injection of lipopolysaccharide (LPS) or saline) which were given in 48 h interval between 14 and 21 d of age. Correlation between dietary Arg concentration and circulating B cells population was determined in Experiment 2. In Experiment 1, LPS injection decreased BW gain and feed intake, and increased feed-to-gain of challenged broilers (14 to 21 d; P < 0.05). LPS injection suppressed (P < 0.05) CD11+ and B cells percentages and phagocytosis by splenic heterophils and macrophages; Arg supplementation tended to decrease the percentage of CD11+, CD14+ and B cells in the spleen (P < 0.10). LPS injection increased (P < 0.05) IL-1ß and IL-6 mRNA expression in the spleen and cecal tonsils. Arginine supplementation decreased (P < 0.05) the mRNA expression of IL-1ß, TLR-4, and PPAR-gamma in the spleen, and IL-1ß, IL-10, TLR-4, and NF'B in the cecal tonsils. In Experiment 2, increasing dietary Arg concentration decreased circulating B cells percentage linearly and quadratically (P < 0.01). Thus, Arg supplementation inhibited CD11+ and CD14+ cells percentages affecting the extracellular recognition of LPS. Further, Arg supplementation suppressed the TLR-4/NF-kappa B cascade, thereby reducing the expression of pro-inflammatory cytokines. Excessive Arg supplementation (1.79%) suppressed circulating and splenic B cell populations. Over all, greater arginine supplementation decreased the measures that are associated with the detrimental effects of an immune response, but did not abrogate the necessary response.