Introducing Mediterranean Lupins in Lambs' Diets: Effects on Growth and Digestibility

Lupins are suitable candidates to replace soybean meal in livestock feeding in the Mediterranean area, presenting a solution for the European Union's dependence on soybean importations. This study aimed to assess the effect of incorporating Lupinus albus and Lupinus luteus into Churra da Terra Quente lambs' diets on growth performance and digestibility. Two trials were conducted over two years. In trial 1, two experimental diets containing 50 g/kg Lupinus albus and 50 g/kg Lupinus luteus were tested. In trial 2, lambs were fed with diets containing higher incorporations of Lupinus luteus (100, 150, and 200 g/kg: LL10, LL15, and LL20, respectively). Total dry matter, hay dry matter, and crude protein intake were calculated, as well as average daily gains. At the end of the growth trials, dry matter, organic matter, and NDF digestibility was determined. Incorporating 50 g/kg of lupins did not affect (p > 0.05) the performance. Lambs fed on LL20 diets presented the lowest HDMI and CPI values (p < 0.05). The highest intakes (p < 0.05) were observed from LL15 lambs. No differences were found in apparent digestibility coefficients between diets (p > 0.05), except for NDF digestibility which was highest (p < 0.05) for LL20. The optimum level of lupin inclusion in lambs' diets seems to be 150 g/kg.