| In this study,we investigate the effect of Scutellaria polysaccharides(SP)in diet on plasma biochemical parameter,antioxidant capacities,and immune status of Crucian carp(Carassius carassius)artificially challenged with A.hydrophila.Fish(weight 7015 g)were random divided into five groups,and reared in a re-circulating system.After challenged with A.hydrophila,fish in the three treated groups were fed with 0.02‰,0.1‰,0.5‰ SP feed,respectively;and one blank control group was fed with normal feed without drug and one postive control group was fed with antibiotic feed(supplemented with enrofloxacin)for 4 days.Each treatement was replicated three times in a completely randomized design,and fish were fed by hand three times a day to near satiation.Effect of Medical plant Scutellaria polysaccharide on plasma biochemical parameters,antioxidant activities and disease resistance against Aeromonas hydrophila in Crucian carp(Carassius carassius).Blood biochemical analysis and antioxidant functions were analyzed after the experimental fish were challenged with A.hydrophila.Plasma total protein(TP),Triglyceride(TG),Aspartate aminotransferase(AST),Alanine aminotransferase(ALT),Albumin(ALB),Alkaline phosphatase(ALP)and Cholesterol(CHOL)neither were not influenced by SP supplementation(P>0.05),whereas(GLU)content was lowest in the group fed 0.5‰ SP and significantly different(P<0.05)from the positive group and(C3)was highest in the 0.02‰ SP for group and significantly different(P<0.05)from the negative and positive groups,while(IgG)in the 0.02%‰,0.1‰ and 0.5‰ SP fed groups was highest and significantly different from the control.After challenge A.hydrophila.Catalase(CAT)activities were highest in the 0.5‰ SP fed group and significantly different(P<0.05)from the antibiotic,while Malondialdehyde(MDA)was lowest in the 0.1‰ SP fed group and significantly different(P<0.05)from the antibiotic.However,no significant interaction(P>0.05)between SP drug-treated groups and the blank control group on the Superoxide dismutase(SOD)activity was observed.Nonetheless,after 48 hours of challenge with A.hydrophila,fish in the 0.5‰ SP fed group showed the lowest cumulative mortality(12.22%),while the control has the highest mortality(22.22%).Effect of Medical plant Scutellaria polysaccharide on the expression of antioxidant enzymes-related genes and immune-related genes in Crucian carp carassius)after challenging with A.hydrophila.Antioxidant enzymes-related genes were assessed by quantitative real time PCR analysis.SOD and CAT genes were significantly up-regulated(P<0.05)and were highest in the 0.02‰ and 0.1 ‰ fed group,while in the in same group,they showed a down-regulation effect,while GSTA was highly up-regulated in the 0.5‰ fed group and significantly different from the control group.The immune status was determined through the expression of TNF-α,IL-1 and IL-10 genes.IL-1 and IL-10 genes were down-regulated in the 0.02‰and 0.5‰ fed group and significantly different(P<0.05)from the control group,while the relative expression of TNF-α was highest in the 0.1 v fed group and significantly different(P<0.05)from the control group.The present study has demonstrated that feeding Crucian carp diets containing Scutellaria polysaccharides(SP)globally have pronounced positive effect on fish health.However,inclusion of 0.02‰ and 0.5‰/Kg feed can be considered as the best for improving antioxidant capacities and immune status of Crucian carp,such that Scutellaria polysaccharides(SP)can be recommended as immunostimulant substance,alternative to the use of antibiotics and synthetic products in aquaculture.However,further studies need to be conducted on the effective use of the bioactive and phytochemical compounds present in(SP)as to develop a complete commercial feed that can enhance the physiological performance without compromising the natural immune system of cultured fish. |
