Dietary oligochitosan supplementation enhances immune status of broilers

Oligochitosan (COS) is a type of prebiotic, which favourably alters the intestinal microflora balance, inhibits the growth of harmful bacteria, promotes good digestion and boosts immune function. The effect of dietary COS supplementation on immune function in broilers was assessed by feeding graded levels (0, SO, 100, 150 mg kg(-1)) of COS. Two thousand four hundred male commercial Aviano broilers (1 day old) were assigned randomly to five dietary treatment groups (60 birds/pen with eight pens per treatment). Diet A was a typical maize- and soybean meal-based diet supplemented with 6mg kg(-1) antibiotics of flavomycin (positive control). Diet B was the basal diet without any supplement. Diets C, D and E were formulated by addition of 50, 100, 150 mg kg(-1) of COS to the basal diet, respectively. On the morning of days 21 and 42, a total of 64 (eight birds/pen with eight pens per treatment) of the growth experimental birds were killed by cervical dislocation, respectively for determination of serum concentrations of IgG, IgA and IgM, and weights of spleen, bursa and thymus. Compared with broilers fed the control and the positive control diets, dietary supplementation with COS increased (P < 0.001) serum concentrations of IgG, IgA, and IgM, with the greatest response for the 100 mg kg(-1) COS supplementation. Chitosan oligosaccharides supplementation also enhanced the immune organ development. Results suggest COS can improve immune response in birds. Through positive modulation of the immune response, COS has great potential as an effective, antibiotic-like growth promoter for poultry. (c) 2006 Society of Chemical Industry.