Relationship between β-Nitropropionic Acid Content of Crownvetch and Toxicity in Nonruminant Animals

Abstract

Crownvetch forage has been reported to contain a toxic constituent, β-nitropropionic acid (BNPA). Feeding trials were conducted to establish the effects of feeding crownvetch forage containing BNPA to weanling meadow voles, chicks, and young pigs. Various degrees of toxicity were observed in all animals when the diet contained ⩾.15% BNPA, either as naturally occurring BNPA in crownvetch forage or as commercially purified BNPA added to the diet. The first indication of toxicity was a 60 to 70% reduction in feed intake, accompanied by reduced weight gains or weight loss and the onset of abnormal behavioral symptoms. The main symptom was ataxia and the severely affected animals often died. The study with young pigs substantiated that reduced feed intake was not the cause of the abnormal behavioral symptoms. These experiments demonstrate that crownvetch forage is toxic to young growing nonruminant animals and that the toxic response is associated with the concentration of BNPA in the forage. On the basis of these findings, crownvetch forage should not be used as a component of nonruminant diets unless the BNPA concentration is extremely low. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science.