Effects Of Enzymatic Hydrolysis Products From Algae On The Intestinal Flora And The Immune-relative Factors Of Sea Cucumber (apostichopus Japonicus)

The effects of enzymatic hydrolysis algae powder by alginate lyase and alginate derived oligosaccharide (ADO) on the non-specific immune system of sea cucumber (Apostichopus japonicus) and the preliminary mechanism were studied by supplying 5% algae powder and 0.1% ADO in diets. The total numbers of the bacteria and the vibrio.spp, the activities of immune-relative factors in the coelomic fluid and the body wall and the changes of the isozymes were determined every 10 days during the experiment period (40 days). The specific content and results are as follows:1.The total numbers of bacteria and vibrio.sp in the intestinal tract of sea cucumber were measured with the plate counting method. The fluctuation range of the total number of bacteria of the control was wider than those of the algae powder group and the ADO group. The total numbers of bacteria of the algae powder group were all smaller than those of the control, but did not have significant differences (P>0.05). The ratios of the total numbers of vibrio.sp to bacteria of the algae powder and ADO groups were higher that of the control. The ADO did not have antibacterial activity to vibrio parahaemolyticus in vitro experiment, so the algae powder and ADO could promote the growth of some bacteria belonging to the vibrio.sp which is one of the dominant flora in the intestinal tract.2.Effects of algae powder and ADO on the activities of lysozyme (LSZ), acid phosphatase (ACP),alkaline phosphatase (AKP) and hemolysin in the coelomic fluid and the body wall were studied by the use of spectrophotometry. The results indicated that all the activities of immune-relative factors of the algae powder and ADO groups were higher than those of the control. The activities of the ACP, AKP, hemolysin and LSZ reached their maximum values on the 20th,20th,30th and 40th day respectively, and they all had significant differences compared with the control.The highest activities of ACP, AKP and hemolysin also had significant differences compared with the control. The coelomic fluid contains a variety of humoral immune factors and immune cells and the immune reactions take place here. So the reactions of the immune-relative factors in the coelomic fluid to the immunologic stimulant were stronger than those of the body wall and the enhancements of the activities of immune-relative factors were also higher.3. The activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) of the algae powder and ADO groups were all higher than those of the control during the experiment period, and they all increased firstly and then decreased. The time that the activities of enzymes in the coelomic fluid reached the peak was 10 days ahead of that in the body wall and the enhancements of the activities were also higher than those in the body wall. The reason may be that the reactions of the immune-relative factors in the coelomic fluid to the immunologic stimulant were stronger than those of the body wall too. The results of the isozymes indicated that algae powder and ADO could not only increase the concentration of the enzymes, but also increased the bands of the isozymes.The algae powder and ADO could sustain the stability of the intestinal flora, promote the growth of the dominant flora and enhance the activities of immune-relative factors suggesting that the presence of algae powder and ADO improved the non-specific immunity of sea cucumber significantly and applying them as non-specific immunostimulants for sea cucumber will have a broad foreground.