a1 Alltech Asia-Pacific Biosciences Centre, Pathumthani,12120 Thailand
a2 Australia Poultry Cooperative Research Centre, Armidale, 2351 NSW Australia
Currently broiler chickens are genetically selected for improved feed conversion ratio and rapid growth rate. This rapid growth rate is generally based on a high rate of feed intake and not due to an increased nutrient digestibility. Increased body weight gain, in turn, is found to be negatively correlated with antibody response (total antibody response and specific anti-sheep red blood cell (SRBC)) in broilers. The interactions between commensal bacteria and GALT immune systems are considered to be the basic mechanism of the host against invading pathogens; achieved by forming bio films and by binding to the intestinal epithelium and therefore effectively blocking the sites from pathogens. Apart from the fact that NSP may shift microbial populations toward beneficial micro-organisms to stimulate the immune system, recent evidence has assumed that exogenous xylanase majorly degraded NSP to oligosaccharides and released more phenolics to act as anti-oxidants. Furthermore, it has been suggested that the dietary fibre anti-oxidants existing in insoluble NSP may actually quench the soluble radicals that are continuously formed in intestinal tracts. During the first week post-hatch, the intestinal immune system may be developed by colonization with beneficial bacteria and enhanced competition with invading pathogens. NSP and associate substrates might not only provide substrates for beneficial bacteria but play an important part in removing free radicals.
(Received January 12 2010)
(Accepted April 19 2010)