Digestibility of Lupinus albus lupin meals in barramundi (Lates calcarifer)

This study examined the digestible dry matter, protein and energy value of lupin kernel meals from three cultivars (Kiev mutant, Andromeda and WALAB2014) of the white lupin (Lupinus albus) and one Australian sweet lupin (Lupinus angustifolius cv. Myallie) when fed to barramundi (Lates calcarifer). Apparent digestibility coefficients were determined using the diet-substitution method with faeces being collected from the fish using stripping techniques. The three L. albus cultivar kernel meals were richer in protein (482–502 g/kg DM) and lipid (82–86 g/kg DM) than the L. angustifolius (383 and 54 g/kg DM respectively). The digestibility of the L. albus protein was consistently high for all three cultivars and not significantly higher than the Myallie (0.969). The energy digestibility of the Kiev mutant (0.677) was similar to that of Myallie (0.511), but the Andromeda (0.793) and WALAB2014 (0.752) were both significantly higher than the Myallie. These differences are reflected in the digestible crude protein (DCP) and digestible energy (DE) content of the meals with Myallie providing only 371 g DCP/kg DM and 10.5 MJ DE/kg DM, while the L. albus cultivars contain between 482 and 502 g DCP/kg DM and 15–17.5 MJ DE/kg DM.

► The digestibilities of white lupin (Lupinus albus) meals were studied in barramundi. ► Kernel meals of L. albus were richer in protein and lipid than the L. angustifolius. ► Protein digestibility was consistently high for cultivars of L. albus kernel meals. ► Energy digestibility of the L. albus was higher than that of other lupin meals.