Submitted to: Journal of Leukocyte Biology
Publication Type: Abstract Only
Publication Acceptance Date: 8/31/2005
Publication Date: 9/29/2005
Citation: Cary, D.C., Eicher, S.D., Patterson, J.A. 2005. The peripheral and micro-environment immune function of neonatal dairy calves fed beta-glucan with and without ascorbic acid. Journal of Leukocyte Biology. 78(1):67.
Technical Abstract: Neonatal dairy calves undergo many natural and imposed stressors; an immune modulator would help alleviate the associated deleterious effects. Beta-glucan and ascorbic acid have been shown to modulate certain immune functions when fed orally. The objective of this study was to examine the innate immune response in peripheral blood and tissues, after twenty-one days of oral feeding of beta-glucan with or without ascorbic acid. Twenty-five bull calves were placed into one of four treatment groups at 3 d-of-age, experimental day 0 (d 0). The control treatment (CTL), received unsupplemented milk replacer for 21 d (n=5); treatment 2 (BG3d) , received unsupplemented milk replacer for 17 d and a fluorescently-labeled beta-glucan (0.9mg/d), in milk replacer on d 18-20 (n=5); treatment 3 (BG20d), received beta-glucan (0.9mg/d) for 17 d and a fluorescently-labeled beta-glucan (0.9mg/d) on d 18-20 (n=10); and treatment 4 (BGA), received beta-glucan (0.9mg/d) plus ascorbic acid (0.5mg/d) for 17 d and a fluorescently-labeled beta-glucan (0.9mg/d) plus ascorbic acid (0.5mg/d) on d 18-20. Weekly jugular blood samples were collected at d 0, d 7, d 14, and d 21. Blood samples were stained with anti-human CD14 (lipopolysaccaride receptor) to indicate presence of monocytes, anti-human CD18 (cell adhesion molecule) to indicate the presence of neutrophils, and anti-bovine DEC205 to indicate the presence of dendritic cells (DC). All calves were euthanized at d 21, and a portion of the lung, liver, spleen, ileum, jejunum, and mesenteric lymph nodes (MLN) were removed. Tissues were homogenized to a single cell suspension and stained with anti-CD14, anti-CD18, and anti-DEC205. At d 14, peripheral blood expression of CD14 was significantly greater in BGA than calves fed no beta-glucan (P<.05), and tended to be greater at d 7 (P<.10). At d 7 and d 14, peripheral blood expression of CD18 was significantly greater in BG20d and BGA than control fed calves (P<.05). On day 21, peripheral blood expression of CD18 was significantly greater in BGA than BG3d (P<.05). Jejunal expression of CD18 tended to be greater in BGA than CTL (P<.10). MLN expression of CD14 was significantly greater in BG20d and BGA (P<.01), and BG3d (P<.05), than CTL. MLN expression of CD18 tended to be greater in BG20d than CTL (P<.10). Our data suggests that feeding beta-glucan results in an up regulation of innate cell surface proteins associated with immune activation, and is further modulated by ascorbic acid. These findings provide mechanism of action of products with potential to decrease morbidity and mortality in dairy calf operations. Beta-glucan was provided by Biothera (Eagan, MN). Ascorbic acid was provided by DSM Nutritional Products (Parsippany, NJ). Mention of trade names or commercial products in this abstract is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.