Alkaloids
The bitter earlier varieties of lupins contained a toxic alkaloid and were not recommended for animal feeding unless the alkaloid was removed by soaking in water. The newly obtained sweet alkaloid-free varieties, which can be distinguished by taste and smaller growth, are palatable to stock. The seeds of modern cultivars of narrow-leaf lupin normally contain less than 0.03% alkaloids (Petterson et al., 1987). A study assessing 329 accessions of the Polish blue lupin (Lupinus angustifolius) collection of wild types and cultivars reported levels below 0.01% of seed dry weight in cultivars (Kamel et al., 2016).
Oligosaccharides
Lupin seeds are known to contain significant levels (from 4 to 20%) of oligosaccharides of the raffinose family that may impair intestinal function and cause flatulence (Pisarikova et al., 2009; Saini, 1989). In blue lupin seeds, alpha-galactoside level was reported to be about 60 g/kg DM or 40.8-73.5 g/kg OM (Roth-Maier et al., 2004; Gdala et al., 1997). Oligosaccharide level is variable and may depend on the variety but also on the conditions of cultivation and harvest (Pisarikova et al., 2009).