PhD Regulation of food intake in mule ducks: Nutritional and environmental strategies

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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

You will carry out your research within the Joint Research Unit for Nutrition, Metabolism, and Aquaculture (UMR 1419 NuMeA) at the IUT des Pays de l’Adour in Mont-de-Marsan. Regular travel to the Saint-Pée-sur-Nivelle site will be required.

Thesis Project Summary

This project is part of the search for novel dietary strategies and aims to propose a solution to improve animal welfare. By investigating alternative methods to force-feeding, it explores ways to guide ducks toward voluntary hyperphagia (the voluntary ingestion of large amounts of feed). Our recent studies have allowed us to identify, for the first time in this species, the key players involved in the regulation of feed intake, ranging from nutrient detection to the induced signaling pathways and brain integration (Lasserre et al., 2026; doi.org/10.1016/j.psj.2026.107070). We now wish to monitor these key players under various conditions in order to identify a strategy that will ultimately allow us to guide ducks toward this target behavior of voluntary hyperphagia.

The main challenge we face with ducks is their ability to regulate their intake based on dietary energy, which leads to a rapid adjustment of their feed intake. Therefore, within the framework of this project, we aim to test three distinct levers hypothesized to influence their feed intake: 1-the metabolizable energy of the diet; 2-the addition of palatability enhancers (appetizers); and 3-intermittent lighting. For each parameter, we expect to detect favorable periods for re-feeding by monitoring the expression of the various markers involved in the regulation of feed intake.

This project does not aim to directly induce hepatic steatosis (fatty liver), but primarily to identify the levers that will allow us to modulate feed intake. It is part of a fundamental research approach, supported by physiological experiments, whose main objective is to finely understand the regulatory mechanisms of feed intake in mule ducks.

Work Programme

In order to understand how to encourage ducks to consume feed "even when they are not hungry," you will be required to conduct three experiments on mule ducks at the INRAE AVIPOLE 0089 facility (Artiguères): 

1. Testing the impact of dietary metabolizable energy (ME): three low-ME diets (-10%, -20%, and -30%) will be compared to a control diet (12.5 MJ/kg) and a high-ME diet (+10%).
2. Adding a functional palatability enhancer: using the high-ME diet (+10%), you will test three doses of capsaicin (5, 150, and 300 ppm) compared to the control diet without capsaicin.
3. Modulating the day/night cycle: Using the most consumed diet (determined from the results of experiments 1 and 2), you will test an intermittent lighting program with a cycle of 1h Light / 3h Dark (repeated: 1h L, 3h D, 1h L, 3h D, 1h L, 3h D, 1h L, 3h D, 2h L, 6h D) compared to a control group under continuous lighting (16h light / 8h dark).

Methodologies: for each experiment, the following procedures will be conducted:

1. Zootechnical and analytical measurements: Live weight gain, liver weight gain, and daily feed consumption will be recorded. Additionally, we will analyze liver energy composition (glycogen, triglycerides TG), molecular data (expression of genes involved in the development of hepatic steatosis), and plasma parameters (glucose, TG, free fatty acids FFA).
2. Evaluation of key players involved in feed intake regulation: You will evaluate changes in the expression of players involved in feed intake at both the gene and protein levels within gustatory and brain tissues. This will include looking at sensory receptors, the calcium signaling pathway, lingual serotonin, and the expression kinetics of orexigenic and anorexigenic neuropeptides. You will also monitor neurotransmitters linked to the hunger/satiety cycle and associated reward pathways (dopamine, serotonin, GABA, glutamate). Finally, circulating plasma hormones related to feed intake will be assayed (chemerin, ghrelin, CCK).

These analyses will be carried out at the NuMeA laboratory in Mont-de-Marsan (plasma and biochemical assays, gene expression) or in Saint-Pée-sur-Nivelle (protein analysis via HPLC-FL). Immunohistochemical analyses in collaboration with the PRC laboratory in Tours are also envisioned.

Ultimately, this project aims to determine whether these three levers can successfully modulate the duck's feed intake to guide it toward voluntary hyperphagia and potentially promote spontaneous fattening.

Specific working conditions: a driver's license and a vehicle are highly recommended, as experiments will take place at the Avipole facility in Artiguères, which is a 15-minute drive from the laboratory.

Training and skills

Recommended training : Master’s degree or Engineering degree in biology or agronomy (5 years of higher education / MSc level).

Desired knowledge : Strong background in nutritional physiology and feeding behavior; proficiency in biochemical analysis techniques, molecular biology (qRT-PCR), and Western Blot; proficiency in statistical analysis techniques; interest in conducting experiments on the animal model; interest in the poultry sector, animal husbandry, and animal welfare.

Appreciated experience : Experience or knowledge of the species or the poultry sector would be an asset.

Skills : Team player, autonomous, involved in laboratory maintenance and sampling.

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

Please submit a cover letter, a CV, and the contact details of a reference person in a single PDF file.