Search results for "aquaculture."
showing 10 items of 344 documents
Biostimulation of in situ microbial degradation processes in organically-enriched sediments mitigates the impact of aquaculture
2019
Fish farm deposition, resulting in organic matter accumulation on bottom sediments, has been identified as among the main phenomena causing negative environmental impacts in aquaculture. An in situ bioremediation treatment was carried out in order to reduce the organic matter accumulation in the fish farm sediments by promoting the natural microbial biodegradation processes. To assess the effect of the treatment, the concentration of organic matter in the sediment and its microbial degradation, as well as the response of the benthic prokaryotic community, were investigated. The results showed a significant effect of the treatment in stimulating microbial degradation rates, and the consequen…
Bacteria associated with winter mortalities in laboratory-reared common dentex (Dentex dentex L.)
2007
A pathological study was conducted on laboratory-reared juvenile common dentex (Dentex dentex) suffering trickling and continuous mortalities. During a 3-month period (October-December), water temperature, clinical signs and mortalities were recorded. Moribund or dead fish were examined for bacteria and parasites. Bacteria were isolated from head kidney and external ulcers, and samples from the gills, intestine, stomach, trunk kidney, gall bladder and liver were taken for histology. Cumulative mortality reached 73%, and 80% of fish examined were positive for bacteria (102 isolates). Vibrio splendidus was the most prevalent in head kidney (59.7%) and ulcers (88.9%), and it was frequently iso…
Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen
2020
Phenotypic variation is suggested to facilitate the persistence of environmentally growing pathogens under environmental change. Here, we hypothesized that the intensive farming environment induces higher phenotypic variation in microbial pathogens than natural environment, because of high stochasticity for growth and stronger survival selection compared to the natural environment. We tested the hypothesis with an opportunistic fish pathogen Flavobacterium columnare isolated either from fish farms or from natural waters. We measured growth parameters of two morphotypes from all isolates in different resource concentrations and two temperatures relevant for the occurrence of disease epidemic…
Jellyfish Stings Trigger Gill Disorders and Increased Mortality in Farmed Sparus aurata (Linnaeus, 1758) in the Mediterranean Sea
2016
11 pages, 4 figures
Concurrent environmental stressors and jellyfish stings impair caged European sea bass (Dicentrarchus labrax) physiological performances
2016
9 pages, 5 figures, 4 tables
Diagnostic accuracy of the light microscope method to detect the eggs of Cardicola spp. in the gill filaments of the bluefin tuna.
2017
Trematode blood flukes of the genus Cardicola are potentially lethal in bluefin tuna cultures. The present study proposed a new method to detect aporocotylid eggs in tuna gills. Aporocotylid eggs were detected by analysing a pair of gill filaments of five transversal areas of the eight holobranches of one hundred Atlantic bluefin tuna and observed with glycerol and a stereomicroscope with an oblique brightfield. Data were gathered according to holobranches, transversal areas and their combination. Eggs were uniformly distributed among the holobranches, but they had the highest prevalence in the second and fifth transversal areas, which is controversial with respect to previous studies of eg…
Effect of Pseudomonas sp. MT5 baths on Flavobacterium columnare infection of rainbow trout and on microbial diversity on fish skin and gills
2005
Use of Pseudomonas sp. strain MT5 to prevent and treat Flavobacterium columnare infection was studied in 2 experiments with fingerling rainbow trout Oncorhynchus mykiss. In the first experiment, length heterogeneity analysis of PCR-amplified DNA fragments (LH-PCR) was used to assess the effect of antagonistic baths on the microbial diversity of healthy and experimentally infected fish. In the 148 samples studied, no difference was found between bathed and unbathed fish, and 3 fragment lengths were detected most frequently: 500 (in 75.7% of the samples), 523 (62.2%) and 517 bp (40.5%). The species contributing to these fragment sizes were Pseudomonas sp., Rhodococcus sp. and F. columnare, re…
Study of Fishmeal Substitution on Growth Performance and Shelf-Life of Giltheadsea Bream (Sparusaurata)
2020
In this work the effect of partial or total replacement of fishmeal by plant protein sources and krill and squid meal on growth performance and shelf-life of gilthead sea bream was evaluated. Plant protein dietswith 50 g kg&minus
Phage-driven loss of virulence in a fish pathogenic bacterium
2012
Parasites provide a selective pressure during the evolution of their hosts, and mediate a range of effects on ecological communities. Due to their short generation time, host-parasite interactions may also drive the virulence of opportunistic bacteria. This is especially relevant in systems where high densities of hosts and parasites on different trophic levels (e.g. vertebrate hosts, their bacterial pathogens, and virus parasitizing bacteria) co-exist. In farmed salmonid fingerlings, Flavobacterium columnare is an emerging pathogen, and phage that infect F. columnare have been isolated. However, the impact of these phage on their host bacterium is not well understood. To study this, four s…
First record of Temnosewellia minor (Platyhelminthes, Temnocephalidae) in Sicily, with a plea for a re-examination of the identity of the publicly av…
2021
Author(s): Vecchioni, Luca; Chirco, Pietro; Bazan, Giuseppe; Marrone, Federico; Arizza, Vincenzo; Arculeo, Marco | Abstract: Ectosymbiotic temnocephalan flatworms belonging to the genus Temnosewellia Damborenea and Cannon, 2001 were collected on Cherax destructor Clark, 1936 in an aquaculture farm in Sicily, Italy. This represents the first record of a temnocephalan species for the fauna of the island. Morphological and molecular identification of the collected specimens proved that they belong to the allochthonous species Temnosewellia minor Haswell, 1888, which was introduced along with crayfishes bred in aquaculture farms. The phylogenetic analyses carried out for the molecular identific…