Performance and intestinal responses to dehulling and inclusion level of Australian sweet lupins (Lupinus angustifolius L.) in diets for weaner pigs

A total of 180 entire male weaner pigs weighing 6.4 ± 0.1 kg (mean ± SEM) and housed in pairs was used in a completely randomised block design with 9 dietary treatments (n = 10 pens). Pigs were blocked based on weaning weight. The diets were (i) a wheat-based control diet containing 240 g/kg of milk products (whey and skim milk powder), and (ii) 8 diets containing whole or dehulled lupins (cv. Coromup) that substituted the milk products at 60, 120, 180 and 240 g/kg of diet (replace 25%, 50%, 75%, or 100% of the milk products in the control diets). The diets were isoenergetic [15 MJ digestible energy (DE)/kg], and were formulated to contain the same ileal standardised digestible lysine content (0.85 g/MJ DE) and ideal patterns of other essential amino acids. Pigs receiving 240 g/kg of dehulled lupins grew slower (P<0.05) than pigs fed the other diets mainly due to decreased feed intake. Pigs fed diets containing more than 180 g/kg of dehulled lupins had a higher faecal β-haemolytic Escherichia coli score on day 3 after weaning (P<0.05). Moreover, inclusion of 240 g/kg of whole lupin or more than 180 g/kg of dehulled lupins increased (P<0.001) plasma urea nitrogen (PUN) levels. Total tract apparent digestibility (TTAD) of dry matter decreased (P<0.001) in all lupin diets compared with the control diet. These data indicate that inclusion of dehulled lupin immediately after weaning should be limited to less than 180 g/kg whilst whole lupins can be included up to 240 g/kg without deleterious effects on production and intestinal health.