The effects of soybean, linseed and marine oils on aerobic gut microbiota of Arctic charrSalvelinus alpinusL. before and after challenge withAeromonas salmonicidassp.salmonicida

Abstract

Populations of heterotrophic bacteria present in the hindgut region of Arctic charr Salvelinus alpinus L. fed dietary soybean, linseed and marine oils before challenge with Aeromonas salmonicida ssp. salmonicida and marine oil after challenge were estimated using the dilution plate technique. There were differences in bacterial composition between the rearing groups before and after challenge, as well as interindividual variations. For example, carnobacteria were only isolated from the hindgut region of fish fed soybean oil and linseed oil before challenge, whereas Carnobacterium spp. and Carnobacterium funditum‐like species were isolated from fish fed the same oils after challenge. Three non‐motile Aeromonas spp. were isolated from infected fish fed marine oil. One of these isolates was identified as identical to A. salmonicida ssp. salmonicida used in&the challenge test by microbial fingerprinting (amplified fragment length polymorphism). Electron microscopic examinations of hindgut regions demonstrated substantial numbers of bacterial cells associated with enterocytes, but bacterial colonization of the enterocyte surface varied between different rearing groups. The potential of bacteria found associated with the hindgut region to inhibit the fish pathogens A. salmonicida, Vibrio salmonicida and Vibrio anguillarum differed between rearing groups.

Morfologia e quantificação da microbiota intestinal do curimbatá (Prochilodus lineatus) e do cascudo cinza (Pterygoplichthys anisitsi) cultivados em cativeiro

“…Neste caso, seria de relevante importância lembrar que condições de estresse (Olsen et al, 2005), estágio reprodutivo (Silva et al, 2005), idade (Bates et al, 2006), mudanças abruptas na dieta bem como a adição de certos componentes nesta exerceram influências muitas vezes negativas sobre a densidade populacional na microbiota intestinal, com alterações também nos gêneros dos micro-organismos componentes dela (Ringo e Olsen, 1999;Ringo et al, 2002;Refstie et al, 2006).…”

“…Nestas, foram encontrados com maior frequência micro-organismos cocoides e leveduriformes. A predominante presença de bactérias cocoides também foi relatada no trabalho de Ringo e Olsen (1999) e Ringo et al (2002). Austin e Al-Zahrani (1988) relataram dificuldades na detecção da presença de leveduras e fungos pela MEV no trato gastrointestinal de peixes.…”

“…Com relação às formas bacilares flageladas unipolares encontradas nas regiões intestinais finais do P. lineatus, estas podem bem corresponder às bactérias do gênero Aeromonas spp., visto ser este gênero predominante em ambientes de água doce e na microbiota de peixes, cuja morfologia apresenta flagelos unipolares, conferindo-lhes motilidade (Boijink e Brandão, 2001;Ringo et al, 2002). No entanto, como mencionado anteriormente, estudos e testes adicionais serão necessários para comprovação dos gêneros destes micro-organismos.…”

Dietary Effect of Soybean (Glycine max) Products on Gut Histology and Microbiota of Fish

“…BakkeMcKellep et al 2007b;Merrifield et al, 2009;Dimitroglou et al 2010) and several studies have observed sensitivity of the gut microbiota of fish to different dietary lipid levels (Lesel et al, 1989; and different dietary plant oils (Ringø et al, 2002;Montero et al, 2006). However, to our knowledge only one study has assessed the effect of dietary SBO on the gut microbiome of fish.…”

“…However, to our knowledge only one study has assessed the effect of dietary SBO on the gut microbiome of fish. In their study with Arctic charr, Ringø et al (2002) evaluated the effect of SBO on the autochthonous gut microbiota. The presence of autochthonous bacteria associated with the microvilli of fish fed the SBO enriched diet is demonstrated in Figure 7.…”