Non-tannin Phenolics Research Articles

Fungal pathogen: A game changer for insect herbivore in sequential attack on tomato

Plants have several means of coping with biotic stress, which involves physiological, cellular and molecular mechanisms. The interplay of two principal phytohormonal pathways, Jasmonic acid (JA) and Salicylic acid (SA) play a crucial role in transmitting stress-induced signals throughout the plant. However, the interplay of these hormonal pathways is not clear when plants encounter biotic agents that trigger antagonistic hormonal signals. To address this, we conducted biochemical and gene expression studies on tomato, Solanum lycopersicum plants, exposed to insect alone (IA), fungus alone (FA), or sequential dual stress with fungi followed by insect (FI) and insect followed by fungi (IF), with untreated control. We also assessed the performance of late-arriving conspecific herbivore on these plant sets. The total phenol, and non-tannin phenols content in IF and FI plants showed similar increase or decrease as FA and IA plants, respectively. Gene expression analysis revealed that JA-related genes (MYC2) were dominant in FI plants, while SA-related genes (PR1) were upregulated in IF plants. Moreover, late-arriving herbivores showed significantly decreased relative growth rate, efficiency of conversion of ingested food (ECI) and digested food (ECD) when feeding on FA and IF plants, indicating that sequential treatments substantially induce plant responses. However, herbivory did not affect the late-arriving conspecific herbivore. Thus, biochemical responses and hormonal interplay of the plant are influenced by both sequence as well as the duration of the biotic stress. Furthermore, while the late-arriving conspecific herbivore is negatively affected by the presence of a pathogen, it remains unaffected by previous herbivory.

Comparative phenolic, chromatic, and sensory composition of five monovarietal wines processed with microwave technology

The effect of MW technology (1,200 Watts for 10 min) on the chemical and sensory composition of five monovarietal wines with different phenolic composition was studied relative to untreated Control wines. MW improved polymeric pigment content by 30, 22 and 31% in Cabernet Sauvignon, Malbec, and Syrah wines, respectively, and anthocyanin extraction and non-tannin phenolics by 24% in Malbec and Syrah wines, respectively. In Nebbiolo and Pinot noir, MW had no effect on phenolics or chromatic characteristics. Anthocyanins in Nebbiolo wines were the lowest and their pigment profile was composed of 18% pyranoanthocyanins, but tannins were the highest, resulting in a tannin to anthocyanin ratio of 16. Pinot noir and Nebbiolo wines had comparable polymeric pigment content, despite dissimilar tannin to anthocyanin ratios, suggesting different mouthfeel characteristics in their respective wines. Conversely, wines of comparable tannin to anthocyanin produced wines of vastly different polymeric pigment content. MW-treated Cabernet Sauvignon wines showed an improved sensory profile.

In vitro ruminal fermentation, methane production and nutrient degradability as affected by fruit and vegetable pomaces in differing concentrations.

Pomaces are food industry by-products and may serve as animal feed to increase sustainability of meat and milk production. The aim of the present study was to evaluate fermentation characteristics of dried fruit and vegetable pomaces in a short-term in vitro experiment using the Hohenheim Gas Test. A selection of six fruit (apple, aronia, orange, pomegranate, red, white grape) and three vegetable (beetroot, carrot, tomato) pomaces was tested in three concentrations (150, 300, 500gkg-1 of dry matter (DM)) as supplement to the basal diet (hay, used as control). Three runs were performed, using rumen fluid from one of three different rumen-cannulated cows in each run. Per run, each compound was tested in duplicate. After 24h incubation, total gas production, methane and CO2 concentration, short-chain fatty acids, in vitro organic matter digestibility as well as microbial counts were determined. In addition, the pomaces' polyphenol content including the fractions non-tannin phenols, condensed tannins and hydrolysable tannins were analysed. Most pomaces did not significantly affect rumen fermentation characteristics in any of the tested dosages and may thus be applied in ruminant nutrition without adverse effects. Aronia significantly decreased (-14.5%) the organic matter digestibility in the highest concentration whereas apple (+12%), carrot (+10%) and beetroot (+8%) increased gas formation related to digestible organic matter. The 500gkg-1 dosage of pomegranate significantly decreased methane formation by about 28% without impairing digestibility. Pomegranate was the only pomace of those high in total tannins that contained exceptionally high amounts of hydrolysable (90% of total tannins) and proportionally low amounts of condensed tannins (10% of total tannins), indicating that the hydrolysable tannins most likely reduced the methane production. Therefore, pomegranate pomace may be an interesting option for a methane mitigating feed supplement in ruminants and should be considered for following in vivo testing.

