PhD in Fish Nutrition

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INRAE presentation

The French National Research Institute for Agriculture, Food, and Environment (INRAE) is a major player in research and innovation. It is a community of 12,000 people with 272 research, experimental research, and support units located in 18 regional centres throughout France. Internationally, INRAE is among the top research organisations in the agricultural and food sciences, plant and animal sciences, as well as in ecology and environmental science. It is the world’s leading research organisation specialising in agriculture, food and the environment. INRAE’s goal is to be a key player in the transitions necessary to address major global challenges. Faced with a growing world population, climate change, resource scarcity, and declining biodiversity, the Institute has a major role to play in building solutions and supporting the necessary acceleration of agricultural, food and environmental transitions.

Work environment, missions and activities

The work will be carried out at UMR 1419 NuMéA  (Nutrition, Metabolism, Aquaculture), located in Saint-Pée-sur-Nivelle (France), and at the Donzacq experimental fish farm, where the experiments related to the PhD project will take place. This PhD is part of the European project EUAqua.org, which aims to transform European organic aquaculture through innovative and sustainable farming strategies. The project seeks to enhance the resilience, health, and environmental sustainability of farmed fish while meeting consumer expectations for high-quality, organic, and eco-friendly seafood.

Within this framework, the PhD project focuses on developing organic aquaculture feeds that are less dependent on fishmeal and fish oil. The successful candidate will be supervised by researchers from UMR NuMéA and will engage with various academic and industry partners in the aquafeed sector.

The position is a full-time 36-month PhD contract, focused on the development and nutritional evaluation of innovative organic aquaculture feeds.

Background of the PhD Project

Organic aquaculture still heavily relies on fishmeal and fish oil sourced from industrial fisheries, which poses a significant challenge to its sustainable development. According to European regulations, up to 60% of the ingredients in organic feeds may be of plant origin. In practice, however, most available organic feeds are still predominantly based on marine-derived raw materials. This dependence is mainly due to the limited availability of protein-rich, organically certified plant ingredients, as well as the regulatory ban on using synthetic amino acids to balance fish diets.

Moreover, current nutritional requirements for fish have been established under optimal experimental conditions using diets primarily based on casein as a protein source. These conditions do not accurately reflect real farming practices. Lowering protein intake may serve as a strategy to reduce fishmeal use in organic farming. New organic-certified ingredients are now also available, such as protein concentrates from peas, fababeans, rapeseed, soy, and sunflower. Additionally, yeast extracts rich in proteins and bioactive compounds are already approved for organic feed use and have shown benefits for fish growth and intestinal and immune health.

It is therefore essential to explore new feed formulation strategies that combine protein intake reduction and diversification of feed resources to significantly reduce reliance on marine ingredients while maintaining high zootechnical performance and ensuring fish health and robustness. Such an approach is key to developing a more sustainable, competitive organic aquaculture model that aligns with environmental and societal expectations.

Research Program

The PhD project will involve three experimental phases:

Step 1: Do current conventional and organic feeds differ in performance?

Experiment 1: Comparative performance evaluation of conventional and organic diets in juvenile rainbow trout.

In France, organic feed use in rainbow trout farming remains limited, making it difficult to assess the effectiveness of these diets. This experiment aims to compare the performance of juvenile trout fed a conventional commercial diet (with 17–20% fishmeal and 10–12% fish oil) and an organic feed composed of approximately 60% fishmeal and 25% fish oil from sustainable sources.

Step 2: Can fishmeal and fish oil levels in organic feeds be reduced by lowering overall protein levels and using organic plant proteins and a protein-rich yeast extract?

Experiment 2: Formulation and evaluation of novel organic feeds with reduced fishmeal and fish oil content.

This step aims to test the feasibility of reducing marine ingredients in rainbow trout feeds while complying with organic regulations. New sustainable diets will be formulated with varying protein levels. A key strategy will be incorporating a high-protein (>60%) certified organic yeast extract, currently being developed by Lallemand—a global leader in yeast, bacteria, and functional ingredient production.

To meet energy requirements, certified organic oils (e.g., rapeseed, soybean) will be used when possible. However, fish oil will still be included to ensure adequate levels of essential long-chain n-3 polyunsaturated fatty acids (EPA and DHA).

These diets will be tested with and without supplementation of essential amino acids (methionine and lysine) to assess the impact of potential imbalances. Previous research suggests that crystalline amino acids may interfere with absorption and bioavailability, potentially affecting protein synthesis. Special attention will be paid to dietary amino acid profiles and their effects on amino acid transporter gene expression and activation of related signalling pathways.

Step 3: Does the SUAVE rainbow trout line perform better than the control line when fed the improved organic feed?

 

Experiment 3: Evaluation of the SUAVE genetic line versus a control line using the best-performing sustainable organic diet from Step 2.

In the final phase, the most promising feed formulation from Step 2 will be tested on the SUAVE rainbow trout line and its control line. Initially selected by INRAE for enhanced use of plant-based diets, SUAVE fish have shown improved growth regardless of feed composition. This experiment will determine whether this line offers additional benefits when fed the new sustainable organic diet.

Additional Information

Experimental feeds will be formulated using Allix software under the supervision of lab engineers and a feed formulator from the Le Gouessant cooperative. Trials will be conducted at the Donzacq experimental fish farm.

The PhD candidate will be responsible for collecting and analyzing zootechnical data, conducting biochemical analyses to assess fish body composition, and investigating physiological responses related to metabolism and immunity. This will primarily involve molecular analyses such as PCR and Western blotting.

Product quality assessments, contaminant analyses, and fillet shelf-life evaluations will be carried out in collaboration with other research units. All necessary equipment is available at the lab, and the work is fully funded by the EUAqua.org project.

Training and skills

Recommended education:  Master’s degree (MSc) in Biology, Aquaculture, Animal Nutrition, or Agricultural Engineering.

Areas of expertise required (relevant fields) : Nutrition, Fish Physiology, Animal Experimentation, Biochemical and/or Molecular Analyses.

Required skills : Enthusiasm and curiosity, autonomy, scientific rigor, good interpersonal skills, organizational ability and teamwork, interest in experimental work, good use of statistics, and scientific writing skills in both French and English.

INRAE's life quality

By joining our teams, you benefit from (depending on the type of contract and its duration):

- up to 30 days of annual leave + 15 days "Reduction of Working Time" (for a full time);
- parenting support: CESU childcare, leisure services;
- skills development systems: training, career advise;
- social support: advice and listening, social assistance and loans;
- holiday and leisure services: holiday vouchers, accommodation at preferential rates;
- sports and cultural activities;
- collective catering.

How to apply

I send my CV and my motivation letter