Research On Screening Chinese Herbal Immunostimulants And Their Effects On Non-specific Immunity For Epinephelus Fuscoguttatus

In recent years, the outbreak of serious diseases in Hainan, Fujian, Guanggong provinces restricts the sustainable and healthy development of Epinephelus fuscoguttatus. Screening and applying appropriate immunostimulants for comprehensively improving the resistance to disease has become one of the current effective means for preventing the aquaculture diseases. The immunostimulants which are most commonly applied in aquaculture are carbohydrates, vitamins, trace elements, nucleotides, probiotics, herbs, etc. Chinese herbs with the advantages of the natural property, muti-function, low-residues and abundant sources, have become one of the most important immunostimulants for aquatic animals. In this study, the white blood of Epinephelus fuscoguttatus was incubated with the extract of Chinese herbs for rapid screening immunostimulants. And than, the immune-enhancing effects of the screened out Chinese herbs were investigated by vivo experiments. Finally, safe and effective immunostimulants for Epinephelus fuscoguttatus were obtained.39kinds of Chinese herbs which have been reported in relevant literature had significant immune-enhancing effects on aquatic animals in literatures were used for screening immunostimulants for Epinephelus fuscoguttatus. The extraction samples were prepared by soaking the Chinese herbs in the normal temperatures water. Via the white blood cell incubated with extraction samples of the39kinds of the Chinese herbs respectively, the Nitroblue tetrazolium (NBT) reduction method was employed to determine the effect of the100mg/mL39kinds of the Chinese herbs and those that mixed with5mg/mL zymosan on the respiratory burst of white blood cell of Epinephelus fuscoguttatus. And than, the method performed by phagocytizing latex beads was employed to determine the effect of the extraction samples of Chinese herbs which could elevate the respiratory burst of white blood cell on the phagocytic activity. The results showed that10of39the Chinese herbs significantly elevated the respiratory burst of white blood cell and their increases were higher than15%.3of39the Chinese herbs combined with zymosan significantly elevated the respiratory burst of white blood cell and their increases were higher than70%. The extraction samples of Spatholobi caulis, Phellodendron and Herba Ecliptae Prostratae were screened out, which could simultaneously elevate the respiratory burst and the phagocytic activity of white blood cell of Epinephelus fuscoguttatus. The effects of the three Chinese herbs on the immune-enhancing effects of Epinephelus fuscoguttatus were investigated by vivo experiments.240Epinephelus fuscoguttatusweighted53±3g were selected to investigate the immune-enhancing effects of Spatholobi caulis, Phellodendron and Herba Ecliptae Prostratae on Epinephelus fuscoguttatus. The Epinephelus fuscoguttatus of three test groups were contiguously fed with feed which contained1%Spatholobi caulis, Phellodendron and Herba Ecliptae Prostratae for28d respectively and sampled at7d,14d,21d and28d to detect the nonspecific immune activity of Epinephelus fuscoguttatus. Growth and immune indices were measured such as the weight, spleen index, RBC cells quantity, WBC cells quantity, the activity of superoxide anion production of the white blood cell, the rate of the phagocytic activity of the white blood cell, the index of the phagocytic activity of the white blood cell, AKP, T-SOD, LSZ, and the total protein content. The results were as follows:after feeding E. fuscoguttatus with Caulis Spatholobi7d, AKP were significantly higher than control,14d RBC, WBC cells quantity and T-SOD were significantly higher than control,21d spleen index, the activity of superoxide anion production of the white blood cell, PA, PI and LSZ were significantly higher than control,28d total protein content were extremely significantly higher than control. After feeding E. fuscoguttatus with Herba Ecliptae Prostratae7d, WBC cells quantity and AKP were extremely significantly higher than control,14d RBC cells quantity,21d PA, PI, LSZ were significantly higher than control,28d the rate of weight gain and the activity of superoxide anion production of the white blood cell were extremely significantly higher than control. After feeding E.fuscoguttatus with Cortex Phellodendri Amurensis7d, WBC cells quantity were extremely significantly higher than control, AKP were significantly higher than control,21d spleen index were extremely significantly higher than control and the rate of weight gain were significantly higher than control,28d the activity of superoxide anion production of the white blood cell were extremely significantly higher than control, LSZ and total protein content were significantly higher than control. During the experiment, apart from the sample needed to be death, non samples dead, showing that continuous feeding E.fuscoguttatus with1%Herba Ecliptae Prostratae,Cortex Phellodendri Amurensis and Caulis Spatholobi was safe.In summary, in this study, the effects of Chinese herbal immunostimulants for Epinephelus fuscoguttatus were screened by incubating the isolated white blood cell with solutions extracted from Chinese herbs, and by feeding Epinephelus fuscoguttatus with feedstuff including Chinses herbs. The results showed that fed with feedstuff mixed with1%Caulis Spatholobi14～21d continuously, spleen index, RBC, WBC cells quantity, PA, PI, the activity of superoxide anion production of the white blood cell, T-SOD, LSZ were higher than control. Fed with feedstuff mixed with1%Herba Ecliptae Prostratae14～21d continuously, RBC cells quantity, PA, PI,LSZ were higher than control. After feeding E. fuscoguttatus with1%Cortex Phellodendri Amurensis21-28d, spleen index, the rate of weight gain, the activity of superoxide anion production of the white blood cell, LSZ and total protein content were higher than control. Caulis Spatholobi, Herba Ecliptae Prostratae and Cortex Phellodendri Amurensis not only can promote the growth performance of Epinephelus fuscoguttatus, but also can increase non-specific immune effect of Epinephelus fuscoguttatus. These results laid a foundation for development and application of new, safe and effective immunostimulants of Epinephelus fuscoguttatus.