Effects of partial removal of alkaloids in sweet white lupin seed on performance and nitrogen balance in lambs

Abstract

The impact on animal performance of extracting alkaloids in lupin seed (LS) was evaluated with 30 lambs (average weight, 14 kg) fed for 90 d. Sunflower seed (SFS) in the control diet was replaced by intact LS, or LS steeped in water (detoxified) to remove alkaloids. The test diets contained either 15% (LUI- 15) or 30% (LUI-30) intact LS, or 15% (LUD-15) or 30% (LUD-30) detoxified LS. Lambs fed SFS exhibited lower (P < 0.05) organic matter intake (OMI) and daily gains (ADG) than those fed LS. During the first 30 d of feeding, OMI was greater (P< 0.01) with diets containing LUD-15 or LUD-30 (752.7 and 727.9 g d–1, respectively) than with LUI-15 or LUI-30 (708.1 and 600.5 g d–1, respectively); ADG was also greater with LUD-15 and LUD-30 (P < 0.01) than with LUI-15 and LUI-30. Nitrogen retention ranged from 6.1 g d–1 for control to 14.6 g d–1 for LUD-15; when corrected for N intake (NI), N retention was similar (P > 0.05) across diets. This study suggests that alkaloids in LS restricted feed intake and limited ADG, but over the 90-d experimental period, lambs seemed to adapt the presence of alkaloids in LS