PSA - Immunology

Bordetellosis, caused by Bordetella avium infection, is characterized by tracheal inflammation, epithelial cell degeneration, and tracheal distortion. The inflammation results from dermonecrotic toxins produced by B. avium. Inflammatory reactions are accompanied by generation of reactive oxygen metabolites (ROM) that kill cells. Antioxidant enzyme activity associated with either sodium selenite (SS) or organic selenium (SP, Sel-Plex, Alltech, Inc., Nicholasville, KY) elevates cellular redox status to reduce ROM. Aspirin (AS) can be an antioxidant because it inhibits synthesis of oxidative prostacyclins that induce ROM. The objective of this work was to examine the influence of AS with either SS or SP on development of bordetellosis in female poults. Experiments were conducted with day of hatch poults given intranasally 107 cfu of W strain B. avium or no challenge and monitored for 21d post challenge. Challenged and non-challenged poults were given 6 experimental diets made with poult starter1. SS (0.3 ppm), 2. SP (0.3 ppm), 3. no selenium or AS, 4. SS (0.3 ppm)+AS (.05%) 5. SP (0.3 ppm)+AS (0.05%), 6. AS (0.05%). At 9 and 14d, 5 poults (1/rep of 7 poults/rep) were killed and necropsied. Regardless of dietary treatment, lower BW (P<0.05) was observed in infected groups. In one experiment, AS prevented epithelial cell degeneration in infected poults. In control groups, SP alone and SP+AS increased thymus weight (g/100 g BW) over other treatments (P<0.06). With infection, SP only was associated with a smaller thymus, but addition of AS maintained thymus wt equal to the other treatments. Bursa and spleen wt were not altered significantly by selenium source, AS, or infection. Abdominal exudate macrophage IL-1 was elevated significantly (P<0.0001) by SS but not by SP or AS, and infection elevated IL-1 (P<0.001). It was concluded that SP and AS can alter the course of developing bordetellosis