laminaran and Fish-Diseases

Four diets supplemented with three different levels of β-1,3-glucan (0.5, 1, and 2 g kg

Topics: Aeromonas hydrophila; Animals; beta-Glucans; Cypriniformes; Diet; Dietary Supplements; Fish Diseases; Gram-Negative Bacterial Infections; Intestines; Malondialdehyde; Peroxidases; Superoxide Dismutase

β-glucans are widely-known immunostimulants that are profusely used in aquaculture industry. The present study was conducted to evaluate the effect of different in-feed doses of β-1,3/1,6-glucans on the expression of antioxidant and stress-related genes (GST, HSP-70, Vtg), inflammation related genes (Il-8, TNFα, CXC-chemokine and CAS) and adaptive immune-related genes (MHC-IIβ, TLR-7, IgM-H, and Mx) of Oreochromis niloticus challenged and non-challenged with Streptococcus iniae. Six experimental groups were established: non-challenged control (non-supplemented diet), challenged control (non-supplemented diet), non-challenged supplemented with 0.1% β-glucan, challenged supplemented with 0.1% β-glucan, non-challenged supplemented with 0.2% β-glucan and challenged supplemented with 0.2% β-glucan. Fish were fed with β-glucan for 21 days prior challenge and then sampled after 1, 3 and 7 days post-challenge. In non-challenged group, variable effects of the two doses of β-Glucans on the expression of the studied genes were observed; 0.1% induced higher expression of HSP70, CXC chemokine, MHC-IIβ and MX genes. Meanwhile, 0.2% induced better effect on the expression of Vtg, TNF-α, CAS and IgM-H, and almost equal effects of both doses on GST and IL8. However, with the challenged group, 0.2% β-Glucans showed better effect than 0.1% at day one post challenge through significant up-regulation of GST, HSP, IL8, TNF-α, CXC, and MHC-IIβ, meanwhile, the effect of 0.1% was only on the expression of HSP70, MHC-IIβ, and TLR7 at day 3 post challenge. No stimulatory role for both doses of β-Glucans on the expression of almost all genes at day 7 post-challenge. We conclude that both doses of β-glucan can modulate the antioxidant, inflammation, stress and immune-related genes in Nile tilapia, moreover, 0.2% β-Glucans showed better protective effect with Streptococcus iniae challange.

Topics: Adjuvants, Immunologic; Animal Feed; Animals; Antioxidants; beta-Glucans; Cichlids; Diet; Dietary Supplements; Dose-Response Relationship, Drug; Fish Diseases; Immunity, Innate; Inflammation; Streptococcal Infections; Streptococcus iniae; Stress, Physiological

Potential immunostimulatory effects of orally administered β-glucan were investigated in combination with immersion vaccination against enteric redmouth disease caused by Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss). A linear, unbranched and pure (purity ≥98%) β-1,3-glucan (syn. paramylon) from the alga Euglena gracilis was applied at an inclusion level of 1% β-glucan in feed administered at a rate of 1% biomass day(-1) for 84 consecutive days. Fish were vaccinated after two weeks of experimental feeding and bath challenged with live Y. ruckeri six weeks post-vaccination. Blood and head kidney were sampled at day 0, 13 (1 day pre-vaccination), 15, 55, 59 (day 3 post-challenge (p.c.)), 70 and 84. Vaccination induced significantly increased survival p.c., whereas the β-glucan had no effect on survival in either unvaccinated or vaccinated fish. Expression in head kidney of genes related to the acute phase response, i.e. interleukin-1β (IL-1β), serum amyloid A (SAA), precerebellin, and hepcidin, was significantly different in vaccinated fish receiving β-glucan compared to vaccinated controls at day 3 p.c., while no effect of β-glucan was observed among unvaccinated fish. Significant interaction between β-glucan and vaccination was found for the regulation of IL-1β, tumour necrosis factor-α, interferon-γ, SAA, precerebellin and hepcidin p.c. For SAA, the significant effect of β-glucan in vaccinated fish persisted at day 14 p.c. and 28 p.c. The difference in gene expression among vaccinated fish was mainly observed as down-regulations in vaccinated, β-glucan fed fish compared to up-regulations or no regulation in vaccinated controls. Slightly increased levels of plasma lysozyme activity were found in fish (both unvaccinated and vaccinated) receiving β-glucan at day 3 p.c. compared to control fed groups. This was associated with a faster clearance of Y. ruckeri in unvaccinated fish receiving β-glucan. In contrast to the trend towards a beneficial effect of β-glucan on plasma lysozyme activity, a trend towards suppression of plasma antibodies was seen in both unvaccinated and vaccinated fish receiving β-glucan. However, the effects of β-glucan were not reflected in the survival curves, and the differences seen in plasma lysozyme activity and antibody levels may have counteracted and set off each other as well as counteracted any potential effect represented by the differences in gene expression found.