Latent Anti-nutrients and Unintentional Breeding Consequences in Australian Sorghum bicolor Varieties.

Modern feed quality sorghum grain has been bred to reduce anti-nutrients, most conspicuously condensed tannins, but its inclusion in the diets of monogastric animals can still result in variable performance that is only partially understood. Sorghum grain contains several negative intrinsic factors, including non-tannin phenolics and polyphenols, phytate, and kafirin protein, which may be responsible for these muted feed performances. To better understand the non-tannin phenolic and polyphenolic metabolites that may have negative effects on nutritional parameters, the chemical composition of sorghum grain polyphenol extracts from three commercial varieties (MR-Buster, Cracka, and Liberty) was determined through the use of an under-studied, alternative analytical approach involving Fourier-transform infrared (FT-IR) spectroscopy and direct ionization mass spectrometry. Supervised analyses and interrogation of the data contributing to variation resulted in the identification of a variety of metabolites, including established polyphenols, lignin-like anti-nutrients, and complex sugars, as well as high levels of fatty acids which could contribute to nutritional variation and underperformance in monogastrics. FT-IR and mass spectrometry could both discriminate among the different sorghum varieties indicating that FT-IR, rather than more sophisticated chromatographic and mass spectrometric methods, could be incorporated into quality control applications.

Edad de rebrote de Erythrina americana Miller y concentración de compuestos fenólicos en el follaje

El follaje de algunos árboles puede utilizarse en la alimentación de pequeños rumiantes, cuando la calidad química y contenido de metabolitos secundarios son adecuados. El uso de Erythrina americana como alimento, requiere del conocimiento de su composición nutricional a diferentes edades de rebrote. El objetivo del estudio fue determinar la influencia de la edad de rebrote de E. americana en el contenido de compuestos fenólicos y composición química del follaje, a partir de 24 árboles que forman parte de los cercos vivos de una explotación ovina. Se utilizó un diseño completamente al azar, el factor fijo fue la edad de rebrote de E. americana (60 días, 90 días y 120 días). Las variables dependientes fueron: materia seca, proteína cruda, cenizas, materia orgánica, fibra detergente neutro, fibra detergente ácido, polifenoles totales, fenoles no taninos, taninos condensados, taninos hidrolizables y taninos totales. La edad de rebrote afectó (P < 0.05) el contenido de proteína cruda, carbohidratos estructurales, polifenoles totales y taninos (condensados, hidrolizables y totales), el resto de las variables no fueron afectadas (P > 0.05). A los 90 días se detectó el mayor contenido de proteína cruda. El menor contenido de carbohidratos estructurales se presentó entre 90 días y 120 días. Conforme se incrementó la edad de rebrote aumentó la concentración de taninos condensados. Los contenidos de proteína cruda, carbohidratos estructurales y taninos condensados en el follaje de E. americana, a una edad de rebrote de 90 días, permiten considerarlo como alimento complementario para pequeños rumiantes.

