Feature article about ParaFishControl in the "International Aquafeed" magazine, June edition 2017, pages 14-19.
Proliferative kidney disease (PKD) is a parasitic infection of salmonid fish characterized by hyper-secretion of immunoglobulins in response to the presence of the myxozoan parasite, Tetracapsuloides bryosalmonae. In this context, we hypothesized that the BAFF/APRIL axis, known to play a major role in B cell differentiation and survival in mammals, could be affected by the parasite and consequently be involved in the apparent shift in normal B cell activity. The results presented in this paper support the premise that the BAFF / APRIL axis plays an important role during PKD, which may open the possibility of new therapeutic treatments against the disease.
The current study is the first to describe the full sequences of the soluble and membrane-bound forms of Gilthead sea bream IgM and IgT and shows for the first time in a fish model their differential expression in different tissues, upon challenge with different pathogens and infection routes.
Three different immunoglobulin (Ig) isotypes can be found in teleost fish, IgM, IgD, and the teleost-specific IgT. It is widely accepted that IgM expression is dominant in absolute terms in all organs and is essential for immune protection against different pathogens upon different routes of infection. IgT, despite being generally less abundant than IgM in number of transcripts and cells, is undeniably crucial in mucosal immune responses, but its role in systemic responses and the role of IgM in mucosal responses should not be discarded. Gilthead sea bream (Sparus aurata) is a marine species belonging to the Sparidae family (Teleostei: Perciformes). It is the main farmed fish species in the Mediterranean basin, representing an important resource for this area. Several diseases hamper their production, and therefore, any advancement in the knowledge of its immune response will help to combat diseases.
This study found that
--> constitutive expression of sIgM was the highest overall in all tissues, whereas mIgT expression was highest in mucosal tissues, such as gills and intestine.
--> IgM and IgT were differentially regulated upon infection.
--> plant-based diets inhibit IgT upregulation upon intestinal parasitic challenge, which was related to a worse disease outcome.
The authors corroborate the importance of IgT in mucosal responses in a fish species very different to the ones used in most previous IgT studies (salmonids and cyprinids). The current results clearly show that the dynamics of expression of IgM and IgT are very different and depend on the types of pathogen or stimulation, immunization, challenge (intramuscular, anal, bath), tissues, and time after challenge. Finally, the authors propose the fish–E. leei infections and the different dietary interventions as models to further study and unravel the insights of the different Ig isotype functions in teleost fish.
INFOBOX: An antibody, also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as bacteria and viruses. The antibody recognizes a unique molecule of the harmful agent, called an antigen.
Press release: December 2016
Parasitic diseases which affect fish species can significantly hamper aquaculture production and economic performance. ParaFishControl is a European Union funded research project addressing the challenges of disease prevention and management to protect the sustainability and competitiveness of the European aquaculture industry. In September, over 70 researchers involved in ParaFishControl, from 13 European countries as well as Canada, came together in Copenhagen, Denmark, to discuss their latest research findings and to map out their future research strategies. Their task - to improve understanding of fish-parasite interactions and to develop respective management tools. For example: diagnostic tests, vaccines, risk maps, and best practice handbooks and management manuals for the prevention, control and mitigation of the most harmful parasitic species affecting key European farmed fish species.
ParaFishControl Project Coordinator Dr Ariadna Sitjà-Bobadilla, from Agencia Estatal Consejo Superior de Investigaciones Cientificas (CSIC), Spain explained: “This has been an exciting time for ParaFishControl! The project is only in its initial stages, but we have already made significant progress and published 11 scientific papers. The ParaFishControl published research includes: the effects of nematode worms on fish and consumer health, the role of fungal communities as suppressors of other fungi, and the decrease in intensity of infection of a gill parasite of gilthead sea bream after feeding infected fish with a mixture of compounds. We have also described, for the first time in Europe, a two-host life cycle of a parasitic myxozoan species and we have comprehensively reviewed the “macrophages first” hypothesis for polarized immune responses”.
