Use of velvet beans, Mucuna spp., as a feed ingredient for poultry: a review

Abstract

Velvet beans (Mucuna spp.) represent a group of legumes that was widely grown in the U.S. in the 1800′s and early 1900′s before being replaced by soybeans. However today, in developing countries, the velvet bean plant is increasingly used as a cover crop because it has many valuable characteristics, such as resistance to insects, weeds and drought that make it economically useful to subsistence farmers. The velvet bean plant is also prolific in seed production, and velvet bean seeds (VB) or Mucuna are sometimes eaten both by humans and other non-ruminant, monogastric animals such as chickens and pigs. Mucuna beans contain moderate amounts of protein (20–25 %) and smaller amounts of fat (3–5 %). Non-structural carbohydrates make up approximately half of Mucuna while the neutral detergent fibre content is about 10%. Minerals and vitamins in VB can contribute significantly to the needs of poultry as is typical of many legumes. The various species of Mucuna have amino acid profiles similar to other legumes, such as soybeans, that are commonly used as protein-supplying feedstuffs. However, VB contain a variety of anti-nutritional/toxic factors that are harmful to monogastric animals. These include: antitrypsin factors; tannins; cyanide; anticoagulants; analgesic, antipyretic and anti-inflammatory factors; L-dopa and others. Research to date has studied the physiological effects of VB on poultry growth, blood chemistry and organ anatomy. Attempts have been made to process the beans and remove the toxic factors by heating, water extraction or other methods but with limited success. To use such a potentially valuable feed ingredient in poultry nutrition, the challenge for the nutritionist is to find ways to diminish the harmful effects of the chemicals in Mucuna by processing or treating the beans to remove or render harmless the toxic chemicals. This review will summarize the history of these efforts.