Quebracho Tannin Extract Research Articles

Effect of dietary Quebracho tannin extract on feed intake, digestibility, excretion of urinary purine derivatives and milk production in dairy cows

ABSTRACTThe aim of this study was to evaluate the effects of dietary Quebracho tannin extract (QTE) on feed intake, apparent total tract digestibility (ATTD), excretion of urinary purine derivatives (PD) and milk composition and yield in dairy cows. Fifty Holstein cows were divided into two groups. To reach a similar performance of both groups, cows were divided according to their milk yield, body weight, days in milk and number of lactations at the start of the experiment averaging 33.2 ± 8.2 kg/d, 637 ± 58 kg, 114 ± 73 d and 2.3 ± 1.6 lactations, respectively. The cows were fed a basal diet as total mixed ration containing on dry matter (DM) basis 34% grass silage, 32% maize silage and 34% concentrate feeds. Three dietary treatments were tested, the control (CON, basal diet without QTE), QTE15 (basal diet with QTE at 15 g/kg DM) and QTE30 (basal diet with QTE at 30 g/kg DM). Two treatments were arranged along six periods each 21 d (13 d adaptation phase and 8 d sampling phase). The ATTD of DM and organic matter were reduced only in Diet QTE30, whereas both QTE treatments reduced ATTD of fibre and nitrogen (N), indicating that QTE impaired rumen fermentation. Nevertheless, feed intake was unaffected by QTE. In Diet CON, urinary N excretion accounted for 29.8% of N intake and decreased in treatments QTE15 and QTE30 to 27.5% and 17.9%, respectively. Daily faecal N excretion increased in treatments CON, QTE15 and QTE30 from 211 to 237 and 273 g/d, respectively, which amounted to 39.0%, 42.4% and 51.7% of the N intake, respectively. Hence, QTE shifted N excretion from urine to faeces, whereas the proportion of ingested N appearing in milk was not affected by QTE (average 30.7% of N intake). Daily PD excretion as indicator for microbial crude protein (CP) flow at the duodenum decreased in treatment QTE30 compared with Diet CON from 413 to 280 mmol/d. The ratios of total PD to creatinine suggest that urinary PD excretion was already lower when feeding Diet QTE15. While there was no effect of Diet QTE15, treatment QTE30 reduced milk yield, milk fat and protein. Both QTE treatments reduced milk urea concentration, which suggest that ruminal degradation of dietary CP was reduced. In summary, adding QTE at dosages of 15 and 30 g/kg DM to diets of lactating dairy cows to improve feed and protein use efficiency is not recommended.

Effects of quebracho tannin extract (Schinopsis balansae Engl.) and activated charcoal on nitrogen balance, rumen microbial protein synthesis and faecal composition of growing Boer goats

ABSTRACTUnder irrigated arid conditions, organic fertiliser rich in slowly decomposable nitrogen (N) and carbon (C) is needed for soil fertility maintenance. Feeding ruminants with condensed tannins will lower ruminal protein degradation, reduce urinary N excretion and might increase the faecal fraction of slowly decomposable N. Supplementation with activated charcoal (AC) might enrich manure with slowly degrading C. Therefore, we investigated the effects of feeding quebracho tannin extract (QTE) and AC on the N balance of goats, the efficiency of microbial protein synthesis in the rumen (EMPS) and the composition of faeces. The feeding trial comprised three periods; in each period, 12 male Boer goats (28 ± 3.9 kg live weight) were assigned to six treatments: a Control diet (per kg diet 500 g grass hay and 500 g concentrate) and to further five treatments the Control diet was supplemented with QTE (20 g and 40 g/kg; diets QTE2 and QTE4, respectively), with AC (15 g and 30 g/kg, diets AC1.5 and AC3.0, respectively) and a mixture of QTE (20 g/kg) plus AC (15 g/kg) (diet QTEAC). In addition to the N balance, EMPS was calculated from daily excretions of purine derivatives, and the composition of faecal N was determined. There was no effect of QTE and AC supplementation on the intake of organic matter (OM), N and fibre, but apparent total tract digestibility of OM was reduced (p = 0.035). Feeding QTE induced a shift in N excretion from urine to faeces (p ≤ 0.001) without altering N retention. Total N excretion tended to decrease with QTE treatments (p = 0.053), but EMPS was not different between treatments. Faecal C excretion was higher in QTE and AC treatments (p = 0.001) compared with the Control, while the composition of faecal N differed only in concentration of undigested dietary N (p = 0.001). The results demonstrate that QTE can be included into diets of goats up to 40 g/kg, without affecting N utilisation, but simultaneously increasing the excretion of slowly decomposable N and C fractions. Feeding AC up to 30 g/kg of the diet increases slowly degradable faecal C concentration, without negative effects on N metabolism of goats.

