Effects Of Chitosan On Growth Of Grass Carps

This study was carried out to investigate the effect of grass carps' dietary adding chitosan on grass carps' growth performance,physical index,the nutritional composition of dirsal muscle,biochemical indicator of serum,antioxidant punch of body tissues and morphological structure of intestinal tract.According to the different dietary factor,five test groups were used,which consisted of control group,antibiotics group,0.25%,0.50% and 1.00%chitosan addition group.450 grass carps with similar body weight(about 70 g)were randomly allotted to five groups with three replicates and with 30 grass carps in each replicate and were fed for 40 d,The results showed that:(1) Growth performance of grass carps and the nutritional composition of dirsal muscle:Chitosan promoted significantly the growth of grass carp,increased crude protein content,reduced crude fat content,impacted on the feeding coefficient.Compared with the control,average weight gain rate with 0.25%,0.50%and 1.00%chitosan addition increased 56.6%,72.8%,65.5%respectively,crude protein content of dirsal muscle increased 4.93%,8.77%,2.81%respectively.The feeding coefficient with 0.25%and 0.50%chitosan addition group both decreased 8.4%,however there were not significant difference.The feeding coefficient with 1.00%chitosan addition significantly increased.(2) Physical index and immune organs weight:Chitosan affected significantly the physical index and increased weight of immune organs of grass carps.Compared with control group,condition factor(CF) with 0.25%and 0.50%chitosan addition group were no significant difference(p＞0.05),while CF with 1.00%chitosan addition group significantly reduced(p＜0.05);the offal index with 0.25%and 1.00%chitosan addition group were no significant difference(p＞0.05),however the offal index with 0.50% chitosan addition group significantly reduced(p＜0.05);post kidney body index(PKBI) increased significantly by adding chitosan,while head kidney body index(HKBI) and spleen body index(SBI) were no significant difference(p＞0.05) among groups.(3)Biochemical indicator of serum and antioxidant punch of body tissues:Chitosan affected significantly the contents of calcium,triglyceride(TG) and malondialdehyde (MDA) in serum of grass carps(p＜0.05),while the contents of inorganic phosphorus,total cholesterol(TC) and superoxide dismutase(SOD) was no significant difference(p＞0.05). Compared with the control,serum MDA reduced 52.6%,60.6%and 61.2%respectively, and serum SOD increased 4.9%,13.4%and 7.9%respectived by 0.25%,0.50%and 1.00% chitosan addition,chitosan significant impacted on grass carp hepatopancreas SOD(p＜0.05),while the hepatopancreas MDA concentration was no significant difference(p＞0.05),compared with the control,hepatopancreas SOD increased 13.8%and 16.3%by 0.25%and 0.50%chitosan addition,while hepatopancreas SOD reduced 4.7% by 1.00%chitosan addition,hepatopancreas MDA respectively reduced 29.3%,40.3%and 12.4%by 0.25%,0.50%and 1.00%chitosan addition.(4) Morphological structure of intestinal tract:Fold height of intestinal mucosa,total thickness of lamina propria and submucosa in foregut and midgut,and layer thickness of midgut were increased significantly with chitosan addition(p＜0.05),while that of them in hindgut were no significant difference(p＞0.05).What's more,appropriate chitosan in feed of grass carps could significantly promote the growth,improve growth performance,increase antioxidant punch and immunocompetence of organism.We suggested that the appropriate chitosan addition was 0.50%in feed of grass carps.