Can voles (Microtus pennsylvanicus) be poisoned by secondary metabolites of commonly eaten foods?

Abstract

Five of the plant species most commonly eaten by meadow voles (Microtus pennsylvanicus) were tested for toxicity in laboratory conditions. These were timothy (Phleum pratense), bromegrass (Bromus inermis), reed phalaris grass (Phalaris arundinacea), white clover (Trifolium repens), and field horsetail (Equisetum arvense). Diets consisted of Purina Rabbit Lab Chow coated with increasing quantities of plant extracts. All but one diet in this study had no effect on growth or on liver and kidneys weights. The highest dose of reed phalaris grass forage (second growth) increased liver weight significantly, but such concentrations do not correspond to those in the diet of Microtus in nature. Therefore, we conclude that none of the plants tested can be considered to be toxic to voles. Our discussion stresses the importance of plant secondary metabolites particularly when voles are stressed by a nutritional imbalance.