Effects of quebracho tannin extract on rumen fermentation and yield and composition of microbial mass in heifers.

To determine the effects of incremental quebracho tannin extract (QTE) infusions on rumen fermentation and yield and composition of microbial mass, a study was conducted that consisted of 1 control period (Control I) without QTE dosing; 4 periods when all animals received 1, 2, 4, or 6% QTE of the diet (DM basis); and a second control period (Control II). Each period consisted of 9 d of adaptation, 6 d of urine collection, and 1 d of rumen sampling. Three rumen-fistulated heifers (495 kg BW [SE 14]) were offered 2.6 kg/d grass hay, 2.6 kg/d concentrates, and 60 g/d mineral-vitamin premix (as fed) in 2 equal meals. Half the daily QTE dosage was intraruminally administered at every meal. Urine and rumen fluids were analyzed for purine derivatives and short-chain fatty acids, respectively. Nitrogen and purine base (PB) concentrations were determined in liquid-associated microbes in rumen fluid (LAMF), liquid-associated microbes in the solid phase (LAMS), and particle-associated microbes (PAM). Increasing QTE dosages linearly increased propionate and butyrate proportions in rumen fluid ( = 0.37, = 0.004 and = 0.51, < 0.001, respectively). Instead, proportions of acetate ( = 0.75, < 0.001), isobutyrate ( = 0.66, < 0.001), and isovalerate ( = 0.49, < 0.001) and urinary purine derivatives excretions ( = 0.66, < 0.001) linearly decreased with increasing QTE infusions. Inconsistent differences were observed for LAMF, but concentrations of PB in LAMS ( ≤ 0.018) and of N in PAM ( < 0.001) were greater at 6% QTE than at Control I, II, and 1% QTE. Hence, low to moderate QTE dosages hamper rumen fermentation and microbial biomass yields. Alongside the nutritional consequences for the host, the methodological implications of these effects should be considered in studies evaluating the targeted use of tannins in ruminant feeding.

Effect of tannin source and pH on stability of tannin-protein complexes

Quebracho (Schinopsis quebracho-colorado Schlecht) is the most extensively tannin extract explored in order to improve the use of protein in ruminant feed. The rock rose (Cistus ladanifer L.) and the grape seed (Vitis vinifera L.) are alternative sources of condensed tannins (CT). The objective of this study was to evaluate the effect of pH on the stability of complexes formed between the rock rose tannins and grape seed and the protein and fiber of soybean meal and compare the results with those obtained with the quebracho tannin extract. The results obtained show that the rock rose and grape seed tannins, such as quebracho tannins, have the ability to bind to soybean meal protein at pH between 6 and 8, reducing the solubility of nitrogen. These complexes are dissociated at pH 2, releasing the protein. This binding pattern supports the concept of using these tannin sources in ruminant nutrition as additives to protect the protein feed from excessive rumen degradation. However it was observed differences among tannin sources. Rock rose and grape seed tannins seem be more effectives in reducing protein degradation in the rumen than quebracho tannins.

