Feed intake in chickens : do not forget short-term regulation

Abstract

Nutritional programs are usually based on a daily schedule, whereas different phenomena related to feed intake come into play on shorter timescales. Feed intake is regulated in the long-term at the central level through feedback from peripheral tissues, enabling energy balance, and also protein homeostasis and homoeothermia. The short-term regulation of feed intake is linked to the necessity to limit the quantity of feed and to provide regular supplies of energy and nutrients. In poultry, it is probably effective in less than one hour and involves signals from the gastro-intestinal tract acting on the central nervous system. Sensorial cues induce very rapid responses (<min). These include visual and tactile abilities, which are particularly important in poultry to appreciate feed. Feeding behaviour depends on the interaction of these different perceptions and also on the animal's experience. Poultry can learn in different ways, by associating different physical cues and/or post-intake feed effects. This information is stored in the long-term memory and reused by animals, enabling them to anticipate feed effects which they have learned to identify. This learning allows poultry to better adapt to their environment by improving their ability to choose, thus influencing feed intake regulation. Taking account of poultry feeding preferences and learning abilities is an ambitious challenge for nutritionists.