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

SIMPLE SUMMARY: Finding alternative protein sources has been one of the most important issues in the animal nutrition field in the last decades. Due to its chemical composition and previously reported positive results on lambs’ performance and digestibility, lupins were the main focus of this study. Data were collected from two distinct trials with seven different diets tested in total. The chemical composition of the raw materials was analyzed, as well as total dry matter, hay dry matter, and crude protein intake. Lambs’ growth was accompanied throughout the trials and their performance was measured. Dry matter, organic matter, and NDF digestibility of each diet was also determined. Low incorporations of lupins had no impact on performance and digestibility of any of the studied fractions. The highest tested incorporation had a negative impact on the overall values of feed intake and the NDF digestibility. The results of this study suggest that low inclusions might have no impact on lambs’ growth, intake, and digestibility. ABSTRACT: 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.