Effects of quebracho tannin extract and activated charcoal on nutrient digestibility, digesta passage and faeces composition in goats

Irrigation agriculture of hot climates suffers from rapid soil organic carbon (C) turnover, high nitrogen (N) leaching and gaseous losses. In this context, we explored the possibility of supplementing ruminants with activated charcoal (AC) and condensed tannins (CT) to increase faecal concentration of long-lived C and slowly decomposable N. For this purpose, we fed AC and quebracho tannin extract (QTE, source of CT) to goats and determined nutrient digestibility, digesta passage and composition of faeces. The feeding trial comprised three periods, with 24 male goats assigned to five treatments and a control. On dry matter (DM) basis, the basal diet (control) consisted of 50% hay, 46.5% crushed maize and 3.5% soya bean meal. Treatment diets contained (on DM basis) 2% and 4% QTE (QTE2, QTE4), 1.5% and 3.0% AC (AC1.5, AC3.0) and a mixture of 2% QTE plus 1.5% AC (QTEAC). Samples of feed, refusals and faeces were analysed for chemical constituents; digesta passage was computed with a one-compartment Gamma-2 model from pulse-dose application of ytterbium-mordanted fibre and quantitative collection of faeces during 7days. Compared to the control, organic matter and N digestibility were reduced with QTE2 and QTE4 (p≤0.001), that of neutral and acid detergent fibre (NDFom, ADFom) decreased with QTE4, QTEAC and both AC treatments (p≤0.001). Ruminal particle passage ranged from 0.051h-1 (QTEAC) to 0.056h-1 (control; p>0.05). Apart from the correlation between total tract mean retention time and faecal C/N ratio (r=-0.35), passage parameters did not affect faeces quality. While faecal N concentration was not altered by both additives, AC enhanced faecal NDFom, ADFom and C concentrations (p≤0.001). Whereas feeding up to 3% AC might slow down the decomposition of manure in the field without negatively affecting the digestive physiology of goats, including QTE seems not advantageous from a physiological and nutrient recycling perspective.

Relationship between milk odd and branched-chain fatty acids and urinary purine derivatives in dairy cows supplemented with quebracho tannins—A study to test milk fatty acids as predictors of rumen microbial protein synthesis

The purpose of this study was to explore the potential of milk odd and branched-chain fatty acids (OBCFA) as biomarkers for rumen microbial protein synthesis in dairy cows, and to study the effects of diets supplemented with different levels of quebracho tannin extract (QTE) on milk OBCFA.The experiment included 50 lactating German Holstein dairy cows divided into two groups of 25 animals each and lasted for six consecutive periods of 21 days (13 days of adaptation and 8 days of feed, milk, and urine sampling). The basal diet was a total mixed ration with a constant forage to concentrate ratio of 65:35 (Control, without QTE). A commercial QTE product was added to the basal diet at 15g and 30g/kg dry matter to create diets QTE15 and QTE30, respectively. Milk fat samples were analysed for OBCFA contents and urine for purine derivatives (PD), nitrogen (N), and creatinine concentrations.The QTE addition increased the concentrations of creatinine and the ratio between total PD and N in urine, whereas the concentrations of allantoin, total PD, and N in urine decreased with QTE addition. Similarly, addition of QTE decreased the proportions (g/100g fat) and yields (g/d) of milk OBCFA, with the exception of anteiso-C15:0 and anteiso-C17:0.Multivariate models to predict concentrations and ratios of PD, N, and creatinine in urine from milk OBCFA explained between 10% and 40% of the variance in the dataset of each predicted parameter. However, the explanation of that variance attributed to milk OBCFA was only between 2% and 26%. For most parameters, models developed from milk OBCFA proportions explained more variance in the dataset than those developed from OBCFA yields. Our findings suggest that milk OBCFA are poor indicators of rumen microbial protein synthesis in dairy cows.

Effects of quebracho tannin extract (Schinopsis balansae) and activated charcoal on feed intake and digestibility by goats and their faecal microbial biomass

