Effction Of High Dissolved Oxygen On Growth, Oxidative Stress, And Immune Capacity Of Acipenser Baerii And Hybird Sturgeon

Environment stress is a pressure on the existence of the fish. The stress may break the balance between environment and the fish, causing the physiological function disorder of the fish, the different stress of factor can make different injury to the fish. Dissolved oxygen and stocking density, et al, is often referred among the stressrs. Thus it is very important to proper dissolved oxygen and stocking density,which has has considerable value in improving the economic benefits of fish farming. This thesis mainly consists of two parts. Part one mainly research for the effects to the growth,the related Physiological function and the immune index of Acipenser baeri Brandt under the high dissolved oxygen environment.Part two mainly discuss about the effects to the growth,the related Physiological function and the immune index of Acipenser baeri Brandt under high oxygen conditions in different density.1、We studied in the effects of high dissolved oxygen to the scrod of Acipenser baeri Brandt, the growth metabolism, the oxidative stress and immune index under the cultural circumstances of circulating water which in( 18±4) ℃.Five kinds of dissolved oxygen contents were set up: 6 mg/L 、8 mg/L 、10 mg/L 、12 mg/L 、14 mg/L.The cultivation density is 100ind/m2. The test last for 40 days in the aggregate. After 40 days, challenge inoculation tests of A.hydrophila(Aeromonas hydrophila infection) to all the experimental groups of the scrod of Acipenser baeri Brandt were carried out.The results reflect that:1After 10 days in this circumstances,with the increase of dissolved oxygen potency, the average body weight of the fish in all groups were continued putting on.And this phenomenon last for about 40 days until to the end of the test;2The average oxygen consumption rate of all groups doesn’t vary with the change of dissolved oxygen;3The vitality of enzyme which were called as SOD and CAT were sharply increased with the higher content of dissolved oxygen potency, however,the active degree of GSH-PX enzyme are not noticeable;4In the test groups of serum of 12 mg/L and 14 mg/L, the vitality of ALT and AST enzyme has the tendency that increased first and then decreased, the potency of albumin shows the tendency that decreased first and then increased;5In the test groups of serum of 12 mg/L and 14 mg/L, the vitality of ALP and ACP, the vitality of the lysozyme and the content of hydrocortisone were increased first and then decreased;6After infection, the death rate of the fish was negatively correlated with dissolved oxygen content.2、The study about the effects of dissolved oxygen content and breeding density to the growth,physiology and immune index to hybrid sturgeon were actualized under the cultural circumstances of circulating water which in(21±0.5)℃.There are two kinds of density type.Type A:25ind/m2 corresponding with the dissolved oxygen level in 6 mg/L、8 mg/L、10 mg/L、12 mg/L;Type B:35ind/m2 corresponding with the dissolved oxygen level in 6 mg/L、8 mg/L、10 mg/L、12 mg/L. This study cost 60 days.The results reflect that:1After 10 days, the average body weight of fish in dissolved oxygen groups increased along with dissolved oxygen density increased. And this phenomenon last for about 60 days until to the end of the test. The weight of fish in Type 25 is heavier than fish in Type 35;2As to test groups in 12 mg/L and 14 mg/L,the activity level of SOD、CAT、MDA that in Type A and Type B groups was significantly higher than that in control group. The activity level of GSH-PX was steady; 3The dissolved oxygen level of hybrid sturgeon in group 25 was 8mg/L、10mg/L and 12mg/L. IN the 20 th day, in plasma of test group, the activity level of AST was significantly higher than that in control group. Since the 30 th day,it return back to a steady level; The dissolved oxygen level of hybrid sturgeon in group 35 was 10mg/L and 12mg/L.From the 20 th day to the 30 th day,plasma in test group was significantly higher than that in control group. Since the 45 th day, it return back to a normal level;The activity level of ALT stay in a steady status.4The dissolved oxygen level of hybrid sturgeon in group 25 was 8mg/L、10mg/L and 12mg/L.IN the 20 th day, in plasma of test group, the density of albumin was significantly higher than that in control group. Since the 30 th day, it return back to a steady level; As to the dissolved oxygen level of hybrid sturgeon in group 35 was 8mg/L,10mg/L and 12mg/L. From the 20 th day to the 30 th day, in plasma of test group, the density of albumin was significantly higher than that in control group. Since the 45 th day, it return back to a normal level;5Since the 20 th day,in group 25, the indexes of spleen in 8mg/L、10mg/L and 12mg/L test groups were significantly higher than that in control group. As to group B,from the 20 th day, the indexes of spleen in 10mg/L and 12mg/L test groups were significantly higher than that in control group.In the 60 th day, as to 8mg/L and 10mg/L test groups, there was a evidently difference between group A and group B. In 10mg/L and 12mg/L test groups,the activity levels of ALP and ACP has the tendency that increased first and then decreased,while there was no markedly difference in different groups. As to lysozyme, there was no markedly difference in different groups.6The dissolved oxygen level of hybrid sturgeon in group 25 was 8mg/L、10mg/L and 12mg/L. The content of hydrocortisone were increased first and then stay in a changeless level,and it come to a crest value in the 20 th day.The dissolved oxygen level of hybrid sturgeon in group 35 was 12mg/L, compared with the control group, the content of hydrocortisone were increased sharply since the 20 th day,then it stay in a changeless level.