Influence of different morphological parts of buckwheat (Fagopyrum esculentum) and its major secondary metabolite rutin on rumen fermentation in vitro

Abstract

It was hypothesized that buckwheat, especially its flowers, influences foregut fermentation in ruminant animals because it is rich in phenolic compounds. The entire fresh aerial buckwheat herb, or its parts (leaves, stems, flowers and grain), were incubated for 24 h together with pure ryegrass (1:1, dry matter basis) in an in vitro ruminal fermentation system (Hohenheim Gas Test). Additionally ryegrass, supplemented with 0, 0.5, 5, or 50 mg rutin trihydrate/g dry matter, was incubated. Contents of extractable phenols (g/kg dry matter) were the highest in buckwheat flowers (88), followed by leaves (63), and the lowest in ryegrass (8). The levels of production of total gas and volatile fatty acids demonstrated that the nutritional value of buckwheat was slightly lower than that of ryegrass. Compared to ryegrass alone, ruminal transformation of dietary protein-N <br />into ammonia was lower with 50 mg rutin, buckwheat flowers and buckwheat leaves. Thus, these treatments appeared to have partly protected dietary protein from ruminal degradation. Rutin, at the highest level, buckwheat flowers and the total aerial fraction of the buckwheat plant suppressed methane per unit of total gas by > 10%, either at elevated (rutin) or reduced total gas volume. This indicates that the ways of the influence on the ruminal fermentation pattern differed between pure rutin and buckwheat. In vivo studies have to confirm these potentially beneficial effects of buckwheat if used as forage for ruminants and clarify the role of further phenolic compounds present in buckwheat. Abbreviations: DM = dry matter, HGT = Hohenheim Gas Test, NDF = neutral detergent fibre, TEP = total extractable phenols, VFA = volatile fatty acids

Identification of polyphenolic compounds and determination of antioxidant activity in extracts and infusions of buckwheat leaves

“…In our study, the average content of digestible carbohydrates was 26.83/100 g. Dogra [19] reported the content of these compounds in leaves in the range of 34.8-42.4/100 g. The average content dietary fibre in assessed strains was in the range 36.01-39.22/100 g. The results obtained in this study are similar to the data published by Dogra [19]. The lower content of fibre (18.4/100 g) was found in leaves of buckwheat by Leiber et al [24]. Leaves contained higher amount of dietary fibre in comparison to the seeds (dehulled and whole seeds).…”

Ruminal degradation of quercetin and its influence on fermentation in ruminants

“…It has to be kept in mind, however, that effects caused using quercetincontaining plant extracts cannot be clearly attributed to a particular compound because of their variable and not clearly defined polyphenolic content. Nevertheless, Lourenço et al (2008) and Leiber et al (2012) showed an increase of VFA concentration even with the pure forms of quercetin and rutin. Thus, Leiber et al (2012), who also used hay as substrate, showed that the addition of rutin (5 and 500 μmol of quercetin equivalents/L) led to a stimulation of gas production whereby the proportion of CH 4 production decreased relative to CO 2 production.…”

“…Hence, application of quercetin in ruminants would only be acceptable if positive effects dominate possible negative effects. Several in vitro studies have already investigated the influence of quercetin or quercetincontaining plant extracts, respectively, on microbial fermentation (Broudiscou et al, , 2002Bodas et al, 2008;Leiber et al, 2012). Those studies, however, yielded inconsistent results.…”

Anthocyane als Marker zur Selektion von Buchweizenpflanzen mit hohem Rutingehalt

“…The incorporation of buckwheat in wheat flour allowed enhancing the antioxidant properties and functional components of wheat bread. It has also been suggested that the bioactive compounds from these plants play an important role in in vitro foregut fermentation in ruminant animals (Leiber et al 2012). Therefore to select buckwheat species and cultivars with high phenolic content or find a way to increase the production of phenolic compounds in the different cultivars of buckwheat-regarding needs of agriculture and functional food industry-is a topic issue.…”