ABSTRACT:The aim of our study was to assess the nutritional value of whole and dehulled ground seeds of Lupinus albus L., cv. Butan by the determination of balance digestibility of nutrients in growing pigs at different levels of replacement of soy protein with lupine. The experiment was performed on 25 pigs of hybrid combination Pietrain × (Duroc × Large White × Landrace) with initial body weights of 30.7 ± 2.21 kg. The feed compound of the control group contained extracted soybean meal (ESM). In four experimental diets, 50% and 100% replacement of soy protein with the inclusion of whole (WL 50, WL 100) or dehulled (DL 50, DL 100) lupine was carried out. Nutrient and amino acid digestibility was determined using the indicator of insoluble ash in 4M HCl in pigs with a mean live body weight of 48.9 ± 3.51 kg . Higher digestibility of crude protein (P < 0.01), ether extract (P < 0.01), crude fibre (P < 0.01), NDF, ADF (P < 0.05), and cellulose (P < 0.05) was found for the diet WL 50 compared with the control group ESM. In the diet DL 50, higher digestibility of crude protein, ether extract, crude fibre, NDF, and cellulose (P < 0.01) was recorded compared with the control. Higher digestibility of lysine and threonine (P < 0.01) was found in the diet WL 50 in comparison with ESM; a lower digestibility of methionine (P < 0.01) was found in the diet DL 50. Lower digestibility of crude protein, NDF, ADF (P < 0.01), and cellulose (P < 0.01) was found at 100% supplementation of soy protein with whole seed lupine (WL 100) compared to the control. A 100% replacement of soy protein with dehulled lupine (DL 100) resulted in significantly higher digestibility of dry matter (P < 0.01), crude protein (P < 0.05), ether extract (P < 0.01), crude fibre (P < 0.01), N-FE (P < 0.01), organic matter (P < 0.01), NDF (P < 0.01), ADF, and cellulose (P < 0.01) compared with the control diet. In this case, digestibility of threonine (P < 0.01) and lysine was higher, that of methionine was lower. The highest concentration and daily output of diaminopimelic acid (DAPA) were observed in the diet WL 100. Daily gains in live body weight were nonsignificantly higher in all experimental animals compared with the controls, the most beneficial conversion being a 100% replacement of soy protein with dehulled lupine (DL 100).Keywords: lupine; dehulled; nutrients; amino acids; digestibility; diaminopimelic acid; growth Supported by the Ministry of Agriculture of the Czech Republic (Grants No. QG 60142 and No. MZE 0002716201).Lupine is rated as being among eight potential sources of plant protein for the production of feeds and foods (Dijkstra et al., 2003). The seeds of sweet lupine cultivars (Lupinus albus, L. angustifolius, L. luteus) contain 28 to 48% crude protein in dry matter depending on lupine cultivar and climatic conditions (Sousa et al., 1996;Linnemann and Dijkstra, 2002). The amino acid profile is characterized by a lower level of sulphur containing amino acids and threonine in comparison with soybean (Simon and Jeroch, 1999); in contrast...