| In recent years, the problems such as uneven quality of juveniles, unstable production and even large-scale diseases have been frequently emerged in the culture of gibel carp(Carassius auratus gibelio) in our country. To relieve these problerms,improving the quality of fish from the source, and breeding cultivate immunity and strong stress resistance of seedling is an effective solution in addition to optimize breeding technology or improve the culture environment. However, the primise of physical fitness improvement is to screen out several immune-related indexes which could indicating the fish healthy status or establish a system of fish health evaluation. In this study, The changes of immune biochemical indexes in plasma under four environmental stresses(high p H of 9.2, low dissolved oxygen of 2 mg/L, high nitrite nitrogen of 2 mg/L and high ammonia nitrogen of 4 mg/L), common disease(gill hemorrhage, red gill disease), and different strains(Carassius auratus gibelio,Carassius auratus Var.Pengzenensi) with different specifications(large, medium, small)were analyzed to screen out indicative plasma indicators and provide basis for healthy breeding of Carassius auratus gibelio. The specific contents are as follows:1.In the chronic stress tests, the effects of four environmental stresses(high p H of9.2, low dissolved oxygen of 2 mg·L-1, high nitrite nitrogen of 2 mg·L-1 and high ammonia nitrogen of 4 mg·L-1) on biochemical and immune indexes(cortisol(COR),glucose(GLU), interferon(IFN), interleukin-2(IL-2), superoxide dismutase(SOD),immunoglobulin M(Ig M), complement 3(C3) and malondialdehyde(MDA)) in the plasma of the C. auratus gibelio juveniles(136.70±7.98 g) were carried out. Stressed carps were sampled at the days of 0, 3, 7, 10 and 15 post-stress. The results indicated that: COR significantly induced under p H, nitrite nitrogen and ammonia nitrogen stresses, while SOD significantly reduced under p H, nitrite nitrogen and ammonia nitrogen stresses, moreover, Ig M significantly increased under nitrite nitrogen and ammonia nitrogen stresses, indicating that these three immune indexes may bebroad-spectrum indicators for indicating stressed status. High values of COR and Ig M,low value of SOD may indicate fish under a stressed condition. GLU, IFN and C3 all strongly increased only under the ammonia nitrogen stress, indicating these three immune indexes may be narrow-spectrum indicator for indicating stressed status. High values of GLU, IFN and C3 may indicate fish under a stressed condition. Additionally,IFN and MDA increased under ammonia nitrogen stress, but decreased under nitrite nitrogen stress, indicating these two immune indexes may be not suitable for indicating carp stressed status.2. In the plasma biochemical test, diseased fish samples were taken respectively from epidemic area of the gill hemorrhage and red gill disease in June 2015, Haifeng farm. Each kind of diseased fish samples were collected from three areas of the pond,each pond were randomly collected 9 tailed of the diseased fish with typical symptoms, C. auratus gibelio collected in the pond from non-endemic area and microscopic examined healthy were selected as control group. The average body length of fish of control group is(15.06 ± 2.20)cm, and their average weight is(114.20 ±42.21)g; The average body length and average weight of disease fishes with gill hemorrhage and red gill disease were respectively(16.37 ± 0.86)cm,(15.76 ± 0.94)cm,(134.79 ± 24.62)g and(145 ± 29.16)g. Comparative analysis of plasma COR, Glu, IFN,IL-2, SOD, Ig M, C3 and MDA between diseased fish group and control group, and the analysis of the differences water quality indicators in areas of the ponds from non-endemic area and endemic area were made. The results showed that water quality indicators of the ponds from non-endemic area and endemic area were both suitable and have no significant difference; fishes suffered from gill hemorrhage and red gill disease have significantly lower COR, Glu, SOD, MDA, IL-2 and C3 than those of the control fishes, and their Ig M and IFN have no significant difference.3 In thise plasma biochemical test, plasma biochemical and immune indexes of three specifications(large, medium, small) of Carassius auratus gibelio and Carassius auratus Var.Pengzenensi were compared. These three specifications of Carassius auratus gibelio and Carassius auratus Var.Pengzenensi respectively are average body length of(18.13 ± 1.03) cm,(15.19 ± 0.43) cm,(12.76 ± 1.60)cm; 1.627 + 0.55 cm,14.54 + 0.56 cm, 12 + 0.51 cm and average weight of(169.74 ± 46.19)g,(99.26 ±5.33)g,(5.756 ± 20.35) g;(11.56 ± 11.97)g,(90.29± 5.91) g,(53.52 ± 6.14)g. Results shows that The differences of plasma COR, GLU,, IFN,, IL-2, SOD, M,, C3, Ig, MDA and were compared and analyzed. The results showed that the IL-2, C3, M Ig, MDAand SOD of Carassius auratus Var.Pengzenensi were significantly higher than those of the Carassius auratus gibelio, especially in the large and medium size.According to the above studies, SOD were screened out as a very potential indicate which could indicate stressed status of Carassius auratus gibelio, its value is low whether it is indicating environmental stresses or biological stresses,which means that Carassius auratus gibelio is relatively weak in resilience(Table 1). What’s more, in addition to SOD, other indicators have different responcese to environmental source of stresses and biological sources of stresses: most indicators were tend to rise under environmental source of stresses while they were tends to decrease once under biological sources of stresses.This phenomenon may indicate that Carassius auratus gibelio can percept and recognise different stresses, and then response in corresponding different ways to deal with stresses. |
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