Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/4/2005
Publication Date: N/A
Technical Abstract: Previous analysis by flow cytometry and RT-PCR showed immune modulation by both beta-glucan and ascorbic acid in mesenteric lymph nodes and blood. The objective of this study was to determine if the beta-glucan was acting locally or systemically. Calves were placed onto treatments at 3 d-of-age (d 0). The control treatment (CTL), received unsupplemented milk replacer for 21 d (n=5); treatment BG3d received milk replacer for 17 d and then an oral fluorescently-labeled beta-glucan (FBG, 0.9mg/d), on d 18-20 (n=5); treatment BG20d received beta-glucan (BG) for 17 d in milk and then oral FBG on d 18-20 (n=10); and treatment BGA, received BG plus ascorbic acid (0.5mg/d) in milk for 17 d and oral FBG plus ascorbic acid on d 18-20 (n=5). Histological analysis showed more beta-glucan in the jejunal tissue of the BG3d calves than for the CTL and the BGA calves (P<0.05), and tended (P=0.08) to be more than the BG20d calves. However, ileum and liver fluorescence was not different. Mesenteric lymph node and spleen fluorescence tended (P<0.10) to be lower for the BGA and CTL calves compared to the BG20d calves. CD18 labeling of the tissues showed that expression in the ileum tended (P<0.10) to be less for the BG3d group than for the CTL calves, but in the jejunum, CD18 fluorescence tended (P<0.10) to be less for the BG3d calves than for the BGA calves and not different than the CTL calves. These data clarify where beta-glucan can be modulating immune responses and that ascorbic acid can further modify that interaction. This information will be essential in the application of oral beta-glucan and vitamin C for immune modulation during periods of stress. 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.