Improvement of robustness and performance in meat-type chickens and ducks by short-term temperature training in the hatcher
The thermoregulatory system plays a central role in various body functions of the organism. It not only keeps the body temperature on an optimum level but also interacts with feed intake, growth rate, immune and stress responses. Perinatal temperature training (PTT) with short-term warm loads (+ 1°C, maximum 2 hrs/day) from day 18 until hatching, has shown long lasting effects on different traits. PTT decreased oxygen consumption during final embryonic development, improved hatching performance, changed the secondary sex ratio in favor to male chickens, and improved performance during the post-hatching growing phase by better weight gain and feed conversion. Improvement of hatching results and post-hatching performance was found in small and large scale experiments. Further, long-lasting changes in physiological parameters (HLR, metabolic hormones T3/T4) indicate better stress response through PTT. Similar results have been found in ducks with short-term cold training. It is assumed that PTT during the last days of hatching reduces the metabolic rate. Hence, the birds have more energy available for performance as well as for adaptation, immune and stress responses during environmental challenges. In conclusion, PTT improves robustness and production efficiency. It is a practicable epigenetic tool, in chickens and ducks which enables realization of the genetic determined performance. Through better adaptation to changing environmental conditions PTT also contributes to the bird`s welfare.