Aquaculture Europe 2021

October 4 - 7, 2021

Funchal, Madeira

Add To Calendar 07/10/2021 14:50:0007/10/2021 15:10:00Europe/LisbonAquaculture Europe 2021A STUDY OF THE DYNAMICS OF THE PROKARYOTIC COMMUNITY IN A RECIRCULATING AQUACULTURE SYSTEM (RAS) FROM A SOLE Solea senegalensis HATCHERYView Room-CasinoThe European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982

A STUDY OF THE DYNAMICS OF THE PROKARYOTIC COMMUNITY IN A RECIRCULATING AQUACULTURE SYSTEM (RAS) FROM A SOLE Solea senegalensis HATCHERY

Diana Bastos Almeida*1,2,3, Catarina Magalhães2,4,5, Zélia Sousa4, Maria Teresa Borges2,4, Eliane Silva1, Isidro Blanquet3, Ana Paula Mucha2,4

 

1 ICBAS – Institute of Biomedical Sciences Abel Salazar, University of Porto

2 CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto

3 SEA8 - Safiestela Sustainable Aquafarming Investments, Lda.

4 FCUP – Faculty of Sciences, University of Porto

5 School of Science, University of Waikato, Hamilton, New Zealand

* diana.almeida@ciimar.up.pt

 



Recirculating aquaculture systems (RAS) allow water reuse by managing waste and nutrient recycling, consequently making intensive fish production compatible with environmental sustainability, and improving fish welfare. A key aspect of these systems is the beneficial bacterial community of the biofilter1. In this study we aim to investigate the dynamics of this community in a sole (Solea senegalensis) hatchery RAS and its interactions with physical-chemical parameters.

Samples from different matrices (water, biofilter and tank wall biofilm) were collected from several compartments (Figure 1A) of a commercial hatchery (including the Pre-Ongrowing and Weaning working in RAS regime). Total DNA was isolated from the different matrices and the V4-V5 region of the 16S rRNA gene was sequenced using Illumina MiSeq® platform and analysed in the DADA2 pipeline using the SILVAngs database.

It was found that biofilm samples (both biofilter carriers and tank biofilm) were richer in terms of prokaryotic diversity than water samples. At beta diversity level, the Bray-Curtis dissimilarity index visualized through NMDS (Figure 1B) revealed high prokaryotic community dissimilarity between samples from the Pre-Ongrowing and the Weaning system. Overall, the prokaryotic communities were dominated by Proteobacteria (12-89%) and Bacteroidetes (8-86%) and a total of 58 genera contributed with more than 3% of the relative abundance across the different samples. The most abundant genera were Tenacibaculum, Sulfitobacter, Leucothrix, Novosphingobium, Marinicella, Pseudoalteromonas, Polaribacter_2, Schleiferia and Algibacter. Genera commonly associated with biofiltration activity in RAS2, such as Nitrospira (nitrificaton), Nitrosomonas (nitrification) and Thiothrix (sulfide-dependent autotrophic denitrification) were found in the Pre-Ongrowing and Weaning biofilter, even though they were not the utmost representative genus found in these matrices. With the Adonis test, using the Bray-Curtis dissimilarity index for the distance matrix, it was found that prokaryotic community shifts were modelled by water parameters such as salinity and pH.

Our results demonstrated that the studied RAS sole hatchery was dominated by a highly dynamic prokaryotic community, sensitive to the physical-chemical changes within the different compartments of the same aquaculture unit, developing different community profiles. These are relevant findings for fine tuning when designing modulation protocols, without compromising fish welfare, since the community appears to be sensible to small variations. Future studies are fundamental to identify how the key players in maintaining a healthy RAS system can be used to achieve a healthy prokaryotic community when imbalances or fish disease outbreaks occur.

[1] Martins, C.I.M., Eding, E.H., Verdegem, M.C.J., Heinsbroek, L.T.N., Schneider, O., Blancheton, J.-P., d’Orbcastel, E.R., Verreth, J.A.J., 2010. New developments in recirculating aquaculture systems in Europe: A perspective on environmental sustainability. Aquacultural engineering. 43, 83-93.

[2] Espinal, C.A., Matulić, D., 2019. Recirculating Aquaculture Technologies, Aquaponics Food Production Systems. Springer, pp. 35-76.

The authors acknowledge Fundação para a Ciência e Tecnologia (FCT) for the PhD fellowship ref. PD/BDE/135542/2018 and Safiestela Sustainable Aquafarming Investments, S. A. (SEA8). This research was supported by the project 39948_FeedMi, supported by Portugal and the European Union through FEDER/ERDF, CRESC Algarve 2020 and NORTE 2020, in the framework of Portugal 2020; and by national funds through FCT—Foundation for Science and Technology within the scope of UIDB/04423/2020 and UIDP/04423/2020.