Potential of Citrullus colocynthis as herbal feed additive for ruminants

To assess the potential of Citrullus colocynthis as herbal feed additive for ruminants, colocynth fruit as a whole, its seeds and peel-pulp were evaluated at various levels (0, 0.5, 1.0, 1.5, 2.0, 2.5, 4.0%) with total mixed ration (roughage to concentrate ratio: 65:35) as substrate in 3×7 factorial design by in vitro gas production technique. Phytochemical analysis revealed significant variation (P<0.01) in total phenols, non-tannin phenols, true tannins, saponins, flavonoids and vitamin C content among different parts of colocynth fruit. Irrespective of the part used, varying level of Citrullus colocynthis had significant effect on net gas production (NGP; ml/24/g), metabolizable energy (ME) availability, methanogenesis, digestibility of neutral detergent fiber (NDF) and true organic matter (TOM) in comparison to control; however the effect was pronounced at 1% level of supplementation. No significant difference in total volatile fatty acids (TVFA) production and acetate production was observed at varying levels of Citrullus colocynthis except at 4% level when total mixed ration (TMR) was used as substrate. Irrespective of its level, supplementation of Citrullus colocynthis fruit as a whole, seeds and peel-pulp significantly improved NGP (P<0.001) and ME (P<0.01) availability in comparison to control group whereas partitioning factor (PF; P>0.578), digestibility of NDF (P>0.905) and true OM (P>0.228) remained unaffected between different test groups. However, TVFA production, acetate, propionate and butyrate concentration was observed lower (P<0.001) in peel-pulp and seed supplemented group. From above results it can be concluded that supplementation of Citrullus colocynthis fruit at 1% level of substrate had potential to improve rumen fermentation characteristics and reduce methanogenesis, however in vivo assessment on ruminants need to be conducted to evaluate the persistency of effects along with health concerns.

Nutritional potentialities of some tree leaves based on polyphenols and rumen in vitro gas production.

Aim:The study was conducted to evaluate eight tree leaves based on polyphenolic content and rumen in vitro incubation and gas production technique (RIVIGPT) for their nutritive potentiality.Materials and Methods:Eight selected tree leaves, namely Sesbania grandiflora, Melia dubia, Dillenia spp., Artocarpus heterophyllus, Commiphora caudata, Moringa oleifera, Leucaena leucocephala, and Acacia auriculiformis, were selected for proximate composition, forage fiber fractions, total phenolics (TPs), non-tannin phenols (NTPs), total tannins (TTs), condensed tannins (CTs), and hydrolysable tannins (HTs); RIVIGP with and without polyethylene glycol (PEG); and in vitro dry matter digestibility (IVDMD) (modified in vitro two stage) analysis was conducted. On the basis of RIVIGPT, the in vitro digestible organic matter (IVDOM) and dry matter intake (DMI) was calculated.Results:Crude protein (CP) content of tree leaves ranged from 9.59 to 25.81%, neutral detergent fiber (NDF) 28.16 to 53.33%, acid detergent fiber (ADF) 21.26 to 41.7%, acid detergent lignin (ADL) 3.62 to 21.98%, TP 1.83 to 17.35%, TT 0.40 to 15.47%, and CTs 0.02 to 15.26%. IVDMD (%) was ranged from 64.95 to 88.12. The mean metabolizable energy (ME) (MJ/Kg) of tree leaves estimated with and without PEG was 7.75±0.56 and 8.75±0.39, in vitro gas production at 24 h (IVGP24) (ml) 31.06±4.14 and 37.09±2.64, initial gas production (a) (ml) 0.49±0.63 and 1.33±0.72, potential gas production (D) (ml) 38.74±4.27 and 43.79±2.44, rate of gas production (k) (h−1) 0.11±0.02 and 0.11±0.013, t1/2(ml) 9.81±2.41 and 7.42±0.80, in vitro gas production at 96 h IVGP96 (ml) 39.50±4.430 and 45.14±2.65, the predicted IVDOM (%) 55.44±4.15 and 61.98±3.03, and DMI (g/Kg W0.75) 103.1±14.76 and 104.3±10.16, respectively. The addition of PEG showed an improvement in IVGP24, IVGP96, ME, predicted IVDOM, and predicted DMI. CP was positively correlated with ME, IVGP24, IVGP96, a+b, k (r=0.749, p<0.05), IVDMD, IVDOM, and DMI (r=0.838, p<0.05) and negatively correlated with a and t1/2. NDF, ADF, and ADL contents were negatively correlated with ME (r=0.899, p<0.05), IVGP24 (r=−0.867, p<0.05), IVGP96 (r=−0.858, p<0.05), a+b (p<0.05), k (r=−0.828, p<0.05), IVDMD, IVDOM (r=−0.853, p<0.05), and DMI and positively correlated with a and t1/2. TP, TT, and CT were negatively correlated with ME, IVGP, IVGP96, a+b, k, IVDMD, IVDOM, and DMI and positively correlated with a (r=0.808, p<0.05) and t1/2. ME (MJ/Kg) was positively correlated with IVGP24 (r=0.938, p<0.05), IVGP96 (r=0.875, p<0.05), a+b (r=0.813, p<0.05), k (r=0.731, p<0.05), IVDMD, IVDOM (r=0.985, p<0.05), and DMI (r=0.727, p<0.05) and negatively correlated with a and t1/2.Conclusion:In the present study, the potentiality of tree leaves was assessed based on CP, ADF, ADL, TP, CT, IVGP, ME, IVDMD, predicted IVDOM, and predicted DMI. Based on this, it can be concluded that S. grandiflora, M. dubia, M. Oleifera, and L. leucocephala were graded as best; A. heterophyllus and C. caudata as moderate; and Dillenia spp. and A. auriculiformis as lowest potential ruminant feed.

