Submitted to: Poultry Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2003
Publication Date: July 6, 2003
Citation: HUFF, G.R., HUFF, W.E., RATH, N.C., BALOG, J.M., TELLEZ, G. IMMUNOMODULATION WITH B-1,3/1,6-GLUCAN (IMMUSTIM®) AFFECTS GROWTH PERFORMANCE AND RESISTANCE TO ESCHERICHIA COLI RESPIRATORY INFECTION OF BROILER CHICKENS. POULTRY SCIENCE MEETING. 2003. v. 82, p. 57. Technical Abstract: There is a need to evaluate potential immunomodulators as alternatives to antibiotics for growth promotion and disease prevention. Immustim®, a feed grade ß-1,3/1,6-glucan, is a helical polysaccharide (poly-glucose) derived from the cell wall of Saccharomyces cervisiae which has immunomodulating activities. The objective of this study was to determine the ability of two Immustim® supplementation programs to protect broiler chicks from an experimental respiratory challenge with E. coli. Chicks were housed in battery-brooders from day of age and fed a standard starter diet or the same diet containing 20 g/ton of Immustim® either continuously (BG25d) or for only the first 7 days prior to challenge (BG7d). At day 7, half of the birds were inoculated in the thoracic air sac with 800 cfu of a serotype O2, non-motile strain of E. coli. All surviving birds were necropsied at day 25. Body weights of survivors (P=0.01), and feed conversion (P=0.002) were protected from the adverse effects of E. coli challenge by BG7d but not by BG25d. Mortality was decreased from 63% (Control) to 53% in BG25d and 47% in BG7d, but these decreases were not significant. The relative weights of the liver (P=0.0009), heart (P=0.057), and bursa of Fabricius (P=0.02) were protected from the effects of the E. coli challenge only by BG7d. Despite positive effects in E. coli challenged birds, BW of non-challenged birds were decreased by both BG25d (P=0.04) and BG7d (P=0.03). These data suggest that supplementation of broiler diets with Immustim® may be valuable for decreasing production losses due to E. coli respiratory disease, but that the immune stimulation may be costly in decreased production values for birds raised in an environment with minimal disease challenges. Supplementation programs designed to stimulate immunity just prior to predicted environmental stressors and disease exposure may increase the efficacy of immunomodulating feed additives.