The aim of this paper was to study a method based on gas production technique to measure the biological effects of tannins on rumen fermentation. Six feeds were used as fermentation substrates in a semi-automated gas method: feed A - aroeira (Astronium urundeuva); feed B - jurema preta (Mimosa hostilis), feed C - sorghum grains (Sorghum bicolor); feed D - Tifton-85 (Cynodon sp.); and two others prepared mixing 450 g sorghum leaves, 450 g concentrate (maize and soybean meal) and 100 g either of acacia (Acacia mearnsii) tannin extract (feed E) or quebracho (Schinopsis lorentzii) tannin extract (feed F) per kg (w:w). Three assays were carried out to standardize the bioassay for tannins. The first assay compared two binding agents (polyethylene glycol - PEG - and polyvinyl polypirrolidone - PVPP) to attenuate the tannin effects. The complex formed by PEG and tannins showed to be more stable than PVPP and tannins. Then, in the second assay, PEG was used as binding agent, and this assay was done to evaluate levels of PEG (0, 500, 750, 1000 and 1250 mg/g DM) to minimize the tannin effect. All the tested levels of PEG produced a response to evaluate tannin effects but the best response was for dose of 1000 mg/g DM. Using this dose of PEG, the final assay was carried out to test three compounds (tannic acid...
The aim of this work was to study the effect of condensed tannins (CT) on the kinetic of gas production in vitro, on the three main species of Azorean pasture: Trifolium repens, Lotus corniculatus and Lolium perenne, using Quebracho extract as the source of CT, and also to calculate total tannins and condensed tannins on the species studied. Lotus corniculatus, Lolium perenne and Trifolium repens were tested in vitro with the inclusion of Quebracho extract in doses of 0%, 2.5% and 5% DM. The total content in tannins was determined in the 3 species. We have found, in comparison with standard tannic acid, that tannins exist in the flower of T. repens (0.81 equivalents of tannic acid) and in L .corniculatus (1.07 equivalents of tannic acid) but not in L .perenne (0 equivalents of tannic acid). The concentration of condensed tannins in the 3 species was: 0.34 mg/mL for T. repens; 0.83 mg/mL for L. corniculatus and 0 mg/ml for L. perenne. We verified that a significant reduction (P < 0.05) of gas production happened for doses of 5% of CT in comparison with the other two concentrations: 0% and 2.5% of CT. The results of this study express a reduction of the fermentation rate, which implies a reduction of gas production, so, a reduction of methane emission to the atmosphere and an increase of exploitation of the protein by ruminants.
Proanthocyanidins from P. contorta leaves and from a commercial quebracho extract were isolated and characterized. Flavonoids, catechins and gallic acid were also identified in the extracts of P. contorta. Compounds were evaluated for their antioxidant properties and for their antiviral activity against an acyclovir-resistant herpes simplex virus type 1 strain. The low molecular weight phenolic derivatives and the proanthocyanidins from P. contorta showed the highest antioxidant activity. Purified proanthocyanidins from both P. contorta and quebracho showed the same maximum non toxic concentrations (25 µg/mL), with 82.2% and 100% of virus inhibition, respectively.
10 pages, 2 tables.; Previously published as proceeding at the XXXIII Jornadas de Estudio AIDA (IX Jornadas sobre Producción Animal). ITEA Vol. Extra 22 (Zaragoza, Spain, Apr 25-27, 2001). https://digital.csic.es/handle/10261/13887; Nine rumen fistulated ewes fed lucerne hay were intra-ruminally dosed for a period of 51 days with 0 (Q0), 35 (Q1) and 70 (Q2) g of quebracho condensed tannin (CT) extract/kg feed daily. Lucerne hay in situ DM, N and NDF 24 h disappearance were significantly lower (P<0.05) in those sheep dosed with the highest level of quebracho extract (Q2) compared with the other two groups (Q0 and Q1). The rumen ammonia-N concentration was also lower in groups treated with quebracho. Neither of the doses affected in vivo DM, NDF or ADF digestibility. However, both reduced apparent CP digestibility (P<0.01). Faecal analyses showed a 30% recovery of the administered CT, regardless of the dose (P>0.10). There were no signs of intoxication by tannins in any of the treatments.; Supported by the Inter-Ministerial Commission of Science and Technology (CICYT) of Spain, ProjectAGF98-0874.; Peer reviewed
This work was carried out with the aim of studying the effect of the administration of commercial quebracho extract
(76% condensed tannins, CT) to sheep, for 70 days. Ten ruminally cannulated ewes were distributed into two experimental
groups (control and quebracho). Zero (placebo) or 0.75 g of quebracho tannins extract per kg of live weight
