Effect Of VC,VE On Blood Parameters And Antioxidant Capability Of Carassius Auratus Gibelio Under Nitrite Stress

Two experiments were conducted in this study to investigate the toxic effect of nitrite on Carassius auratus gibelio and whether high level vitamin C(VC),vitamin E(VE) can improve the anti-stress ability of Carassius auratus gibelio under nitrite stress.1.Effects of nitrite exposure on blood index of Carassius auratus gibelio150 healthy Carassius auratus gibelio,with the average weight of 37.59±3.29g were randomly divided into 3 groups(group 1,group 2,group 3,for 0.05,0.32,1.28mg/l nitrite, respectively) of 5 replicates of 10 caudaes each,respectively.After under the 48h and 14d's to nitrite sodium,blood parameter were sampled and analyzed to study the toxic effect of nitrite on biochemical parameter of blood of Carassius auratus gibelio.The results shows that:The concentration of nitrite and exposure time significantly affected the serum LDH, and the significant interaction effect of exposure time and concentration was observed (p＜0.01).The activity of serum glutamate pyruvate transaminase(GPT), glutamic-oxaloacetic transaminase(GOT),lactate dehydrogenase(LDH) in group 3 were significantly higher in 48h and 14d's exposure to nitrite,compared to control group(0.05mg/l of nitrite)(p＜0.05),and the activity of three enzymes in group 3 was higher than the group 2.Under 48h's exposure to nitrite,serum urea significantly increased with the increasing of nitrite concentration(p＜0.05),whereas serum urea in 1.28mg/l dose group significantly decreased after the exposure of 14d,compared to control group(0.05mg/l of nitrite)(p＜0.05).The significant interaction effect between exposure time and concentration was observed(p＜0.01).The concentration of nitrite and exposure time also interacted remarkably on plasma K~+(p＜0.05),and exposure time did not significantly affected plasma K~+.Plasma Cl~-was significantly decreased after the exposure of 48h in 0.32mg/l and 1.28mg/l dose group, but plasma Cl~-was not affected by the increasing of exposure time,the concentration of nitrite and exposure time had no significant interaction on plasma Na~+,Cl~-.The result of experiment one demonstrated that some biochemical indexes in blood of Carassius auratus gibelio were significantly affected by the exposure of nitrite.Blood biochemical parameter could reflect the toxic effect of nitrite on tissue,especially the hepatopancreas,gill and water pollution;nitrite exposure could cause damage to hepatocyte and hypoxia of tissue,the way of metabolism may change to adapt the anaerobic life;Nitrite exposure may affect nitrogen metabolism,serum urea production increased;exposure to nitrite seemed not to induce plasma Na~+unbalance.2.Effects of VC,VE on blood indices,antioxidative ability and HSP70 expression in tissue of Carassius auratus gibelio under nitrite stress168 healthy Carassius auratus gibelio with the average weight of 251.04±45.02g were selected in the experiment two.The fishes were randomly divided into 4 groups (C group,N group,N+HE group,N+HC group) of 7 replicates of 6 caudaes each, respectively.The fishes of 4 groups fed 3 species of diet(Ⅰ,Ⅰ,Ⅱ,Ⅲ) respectively for 21d.Physiological and biochemical parameter in blood,anti-oxidative indexes in serum and hepatopancreas,heat shock protein 70(HSP70) expression in hepatopancreas and kidneys were determined to reflect toxic effect of nitrite on Carassius auratus gibelio and the anti-stress effect of high dose of VC,VE.The results showed that:After exposure to 0.85mg/l nitrite for 21d,the number of red blood cell(RBC) and hematocrit(HCT) significantly increased(p＜0.05),haemoglobin(Hb) decreased;During nitrite exposure,the group fed 500mg/kg VC,350mg/kg VE did not affect the number of RBC,HCT,whereas the level of Hb in the group which fed 500mg/kg VC,350mg/kg VE could recover to the normal level.K~+,Cl~-level in plasma significantly decreased(p＜0.05), plasma Na~+concentration was did not show changes.High levels of VE did not affect the plasma ion(K~+,Cl~-,Na~+) levels,whereas plasma ion levels in the group with high levels of VC could return to the normal levels.During nitrite exposure,serum LDH activity significantly increased(p＜0.05), meanwhile the activity of serum GPT,GOT increased;Serum LDH activity in both groups with high level of VC,VE almost decreased to the normal level.Serum glucose(GLU) level significantly decreased after 21d's exposure to nitrite(p＜0.05);After exposure to nitrite,serum GLU level in the group with high levels of VC significantly increased(p＜0.05),but the level of VE did not affect GLU level.After 21d's exposure to nitrite,the activity of superoxide dismutase(SOD) and glutathione peroxidase(GSH-PX),total antioxidative capacity(T-AOC) in serum and hepatopancreas decreased,whereas maleic dialdehyde(MDA) concentration significantly increased(p＜0.05);in the groups with high levels of VC,VE,the activity of SOD and GSH-PX,T-AOC in serum and hepatopancreas increased,whereas MDA content significantly decreased(p＜0.05),high level of VC or VE could strengthened antioxidant ability of Carassius auratus gibelio.After exposure to nitrite,HSP70 expression in hepatopancreas and kidneys significantly increased(p＜0.05),suggesting protective function on cells or repairing the damaged cells;Under the same exposure to nitrite, HSP70 expression in hepatopancreas and kidneys with high levels of VC,VE significantly decreased(p＜0.05).The result of experiment two indicated that nitrite stress caused damage to tissue, cell injury of organs,which led to release of tissue-specific enzymes into blood,causing activity of enzymes increased;Nitrite stress could affect plasma ion level,GLU,HSP70 expression;An imbalance between prooxidant forces and antioxidant defenses is one of the toxicity mechanisms of nitrite on Carassius auratus gibelio.High level of VC or VE in diet could reduce the passive influences induced by nitrite stress at some degree, increasing stress resistance of Carassius auratus gibelio.