Faecal microorganisms directly influence autochthonous soil microbial biomass, microbial residues and subsequent soil C and N cycling. This study investigated the effects of feeding activated charcoal (AC) and quebracho tannin extract (QTE) on feed and nutrient intake, apparent nutrient digestibility and faecal excretion of C, N and fibre fractions in growing male goats, and on faecal microbial biomass. The completely randomised feeding trial comprised of three subsequent periods with 12 male Boer goats (age 4.8 ± 0.59 months, weight 28 ± 3.9 kg) assigned to five treatments and a control. Experimental diets contained 2 and 4% QTE (QTE2, QTE4), 1.5 and 3.0% AC (AC1.5, AC3.0) and a mixture of 2% QTE plus 1.5% AC (QTEAC). Faecal microbial biomass was measured using ergosterol and amino sugars as indices for fungi and bacteria. There were no significant effects of QTE and AC on intake of feed and nutrients. Faecal concentration of slowly decomposable carbohydrates increased with QTE as well as with AC feeding (p < 0.001), whereas faecal N concentration only increased with QTE feeding (p < 0.001). Although total microbial C concentration in faeces was not affected by QTE and AC feeding, QTE shifted the microbial community towards fungi (p < 0.01). The results demonstrate that including up to 4% QTE in goat diets enhances the concentration of slowly decomposable N and C fractions in the faeces, whereas feeding up to 3% AC increases the faecal concentration of slowly decomposable C fractions and the faecal C/N ratio.

Quebracho paraguayo y extracto tánico para la curtición española: la revista barcelonesa "La Piel y sus Industrias" (1909-1940)

La unión entre economía y periodismo es el objetivo de este artículo en el que se analiza el papel ejercido por los hermanos Pedro Pablo y Carlos de Corral y Tome al internacionalizar el árbol de quebracho colorado paraguayo, y al importarlo a la ciudad de Barcelona para la producción del curtido. Su “S.A. de Extractos Tánicos” inaugurada en el ano 1909, legalizó la utilización del extracto tánico del quebracho, y permitió elaborar zapatos y botas para la sociedad civil y para los ejércitos europeos. Estos empresarios españoles fundaron en el mismo año la original revista El Arte de Curtir, que fue rebautizada en 1928 con el nombre de La Piel y sus Industrias. Economía y periodismo permiten reconstruir las estrategias de fabricación de extractos tánicos vegetales utilizadas por los curtidores desde inicios del siglo XX hasta la Guerra Civil española, momento en que se impuso el tanino sintético.

Influence of ruminal Quebracho tannin extract infusion on apparent nutrient digestibility, nitrogen balance, and urinary purine derivatives excretion in heifers

Six fully grown heifers (491kg body weight, standard deviation 35) fitted with ruminal cannulae received incremental dosages of a commercial Quebracho tannin extract (QTE) to investigate its effects on apparent total tract nutrient digestibilities, nitrogen balance, and purine derivatives excretion as an indicator of duodenal microbial crude protein flow. The basal diet comprised 2.6kg/d grass hay, 2.6kg/d concentrate feed, and 60g/d of a mineral premix (as-fed basis) and was offered in two equal meals. The QTE was administered at 0 (CON 1), 1, 2, 4, or 6% of the daily DM intake from the basal diet (i.e., 45g, 90g, 180g, and 270g/d; as-fed basis). For this, half of the daily QTE dosage was suspended in water and intraruminally infused during each feeding. All animals simultaneously received the same QTE dosage. Every period comprised 9d of adaptation and 6d of total urine and feces collection. Subsequent to highest QTE dosage, infusion was ceased and after 14d of adaptation, urine and feces were collected again for 10d (CON 2). The QTE infusions at ≥4% lowered apparent total tract organic matter digestibility (P≤0.045). The effects were more pronounced for neutral detergent and acid detergent fiber digestibilities which decreased from 0.718 and 0.626 without QTE to 0.590 and 0.493 at 6% QTE, respectively (P<0.001). Nitrogen excretion linearly decreased in urine (P=0.003) and linearly increased in feces (P<0.001) with incremental QTE dosages. Irrespective of the dosage level, nitrogen retention was higher with than without QTE infusion (P≤0.035). Urinary purine derivatives excretion declined from 103mmol/d at 1% QTE to 80mmol/d at 6% QTE (P<0.001), indicating a 36% decrease in estimated duodenal microbial crude protein flow. At QTE dosages of ≥4% of DM intake, reduced carbohydrate digestibility will lower energy supply to the host animal. The pronounced decrease in estimated microbial protein synthesis even at moderate QTE levels is unlikely to be compensated by the increase in rumen-escape protein. The QTE addition to ruminant diets might not improve protein supply and performance of cattle.

