Perinatal epigenetic temperature adaptation in avian species: Comparison of turkey and muscovy duck

1. Heat production (HP) and body core temperature (CT) where measured in 1- to 10-day old Muscovy ducklings and turkey chick, incubated during the last week before hatching at a lower (34.5 degreesC, LT-group) or at higher (38.5 degreesC, HT-group), than the normal temperature of 37.5 degreesC (control C-group). 2. In Muscovy ducklings, on the 1st day post-hatching HP was affected by exposure to low T-a of 10 degreesC T-a 28.2 +/- 3.9 W kg(-1) in the LT-group vs. 18.1 +/- 2.4 W kg(-1) in normal controls. On the same day, CT was higher (39.5 +/- 1.1 degreesC) in the HT- than in the CT-group (37.5 +/- 2.9 degreesC). 3. In turkeys, the relationships between T,, and HP could be described by parabola-like functions. Apart from the first day of life, the HP of the LT-group and the HT-group was higher than of the CT-group. 4. The low prenatal temperature of incubation resulted in a decrease of the preferred temperature in the LH-group and in an increase in the HT-group. 5. It is concluded that changes in incubation temperature at the end of embryonic development may induce an epigenetic temperature adaptation, which results in a long-lasting cold- and warm-adaptation in ducks but not in turkeys. (C) 2004 Elsevier Ltd. All rights reserved.