Polyphenolic composition of a permanent pasture: variations related to the period of harvesting

Abstract

Phenolics contribute to the micronutrient composition of forages, which in turn may affect animal product composition. To assess the importance of these compounds, the polyphenolic and botanical composition of a permanent mountain pasture in the Massif Central (France) were studied at three stages of growth. Phenolic fractions (acids, flavonoids and total) were analysed using HPLC and specific colorimetric methods over the whole pasture and in nine main species. On a botanical level, 43 species including 31 dicotyledons composed a mountain variant of Cynosurion grouping. Over time, the species growing on the field changed, the main plants being Festuca nigrescens and eight dicotyledons. In whole pasture, about 170 different compounds were separated by HPLC, of which only 30 were common to all stages. The total polyphenolic content was estimated as 31, 32 and 19 g kg −1 DM for the three stages. They were mainly composed of dihydroxycinnamic derivatives (3,5-di-O-caffeoylquinic, chlorogenic, 1,5-di-O-caffeoylquinic acids), and of flavonoids in lesser proportions. Some polyphenols were peculiar to a few species and others were ubiquitous. The two major dicaffeoylquinic acids were identified for the first time in Achillea millefolium and Knautia arvernensis. Colorimetric measurements of phenolic fractions were in good agreement with HPLC analysis (P < 0.01) for all species studied. Thus, on the mountain pasture studied, a cow would be expected to ingest up to 500 g of polyphenols daily, which could affect the quality of animal products.

Effects of species-diverse high-alpine forage on in vitro ruminal fermentation when used as donor cow's feed or directly incubated

“…Both alpine forage sources were characterized by an elevated content of PSC, as indicated here by TEP, as had been expected from the literature (Jeangros et al, 1999;Fraisse et al, 2007). Purified PSC or plant extracts and plants rich in PSC have been occasionally demonstrated to alter ruminal fermentation processes in vitro in the short term (Makkar et al, 1995;Patra et al, 2006;Soliva et al, 2008;Jayanegara et al, 2011b).…”

Variation in fatty acid composition of milk and cheese from cows grazed on two alpine pastures

“…On the contrary, milk and cheese FA compositions, showing very similar results as expected, were influenced by the type of vegetation and the period of exploitation due to the evolution of plant phenological stage and chemical composition over time, as expressed by DM, CP, and ADL content (Tab. II), and by literature data on PSM [22,23,38]. Changes in milk FA composition were likely not only to be affected by animal lactation stage [36,40], but were also affected by changes in forage chemical composition [20].…”

“…Paddock F vegetation had a higher specific contribution of PSM-rich species than T (42-46% vs. 29-27%) because of the abundance of species from the Compositae, Rosaceae, Polygonaceae, and Fabaceae families, all generally rich in either volatiles [38] or polyphenols [23,31]. Paddock T vegetation was dominated by Trifolium alpinum, a species from the Fabaceae family known to be rich in polyphenols [39].…”

“…Then, each group moved to experimental paddocks where cows grazed for another 6 days (P1, d [7][8][9][10][11][12]. At the end of Period 1, following a cross-over design, the two groups were crossed (G1 to T paddocks and G2 to F paddocks) and two pairs of new paddocks were exploited according to the same scheme (A2, d 13-18 and P2, d [19][20][21][22][23][24].…”

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

“…in total phenols (Broudiscou et al, 2000;Fraisse et al, 2007;Kälber et al, 2011). Common buckwheat (Fagopyrum esculentum) is a dicotyledonous crop plant growing in temperate regions which contains comparably high concentrations of phenolic compounds (Hinneburg and Neubert, 2005).…”