and day were intra-ruminally administered to the animals. The nylon bag technique was used to examine alfalfa hay
in situ dry matter (DM), nitrogen (N) and neutral-detergent fiber (NDF) disappearances. In vivo digestibility, pH and
ammonia-N and volatile fatty acid (VFA) concentrations were also measured. The daily ruminal administration of quebracho
extract did not affect rumen fermentation parameters such as pH and ammonia-N and VFA concentrations, but
reduced significantly the alfalfa hay DM potentially degradable fraction and the fractional rate of N degradation. Only
on day 8 of the experiment were the DM and NDF disappearance values, after 24 h of in situ incubation, significantly
lower in the animals treated with quebracho. No differences were observed on any other day of the experiment. Furthermore,
the quebracho CT extract significantly decreased the in vivo digestibility of the following diet components:
11 pages, 4 figures, 3 tables.-- PMID: 12859907 [PubMed].-- Printed version published Jul 2003.; This experiment was carried out to study the toxicity of quebracho tannin extract (containing 760 g of condensed tannins [CTs] per kg), with the aim of validating its use as a feed additive for improving the digestive utilization of protein-rich feeds. Four groups (Q(0), Q(1), Q(2) and Q(3)) of four sheep were dosed intra-ruminally once daily, for up to 21 days with, respectively, 0, 0.5, 1.5 or 3.0 g quebracho tannin extract/kg live-weight (LW). Feed intake, live-weight changes, plasma biochemistry, indicators of hepatic detoxification function, gross lesions and histopathology were examined. Animals in groups Q(0), Q(1) and Q(2) consumed all the offered feed. In contrast, feed intake was practically nil after 6 days of quebracho dosing in group Q(3), this being associated with a loss of 4.7+/-1.30 kg LW in 10 days (P<0.05). Sheep from groups Q(0), Q(1) and Q(2) remained healthy throughout the experiment. Ewes from group Q(3) became weak and depressed on day 5 and after 8 days of dosing remained recumbent. They were humanely killed after 10 days to avoid suffering. In general, neither gross lesions nor microscopical changes were observed in animals from groups Q(0)...
14 pages, 1 figure, 5 tables.-- Available online Aug 23, 2003.; Previously published as proceeding at the XXXIII Jornadas de Estudio AIDA (IX Jornadas sobre Producción Animal). ITEA Vol. Extra 22 (Zaragoza, Spain, Apr 25-27, 2001). https://digital.csic.es/handle/10261/14343; Sixteen Merino ewes, fitted with ruminal cannulae, were divided into four groups of four, with the aim of studying effects of different doses of quebracho tannins on rumen fermentation in sheep. Zero (control, Q0), 0.5 (Q1), 1.5 (Q2) and 3.0 g (Q3) of quebracho tannins extract (containing 76% condensed tannins (CTs)) per kg LW per day (equivalent to 0, 28, 83 and 166 g/kg DM (dry matter) feed, respectively) were intra-ruminally administered, for up to 21 days. The rumen in sacco technique was used to examine in situ DM, crude protein (CP), neutral-detergent fibre (NDF) and acid-detergent fibre (ADF) disappearances, and a gas production method was used to examine rate and extent of in vitro gas production and in vitro dry matter disappearance (ivDMD). Alfalfa hay (AH), barley straw (BS) and Erica arborea (EA) were used in all the incubations. In vivo pH and ammonia-N and volatile fatty acid concentrations were also measured. Ewes from groups Q0, Q1 and Q2 remained healthy throughout the experiment and consumed the entire ration offered. However...
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Publicado em 01/06/2002EN
Relevância na Pesquisa
Ziziphus mistol Griseb. (Rhamnaceae) trees are avoided by the leaf-cutting ant Acromyrmex striatus Roger (Formicidae, Attini) in a semi-arid Chaco forest of Santiago del Estero Province, Argentina. In order to find out the chemical fraction responsible of ant rejection, we analyzed putative chemical defenses (tannins, phenolics and saponins) in young and mature leaves of Ziziphus mistol and carried out field bioassays to test both polar and non-polar leaf extracts for ant-repellence. We included into our bioassays two flavonoid compounds, namely quercetin and its glycoside rutin, which are common in Ziziphus mistol leaves, and commercial quebracho tannin. Condensed tannins and total phenols were significantly in higher concentrations in mature than in young leaves. We were unable to detect hydrolyzable tannins on both young and mature leaves. Saponins were only detected in young leaves. The non-polar extract was significantly repellent, whereas the polar extract was not significantly attractive. Tannin, quercetin and rutin did not exhibit significant attractiveness or repellence at the tested concentrations. Our results suggest that some unidentified constituent(s) of the non-polar fraction of the foliar extract, likely of terpenoid nature...