ruminant

lupin seed

protein

amino acid

nutritive value

The chemical composition, amino acid profiles, protein and amino acid ruminal and intestinal digestion and nutritive value of lupin seeds produced from yellow (Lupinus luteus L.) cv. Popiel, white (L. albus L.) cv. Bac, Bardo, and narrow-leaved (L. angustifolium L.) cv. Emir, Mirela, Sur, species were estimated. The seeds contained (per kg of dry matter) 307-442 g crude protein, 0.7-8.05 g of alkaloid, 16.3-20.6 MJ, 1.04-1.42 UFV, 68-85 g PDI, 207-283 g PDIN, 136-146 g PDIE. The seed protein included an average of 0.6-0.8 g/16 g N of methionine and 4.6 of lysine. The coefficients of effective rumen degradability of seed protein ranged from 0.82 (average for yellow and white lupin) to 0.75 (for cv. Sur of narrow-leaved lupin). The rumen degradable protein comprised 61% easily soluble protein and 30-39% slowly degradable protein (7.9% h^-1). The intestinal digestion coefficient of rumen-undegraded protein averaged 0.94. Methionine and lysine tended to be less digestible in the postruminal part of the alimentary tract than other amino acids.