Assessment of phytochemical constituents, fatty acids profile and in vitro antioxidant activity in soapnut shell powder

Sapindus mukorossi, commonly called as soapnut, is an extremely valuable medicinal plant which possesses several biological and pharmacological properties. The present study was carried out to determine the phytochemical composition, saponin content, fatty acid profiles and in vitro assessment of antioxidant potential of soapnut shell powder (SSP) as a phytogenic feed additive for livestock and poultry feeding. The DM, CP, EE, CF, TA, Ca and P levels in SSP were 95.16, 5.01, 1.78, 2.21, 7.49, 0.24 and 0.41%, respectively. Total phenol (TP), non tannin phenols (NTP), total tannin (TT), condensed tannin (CT) and hydrolysable tannin (HT) levels in SSP were 1.43, 0.60, 0.83, 0.36 and 0.47%, respectively. The crude saponin extracted from SSP was 28.4% (DMB). SSP was composed of 68.8% saturated and 31.2% unsaturated fatty acids, respectively. The total antioxidant activity at the concentration 250 μg/ml of SSP was 57.16%. Thus, it could be concluded that SSP had high antioxidant activity which may be beneficial for livestock and poultry feeding.

Effects of extracts obtained from Cistus ladanifer L. on in vitro rumen biohydrogenation

Cistus ladanifer (rockrose) is a tanniferous and aromatic shrub abundant in marginal fields of Mediterranean countries that when fed to lambs has been associated with changes in rumen biohydrogenation that led to an increased concentration of vaccenic acid (t11-18:1) in abomasal digesta and meat. It is not clear what type of secondary compounds present in C. ladanifer might be responsible for its effects on rumen biohydrogenation. Thus, we tested the effects of essential oil (EO), dichloromethane extract (DE), total phenolics (TP), non-tannin phenols (NTP) and condensed tannins (CT) fractions on in vitro rumen biohydrogenation. Five in vitro batch incubations replicates were conducted in Hungate tubes containing 60mg of feed substrate (Control), or 60mg of feed substrate plus 6mg of each C. ladanifer extract incubated for 6h with 6mL of buffered ruminal fluid. Volatile fatty acids (VFA) and long chain fatty acids (FA) were analyzed at 0 and 6h and the biohydrogenation of c9-18:1, c9,c12-18:2 and c9,c12,c15-18:3 and the yield of biohydrogenation products were computed. The production of total VFA was not affected by the C. ladanifer extracts and averaged 6.87mmol/L. The disappearance of c9,c12-18:2 and c9,c12,c15-18:3 was higher in CT than in Control and EO (P<0.05). The gain in 18:0 and t11-18:1, relative to initial subtract availability, was higher in CT than in Control and EO (P<0.05). Both CT and DE increased (P<0.05) the c9,t11-18:2 yield, relative to initial subtract availability, compared with Control and EO treatments. The 10-oxo-18:0 was the major oxo FA found and was highest for CT and lowest in EO and DE treatments. The results showed that CT was the most effective fraction of C. ladanifer regarding its effects on rumen biohydrogenation, inducing larger accumulation of t11-18:1, which was achieved not by inhibition of its last reductive biohydrogenation step (i.e. formation of 18:0) but by the promotion of the initial biohydrogenation steps.

