Effects Of Dietary Chitosan On Growth Performance,Immune Function And Small Intestine Structures Morphological In Male Broilers

Three experiments were conducted to explore the effects of different dose of chitosan on growth performance,immune function and small intestine structures morphological in broilers. A total of 270, 1d old Arbor Acres male broilers were randomly allotted to five dietary treatments (9 birds per pen with 6 pens per treatment). The experiment period were 42 d, and divided into two stages (0-21d, 22-42d). The control birds were fed the basal diet alone, the second treatment were fed basal diet added chlortetracycline (0-21d was 80mg/kg, and 22-42d was 50mg/kg) as positive control group, the other treatments fed the basal diet supplemented with 50,100,150 mg/kg chitosan respectively. Basal diet was corn-soybean meal based diet. On the morning of 1d,21d and 42d , all of birds were weighted ,and records the consumption of feeds in above two phages; On 21d and 42d, 30 birds were selected and blood from heart then killed to explore the effects of chitosan on serum parameters,immune function and small intestine structures morphological. Results showed that: (1) There was no significant differences (P >0.05) in ADG, ADFI and FCR among CHS and CTC groups during 0-3 wks; during 4-6 wks, there was significantly differences (P < 0.05) in ADG and no significant differences (P > 0.05) in ADFI and FCR among CHS groups. The treatments had maximal ADG was 100 mg/kg CHS group. The overall period of the experiment indicated that there was no differences (P > 0.05) in ADFI, but have significant differences (P < 0.05) in FCR and ADG (P= 0.067), FCR minimum at 100 mg/kg CHS group. So, we make sure that CHS could enhanced ADG and reduced FCR. (2) In aspect of serum parameters, the results showed that CHS groups significantly decreases (P < 0.05) the concentration of serum TC and TG, and significantly enhanced (P < 0.05) levels of serum TP and the secretion of serum GH and IGF-1 in 42 d, there was no influence (P> 0.05) on serum glucose and UA. Among all groups we could get optimal effects from 100 mg/kg CHS groups. So we could elementary make sure that the optimal dose of CHS added to broiler diets was 100 mg/kg. Chitosan may exert its beneficial effect through enhancing the secretion serum levels of GH and IGF-1. (3) Dietary chitosan significantly enhanced spleen index and thymus index (P < 0.05) in 42d, with increasing doses of the more obvious effects. Chitosan enhanced lymphocyte proliferation in 42d(P =0.094),and significantly enhanced concentration of serum IgA in 21d and serum IgA,IgG in 42d; chitosan had no effects on concentration of serum IL-2,INF-γ, but enhanced levels of serum IL-4, and reduced levels of TNF-a, it means that chitosan played its immune regulation roles mainly through affect Th2 cytokines. (4) Chitosan significantly reduced jejunum crypt depth (P < 0.01), but had no effects on other morphological parameters; Meanwhile, ileal crypt depth shallowed, villus width broadens, wall thinning, duodenal villus height increased and crypt depth shallow, wall thinning. The results showed that dietary chitosan improved intestinal morphology, and mainly affect duodenum and ileum. The reason may be related to increased intake of feeds, and enhanced feeding and nutrition-related hormone levels and lower serum levels of TNF- a.