Effect of differing proportions of protein-rich common vetch seeds (Vicia sativa L. cultivar Slovena) in organic diets for broiler chickens

Abstract The common vetch is a legume with low requirements for soil type and water availability and a good weed suppression together with an intercropping partner, thereby recommending itself for organic agriculture, especially in view of climate change. The use of the protein-rich seeds of common vetch for poultry, however, is limited due to anti-nutritional factors (ANF). This study was conducted to examine the use of common vetch seeds (cultivar: Slovena) in 100% organic diets for slow-growing broiler chickens. The common vetch seeds were found to be rich in protein and lysine (343 and 21.5 g/kg dry matter), and their vicine (5.69 g), convicine (0.75 g) and γ-glutamyl-β-cyanoalanine (6.9 g) levels were at the lower range of previous reports, while tannin levels (8.1 g total tannins/kg dry matter) were at the higher end. A vetch-free control and experimental diets containing 75, 100 and 125 g common vetch seeds/kg of diet were fed during the grower (day 29–49) and finisher (day 50–70) period of two consecutive fattening periods, to a total of 8 groups of 20 mixed-sex broilers per treatment. No differences in feed intake, animal performance and welfare status were found, therefore including up to 125 g common vetch seeds/kg of diet can be recommended. Based on a comparison of the ANF contents with previous reports, higher inclusion rates should be possible, as negative effects can be expected at 350 g common vetch seeds/kg of diet, which is higher than necessary in diet formulation anyway.