title: Dietary immunostimulants influence specific immune response and resistance of healthy and immunocompromised Asian catfish Clarias batrachus to Aeromonas hydrophila infection.
abstract: In order to determine the efficacy and immunoreversal effect of the 4 dietary immunomodulators, viz. lactoferrin, beta-1,3 glucan, levamisole and vitamin C, on disease resistance of a commercially important catfish, Clarias batrachus, fish were fed diets supplemented with various levels of these substances in 2 subgroups, healthy and immunocompromised, during a 30 d trial. An artificial immunosuppressive state was induced by giving 3 intraperitoneal (i.p.) injections of cyclophosphamide (CYP) at a dose level of 200 mg kg(-1) body weight at 1 wk intervals in the immunocompromised vaccinated subgroup and 3 consecutive injections 3 d before challenge in the immunocompromised non-vaccinated subgroup. On the first day of the experiment, the fish were vaccinated against a formalin-killed Aeromonas hydrophila bacterin. After 30 d, antibody titre (as measured through bacterial agglutination titre) and disease resistance against A. hydrophila were determined. The results demonstrate that all 4 immunomodulators were capable of significantly (p < 0.05) enhancing the specific immune response; this was evident through raised antibody titre and protection against A. hydrophila in both healthy and immunocompromised vaccinated subgroups compared to their respective controls. Similarly, all 4 substances significantly raised the survival rates in immunocompromised and healthy non-vaccinated fish. Thus, these substances were capable of reducing the immunosuppression induced by CYP injections in both vaccinated and non-vaccinated fish compared to their respective controls. Among the 4 substances studied, beta-1,3 glucan was found to be the most effective immunomodulator, followed by levamisole, lactoferrin and vitamin C in Asian catfish. Therefore, the results support the introduction of these substances into the diet of fish grown in farms under immunosuppressive/stressful conditions in order to enhance protection against infection and offer economic benefits.
authors.affiliation: Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar 751 002, India.
authors.forename: Jaya
authors.initials: J
authors.lastname: Kumari
authors.forename: P K
authors.initials: PK
authors.lastname: Sahoo
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000494:pharmacology*; D016980:Aeromonas hydrophila / Q000276:immunology*; D000818:Animals; D000906:Antibodies / Q000097:blood; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology; D002397:Catfishes / Q000276:immunology* / Q000382:microbiology; D003520:Cyclophosphamide / Q000494:pharmacology; D019587:Dietary Supplements; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D016905:Gram-Negative Bacterial Infections / Q000276:immunology / Q000662:veterinary*; D007113:Immunity, Innate / Q000187:drug effects / Q000276:immunology; D016867:Immunocompromised Host / Q000187:drug effects; D007781:Lactoferrin / Q000008:administration & dosage / Q000494:pharmacology; D007978:Levamisole / Q000008:administration & dosage / Q000494:pharmacology; D016019:Survival Analysis; D013997:Time Factors; D047071:beta-Glucans / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D000276:Adjuvants, Immunologic; D000906:Antibodies; D001428:Bacterial Vaccines; D047071:beta-Glucans; D007978:Levamisole; D003520:Cyclophosphamide; C033363:beta-1,3-glucan; D007781:Lactoferrin; D001205:Ascorbic Acid