Proximate and amino acid composition of seeds of Canavalia ensiformis.Toxicity of the kernel fraction for chicks

Abstract

A proximate analysis of Canavalia ensiformis seeds (CE) appears sto be very similar to that of Faba bean seeds. The crude protein content (31.3% dry matter, DM) of CE should be corrected for its content of a non-nutritional amino acid, canavanin (3.6% DM). The usable nitrogen sources in CE represent approximately 24% DM. CE has relatively low content of lysine as compared to other legume seeds. Stasrch (35.7% DM) is the main source of energy. Whole seeds contain 20.1% DM of water-insoluble cell wall and 1.6% DM of water-soluble non-starch polysaccharides. About half of these 2 fibre fractions come from the testa. Condensed tannins are only present as traces in CE. The effects of testa and kernel fractions and whole seed, equivalent to 30% CE in nutritionally balanced diets, were measured on food intake and growth reactions of 1 day-old and 15-22 day old chicks. Testa appeared to be devoid of sizeable toxic activity under the present conditions, while kernel and whole seed strongly depressed both parameters: growth was stopped and food intake was decreased by 70%. An early food intake reaction (less thasn 4 h) of the birds was noted and suggested to be an interesting signal of the toxicity of CE.