Funder and dates: BBSRC (BB/L000288/1) Nov 2013 - ongoing
Collaborators/partners: SRUC, Roslin Institute
Broiler breeder chickens are food restricted to ensure good reproduction and health, but the resulting hunger is a welfare problem. Restriction of energy intake and growth by providing more of a lower energy density food (e.g. high dietary fibre) might reduce hunger. To determine this requires a better understanding of how the brain integrates information about the energy content and other aspects affecting satiety such as gut fill, and how this affects behaviour and feeding motivation.
The arcuate nucleus of the hypothalamus is key to the regulation of energy intake: AGRP mRNA is an integrated measure of hunger being responsive i) to both short and long term aspects of food intake, and ii) to manipulations of energy density. In a series of experiments, we will measure different variables relating to hunger in the same birds: i) home pen behaviour ii) foraging motivation by imposing a natural cost (of walking through water) on access to a foraging area without food (which avoids altering the hunger state). iii) expression of AGRP and related neuropeptides and receptors (POMC, CCKAR) iv) expression of gut hormone genes (CCK, Ghrelin, MCH, GLP-1).
The principal benefit from this research will be a greater understanding of how diluting diets with fibre can improve welfare by producing satiety or a feeling of fullness. The project will deliver validated behavioural and physiological measurements of hunger and greater understanding of the way in which satiety and hunger in birds are controlled. We expect that by the end of the project we will have a clear assessment of whether fibre dilution does produce a signature of satiety in the brain and if commercially relevant diets can improve welfare. This will aid the poultry industry in identifying diets which enhance satiety and would represent a step towards solving the broiler breeder paradox.