Effects of activated charcoal and quebracho tannins added to feed or as soil conditioner on manure quality in organic agriculture

Animal manure is one of the major nutrient and carbon (C) sources in many low to medium input systems of irrigated agriculture in subtropical drylands, particularly if managed under the constraints of organic regulations. Under year-round hot and irigated conditions, high losses of C, nitrogen (N) and other nutrients may lead to soil quality deterioration and reduced crop yields. In an effort to develop approaches slowing down decomposition of soil applied manure, activated charcoal (AC) and quebracho tannin extract (QT) were either fed to goats or directly mixed with manure prior to application in a 2-year field experiment conducted with sweet corn (Zea mays L.) and radish (Raphanus sativus L.) in the Batinah Plain of Oman. Sun-dried faeces of goats fed AC had a 15 % higher C concentration and a 25 % higher C/N ratio than pure goat manure, whereas QT feeding only increased sodium (Na) concentration. While sweet corn performed best under equivalent mineral fertilization, the addition of AC and QT to goat feed or to goat manure reduced growth and development of sweet corn by 20 and 30 %, respectively, compared to pure goat manure, regardless of the application method. Radish yielded highest when fertilized with either pure goat manure or AC-amended goat manure, whereas mineral fertilizer and QT-amended manure applications inhibited its growth. Activated charcoal may be a promising additive to increase soil organic matter and increase soil fertility, if it does not hamper nutrient supply to crops. Quebracho tannins, however, impaired crop production, and further research is needed to evaluate whether tannins from other sources added to agricultural soils have similar detrimental effects on crops.

Milk fatty acid composition, rumen microbial population, and animal performances in response to diets rich in linoleic acid supplemented with chestnut or quebracho tannins in dairy ewes

The aim of the study was to evaluate milk fatty acid (FA) profile, animal performance, and rumen microbial population in response to diets containing soybean oil supplemented or not with chestnut and quebracho tannins in dairy ewes. Eighteen Comisana ewes at 122±6 d in milking were allotted into 3 experimental groups. Diets were characterized by chopped grass hay administered ad libitum and by 800 g/head and day of 3 experimental concentrates containing 84.5 g of soybean oil/kg of dry matter (DM) and 52.8 g/kg of DM of bentonite (control diet), chestnut tannin extract (CHT diet), or quebracho tannin extract (QUE diet). The trial lasted 4 wk. Milk yield was recorded daily, and milk composition and blood parameters were analyzed weekly. At the end of the experiment, samples of rumen fluid were collected to analyze pH, volatile fatty acid profile, and the relative proportions of Butyrivibrio fibrisolvens and Butyrivibrio proteoclasticus in the rumen microbial population. Hepatic functionality, milk yield, and gross composition were not affected by tannin extracts, whereas milk FA composition was characterized by significant changes in the concentration of linoleic acid (CHT +2.77% and QUE +9.23%), vaccenic acid (CHT +7.07% and QUE +13.88%), rumenic acid (CHT −1.88% and QUE +24.24%), stearic acid (CHT + 8.71% and QUE −11.45%), and saturated fatty acids (CHT −0.47% and QUE −3.38%). These differences were probably due to the ability of condensed versus hydrolyzable tannins to interfere with rumen microbial metabolism, as indirectly confirmed by changes in the relative proportions of B. fibrisolvens and B. proteoclasticus populations and by changes in the molar proportions of volatile fatty acids. The effect of the CHT diet on the milk FA profile and microbial species considered in this trial was intermediate between that of QUE and the control diet, suggesting a differential effect of condensed and hydrolyzable tannins on rumen microbes. Compared with control animals, the presence of B. fibrisolvens increased about 3 times in ewes fed CHT and about 5 times in animals fed QUE. In contrast, the abundance of B. proteoclasticus decreased about 5- and 15-fold in rumen liquor of ewes fed CHT and QUE diets, respectively. The use of soybean oil and a practical dose of QUE or CHT extract in the diet of dairy ewes can be an efficient strategy to improve the nutritional quality of milk.