Topics: Acute-Phase Proteins; Animals; Antibodies, Bacterial; Bacterial Vaccines; beta-Glucans; Cytokines; Euglena gracilis; Fish Diseases; Gene Expression Profiling; Gene Expression Regulation; Head Kidney; Immersion; Immunologic Factors; Muramidase; Oncorhynchus mykiss; Survival Analysis; Vaccination; Yersinia Infections; Yersinia ruckeri

Topics: Adjuvants, Immunologic; Animals; beta-Glucans; Fish Diseases; Injections, Intraperitoneal; Loma; Microsporidiosis; Oncorhynchus mykiss; Time Factors

This study investigated the effects of short and prolonged administration of a yeast beta-glucan on non-specific immune parameters, growth rate and the disease resistance of Asian catfish, Clarias batrachus. Fish fed with a basal diet (control) and test diet (basal diet supplemented with 0.1% glucan) for 1, 2 and 3 weeks were assayed for superoxide production, serum myeloperoxidase (MPO) content, natural haemagglutinin level, complement and lysozyme activities. Fish were weighed at weekly intervals and specific growth rate (SGR, % increase in body weight per day) was determined. After each week, fish were challenged with Aeromonas hydrophila to measure the level of protection. Results showed that glucan administration at 0.1% in feed, significantly (P<0.05) enhanced MPO and lysozyme levels, superoxide production, haemagglutination titre and level of protection against A. hydrophila challenge, irrespective of length of exposure. The alternative complement activity and SGR were not affected by the dietary supplementation of yeast glucan. As glucan feeding at 0.1% for 1 week is able to enhance the non-specific immunity and disease resistance of catfish efficiently, short-term feeding might be used in farmed catfish diets to enhance disease resistance.

Topics: Adjuvants, Immunologic; Aeromonas hydrophila; Animal Feed; Animals; beta-Glucans; Catfishes; Complement System Proteins; Dietary Supplements; Fish Diseases; Gram-Negative Bacterial Infections; Hemagglutination; Immunity, Innate; Muramidase; Nitroblue Tetrazolium; Peroxidase; Random Allocation; Respiratory Burst; Time Factors

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.

Topics: Adjuvants, Immunologic; Aeromonas hydrophila; Animals; Antibodies; Ascorbic Acid; Bacterial Vaccines; beta-Glucans; Catfishes; Cyclophosphamide; Dietary Supplements; Fish Diseases; Gram-Negative Bacterial Infections; Immunity, Innate; Immunocompromised Host; Lactoferrin; Levamisole; Survival Analysis; Time Factors

In order to determine the impact on disease resistance of four dietary immunomodulators viz., beta-1,3 glucan, levamisole, vitamins C and E, in an important farmed Indian major carp species, rohu (Labeo rohita Ham.), fish were fed diets containing various levels of these substances during a 60 day trial. Aflatoxin B1 (AFB,) at 125 mg kg(-1) body weight was injected intraperitoneally (i.p.) into fish to induce an immunosuppressive state on the first day of the experiment in some individuals. The fish were vaccinated against formalin-killed Edwardsiella tarda vaccine on day 30 of the experiment. Specific immunity, as measured by bacterial agglutination titre and disease resistance against E. tarda, was determined at the end of the trial. The results demonstrate that all the four immunomodulators were capable of significantly (P<0.05) increasing specific immunity and reducing mortality in immunocompromised fish but failed to enhance specific immunity and protection in healthy fish. The increased bacterial agglutination titre by beta-1,3 glucan, and reduced mortality losses by both beta-1,3 glucan and levamisole were marked in healthy vaccinated fish compared with their controls. Similarly, all four substances significantly reduced the mortality rates in immunocompromised and healthy unvaccinated fish. Out of these four substances, glucan was recorded to be the most effective immunomodulator in rohu. The present results suggest that the introduction of these substances into the diet of fish grown in farms under immunosuppressive/stressful conditions could increase their resistance to infection by reducing mortality rates and offer economic benefits.

Topics: Adjuvants, Immunologic; Aflatoxin B1; Agglutination Tests; Animal Feed; Animals; Antibodies, Bacterial; Antioxidants; Ascorbic Acid; Bacterial Vaccines; beta-Glucans; Cyprinidae; Edwardsiella tarda; Enterobacteriaceae Infections; Fish Diseases; Glucans; Immunization; Immunocompromised Host; Injections, Intraperitoneal; Levamisole; Vitamin E

The serum of blue gourami, Trichogaster trichopterus (Pallus), contains a calcium-dependent, N-acetyl-galactosamine-binding lectin (BGL) which efficiently activates and enhances the non-specific immune response of fish towards a virulent strain of Aeromonas hydrophila. In the in vitro studies, a lectin concentration range of 0.05-1.0 ng ml(-1) was found to significantly promote phagocytic uptake of the bacteria by macrophages. This effect was further augmented when purified lectin was combined with laminarin (beta-1,3-D-glucan). Supernatants obtained from these lectin-stimulated macrophage cultures also exhibited significant bacteria-killing activities. In addition, complement from naive fish serum, in the presence of purified BGL, was able to kill A. hydrophila. Finally, challenge experiments demonstrated that BGL could confer effective immune protection to naive blue gourami against an Aeromonas infection.

Topics: Aeromonas hydrophila; Animals; Fish Diseases; Glucans; Lectins; Macrophages; Perciformes; Phagocytosis; Polysaccharides; Receptors, Immunologic; Receptors, N-Acetylglucosamine; Receptors, Thyroid Hormone