Assessment of ileal digestibility of lupin amino acids and their use in formulating diets for pigs

The apparent and true ileal digestibility of protein and amino acids of fiv e yellow lupin cultivars grown in Poland was estimated on growing castrated male pigs. The nitrogen retention was determined on young boars fed a barl ey-yellow lupin diet supplemented with crystalline lysine, methionine and t ryptophan. The apparent ileal digestibility of the seed protein was from 81.9 to 84.9% . There were no significant differences in protein or in amino acid apparen t digestibility among the yellow lupin cultivars. The true ileal digestibil ity of crude protein was from 87.5 to 90.5%. Nitrogen retention was signifi cantly lower (P<0.05) in pigs fed the diet supplemented with amino acids ac cording to pig requirements for total amino acids (methionine constituted 3 6% of the sulphur containing amino acids) than in those fed the same diet b ut with higher methionine content (50% of sulphur containing amino acids) o r the diet supplemented according to the requirements for ileal digestible amino acids.