Effect of Quebracho Tannin Extract on Soybean and Linseed Oil Biohydrogenation by Solid Associated Bacteria: An in vitro Study

An in vitro trial was carried out to study the effects of Quebracho tannins extract (QE) on fatty acid profile of rumen solid adherent bacteria (SAB) during the fermentation of diets supplemented with soybean or linseed oil, as sources of linoleic (LA; 18:2 n-6) and α-linolenic acid (α-LNA; 18:3 n-3), respectively. Two control diets were prepared using a basal mixture of grass hay [760 g/kg on dry matter (DM)], soybean meal (55 g/kg DM), barley meal (130 g/kg DM), vitamin mineral premix (20 g/kg DM) and 35 g/kg DM of soybean (SOC diet) or linseed oil (LOC diet) as lipid supplement. Other two diets (SOCT and LOCT) were obtained by integrating SOC and LOC with QE (49 g/kg DM). The results confirmed that Quebracho tannins may be an effective method for reducing in SAB the biohydrogenation of LA (17.3 vs 34.5 g/100 g of fatty acid in SOC and SOCT, respectively) and LNA (10.7 vs 21.4 g/100 g of fatty acid in LOC and LOCT, respectively), but not for increasing the rumen accumulation of cis9, trans11 18:2 (0.77 vs 0.32 g/100 g of fatty acid in SOC and SOCT, respec tively; 0.51 vs 0.43 g/100 g of fatty acid in LOC and LOCT, respectively) and trans11 18:1 (6.15 vs 3.64 g/100 g of fatty acid in SOC and SOCT, respectively; 5.53 vs 4.47 g/100 g of fatty acid in LOC and LOCT, respectively).

A new approach for in vitro bioassay to measure tannin biological effects based on a gas production technique

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, quebracho extract and acacia extract) to establish a curve of biological equivalent effect of tannins. For this, five levels of each compound were added to 1 g of a standard feed (Lucerne hay). The equivalent effect showed not to be directly related to the chemical analysis for tannins. It was shown that different sources of tannins had different activities or reactivities. The curves of biological equivalence can provide information about tannin reactivity and its use seems to be important as an additional factor for chemical analysis.

Use of condensed tannin extract from quebracho trees to reduce methane emissions from cattle1

Our objective was to determine if condensed tannin extract from quebracho trees (Schinopsis quebracho-colorado; red quebracho) could be used to reduce enteric methane emissions from cattle. The experiment was designed as a repeated 3 x 3 Latin square (4 squares) with 3 treatments (0, 1, and 2% of dietary DM as quebracho tannin extract) and 3 28-d periods. Six spayed Angus heifers (238 +/- 13.3 kg of initial BW) and 6 Angus steers (207 +/- 8.2 kg of initial BW) were each assigned to 2 squares. The measured condensed tannin content of the extract was 91%, and the basal diet contained 70% forage (DM basis). Feeding quebracho tannin extract had no effect on BW, ADG, or nutrient intakes. Furthermore, it had no effect on DM, energy, or fiber (ADF and NDF) digestibility, but apparent digestibility of CP decreased linearly (P < 0.001) by 5 and 15% with 1 and 2% quebracho tannin extract, respectively. There were no effects of quebracho tannin extract on methane emissions (g/d, g/kg of DM, % of GE intake, or % of DE intake). Feeding up to 2% of the dietary DM as quebracho tannin extract failed to reduce enteric methane emissions from growing cattle, although the protein-binding effect of the quebracho tannin extract was evident.

