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dc.contributor.authorTalukdar, Sandipan
dc.contributor.authorRingø, Einar
dc.contributor.authorGhosh, Koushik
dc.date.accessioned2017-03-07T15:55:08Z
dc.date.available2017-03-07T15:55:08Z
dc.date.issued2016
dc.description.abstractBackground. Although, presence of tannase-producing and/or tannin tolerant gut bacteria has been documented in ruminants and non-ruminant herbivores, the topic is rarely addressed in fi sh. The present study aimed at enumeration of autochthonous tannase-producing bacteria in the gut of freshwater teleosts. <p> Materials and methods. This study covered seven freshwater teleost fi sh species: rohu, Labeo rohita (Hamilton, 1822); catla, Catla catla (Hamilton, 1822); mrigal, Cirrhinus mrigala (Hamilton, 1822); grass carp, Ctenopharyngodon idella (Valenciennes, 1844); common carp, Cyprinus carpio Linnaeus, 1758; silver carp, Hypophthalmichthys molitrix (Valenciennes, 1844); and Nile tilapia, Oreochromis niloticus (Linnaeus, 1758). Gastrointestinal (GI) tracts of the fi sh studied were divided into proximal (PI) and distal (DI) parts, homogenized and plated onto Tryptone Soya Agar (TSA) plates. The pure colonies were spotted on selective tannic acid (TA) agar plates to determine the tannase-producing bacteria. Extracellular tannase-producing capacity of the isolates was determined through qualitative and quantitative assay using TA media plates or broth, respectively at three different pH levels (5.5, 7.0, and 8.5). Further, 16S rRNA gene fragments of the promising tannase-producing bacteria were sequenced, aligned, analysed, identifi ed, and deposited to the GenBank. <p> Results. Totally 685 strains were isolated on TSA plates, of which 116 strains (37 from PI and 79 from DI) grow on TA media and were defi ned as tannase-producers. The highest percentage of tannase-producing strains was noticed in the DI regions of grass carp, Ctenopharyngodon idella (38.98%), and tilapia, Oreochromis niloticus (37.74%). The lowest frequency of tannase-producing bacteria was revealed in PI region of catla, Catla catla (2.12%). The intestine of Indian major carps was relatively poorly colonized by tannase-producing bacteria compared to that of exotic carps. Evaluation of tannase-producing capacity revealed that the majority of the isolates exhibited maximum extracellular tannase production at pH 7.0. Quantitative evaluation, showed highest tannase activity by strain HMT1 (0.28 ± 0.001 U) isolated from silver carp, Hypophthalmichthys molitrix, followed by strains ONH2Ph (0.19 ± 0.005) and ONH13B (0.17 ± 0.009 U) isolated from tilapia. Analyses of the 16S rRNA partial gene sequences revealed that strains ONH2Ph and ONH13B showed high similarity to Bacillus subtilis (KP765736) and Brevibacillus agri (KP765734), respectively. Whereas, strain HMT1 was most closely related to Klebsiella variicola (KP765735). <p> Conclusions. The study revealed existence of tannase-producing bacterial symbionts within fi sh GI tracts. Tannindegrading bacteria detected in the presently reported study might aid in overcoming the anti-nutritional effects of dietary tannins within fi sh gut.en_US
dc.descriptionPublished version. Source at <a href=http://dx.doi.org/10.3750/AIP2016.46.3.04> http://dx.doi.org/10.3750/AIP2016.46.3.04 </a>en_US
dc.identifier.citationTalukdar S., Ringø E., Ghosh K. 2016. Extracellular tannase-producing bacteria detected in the digestive tracts of freshwater fi shes (Actinopterygii: Cyprinidae and Cichlidae). Acta Ichthyol. Piscat. 46 (3): 201–210.en_US
dc.identifier.cristinIDFRIDAID 1418828
dc.identifier.doi10.3750/AIP2016.46.3.04
dc.identifier.issn0137-1592
dc.identifier.issn1734-1515
dc.identifier.urihttps://hdl.handle.net/10037/10474
dc.language.isoengen_US
dc.publisherSzczecińskie Towarzystwo Naukoween_US
dc.relation.journalActa Ichthyologica et Piscatoria
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497en_US
dc.subjectfreshwater teleostsen_US
dc.subjectgut bacteriaen_US
dc.subjectautochthonous bacteriaen_US
dc.subjecttannaseen_US
dc.titleExtracellular tannase-producing bacteria detected in the digestive tracts of freshwater fishes (Actinopterygii: Cyprinidae and Cichlidae)en_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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