Effect of ensiling moist field bean (Vicia faba), pea (Pisum sativum) and lupine (Lupinus spp.) grains on the contents of alkaloids, oligosaccharides and tannins

Abstract

Ensiling legume grain may be an inexpensive and ecologically interesting method to produce a high-protein feed of local origin. The typically patchy maturation recommends harvesting and ensiling the seeds in moist condition. Developing a method for preserving legume grains harvested before maturation by lactic acid fermentation would have several advantages. Under laboratory conditions, crushed legume seeds of beans, peas and lupines with high moisture content of 35 % were ensiled with different additives (molasses and lactic acid bacteria). To characterize the final silages, contents of proximate nutrients and antinutritional factors (alkaloids, oligosaccharides, tannins) were analysed. The addition of lactic acid bacteria ensured a fast and pronounced lactic acid production and decreased contents of undesired fermentation products like ethanol. An additional use of molasses for ensilage did not provide a remarkable additional benefit. Excluding sugar and starch, the contents of proximate nutrients were not remarkably altered after ensiling. As an overall effect, lactic acid fermentation reduced tannins and oligosaccharides. It can be supposed that the oligosaccharides after breakdown of the complex molecules acted as a source of fermentable carbohydrates. A relevant reduction of alkaloids did not occur. The lactic acid fermentation of legume grains can be recommended as an appropriate method for conservation. With respect to the economic advantages and compared with methods of chemical preservation, the lactic acid fermentation of legume grains under anaerobic conditions is an environmentally compliant procedure and therefore also an option for organic farming.

Scientific opinion on the risks for animal and human health related to the presence of quinolizidine alkaloids in feed and food, in particular in lupins and lupin‐derived products

“…Gefrom et al. () have studied the effect of ensiling on the concentration of QAs in crushed lupin seeds. A sweet (Bora) and a bitter (Azuro) cultivar of L. angustifolius were harvested at 65% dry matter content and four different kinds of model silages were prepared.…”

Lupin as a perspective protein plant for animal and human nutrition – a review

“…grains on the contents of alkaloids, oligosaccharides and tannins was studied by Gefrom et al (2013). As an overall effect, lactic acid fermentation reduced the content of tannins and oligosaccharides.…”

Nutrient and plant secondary compound composition and iron‐binding capacity in leaves and green stems of commonly used plant browse (Carolina willow; Salix caroliniana) fed to zoo‐managed browsing herbivores

“…For example, ensiling Cotswold Common, Reznos, and Teruel sainfoin ( Onobrychis viciifolia ) resulted in a reduction of extractable tannins compared to fresh plant material [Lorenz et al, ]. Alipour and Rouzbehan [] and Gefrom et al [] also found that the ensiling process reduced tannins in ensiled legume grain and grape pomace. The reduction in tannins during ensiling seems to be a function of chopping, storage time, and anaerobic conditions possibly as a result of enzymatic and/or oxidative reactions [Makkar and Singh, ; Ben Salem et al, ; Alipour and Rouzbehan, ].…”