Comprehensive study of the phenolic composition of the edible parts of jambolan fruit (Syzygium cumini (L.) Skeels)

Jambolan fruit has been used in traditional Indian medicine and has recently attracted interest as a functional food. The comprehensive study by HPLC–DAD-ESI-MS/MS has revealed the occurrence of around 74 individual phenolic compounds in the edible parts of jambolan, including 9 anthocyanins (mainly based on delphinidin, petunidin and malvidin), 9 flavonols (myricetin, laricitrin and syringetin glycosides), 19 flavanonols (dihexosides of dihydromyricetin and its methylated derivatives), 8 flavan-3-ol monomers (mainly gallocatechin), 13 gallotanins and 13 ellagitanins, together with some proanthocyanidins (highly galloylated prodelphinidins) and free gallic and ellagic acids. No hydroxycinnamic acid derivatives were detected. The skin of the jambolan fruit accumulated great amounts of phenolic compounds, almost all of the non-tannin phenolics. In contrast, condensed tannins (proanthocyanidins) and hydrolyzable tannins (gallotannins and ellagitannins) were present in both edible parts, accounting for greater amounts in the skin. Overall, the main phenolics of jambolan were anthocyanins and hydrolyzable tannins (similar amounts of gallotannins and ellagitanins), followed by flavanonols, flavonols and flavan-3-ols.

Concentrations of specific phenolic compounds in six red sorghums influence nutrient utilisation in broiler chickens

Concentrations of polyphenolic compounds and free, conjugated and bound phenolic acids were determined in six red grain sorghum varieties harvested on the Liverpool Pains in 2009. Categories of polyphenolic compounds quantified included total phenolics, anthocyanins, flavan-4ols, luteolinidin, apigeninidin, 5-methoxy-luteolinidin, 7-methoxy-apigeninidin, apigenin, luteolin, eriodictyol and naringenin. Phenolic acids that were quantified included p-hydroxybenzoic, vanillic, caffeic, p-coumaric, ferulic, syringic and sinapic acids. These sorghums were also extensively characterised for additional properties including rapid visco-analysis (RVA) of starch pasting profiles, protein solubility and quantification of kafirin and phytate. A pigmented testa was not detected in the six varieties by the quantal Clorox bleach test, which indicated that they were Type I sorghums that do not possess condensed tannin. This was confirmed by vanillin assays. The six varieties were incorporated into unprocessed sorghum–casein mash diets and offered to broiler chickens to compare nutrient utilisation parameters and protein (N) digestibility coefficients. One objective of this study was to assess if non-tannin phenolic compounds influence energy utilisation in broiler chickens. Negative correlations between certain conjugated phenolic acids in sorghum and parameters of energy utilisation (AME, ME:GE ratios, AMEn) in birds were observed. For example, p-coumaric (r=−0.826), ferulic (r=−0.831) and total conjugated phenolic acids (r=−0.832) were negatively correlated with ME:GE ratios to significant (P<0.05) extents. Interestingly, protein solubility was positively correlated to AME (r=0.874), ME:GE ratio (r=0.862) and AMEn (r=0.837) to significant (P<0.05) extents. This study suggests that specific phenolic compounds, namely conjugated phenolic acids of which ferulic and p-coumaric acids were the most abundant, negatively influence energy utilisation in sorghum-based broiler diets. Therefore, our tentative conclusion is that specific non-tannin phenolics are deleterious rather than innocuous components of grain sorghum in the context of chicken-meat production.

