Going to sleep with a full belly: Thermal substitution by specific dynamic action in shorebirds.

Going to sleep with a full belly: Thermal substitution by specific dynamic action in shorebirds. Comp Biochem Physiol A Mol Integr Physiol. 2020 Mar 17;:110689 Authors: González-Medina E, Cabello-Vergel J, Playà-Montmany N, Villegas A, Parejo M, Abad-Gómez JM, Sánchez-Guzmán JM, Masero JA Abstract Many bird species occupy habitats where environmental temperatures fall well below their thermoneutral zone (TNZ), so they must deal with high energy costs of thermoregulation to keep in heat balance. In such circumstances, specific dynamic action (SDA) - also referred to as heat increment of feeding - could be used to substitute for these high thermoregulatory costs. If birds ingest food before going to roost in cold environments, the SDA will be beneficial as an energy-conserving mechanism by thermal substitution. We investigated the magnitude and duration of SDA in a small-sized shorebird, the dunlin Calidris alpina, while feeding on living prey. We simulated in the aviary the food availability of a semidiurnal tidal cycle, and calculated the thermal substitution by SDA below their TNZ at the beginning of the "high tide" (resting period), after feeding ad libitum during the "low tide" (feeding period). Within TNZ (25 °C), dunlins consumed 12% (2.15 kJ) of the gross energy intake in excess by the SDA, with a duration of ~95 min. At 10 °C, i.e. below the lower critical limit of TNZ, SDA magnitude and duration were reduced by...
Source: Comparative Biochemistry and Physiology. Part A, Molecular and integrative physiology. - Category: Physiology Authors: Tags: Comp Biochem Physiol A Mol Integr Physiol Source Type: research