Seed protein amino acid composition of important local grain legumes Lupinus angustifolius L., Lupinus luteus L., Pisum sativum L. and Vicia faba L.

Summary

Grain legumes are regarded as highly valuable protein source for human and animal nutrition. Legume protein quality is mainly limited by the amino acids (AAs) tryptophan and sulphur AA. Organic farming in particular requires high seed protein quality for livestock feeding, as chemically produced AAs must not be feeded. Breeding attempts to increase contents of limiting AA are required. In the present survey, the AA content of 107 cultivars of important European grain legume species (Lupinus angustifolius, Lupinus luteus, Pisum sativum and Vicia faba) was analysed. AA contents were related to the requirements of growing pigs and human nutrition. Feed quality could be enhanced by choice of high quality varieties according to ideal protein concepts. For example for sulphur, AA feed quality for pigs could be increased by up to 22% (e.g. for L. angustifolius: ideal protein = 100, sample mean = 59.7, sample maximum = 72.7).
Regarding livestock nutrition, ranges of limiting AA never reached the qualities reported for soybean seeds. However, an inclusion of high quality legume lines would reduce the need for other high quality components in feed compositions.