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Thu Duc District, Vietnam

Sirimanapong W.,University of Stirling | Sirimanapong W.,Mahidol University | Adams A.,University of Stirling | Ooi E.L.,Novus Aqua Research Center | And 6 more authors.
Fish and Shellfish Immunology | Year: 2015

Immunostimulants are food additives used by the aquaculture industry to enhance the immune response of fish, and although β-glucans are now commonly used for this purpose in aquaculture, little is known about their effects on the immune response of Pangasianodon hypophthalmus. Thus, a variety of immune parameters (e.g. phagocytosis, respiratory burst, lysozyme, complement, peroxidase, total protein, total anti-protease, total IgM, natural antibody titres, and specific IgM titres) was examined in this species after feeding fish with a basal control diet or diets supplemented with 0.05, 0.1, or 0.2g/kg fungal-derived β-glucan or 0.1% commercial yeast-derived β-glucan, as a positive control diet, for a period of four weeks. The effect of the glucans on disease resistance was then evaluated by experimentally infecting the fish with Edwardsiella ictaluri by immersion and mortalities monitored for 14 days. Samples were collected from fish for analysis at 0, 1, 3, 7, 14, 21 and 28 days post-feeding (dpf), and also at 14 days post infection (dpi). The lowest dose of fungal-derived β-glucan (0.05%) appeared insufficient to effectively stimulate the immune response of the fish, while those fed with the two highest levels of fungal-derived β-glucan had enhanced immune responses compared to the control group. Significantly elevated levels of respiratory burst activity on all days examined (. P<0.05) and lysozyme activity on 7dpf were found in the group fed 0.2% fungal-derived β-glucan, while plasma anti-protease activity was significantly enhanced (. P<0.05) by 21dpf, natural antibody titres by 3dpf and complement activity by 7dpf and also at 14dpi in the group fed 0.1% fungal-derived β-glucan. No statistical differences was seen in the level of mortalities between the dietary groups, although the group fed with the control diet had the highest level of mortalities and the groups fed with commercial yeast-derived β-glucan and 0.2% fungal-derived β-glucan the lowest. •The immune response of Pangasianodon hypophthalmus, or striped catfish, was examined.•Immunostimulant diets containing β-glucan were fed to striped catfish.•The immunostimulatory role of β-glucan on striped catfish immunity was studied.•Difference levels of β-glucan in the diets of striped catfish were evaluated.•β-glucan supplemented diet stimulated the immune response of striped catfish. © 2015 Elsevier Ltd. Source


Sirimanapong W.,University of Stirling | Sirimanapong W.,Mahidol University | Thompson K.D.,University of Stirling | Thompson K.D.,Moredun Research Institute | And 10 more authors.
Fish and Shellfish Immunology | Year: 2015

Pangasianodon hypophthalmus (striped catfish) is an important aquaculture species and intensification of farming has increased disease problems, particularly Edwardsiella ictaluri. The effects of feeding β-glucans on immune gene expression and resistance to E. ictaluri in P. hypophthalmus were explored. Fish were fed 0.1% fungal-derived β-glucan or 0.1% commercial yeast-derived β-glucan or a basal control diet without glucan. After 14 days of feeding, the mRNA expression of immune genes (transferrin, C-reactive protein, precerebellin-like protein, Complement C3 and factor B, 2a MHC class II and interleukin-1beta) in liver, kidney and spleen were determined. Following this fish from each of the three diet treatment groups were infected with E. ictaluri and further gene expression measured 24 h post-infection (h.p.i.), while the remaining fish were monitored over 2 weeks for mortalities. Cumulative percentage mortality at 14 days post-infection (d.p.i.) was less in β-glucan fed fish compared to controls. There was no difference in gene expression between dietary groups after feeding for 14 days, but there was a clear difference between infected and uninfected fish at 24 h.p.i., and based on principal component analysis β-glucans stimulated the overall expression of immune genes in the liver, kidney and spleen at 24 h.p.i. © 2015 Elsevier Ltd. Source


Sirimanapong W.,University of Stirling | Sirimanapong W.,Mahidol University | Thompson K.D.,University of Stirling | Kledmanee K.,Mahidol University | And 4 more authors.
Fish and Shellfish Immunology | Year: 2014

Aquaculture production of Pangasianodon hypophthalmus is growing rapidly in South East Asia, especially in Vietnam. As it is a relatively new aquaculture species there are few reports evaluating its immune response to pathogens. Thus, functional assays for P.hypophthalmus were optimised to evaluate both innate and adaptive immune responses, and were then used to examine immune response following stimulation with live and heat-killed Aeromonas hydrophila. These were used as models of infection and vaccination, respectively.Four treatment groups were used, including a control group, a group injected intraperitonally (IP) with adjuvant only, a group injected with heat-killed A.hydrophila (1×109cfuml-1 mixed with adjuvant), and a group injected with a subclinical dose of live A.hydrophila. Samples were collected at 0, 1, 3, 7, 14 and 21 days post-injection (d.p.i.) to assess their immune response. The results indicated that challenge with live or dead bacteria stimulated the immune response in P.hypophthalmus significantly above the levels observed in control groups with respect to specific antibody titre, plasma lysozyme and peroxidase activity, and phagocytosis by head kidney macrophages at 7 or/and 14d.p.i. At 21d.p.i., total and specific antibody (IgM) levels and plasma lysozyme activity in fish injected with either live or dead A.hydrophila were significantly different to the control groups. Differential immune responses were observed between fish injected with either live or dead bacteria, with live A.hydrophila significantly stimulating an increase in WBC counts and plasma peroxidase activity at 3d.p.i., with the greatest increase in WBC counts noted at 21d.p.i. and in phagocytosis at 14d.p.i. By 21d.p.i. only the macrophages from fish injected with dead A.hydrophila showed significantly stimulation in their respiratory burst activity. This study provides basic information on the immune response in pangasius catfish that can be useful in the health control of this species. © 2014 Elsevier Ltd. Source

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