Oral administration of beta-1,3/1,6-glucan to dogs temporally changes total and antigen-specific IgA and IgM

Abstract

The effect of oral administration of beta-1,3/1,6-glucans from Saccharomyces cerevisiae on humoral immunity in domestic dogs is not known. In this study, 15 beagle dogs were orally given MacroGard tablets, which contain 150 mg of this beta-glucan, daily for 4 weeks. At the end of this period, the total serum immunoglobulin A (IgA) level decreased significantly in the group treated with the glucan compared to that in the control group as well as compared to the concentrations before supplementation. In contrast, the total serum IgM level rose significantly, whereas no effect on the IgG level occurred. Similar changes were seen in Bordetella-specific IgA and IgM titers following vaccination during the supplementation period. The IgA concentration also became significantly lower in the saliva and tears of the glucan group than in the placebo group. The effects disappeared 1 week after the cessation of the supplementation. In conclusion, the results showed a temporary change in the isotype profile during glucan supplementation.

FIG. 1.

Effect of glucan administration on changes (Δ) in total IgM and IgA concentrations (mg/dl) in serum compared to those on day 0 (D0). The bars indicate the standard errors of the means (for the glucan-treated group, n = 10; for the placebo-treated group, n = 9). *, significant difference (P < 0.05) between groups; →, duration of β-glucan or placebo supplementation.

FIG. 2.

Changes (Δ) in total IgA concentrations (mg/dl) in saliva and tears from the two groups of dogs. Bars indicate the standard errors of the means. *, significant difference (P < 0.05) between the placebo-treated group and the glucan-treated group at the indicated time point; →, duration of β-glucan or placebo supplementation.

FIG. 3.

Effect of glucan administration on mean specific IgM, IgA, and IgG titers (log₂) to Bordetella bronchiseptica antigen in serum. Bars indicate the standard errors of the means. *, significant difference (P < 0.05) between groups; ↑, time of vaccination; ←→, duration of β-glucan or placebo supplementation.