Article

Colonization of Vibrio pelagius and Aeromonas caviae in early developing turbot (Scophthalmus maximus L.) larvae.

Foundation of Applied Research, University of Tromsø, Norway.
Journal of Applied Microbiology (Impact Factor: 2.39). 03/1998; 84(2):227-33. DOI: 10.1046/j.1365-2672.1998.00333.x
Source: PubMed

ABSTRACT Polyclonal antisera made in rabbits against whole washed cells of Vibrio pelagius and Aeromonas caviae were used for detection of these bacterial species in the rearing water and gastrointestinal tract of healthy turbot (Scophthalmus maximus) larvae exposed to V. pelagius and/or Aer. caviae. The results demonstrated that this method is suitable for detection of V. pelagius and Aer. caviae in water samples and larvae at population levels higher than 10(3) ml-1 and 10(3) larva-1. Populations of aerobic heterotrophic bacteria present in the gastrointestinal tract of turbot larvae, estimated using the dilution plate technique, increased from approximately 4 x 10(2) bacteria larva-1 on day 3 post-hatching to approximately 10(5) bacteria fish-1 16 days post-hatching. Sixteen days after hatching, Vibrio spp. accounted for approximately 3 x 10(4) cfu larva-1 exposed to V. pelagius on days 2, 5 and 8 post-hatching. However, only 10(3) of the Vibrio spp. belonged to V. pelagius. When larvae were exposed to Aer. caviae on day 2 post-hatching, the gut microbiota of 5-day old larvae was mainly colonized by Aeromonas spp. (10(4) larva-1), of which 9 x 10(3) belonged to Aer. caviae. Later in the experiment, at the time when high mortality occurred, 9 x 10(5) Aer. caviae were detected. Introduction of V. pelagius to the rearing water seemed to improve larval survival compared with fish exposed to Aer. caviae and with the control group. It was therefore concluded that it is beneficial with regard to larval survival to introduce bacteria (V. pelagius) to the rearing water.

Full-text

Available from: Olav Vadstein, Oct 26, 2014
0 Followers
 · 
89 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of present study was to evaluate the effect of different levels of yeast probiotic on growth, feed utilization and survival of rainbow trout (Oncorhynchus mykiss) alevins. This experiment conducted in a completely randomized design with four treatments which had triplicates. Four levels of yeast (0, 3%, 6% and 9% of ration) were added to the basic diet. Fish alevins were fed by experimental diets 4 times a day at 5 to 6% of body weight for 30 days. Rainbow trout larvae (average individual weight, 176 mg) were randomly distributed with density of 4 fish/l into twelve 10 liter fiberglass tanks. The results indicated that the Saccharomyces cerevisiae could not influence growth and feeding parameters in rainbow trout alevin. The final body weight and specific growth rate (SGR) in experimental treatments had not significant difference in comparison with control treatment (P≥0.05). The bakers yeast had not significant positive effects on food conversion efficiency (FCE), thermal growth coefficient (TGC) and feed conversion ratio (FCR). This study showed that S. cerevisiae had not high efficiency in feeding parameters and growth performance of rainbow trout alevin.
  • Source
    Probiotic in animals, Edited by Everlon Cid Rigobelo, 01/2012: pages 231-246; InTech., ISBN: 978-953-51-0777-4
  • [Show abstract] [Hide abstract]
    ABSTRACT: AimsThis study aimed to select and validate different methodological strategies to quantify the expression of the virulence genes ascC and ascV by qPCR in Aeromonas salmonicida subsp. salmonicida (A. salmonicida).Methods and resultsUsing the geNorm, Normfinder, and BestKeeper algorithms, reference genes for the qPCR were selected based on their in vitro expression stabilities in three A. salmonicida strains. Gene amplification efficiency was calculated by Real-time PCR Miner and LinReg PCR programs, which have not been used previously in the analysis of bacterial gene expression. The expression of the ascC and ascV virulence genes in a virulent A. salmonicida strain was evaluated by three quantification models, including single (least or most stable) or three most stable reference genes, combined with constant or specific gene amplification efficiency. The most stable reference genes were gyrB, proC, and rpoC, while rpoD and fabD were the least stable. Quantification models showed different expression patterns.Conclusions The optimal strategy to quantify mRNA expression was to use a combination of the three algorithms and the quantification model including the three most stable reference genes. Real-time PCR Miner or LinReg PCR were valuable tools to estimate amplification efficiency.Significance and Impact of the studyThe methods used in this study gave more reliable expression data using qPCR than previously published methods. The quantification and expression dynamics of virulence genes will contribute to a better understanding of how A. salmonicida interacts with its host and the environment, and therefore to the prevention of epizootics due to this pathogen.This article is protected by copyright. All rights reserved.
    Journal of Applied Microbiology 12/2014; 118(4). DOI:10.1111/jam.12740 · 2.39 Impact Factor