“Another partner, the University of Santiago de Compostela (USC), has been working on turbot scuticociliatosis, a disease caused by protozoans, which has been recognized as an emerging problem, inflicting significant economic loss in the global aquaculture industry, by affecting different fish species. Researchers at USC have discovered that the antimalarial drugs chloroquine and artemisinin as well as the chemical substance curcumin which is produced by some plants inhibit some enzymes of this parasite. These findings highlight potential for treating this disease in aquaculture” Dr Sitjà-Bobadilla added.
For a list of all publications, please visit: www.parafishcontrol.eu/parafishcontrol-results2
ParaFishControl, funded by the European Union’s Horizon 2020 funding programme, has been going on since April 2015 and will continue until 2020. In that time, ParaFishControl will carry out a variety of activities to ensure the research findings are shared with a variety of stakeholders such as scientists working in academia or industry, fish farmers/growers, fish health professionals, agricultural advisors, breeders, consumers and policy makers as well as the general public.
(Left) Thelohanellus sp. © Csaba Szekely, (right) Sparolegnia sp. © Kurt Buchmann
We would like to thank all the Mediterranean Aquaculture industry experts that participated in the ParaFishControl Project Expert consultation on Mediterranean fish parasites in Residència d'Investigadors, Hospital, 64 Barcelona on the 10th - 11th November 2016 for a very interactive, open and productive meeting!
ParaFishControl Parasite Experts prepared the Literature reviews. CEFAS with CSIC, AQUARK and Parasite Leaders developed questionnaires on disease characteristics, incidence and prevalence, impact of farm characteristics and environmental factors, pathways for parasite introduction, impact of management practices, treatment strategies and mixed infections. Mediterranean Experts were invited and filled the questionnaires and after CEFAS analysed the responses industry experts were invited to review the results and discuss each parasite profile in the expert consultation meeting.
ParaFishControl partners along with Mediterranean industry fish pathologists discussed the impact of four of the most important parasites in the Mediterraenan mariculture industry.
We had a great opportunity to exchange information and discuss the ParaFishControl questionnaire in order to put together different pieces of the puzzle to improve our understanding of the parasites and their impact to the industry.
The meeting was organized by Ariadna Sitjà-Bobadilla (CSIC) – PARAFISHCONTROL Coordinator and Panos Christofilogiannis (AQUARK) – ParaFishControl Industry Forum Leader with the contribution and participation of the following experts: Birgit Oidtmann (CEFAS), Oswaldo Palenzuela (CSIC), Ivona Mladineo (IZOR), Marialetizia Fioravanti (Un. BOLOGNA), Paola Beraldo (Un. UDINE), Albert Girons (ICTIOVET), Elena Planas Callao (BIOMAR), Foteini Athanasopoulou (Un. THESSALY), Anastasia Dourala (SELONDA Group), Carlos Zarza (ARC SKRETTING), Francesc Padros (Un. AUTONOMA BARCELONA), Kantham Papanna (NIREUS Group), Meritxell Diez (Grupo CULMAREX), Ioannis Petropoulos (ANDROMEDA Group), Georgios Spiliopoulos (ANDROMEDA Group), Alastair Cook (CEFAS), Panos Varvarigos (VETCARE), Maria Mercè Isern I Subich (NUTRIAD International) and Daniel Gijón (SKRETTING SPAIN)
We all expressed our will to continue this active collaboration throughout the ParaFishControl project where we plan to interact with all the stakeholders through epidemiological studies, fish farm visits, economic impact assessment to finally develop guidelines for integrated pest management practices to better manage parasitic diseases in Mediterranean mariculture.
Join our LinkedIN Group to follow the progress of this work in www.linkedin.com/groups/8429051
ParaFishControl (www.parafishcontrol.eu) has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 634429. This output reflects the views only of the author(s), and the European Union cannot be held responsible for any use which may be made of the information contained therein.