The development of sustainable aquafeed ingredients is key to reduce the current dependence on fishmeal and fish oil, the primary sources of long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA), namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for marine finfish and shrimp aquaculture. Terrestrial plant-based ingredients have emerged as alternatives, yet their lack of n-3 LC-PUFA and potential anti-nutritional factors limit their application in the formulation of aquafeeds. The present study evaluated the ability of the marine gammarid amphipod Gammarus locusta to perform the trophic upgrade of terrestrial plant-based coproducts into EPA and DHA rich amphipod biomass.
Newborn G. locusta were cultured to sexual maturity under the following diets: Ulva sp. (used as control), peas, green beans, and carrot. Fatty acid profiles were determined by gas chromatography–mass spectrometry (GC-MS). Results demonstrated that the fatty acid composition of G. locusta fed Ulva displayed the highest levels of EPA, although this n-3 LC-PUFA was absent from its diet. Amphipods supplied with terrestrial plant diets were able to perform their trophic upgrade, by presenting EPA and DHA in their fatty acid profile, although these biomolecules were absent from their diet. These results highlight the ability of G. locusta to biosynthesize these n-3 LC-PUFA de novo.
Further studies are need to shed light on the ability of G. locusta and other marine gammarid amphipods to trophically upgrade low-cost terrestrial diets into high-value biomass rich in n-3 LC-PUFA. Subsequently, the scaling up of their production using low-cost farming protocols must also be investigated, making possible to offer n-3 LC-PUFA amphipod biomass as a sustainable ingredient for the formulation of aquafeeds for marine species.
This study was performed under project “BLUE BIOECONOMY PACT” (Project Nº. C644915664-00000026), co-funded by the Next Generation EU European Fund, under the incentive line “Agendas for Business Innovation” within Component 5—Capitalization and Business Innovation of the Portuguese Recovery and Resilience Plan (RRP), as well as project “PUFAPODS Merging blue and green food systems - Using marine gammarid amphipods supplied with plant food processing side streams to produce n-3 LC-PUFA” which is supported by FCT/MEC https://doi.org/10.54499/LA/P/0094/2020).