Thermal and mechanical properties of woodflour/tannin adhesive composites

AbstractComposite materials formulated with a natural polyphenolic matrix (commercial tannin adhesive made from quebracho tannin extract), pine woodflour as reinforcing material, and hexamethylenetetramine as hardener were prepared and tested. Scanning electron microscopy of fractured samples was used to analyze the efficiency of the wetting and adhesion of the filler to the surrounding matrix. Thermogravimetric analysis was used in the thermal characterization of the woodflour and the tannin extract. Flexural, compression, and dynamic‐mechanical tests were performed on composites to study the relationship of the filler content and particle size with the composite final properties. Moreover, the influence of the moisture content on the physical and mechanical properties of the different composites was analyzed. Results indicated that the mechanical properties were severely affected by the absorbed moisture. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3074–3082, 2004

Intoxication of Sheep with Quebracho Tannin Extract

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, Q 1 and Q 2. However, Q 3 sheep showed striking lesions in the digestive tract (well-demarcated ulcers filled with necrotic material in the mucosa of the rumen and reticulum, distension of abomasum and small intestine, and dense mucous material in the caecum), and changes in plasma biochemistry. Cytochrome P-450 and glutathione concentrations were significantly reduced in Q 3 sheep ( P<0.05). It is concluded that quebracho tannin extract is not toxic for ruminants, except in concentrations too high to be encountered under practical conditions.

Post-ruminal protein supply and N retention of weaner sheep fed on a basal diet of lucerne hay ( Medicago sativa) with increasing levels of quebracho tannins

The ability of low to moderate levels (<5% DM) of dietary condensed tannins (CT) to promote useable rumen-escape protein was evaluated using a quebracho tannin extract (QTE) given with high quality (4.0% N) lucerne hay to weaner sheep in a metabolism trial. The QTE (73.4% (w/w) CT in DM) was given as a liquid drench at levels of 0, 20, 40, and 60 g per day with 1 kg DM per day of hay. The trial comprised 12 animals in groups of three per dose rate. The hay was offered continuously from automated individual feeders to achieve ‘steady-state’ conditions for digesta flow measurement using Cr 2O 3 from intra-ruminal controlled release capsules. A diet acclimatisation period of 10 days was followed by 7 days for total collection of urine and faeces to determine digestibility and N retention, and microbial protein synthesis from total purine derivatives in urine. Animals were slaughtered at the end of the metabolism trial and digesta were sampled from the abomasum and the terminal ileum for determination of digesta flow rate, and rumen fluid for NH 3-N concentration. Despite the low levels of CT given, we found no evidence to support the generalised hypothesis that low to moderate amounts of CT improve N utilisation by sheep. The dose response to QTE showed no effect for rumen digestion of N (mean NH 3-N=291±19.0 mg/l, r 2=0.43) and OM (mean DOMADR (%)=81±23.5, r 2=0.03), and consequently the abomasal NAN (mean 20.5±2.32 g per day, r 2=0.109) and microbial-N supply (mean 11.5±1.38 g per day, r 2=0.57) were not affected, hence rumen-escape protein was also unaffected. Significantly though, the apparent N digestibility was reduced by 10% units ( r 2=0.970) associated with a significant increase in faecal N ( r 2=0.984) due to QTE. The excess faecal N was directly related to the decline in apparent absorption of NAN in the small intestines from a baseline of 12.6 g per day to as low as 7.2 g per day ( r 2=0.904). However, this decline was not sufficient to alter N retention (mean 13.2±4.18 g per day, r 2=0.58). The failure of the QTE to improve the protein supply post-ruminally is at odds with the general hypothesis for CT enhancing rumen-escape protein by reducing N degradation in the rumen. Nevertheless, the ability for CT to dramatically reduce protein absorption in the small intestines was well highlighted. These results suggest that QTE given as a dietary supplement is unlikely to improve the absorbable protein content of forages.

MUF upgrading and phenol substitution by tannin in PMUFs

A commercial melamine-urea-formaldehyde resin was upgraded by addition of 4% and 6% modified quebracho tannin extract directly in the glue mix. The glue mixes were used to prepare beech and okoume 7-ply exterior grade plywood.

Purified tannins from quebracho colorado

The acetone-water solubles from quebracho tannin extract were separated into three fractions of different molecular weights. The purified tannins yielded sugars and gallic acid upon acid hydrolysis, and lignin derived degradation products upon KMnO 4 oxidation. It was concluded that the sugars and the lignin are covalently linked to the condensed tannins.

635. The occurrence of 2-benzyl-2-hydroxycoumaran-3-ones in quebracho tannin extract

635. The occurrence of 2-benzyl-2-hydroxycoumaran-3-ones in quebracho tannin extract