The production of fat palmipeds is a poultry activity which is based on the observation of the natural phenomenon of fat accumulation in the liver of migratory birds. The production of foie gras is an ancestral form of production which began over 4,500 years ago in Egypt.
Only a few strains, or lines, of palmipeds selected are capable of producing foie gras, the Cairina moschata and the Cairina moschata x Anas platyrhynchos. In addition, palmipeds have specific anatomical characteristics (possible alignment of the beak and neck thanks to the absence of cartilaginous glottis, elasticity of the walls of the esophagus, etc.), which enable them to swallow rapidly large quantities of food, such as large fish and frogs, and which predispose them to fattening during the production of foie gras.
Thus, in the European Union, the rearing method used in the production of foie gras is based on two successive phases:
During this phase the palmipeds systematically have access to open-air runs.
In order to prepare the animals for fattening, a transition phase enables the animals to get used to eat meals, thereby developing their suitability for fattening.
What is "assisted feeding"?
Once they have been prepared, the adult animals are placed in specialised installations to be fattened. “Assisted feeding” consists in feeding them with know-how and dexterity by qualified professionals.
Palmipeds are big eaters, at certain periods they have a tendency to eat more than necessary.
Like numerous birds, they have a beak, a gullet and esophagus which expand to swallow all kinds of prey, as can be observed in the natural world.
Only healthy adult ducks and geese (from 10 to 15 weeks), after a period of ad-libitum feeding, will receive twice every 24 hours, during approximately 12 days for ducks and 16 days for geese, a progressive ration which consists of filling their crop. Various scientific studies have demonstrated that ”gavage” does not stress the palmipeds as they gradually get used to receiving the food that gives them a feeling of satiety. This phase represents 10% of the animal’s rearing cycle.
Species reared to produce foie gras
Barbary duck – Grey goose – Mulard duck
Fattening is a reversible phenomenon
After fattening, when a duck or a goose is returned to its meadow, its liver returns to its initial weight in a matter of days, without any alteration of its physiological functions.
This reversibility of fattening* is identical to the natural process when a bird (duck, goose) has exhausted its fat reserves after a long migratory journey.
* study on reversibility – Professors P. Benard, G. BENARD, T. Bengone, D. Prehn, J. Tanguy, R. Babilé, F. Grimm - ENSA, Env – Toulouse 1994-1999
Steatosis = fattening of the liver = breakdown of sugars into fatty acids = integrity of the liver cells is preserved.
Cirrhosis = breakdown of sugars into alcohol = pathology.