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Castanea sativa Mill. (Fagaceae) is a deciduous tree grown for its wood and edible fruits. Chestnut processing produces residues (burs, shells, and leaves) exploitable for their diversity in bioactive compounds in animal nutrition. In fact, plant-specialized metabolites likely act as rumen modifiers. Thus, the recovery of residual plant parts as feed ingredients is an evaluable strategy. In this context, European chestnut leaves from northern Germany have been investigated, proving to be a good source of flavonoids as well as gallo- and ellagitannins. To this purpose, an alcoholic extract was obtained and an untargeted profiling carried out, mainly by means of ultra-high-performance liquid chromatography/high-resolution tandem mass spectrometry (UHPLC-HR MS/MS) techniques. To better unravel the polyphenol constituents, fractionation strategies were employed to obtain a lipophilic fraction and a polar one. This latter was highly responsive to total phenolic and flavonoid content analyses, as well as to antiradical (DPPH● and ABTS+●) and reducing activity (PFRAP) assays. The effect of the alcoholic extract and its fractions on rumen liquor was also evaluated in vitro in terms of fermentative parameter changes and impact on methanogenesis. The data acquired confirm that chestnut leaf extract and the fractions therefrom promote an increase in total volatile fatty acids, while decreasing acetate/propionate ratio and CH4 production. [ABSTRACT FROM AUTHOR]

The genus Quercus supplies a large amount of residual material (e.g., bark, acorns, leaves, wood), the valorization of which can favor a supply of antioxidant polyphenols to be used in the pharmaceutical, nutraceutical, or cosmeceutical sector. The recovery of specialized metabolites could also benefit livestock feeding, so much so that polyphenols have gained attention as rumen fermentation modifiers and for mitigating the oxidative imbalance to which farm animals are subject. In this context, leaves of Quercus robur L. from Northern Germany were of interest and the alcoholic extract obtained underwent an untargeted profiling by means of ultra-high-performance liquid chromatography/high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) techniques. As triterpenes and fatty acids occurred, the alcoholic extract fractionation pointed out the obtainment of a polyphenol fraction, broadly constituted by coumaroyl flavonol glycosides and condensed tannins. Total phenol, flavonoid and condensed tannins content assays, as well as antiradical (DPPH● and ABTS+●) and reducing activity (PFRAP) were carried out on the alcoholic extract and its fractions. When the effects on rumen liquor was evaluated in vitro in terms of changes in fermentation characteristics, it was observed that oak leaf extract and its fractions promoted an increase in total volatile fatty acids and differently modulated the relative content of each fatty acid. [ABSTRACT FROM AUTHOR]

In recent years, animal husbandry has aimed at improving the conditions of livestock animals useful for humans to solve environmental and health problems. The formulation of animal feeds or supplements based on antioxidant plant compounds is considered a valuable approach and an alternative for livestock productivity. Forest biomass materials are an underestimated source of polyphenolic compounds whose sustainable recovery could provide direct benefits to animals and, indirectly, human nutrition. In this context, an alcohol extract from leaves of Fagus sylvatica L. was first investigated through an untargeted ultra-high-performance liquid chromatography–high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) approach. Then, it was fractionated into a fatty acid-rich and a polyphenolic fraction, as evidenced by total lipid, phenol, and flavonoid content assays, with antiradical and reducing activity positively correlated to the latter. When tested in vitro with rumen liquor to evaluate changes in the fermentative parameters, a significant detrimental effect was exerted by the lipid-rich fraction, whereas the flavonoid-rich one positively modulated the production of volatile fatty acids (i.e., acetate, butyrate, propionate, etc.). [ABSTRACT FROM AUTHOR]

Abstract The aim of the research was to evaluate the effect of three Eucalyptus globulus extracts rich in phenolic compounds, especially flavonoids, on rumen fermentation, methane (CH4) production, organic matter degradability and protozoa population using an in vitro gas production technique. Four concentrations (0, 50, 75 and 100 mg) of three Eucalyptus extracts (ethyl acetate, n-butanol and aqueous) were added to a diet of ruminants (forage: concentrate ratio 60:40) and incubated at 39°C under anaerobiosis with buffered rumen fluid. After 24 h, the fermentation fluid was analysed for ammonia-N and volatile fatty acids (VFA). Organic matter degradability (OMD) and protozoa were also determined; in vitro gas production was also recorded and CH4 concentration was measured. Compared to the control, CH4 production was significantly lower for ethyl acetate extract (P<0.05), but higher for n-butanol and aqueous extracts. Production of ammonia- N was lower in all Eucalyptus extracts (P<0.05). Propionate production (P<0.05) increased for ethyl acetate and n-butanol extracts, whereas no effect was registered for VFA, for all Eucalyptus extracts. Ethyl acetate extract decreased in vitro OMD (P<0.05), whereas n-butanol and aqueous extracts were comparable to the control. Protozoa population decreased (P<0.05) for all extracts in comparison with the control. Eucalyptus ethyl acetate extract might be promising to be used as a potent anti-methanogenic additive. Moreover, the assessment of the right dosage seems to be important to decrease methane production, without reducing feed nutritional value. [ABSTRACT FROM AUTHOR]