Effect of Chitosan on Nitric Oxide Content and Inducible Nitric Oxide Synthase Activity in Serum and Expression of Inducible Nitric Oxide Synthase Mrna in Small Intestine of Broiler Chickens (Report‪)‬

INTRODUCTION Chitosan, a deacetylated chitin, is a natural alkaline polysaccharide with positive charges, and it is widespread in nature. The exoskeletons of arthropods such as crabs, shrimps, insects, and other marine creatures in the crustacean family are good sources of chitosan. In addition, the extraction of chitosan is relatively cheap and easy. Research efforts devoted to elucidating the effects of chitosan on growth and immune functions of animals have been extensive. It had been reported that chitosan could improve growth performance of broiler chickens (Suk, 2004), and it had dose-dependent effects on growth performance in broiler chickens (Shi et al., 2005a), and the higher dietary chitosan had adverse effects on growth in chickens (Razdan and Pettersson, 1996; Razdan et al., 1997). Previous studies have indicated that chitosan could accelerate the wound healing and exert anti-inflammatory effects and stimulate both B and T lymphocytes (Seferian and Martinez, 2000; Chou et al., 2003). Studies in rats demonstrated that chitosan had a significant enhancing effect on cellular and humoral immune function, and activating macrophages for tumoricidal activity and stimulating macrophages to produce interleukin-1 (IL-1) (Nishimura et al., 1986; Zaharoff et al., 2007). Yin et al. (2008) reported that chitosan oligosaccharide could enhance the cell-mediated immune response in early-weaned piglets by modulating the production of cytokines and antibodies. [beta]-1,3/1,6-glucan have a transient immuno-enhancing effect on the cellular and humoral immune function of weanling piglets (Zhong et al., 2008). Shi et al. (2005b) demonstrated that chitosan could strengthen immune functions of broiler chickens.