Diet choice and nutrition of captive snowshoe hares (Lepus americanus): Interactions of energy, protein, and plant secondary compounds

Abstract

:We examined consumption and digestibility of winter browse in captive snowshoe hares (Lepus americanus Erxl.) to determine how energy content, protein quality and plant secondary chemicals interact to affect their diet choice and nutrition. We found that preferred foods of snowshoe hares have higher apparent digestibilities of dry matter and energy than nonpreferred foods. Digested crude protein was unaffected by increased consumption of preferred foods, but declined when hares consumed nonpreferred foods. Rate of weight loss in hares increased with increasing consumption of nonpreferred twigs. Hares did not compensate for low protein or low energy content by eating more twigs. Weight changes were correlated with the energy content of the food and its digestibility, whereas consumption was correlated with phenol and protein content. If hares can increase consumption of preferred foods, they may simultaneously meet both their energy and protein requirements. If they are obliged to increase consumption of nonpreferred foods, then protein requirements may never be met due to the effects of secondary compounds. During periods of limited food availability, snowshoe hares should select a mixed diet that may include small quantities of poor-quality food items, regardless of preference, allowing them time to find good-quality foods.