Digestibility and Nitrogen Balance of Non Conventional Protein Sources Fed to Pigs of Two Different Genotypes

European livestock production depends, to a large extent, on soya bean meal import. Due to this fact, economic incentives are supplied to produce alternative protein and oil crops (solvent-extracted meals have, in fact, a high protein content). Furthermore, since the most soya bean is genetically modified, concerns regarding the inclusion of soya bean in feed formulation may arise, especially in the case of typical and organic chains. Apart from soya bean, the most common protein crops suitable for animal feeding are field pea (Pisum sativum), lupin (Lupinus luteus, albus, angustifolius) and sunflower (Helianthus annuus). In Italy, as well as in other Mediterranean countries, the production of these vegetables has recently grown together with the cultivation of crops that are particularly apt to dry/hot climate, such as field beans (Vicia faba) and grass pea (Lathyrus sativus). These non-conventional vegetable protein sources, which can be easily produced in non-intensive areas, could hold particular interest for outdoor-reared pigs, including animals raised under organic conditions and belonging to autochthonous breeds. Nevertheless, legume seeds often contain several anti-nutritional factors (ANFs) that could interfere in the digestive process of dietary components. In order to study the digestibility and the nitrogen balance of diets containing different vegetable protein sources totally replacing soya bean meal in pig formulations, two consecutive trials have been carried out. The following raw ingredients were tested: field bean meal (Vicia faba), field pea meal (Pisum sativum), sunflower cake (Helianthus annuus), common bean meal (Phaseolus vulgaris), grass pea meal (Lathyrus sativus) and soybean cake (Glycine max). The diets were fed to growing-fattening pigs either belonging to a “conventional” (Duroc* Large White) or a local Italian breed (Cinta Senese) and kept in digestibility cages. As expected, the local breed showed a lower nitrogen retention than the “conventional” one, while fibre digestibility was generally higher in autochthonous pigs. From our results it can be concluded that, regardless of genotype (either “conventional” or local breed), field bean meal, field pea meal, sunflower cake, grass pea meal, and soya bean cake, but not common bean meal, can be effectively included in growing-fattening swine formulations.