[外文]Effect of oligochitosan on lipid metabolism and bursa and spleen development in broiler chicken
Abstract: To study the effect of oligochitosan on lipid metabolism, bursa and spleen development, and lymphocyte apoptosis in broiler chicken. 480 AA broiler chickens at 1 day of age were randomly assigned to the control group and test I, II and III groups, with 120 chickens and 6 replicates per group. Control group was given the basic diet and test I, II and III groups were given basic diets with the addition of 50mg/kg chlortetracycline, 20 and 40mg/kg chitosan respectively for a duration of 42d. Results: at 21d, the concentration of serum triglycerides (TG) was significantly reduced (P<0.00) and the periarterial lymphatic sheath area of the spleen was markedly increased (P<0.00) in broiler chickens of test II group compared to the control group. On the other hand, the serum total protein (TP) concentration, fabricius index, and periarterial lymphatic sheath and bursal lobular areas of the spleen were significantly increased (P<0.00) while the concentrations of serum TG and total cholesterol (TC) were markedly reduced (P<0.00) in test III group broiler chickens compared to the control group. At 42d, while the serum TP concentration, splenic perarterial lymphatic sheath and lobule areas were significantly increased (P<0.00), the concentration of serum low density lipoprotein (LDL) was markedly decreased (P<0.00) in test II group broiler chickens compared to the control. The concentration of serum high density lipoprotein (HDL), bursa weight and index, splenic periarterial lymphatic sheath and lobule areas were significantly increased (P<0.00), and the serum TC, TG and LDL concentrations were markedly decreased (P<0.00) in test III group broiler chickens compared to the control. At both 21d and 42d, the numbers of splenic and bursal apoptotic cells in broiler chickens were significantly lower than those of the control (P<0.00). Our results showed that the supplementation of 20 and 40mg/kg chitosan in daily diet could reduce the level of serum lipids in broiler chicken to various degrees, promote bursa and spleen development and inhibit lymphocyte apoptosis. These indicated that appropriate amounts of chitosan supplementation have a role in regulating lipid metabolism and promoting immune organ development, and supplementation of 40mg/kg chitosan shows the best effects.
Keywords: oligochitosan; broiler chicken; spleen; lipid metabolism; bursa; tissue structure; lymphocyte apoptosis