title: Dietary β-glucan (MacroGard®) enhances survival of first feeding turbot (Scophthalmus maximus) larvae by altering immunity, metabolism and microbiota.
abstract: Reflecting the natural biology of mass spawning fish aquaculture production of fish larvae is often hampered by high and unpredictable mortality rates. The present study aimed to enhance larval performance and immunity via the oral administration of an immunomodulator, β-glucan (MacroGard(®)) in turbot (Scophthalmus maximus). Rotifers (Brachionus plicatilis) were incubated with or without yeast β-1,3/1,6-glucan in form of MacroGard(®) at a concentration of 0.5 g/L. Rotifers were fed to first feeding turbot larvae once a day. From day 13 dph onwards all tanks were additionally fed untreated Artemia sp. nauplii (1 nauplius ml/L). Daily mortality was monitored and larvae were sampled at 11 and 24 dph for expression of 30 genes, microbiota analysis, trypsin activity and size measurements. Along with the feeding of β-glucan daily mortality was significantly reduced by ca. 15% and an alteration of the larval microbiota was observed. At 11 dph gene expression of trypsin and chymotrypsin was elevated in the MacroGard(®) fed fish, which resulted in heightened tryptic enzyme activity. No effect on genes encoding antioxidative proteins was observed, whilst the immune response was clearly modulated by β-glucan. At 11 dph complement component c3 was elevated whilst cytokines, antimicrobial peptides, toll like receptor 3 and heat shock protein 70 were not affected. At the later time point (24 dph) an anti-inflammatory effect in form of a down-regulation of hsp 70, tnf-α and il-1β was observed. We conclude that the administration of MacroGard(®) induced an immunomodulatory response and could be used as an effective measure to increase survival in rearing of turbot.
authors.affiliation: Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany. Electronic address: jmiest@geomar.de.
authors.forename: Joanna J
authors.initials: JJ
authors.lastname: Miest
authors.affiliation: Experimental Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany. Electronic address: carmen.arndt@gmx.net.
authors.forename: Carmen
authors.initials: C
authors.lastname: Arndt
authors.affiliation: Fish Disease Research Unit, University of Veterinary Medicine, Hanover, Germany. Electronic address: marana@interia.pl.
authors.forename: Mikolaj
authors.initials: M
authors.lastname: Adamek
authors.affiliation: Fish Disease Research Unit, University of Veterinary Medicine, Hanover, Germany. Electronic address: Dieter.Steinhagen@tiho-hannover.de.
authors.forename: Dieter
authors.initials: D
authors.lastname: Steinhagen
authors.affiliation: Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany. Electronic address: treusch@geomar.de.
authors.forename: Thorsten B H
authors.initials: TB
authors.lastname: Reusch
mesh_terms: D000333:Aeromonas / Q000235:genetics; D000818:Animals; D001156:Artemia; D002918:Chymotrypsin / Q000235:genetics; D003176:Complement C3 / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004032:Diet; D019587:Dietary Supplements; D029941:Fish Proteins / Q000235:genetics; D005412:Flatfishes / Q000254:growth & development / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D041965:Flavobacteriaceae / Q000235:genetics; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D007155:Immunologic Factors / Q000494:pharmacology*; D053583:Interleukin-1beta / Q000235:genetics; D050356:Lipid Metabolism / Q000235:genetics; D064307:Microbiota / Q000187:drug effects; D012403:Rotifera; D014357:Trypsin / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D014733:Vibrio / Q000235:genetics; D047071:beta-Glucans / Q000494:pharmacology*
chemical_list: D003176:Complement C3; D004269:DNA, Bacterial; D029941:Fish Proteins; D018840:HSP70 Heat-Shock Proteins; D007155:Immunologic Factors; D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha; D047071:beta-Glucans; D002918:Chymotrypsin; D014357:Trypsin
keywords: Beta-glucan; Complement component C3; Fish larvae; Immunity; Immunostimulation; Survival; Trypsin; Turbot