Effects Of Several Immunostimulants On Japanese Seabass (Lateolabrax Japonicus) & Primary Investigation To Immunostimulatory Fatigue

Four experiments are conducted to investigate the effects of several immunostimulants on the non-specific immune response and disease resistance against Vibrio anguillarum on Japanese Seabass(Lateolabrax japonicus) and the phenomenon of immunostimulatory fatigue.The results are as below.To determine the effects of dietary compound probiotics on the non-specific response of Japanese sea bass(Lateolabrax japonicus), specimens are fed with diets containing 0(control group), 500mg/kg(PR-500),and 3000mg/kg(PR-3000) compound probiotics respectively for 84 days. Special growth rate, lysozyme activity and alternative pathway haemolytic complement(ACH50) of serum, and the acid phosphatase ,the alkaline phosphatase and the superoxide dismutase activity of liver, and the respiratory burst and bactericidal activity of the head kidney macrophages are examined respectively 42 days and 84 days later. To determine the effect of probiotics on the disease resistance, the sea bass are injected peritoneally with Vibrio anguillarum 84 days later.The results show that total amout of the macrophages and the bactericidal activity of the macrophages of PR-500 and PR-3000 are significant higher than that of the control group(P<0.05)while the cumulative death rate of the two groups after peritoneal injection with Vibrio anguillarum are significantly lower than the control group(P<0.05).A3αpeptidoglycan(PG) is added to the fundamental diets in the ratio of 0(control group) ,100mg/kg(PG-100),and 500mg/kg(PG-500) . Special growth rate, lysozyme activity and alternative pathway haemolytic complement(ACH50) of serum, and the acid phosphatase ,the alkaline phosphatase and the superoxide dismutase activity of liver, and the respiratory burst and bactericidal activity of the head kidney macrophages were also examined respectively 42 days and 84 days later. To determine the effects of A3αpeptidoglycan(PG) on the disease resistance, the specimens are also injected peritoneally with Vibrio anguillarum 84 days later. The results show that 42 days later there is not significant difference exists in the activity of ACP while the SOD activity of PG-500 is significantly higher than the control group and the AKP activity of the two experimental groups are significantly higher than the control group. After 84 days,s feeding, the results show that the AKP activity and the bactericidal activity of the head kidney macrophages in the experimental groups is not significantly different from that of the control group(P>0.05).Further more the lysozyme activity of PG-100 is significantly lower than the control group and the ACH50 of the experimental groups and the respiratory burst of PG-500 are significantly lower than the control group(P<0.05).There is not significant difference exists in cumulative death rate after having peritoneally injected for 46 hours.To determine the effect of dietary kalium alginate on the non-specific response of sea bass(Lateolabrax japonicus), specimens are fed with diets containing 0(control group), 1000mg/kg(Al-1000), 5000mg/kg(Al-5000) kalium alginate for 84 days. Special growth rate, lysozyme activity and alternative pathway haemolytic complement(ACH50) of serum, and the acid phosphatase ,the alkaline phosphatase and the superoxide dismutase activity of liver, and the respiratory burst and bactericidal activity of the head kidney macrophages are examined respectively 42 days and 84 days later. To determine the effect of kalium alginate on the disease resistance, the sea bass are injected peritoneally with Vibrio anguillarum 84 days later.The results show that the ACP activity and the AKP activity of the experimental groups are significantly lower than the control group while the SOD activity of the Al-1000 is significantly higher than the control group after 42 days,s feeding(P<0.05).There isn,t significant difference in SGR exists between the three groups(p>0.05)as well as in the SOD activity and ACH50 .The bactericidal activity of the head kidney macrophages and respiratory burst activity of Al-5000 are significantly higher than the control group(P<0.05).The cumulative death rate of the experimental groups are significantly lower than the control group (P<0.05).A primary investigation to immunostimulatory fatigue for Japanese sea bass is conducted after three experiments as above.The specimens are divided into three groups: control group (fed with diets containing 500mg/kg peptidoglycan for 60 days),PG-Vc group(fed with diets containing 500mg/kg peptidoglycan for the first 30 days and then fed with diets containing 4g/kg vitamin C for another 30 days),and PG-Gl group(fed with diets containing 500mg/kg peptidoglycan for the first 30 days and then fed with diets containing 4g/kg glucan for another 30 days). The results that the ACP activity and the SOD activity increased significantly and then decreased significantly during the first 30 days show that immunostimultory fatigue occurrs .The ACP activity and ACH50 of PG-Vc group are significantly higher than the control group. The SOD activity and lysozyme activity of the experimental groups are significantly higher than the control group(P < 0.05).The cumulative death rate of the experimental groups are significantly lower than the control group(P<0.05).