Seasonal Variations in Condensed Tannin Concentration of Three Lotus Species

Abstract

High concentrations of CTs depress voluntary feed intake, digestive efficiency, and animal productivity (Barry Condensed tannins (CTs) are commonly found in herbage of Lotus and Duncan, 1984;Aerts et al., 1999). High CT concenspp. and can have beneficial or detrimental effects on feed value and animal performance. Our objectives were to (i) determine the level tration is also associated with high lignin, low crude of CT concentration and its seasonal variations in three widely grown protein, and low in vitro digestible dry matter (DM) Lotus spp.; (ii) assess the distribution of CTs in leaves, stems, and concentration (Miller and Ehlke, 1994). On the other flowers; and (iii) determine if herbage of greenhouse-grown Lotus hand, low to moderate concentration of CTs have benespp. contains CT concentrations with equivalent rank to field-grown ficial effects on livestock. Condensed tannins reduce plants. Field herbage samples were taken in spring, summer, and bloat and increase protein absorption in grazing rumifall and analyzed for CTs by near infrared reflectance spectroscopy nants (McLeod, 1974). Protein in forage legumes is often (NIRS). Herbage of big trefoil (L. uliginosus Schkur.) germplasm poorly utilized by ruminants because of extensive degra-ARS-1221 and narrowleaf trefoil (L. glaber Mill.) germplasm ARS-1207 had the greatest and lowest CT concentrations averaging 154 dation in the rumen. Condensed tannins facilitate the and 8 g catechin equivalent (CE) kg Ϫ1 dry matter (DM), respectively. bypass of protein that might otherwise be lost through The birdsfoot trefoil (L. corniculatus L.) cultivar ARS-2620 had a microbial deamination in the rumen (Barry et al., 1986; greater CT concentration than 'Norcen', but both had moderate CT Tanner et al., 1994). This bypass is made possible by levels averaging 39 and 23 g CE kg Ϫ1 DM, respectively. Herbage CT reactive components of CTs, which complex with soluconcentration of Norcen, ARS-2620, and ARS-1221 was higher in ble proteins, making them insoluble at rumen pH (pH spring and summer compared with fall while that of ARS-1207 was 5.8-6.8) but soluble and released at the more extreme low in spring, summer, and fall. Generally, stems had less CT than pH conditions found in the abomasum (pH 2.5-3.5) and leaves and flowers, but there was no detectable CTs in stems of ARS-1207. The rankings of the four entries for herbage CT concentration small intestine (pH 7.5-8.5) (Barry and Manley, 1984). in the greenhouse and field were the same. This is the first report of This process increases the absorption of essential amino CT concentrations for the germplasms ARS-1221 and ARS-1207, acids in the small intestine (Waghorn et al., 1987). It has which are suitable candidates for genetic improvement to develop been shown that moderate CT concentrations increased cultivars with desirable CT levels.lactation, wool growth, and live weight gain, without reducing voluntary feed intake (Aerts et al., 1999). Condensed tannins can also improve animal health by over-

Tanniferous forage plants: Agronomic performance, palatability and efficacy against parasitic nematodes in sheep

“…The accumulated experimental evidence for and against the so-called plant defense theory [15][16][17][18] is equivocal 19,20 and its usefulness for the practical application in agronomy disputable 14 . Previous studies of seasonal fluctuations of tannin concentrations in forage plants yielded conflicting results 14,[21][22][23][24] and mechanisms driving seasonal and developmental dynamics of tannin concentrations under field conditions are not yet well understood. Based on an experiment with potted Onobrychis viciifolia and Lotus corniculatus, it has been suggested that fluctuations in condensed tannin concentrations in harvestable aboveground biomass are functions of biomass proportions between tannin-rich leaves and tannin-poor stems in pure stands, and of biomass proportions between tanniferous and non-tanniferous plant species in mixed stands 14 .…”

Forage Yield and Quality of Chicory, Birdsfoot Trefoil, and Alfalfa During the Establishment Year

“…Additionally, condensed tannin concentrations in trefoil were much greater than in the other two forages examined. While tannin levels in trefoil can vary from as low as 23 g kg -1 DM to 110 g kg -1 DM, with concentrations lowest in unstressed, monoculture stands [39,40], variance in tannin levels throughout the growing season is common [41]. The availability of birdsfoot trefoil could provide beneficial nutritional effects because the tannin levels required to control bloat and increase amino acid absorption are 5 g kg -1 DM and 30-40 g kg -1 DM, respectively [42,33].…”

The effects of seasonal climate changes in the caatinga on tannin levels in Myracrodruon urundeuva (Engl.) Fr. All. and Anadenanthera colubrina (Vell.) Brenan

“…Periods of high temperatures are known to increase the concentration of phenolic compounds in many plants. Species of Lotus, for example, demonstrate seasonal variations in tannin concentration (Gebrehiwot et al, 2002), which have been shown to be signifi cantly higher during the spring and summer. The same response was seen with Alnus rubra Bong (González-Hernández et al, 2000).…”