The Immune Effects Of Gonad Canker Disease And Isolation And Identification Of The Pathogenic Of Pustules Symptoms In Acipenser Gueldenstaedti

This article could be divided into three parts.The first part reports the efficacy of the bivalent vaccine against Aeromonas hydrophilia and Yersinia Ruckeri.This will be basis for vaccine development in the future.The second part reports the effects of dietary chitosan supplement on growth performance and immunity in Russian sturgeon.The last part reports the explortion of the pathogenic of sturgeon pustules symptom and its santibiotic sensitivity,in order to provide preferences for diseases prevention and treatment of sturgeon.1 Immune efficacy of the bivalent inactivated vaccine composed of Aeromonas hydrophilia and Yersinia Ruckeri in Acipenser gueldenstaedtiThe bivalent inactivated vaccine composed of Aeromonas hydrophilia and Yersinia Ruckeri.The immunogenicity of bivalent inactive vaccine was tested by examining the superoxide dismutase(SOD)activity,lysozyme(LZM)activity,contents of complement C3 and immunoglobulinM(IgM),the antibody titer and the challenge test of live pathogen was carried out,too.Results showed that: the SOD activity,LZM activity,contents of complement C3 and IgM in serum of Acipenser gueldenstaedti had a different degree of increase compared with control group.And add adjuvants bivalent inactivated vaccine immunization effect was stronger.The antibody titer in Acipenser gueldenstaedti immunized with bivalent inactivated vaccine was induced,after 2 weeks came to a head,then declined.After strengthen immunization,The antibody titer reached the peak value again after the first 5 weeks post-immunization.And antibody titer induced by adjuvants bivalent inactivated vaccine group was higher than without adjuvants bivalent inactivated vaccine group,but the antibody titer for the two kinds of bacteria of control group has been less than 4 value during the test.The challenge test of both pathogen was carried out after 8 weeks,the relative survival to Aeromonashydrophilia and Yersinia Ruckeri challenge were 61.54% and 60.71%,increased by7.69% and 7.14%,respectively,compared with the group without adjuvant.Results indicate that the bivalent inactivated vaccine can effectively protect Acipenser gueldenstaedti from Aeromonas hydrophilia and Yersinia Ruckeri infection.2 Effects of chitosan on growth performance and immunity in Acipenser gueldenstaedtiA 50-day feeding trial was conducted to investigate the effects of dietary chitosan supplement on growth performance and immunity of juvenile Russian sturgeon(initial body weight of 12 g).In total,540 fish were assigned to six groups(30 fish per replicate,triplicate experiments).The fish were fed basal experimental diets supplemented with different levels of chitosan: 0(control group),1.25,2.5,5,7.5 and 10g/kg respectively.The results showed that the weight growth rate(WGR),specific growth rate(SGR)in 2.5 and 5 g/kg groups significantly higher than that in control group(P<0.05),whereas feed coefficient(FC)decreased significantly(P<0.05),but the growth in 10 g/kg group was inhibited.The superoxide dismutase(SOD)activity in 1.25 and 2.5 g/kg were significantly higher than that in control group(P<0.05),while the SOD activity in the other three groups were significantly lower than that in control group(P<0.05).Lysozyme(LZM)activity in serum of 2.5 and 5 g/kg groups were higher increased significantly(P<0.05),while 7.5 and 10 g/kg groups were significantly lower than that in control group(P<0.05).The alkanlin phoshpatase(AKP)activity,acid phosphatase(ACP)activity and content of complement C3 in 1.25,2.5,5 g/kg groups were significantly higher than those in control group(P<0.05).No significant difference was observed on serum IgM in all supplementation group(P>0.05).These results indicated that dietary chitosan supplementation can improve the growth performance and immunity in juvenile Russian sturgeon.Based on the WGR,SGR and non-specific immunity,the chitosan supplement in diets was suggested to be 2.5 g/kg for juvenile Russian sturgeon.3 Isolation and identification of the pathogenic of pustules symptoms in sturgeonThree dominant bacteria species were isolated from the dying sturgeon.Strain BX0815 was found to be pathogenic after artificial infection.The infection symptoms of the test sturgeons were similar to natural symptoms,and the same pathogenic strain was isolated again.According to morphology,physical and chemical characters,Molecular biology analysis methods and drug susceptibility,the results showed thatstain BX0815 was gram negative and identified as Aeromonas sobria.The 16 S rDNA sequence of the strain showed a homology of 100% with the A.sobria.(GenBank accession NO.FJ461353.1).And the constructed phylogenetic tree was identified the BX0815 isolated as A.sobria further.Drug susceptibility test results showed that strain BX0815 was sensitive to 15 kinds of antimicrobial drugs,such as norfloxacin,gentamycin and florfenicol.The experiment proved that the pathogenic of sturgeon pustules symptoms is Aeromonas sobria.Isolation and identification of the pathogenic bacteria from Sturgeon and its antibiotic sensitivity provided preferences for selecting drugs to prevent and treat diseases.