Lupin Seed for the Crop-Livestock Food Chain

The ban on animal protein supplements in animal nutrition and, particularly, the increase in the demand for alternative protein sources to replace soybean meal in organic farming has stimulated research on GM-free feeds and renewed interest in grain legumes. Of these lupin appears to be one of the more interesting and promising crops for ruminant diets, due to its key role in low-input cropping systems and its high protein content. The aim of this study was to evaluate the productive and nutritional characteristics of several sweet varieties of lupin seeds cultivated in the Mediterranean region. The trial was carried out during the years 2007/08 on a volcanic soil in East Sicily, employing 8 sweet cultivars belonging to Lupinus albus, L. angustifolius and L. luteus species. Yield and its components (pod plant-1, seed pod-1, 1000 seed weight) were evaluated. Crude protein, fibre fractions and alkaloid content were also determined. L. albus exhibited the highest yields (2.2 t ha-1), with an intermediate value of pod x plant (15.4). L. luteus yielded 1.5 t ha-1 and L. angustifolius 0.5 t ha-1. L. luteus showed higher levels of crude protein (34.2%) although the greatest protein yield per hectare was recorded in L. albus (0.7 t ha-1). L. angustifolius showed the highest mean values of NDF (28.1%) and ADF (25%), whereas L. luteus the lowest mean values of ADL (1.75%). Six alkaloids were detected and quantified, among which, the Iso-lupanine always was the most abundant (1.5 mg 100g-1, on average). Lower concentrations of quinolizidine were observed in L. luteus (0.9 – 1.4 mg 100g-1) as compared with L. angustifolius (1.5 – 5.5 mg 100g-1) and L. albus (3.8 – 7.5 mg 100g-1). Alkaloid content was always lower than the safe limit of toxicity (< 0.20‰) indicated for human and animal consumption.