THERMOCHICK

Meat-type chickens have long been selected on growth performance traits. However, the significant improvement in chicken body weight and muscle growth has not been associated with similar growth of specific visceral organs such as heart and lungs. The consequence of such a discrepancy is a reduced ability to cope with extreme environmental temperatures. In the context of global warming and increasing development of intensive poultry production in countries submitted to hot climates, the reduction of feed intake and growth reported under warm conditions in fast-growing genotypes induces significant financial loss for poultry producers. In France, hot spells of 2003 resulted in the death of several millions of meat-type chickens. In order to improve bird thermotolerance and welfare without impairing growth, a new method of early heat-conditioning of eggs or chicks is reported to improve chicken thermotolerance later during the growth period. In the context of the search for new technical breeding systems better adapted to global warming, understanding the mechanisms of early-thermal conditioning and exploring their consequences for thermotolerance, growth and carcass quality meets both scientific and applied objectives. The aim of the project THERMOCHICK is therefore to determine the effects of heat-conditioning during embryogenesis and early post-hatch period on acquisition of thermotolerance and on mechanisms involved in muscle energy and protein metabolism affecting heat production. The associated effects on growth performances, oxidative stress and meat quality traits will also be considered, as well as the in vitro hormonal regulation of the mechanisms involved in heat-conditioning. The use of pedigree population of chickens will also allow determining the genetic parameters of physiological markers of thermotolerance to evaluate their potential interest for further genetic selection to improve thermotolerance in chicken. The project THERMOCHICK gathers the skills of four young researchers in protein and energy metabolism, muscle cell biology and knowledge of genetics × environment interactions in order to study the mechanisms controlling early heat-conditioning in chickens. Their laboratory, INRA Poultry Research Unit (URA), has now acquired an internationally-recognized expertise on early thermal conditioning, which constitutes a very promising technique for poultry production.