Dr. Walter Arnold (University of Vienna) and colleagues were interested in studying how Northern ungulates cope (physiologically) with limited food supplies during the winter months. Ungulates are known to reduce energy expenditure during the winter. A new study published Wednesday in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology describes how these animals adjust their nutritional intake. Dr. Arnold's team examined intestinal transport of peptides and glucose in red deer (Cervus elaphus). Interestingly, although animals were provided food ad libitum, the total energy intake and visceral organ masses were lower during the winter and the animals were using fat reserves for metabolic fuel. The research team also found that nutrients were absorbed significantly more efficiently as evidenced by higher extraction of proteins from the forage (determined by less protein in the feces). In addition, intestinal transport of peptides and glucose were upregulated during the winter to help the animals compensate for reduced food availability. These results suggest that the decreased appetite of the animals (evidenced by reduced food intake even with freely available food) may be a means to conserve energy by reducing time spent foraging in the wild.
Arnold W, Beiglböck C, Burmester M, Guschlbauer M, Lengauer A, Schröder B, Rosmarie Wilkens M, Breves G. Contrary seasonal changes of rates of nutrient uptake, organ mass, and voluntary food intake in red deer (Cervus elaphus). American Journal of Physiology - Regulatory, Integrative and Comparative Physiology. Published 27 May 2015, DOI: 10.1152/ajpregu.00084.2015