Effect of solid-state fermented and enzyme-supplemented lupins on performance and ileal amino acid digestibility in broiler chickens

Context. The importance of lupin in animal nutrition has increased over the years due to its moderate protein content and relative availability. Low inclusion rate in broiler diet has been associated with the presence of antinutritional factors. The established beneficial effect of fermentation as a processing strategy and dietary enzyme use in improving the nutritional value of legumes such as lupins, thus, necessitated this study. Aims. This study determined the effect of solid-state fermented lupin (SSFLP) and enzyme-supplemented lupin (LP) on the performance and ileal amino acid digestibility in broiler chickens. Methods. In Experiment 1 (performance trial), a total of 300 day-old Ross 308 male broiler chicks were distributed into six dietary treatments, with five replicates of 10 birds each. Diet 1 was based on a corn-soybean meal (SBM), Diets 2 and 3 contained 250 g/kg LP and 250 g/kg SSFLP respectively. Diet 4 contained 250 g/kg LP + phytase (PHY). Diet 5 contained 250 g/kg LP + xylanase (XYL). Diet 6 contained 250 g/kg LP + PHY + XYL. PHY at 500 phytase units (FTU)/kg and XYL at 1000 units/kg were added to the respective diets. In Experiment 2 (digestibility trial), a total of 240 21-day-old Ross 308 male broiler chicks was assigned to six dietary treatments with five replicate cages of eight birds each. Diet 1 was based on SBM, Diets 2 and 3 contained 650 g/kg LP and 650 g/kg SSFLP respectively. Diet 4 contained 650 g/kg LP + PHY. Diet 5 contained 650 g/kg LP + XYL. Diet 6 contained 650 g/kg LP + PHY + XYL. Key results. Dietary inclusion of SBM and LP + PHY enhanced broiler performance from 1 to 21 days. PHY-supplemented LP diet improved birds' bodyweight gain and feed intake compared with the rest of the LP diets. Dietary inclusion of LP + PHY + XYL improved the apparent ileal digestibility (AID) of some amino acids (AA). SSF of LP had no effect on the AA contents, lowered AA digestibility and depressed weight gain in the birds. Although SSFLP diet did not improve performance, it effectively increased phosphorus (P) retention in broiler chickens. Feeding SSFLP and enzyme-supplemented LP diets enhanced the AID of calcium and P, as well as calcium retention. Conclusions. Adding supplemental PHY to LP diet enhanced broiler performance, as indicated by the BWG and FI of these birds, which were significantly higher than those of birds fed on other LP-based diets and comparable with those of birds fed on the SBM diet from 1 to 21 days. Although the SSFLP diet did not improve broiler performance, it was effective in increasing P retention when compared with LP diets. The inclusion of LP + PHY + XYL diet improved the AID of amino acids.