The influence of alpha-galactosidase supplementation on the ileal digestibility of lupin seed carbohydrates and dietary protein in young pigs

Eighteen cannulated piglets were used in two experiments (six in Experiment 1 and 12 in Experiment 2) to determine the effect of supplementation of the diet with microbial alpha-galactosidase on the ileal digestibility of the raffinose family oligosaccharides and other nutrients of lupin-based diets, Three semi-purified diets with the seed meal of yellow lupin (Lupinus luteus L.) cvs June and Amulet or narrow-leafed lupin (Lupinus angustifolius) cv Saturn were offered to pigs with or without the enzyme supplementation (5 g kg(-1)). About 80% of the alpha-galactosides were digested up to the end of the small intestine of pigs (Experiment 1) fed on the diet with cv June without the enzyme supplementation. When alpha-galactosidase was added to the diet, digestibility of alpha-galactosides significantly increased to 97%. Results of Experiment 2 showed that the ileal digestibility of sucrose (92.9%), stachyose (71.9%) and verbascose (83.4%) of narrow-leafed lupin cv Saturn was higher than the corresponding values for yellow lupin cv Amulet (86.3, 60.1 and 77.8%). The ileal digestibility of raffinose was 52.2% for cv Saturn and 40.7% for cv Amulet. The ileal digestibility of total non-starch polysaccharides (NSP) was 11% for cv Amulet and 14% for cv Saturn. alpha-Galactosidase supplementation significantly improved the digestibility of the raffinose series oligosaccharides and positively affected the ileal digestibility of most amino acids (P < 0.05). (C) 1997 Elsevier Science B.V.