An in vivo and a in vitro experiment were conducted to evaluate the effects of arginine on immunity of carp.In the in vitro experiment,arginine with the concentrations of 0,0.5,1.0,1.5 and 2.0 mmol/L were added in the culture medium,after different incubation time of kidney leukocytes,the proliferation index,respiratory burst activity,phagocytosis activity and bactericidal rate were assayed respectively.In the in vivo experiment,the carp of average body weight 37 g were divided into 5 groups,and each group had three replicates,each replicate had 10 fish.Arginine at 0,25,50,100,200 mg/kg were injected into fish cavity,and then fed them with commercial diets for 2 weeks.Then,the proliferation index,respiratory burst activity and phagocytic activity of kidney leukocytes were determined.At the same time,the nitric oxide (NO) content and nitric oxide synthase (NOS) activity in serum and hepatopancreas,and serum albumin (ALB) content were determined.The in vitro experiment results showed that added arginine could increase the proliferation index,respiratory burst activity,phagocytosis activity and bactericidal rate of kidney leukocytes.After 12 and 24 h incubation,the proliferation index of kidney leukocytes in 1.0,1.5 and 2.0 mmol/L arginine groups was significantly higher than that in 0 mmol/L arginine group (P<0.05);after 6,12 and 24 h incubation,the respiratory burst activity of kidney leukocytes in 1.0 mmol/L arginine group was significantly higher than that in 0 mmol/L arginine group (P<0.05);after 12 and 24 h incubation,the phagocytosis activity of kidney leukocytes in 1.0,1.5 and 2.0 mmol/L arginine groups was significantly higher than that in 0 mmol/L arginine group (P<0.05);after 18 h incubation,the bactericidal rate of kidney leukocytes in 1.0,1.5 and 2.0 mmol/L arginine groups was significantly higher than that in 0 mmol/L arginine group (P<0.05).The in vivo experiment results showed that the proliferation index,respiratory burst activity and phagocytosis activity of kidney leukocytes in 50,100 and 200 mg/kg arginine groups was significantly higher than that in 0 mg/kg arginine group (P<0.05);the serum ALB and NO contents in 100 and 200 mg/kg arginine groups were significantly higher than those in 0 mg/kg arginine group (P<0.05);the serum NOS activity in 50,100 and 200 mg/kg arginine groups was significantly higher than that in 0 mg/kg arginine group (P<0.05);the hepatopancreas NO content in 50,100 and 200 mg/kg arginine groups was significantly higher than that in 0 mg/kg arginine group (P<0.05);the hepatopancreas NOS activity in 25 and 50 mg/kg arginine groups was significantly higher than that in 0 mg/kg arginine group (P<0.05).Generally,the arginine can enhance on the immunity of leukocytes in carp,and the optimum arginine concentration is 1.0 mmol/L in vitro experiment.In normal feeding condition,the optimum arginine injection concentration for carp is 50 to 100 mg/kg in vivo.%本试验采用体外和体内2种方法来研究精氨酸(Arg)对鲤鱼免疫力的影响.体外试验中,在培养基中分别添加0、0.5、1.0、1.5和2.0 mmol/L的Arg,将肾脏白细胞培养不同的时间段后测定增殖指数、呼吸爆发活力、吞噬活力和杀菌率.体内试验中,将平均体重37 g的鲤鱼随机分为5组,每组3个重复,每个重复10条,分别体内注射0、25、50、100和200 mg/kg鱼体重的Arg,商业饲料投喂2周,进行肾脏白细胞增殖指数、呼吸爆发活力和吞噬活力的测定,以及血清和肝胰脏一氧化氮(NO)含量、一氧化氮合成酶(NOS)活性及血清白蛋白(ALB)含量的测定.体外试验结果表明:添加Arg能够提高肾脏白细胞的增殖指数、呼吸爆发活力、吞噬活力和杀菌率.培养12和24 h后,1.0、1.5和2.0 mmol/L Arg组肾脏白细胞增殖指数显著高于0 mmol/L Arg组(P<0.05);培养6、12和24 h后,1.0 mmol/L Arg组肾脏白细胞呼吸爆发活力显著高于0 mmol/L Arg组(P<0.05);培养12和24 h后,1.0、1.5和2.0 mmol/L Arg组肾脏白细胞吞噬活力显著高于0 mmol/L Arg组(P<0.05);培养18 h后,1.0、1.5和2.0 mmol/L Arg组肾脏白细胞杀菌率显著高于0 mmol/L Arg组(P<0.05).体内试验结果表明:50、100和200 mg/kg Arg组肾脏白细胞呼吸爆发活力、吞噬活力和增殖指数显著高于0 mg/kg Arg组(P<0.05);100和200 mg/kg Arg组血清ALB和NO含量显著高于0 mg/kg Arg组(P<0.05),50、100和200 mg/kg Arg组血清NOS活性显著高于0 mg/kg Arg组(P<0.05);50、100和200 mg/kg Arg组肝胰脏NO含量显著高于0 mg/kg Arg组(P<0.05),25和50 mg/kg Arg组肝胰脏NOS活性显著高于0 mg/kg Arg组(P<0.05).由此可见,Arg提高了鲤鱼肾脏白细胞的免疫力,体外试验表明Arg的适宜浓度为1.0 mmol/L.正常摄食情况下,Arg在鲤鱼体内注射适宜浓度为50~100 mg/kg.
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