Aquaculture America 2023

February 23 - 26, 2023

New Orleans, Louisiana USA


Sílvia F. S. Pires*, Vitória Pereira, Teresa C. Baptista, Domitília Matias, Pedro Bem-Haja, Rui J.M. Rocha, Amadeu M.V.M. Soares and Andreia C.M. Rodrigues


*CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal



Marine bivalves frequently require depuration before being commercialized alive for human consumption. This process is vital to the food safety of these food items and aims to reduce microbiological fecal contamination (content of Escherichia coli). After depuration, bivalves are packaged and commercialized refrigerated (4 – 6°C). During this food supply chain, bivalves may suffer nutritional loss as they are in starvation. Thus, adding microencapsulated algae-based food during the depuration process can reduce the possible nutritional losses of the organisms, assuring their quality. To evaluate that, clams (Ruditapes philippinarum) depuration was performed for 48h in 250L recirculated tanks, with a filtration system composed of a protein skimmer, a 25W UV-c unit, and a temperature control system (15 ± 1°C). During depuration, one of the groups (Diet) was fed with a microencapsulated diet, incorporating Nannochloropsis sp. in 40µm diameter pellets, after 22h and 46h. The other group, which served as a control (Ctrl), was not fed during the trial. Samples for microbiological analyses and biochemical biomarkers were collected at 24h and 48h depuration periods. Additionally, clams were sampled for biochemical biomarkers 6 days after depuration to evaluate whether food addition during depuration would promote the energy budget of the animals during the posterior shelf-life.

After 24h depuration, the clams fed presented higher values of protein content and, after 48h, presented higher lipid content. Regarding energy consumption, both groups presented similar results. Depuration process significantly decreased E. coli values reducing from 9450 NMP/100g to 490 NMP/100g in the Diet group and 330 NMP/100g in the Ctrl group and, Salmonella sp. was not detected in all groups of clams. Further studies are needed, encompassing different types and concentrations of microalgae in feeds. However, preliminary results indicate that adding food during the depuration process may contribute to maintaining bivalves’ quality and add value to this natural resource.

This work is part of the project DepurD (MAR-01.03.01-FEAMP-0046), supported by Portugal and the European Union through MAR2020, Portugal2020 and FEAMP