A review of the potential of Lathyrus sativus L. and L. cicera L. grain for use as animal feed

The use of two closely related species, Lathyrus cicera and L. sativus, as grain legumes for human and animal consumption, dates to the Neolithic peri od. Due to its tolerance to harsh environmental conditions L. sativus is st ill used widely for human food in Ethiopia and the Indian sub-continent, al though cultivation has diminished in many other regions. The grain of both L. cicera and L. sativus contains a neurotoxin, 3-(-N-oxa lyl)-L-2,3-diamino propionic acid (ODAP), which can cause a paralysis of th e lower limbs (lathyrism). Due to the occurrence of lathyrism in humans rec ent plant breeding has produced cultivars with low ODAP concentrations. The susceptibility of animal species to lathyrism is poorly understood, althou gh horses and young animals are more susceptible. Older published animal fe eding studies are of limited use, since the presence and role of ODAP was u nknown until the 1960s. More recent feeding studies indicate that low ODAP lines of L. cicera or L. sativus can be safely incorporated at inclusion ra tes up to 40, 30 and 70% of the diet of poultry, pigs and sheep, respective ly, without growth reductions. The compositions of both L. cicera and L. sativus are similar to other comm only used feed grain legumes, respective protein contents are 25 and 27%. A ntinutritional factors (ANFs), other than ODAP, are present in both L. cice ra and L. sativus at concentrations similar to those found in other grain l egumes; including trypsin inhibitors, chymotrypsin inhibitors, amylase inhi bitors, lectins, tannins, phytate and oligosaccharides. The effect of ANFs in L. cicera and L. sativus on animal performance is nor well understood an d sometimes confounded with ODAP effects. Heating of grain will reduce leve ls of the proteinaceous ANFs and in some cases ODAP as well. Variation recorded in the germplasm of L. cicera and L. sativus has not bee n greatly utilised in plant breeding to lower levels of ANFs, with the exce ption of ODAP, leaving considerable potential for rapid improvement of cult ivars. L. cicera and L. sativus are low production cost legumes adapted to low rainfall environments and have considerable potential as good quality, cheap protein sources. As world demand for legume feed protein is likely to increase, due to increasing demand for animal food products, both L. cicer a and L. sativus are crops that should be considered in regions with suitab le environments. (C) 2000 Elsevier Science B.V. All rights reserved.