Evaluation of several tropical tree leaves for methane production potential, degradability and rumen fermentation in vitro

The objective of this study was to investigate 18 tree leaves for methane production potential, degradability and rumen fermentation characteristics in vitro. The higher concentrations (P<0.01) of total phenolics were noted in Prosopis cineraria (99.7gkg−1), Acacia tortilis (89.4gkg−1) and Psidium guajava (89.3gkg−1), non-tannin phenolics in A. tortilis (36.6gkg−1) followed by Syzygium cumini (26.0gkg−1), total tannins in P. cineraria (82.1gkg−1) and P. guajava (74.3gkg−1), and condensed tannins in A. tortilis (47.2gkg−1), P. guajava (46.6g kg−1) and P. cineraria (43.2gkg−1). Among the 18 leaves, methane production expressed as mlg−1 degradable organic matter (OM) was lower (P<0.01) for Acacia nilotica (12.6ml), P. cineraria (12.9ml), Ficus religiosa (13.9ml), S. cumini (13.8ml) and Azadirachta indica (13.7ml) than other tree leaves. Total volatile fatty acid (VFA) concentration was greater (P<0.01) for Tamarindus indica, followed by Acacia nilotica and lowest for S. cumini. Degradability of dry matter (DM) was higher (P<0.01) for Moringa oleifera, Acacia senegal, Acacia excelsa, Morus alba, A. indica and F. religiosa (77–83%), and lowest for Bambusa sp. (45%) and Ficus benghalensis (52%). Microbial biomass production was lowest for Bambusa sp. leaves and higher (P<0.01) for S. cumini, A. tortilis, A. nilotica, P. guajava than other leaves. Overall, the leaves of S. cumini, A. indica, F. religiosa and A. nilotica not only produced less methane per unit of degradable OM, but also had generally greater OM degradability and favored production of microbial biomass compared with other leaves. These leaves could be explored for decreasing methane production in small ruminant production systems of tropical developing countries.

Short communication: The effect of different inclusion levels of polyethylene glycol as a silage additive on ensilage characteristics of pomegranate peel and in vitro rumen fermentation

This study was conducted to evaluate the effects of ensiling pomegranate peel (PP) with different levels of polyethylene glycol (PEG) on its chemical composition, tannin content, in vitro gas production and fermentation characteristics. Fresh PP was chopped and ensiled in mini silos made of polyvinyl chloride tubing. Five levels of PEG were studied: 0 (control), 5, 10, 15, and 20% of fresh PP (dry matter basis). Total phenolics, total tannins, crude ash, crude protein, neutral detergent fiber and acid detergent fiber content and pH decreased with increasing PEG levels, whereas dry matter and non-fiber carbohydrates content, non-tannin phenols, lactic acid and ammonia concentrations and buffering capacity increased. The water soluble carbohydrates and ether extract concentrations were not influenced by the addition of PEG. The partitioning factor and efficiency of microbial biomass production were quadratically decreased (p=0.020 and p=0.032, respectively) as PEG inclusion increased, but the in vitro apparent dry matter disappearance did not differ among treatments. Compared to control, the in vitro true disappearance and in vitro fiber digestibility had a tendency to be higher in silages treated with PEG (p=0.081 and p=0.069, respectively). The metabolizable energy content and total volatile fatty acids concentration increased quadratically by PEG inclusion. The asymptotic gas production and rate of gas production were higher in PEG-treated silages. Overall, ensiling PP with PEG can improve the fermentation characteristics of this by-product.

Detannification of Oak (Quercus leucotrichophora) Leaves Through Simple Physical Treatments

Oak (Quercus leucotrichophora) leaves are adequately available as scarcity fodder in North West Himalayan Region of India, but poisoning, even death due to its consumption, limits its use as a sole feed in hill cattle, sheep and goat. Information on easily adaptable technology for detoxification and detannification of leaves are lacking in the literature. Therefore, present experiment was planned for a nutrient protective detoxification and detannification process of Q. leucotrichophora leaves. Five different physical treatments viz., water soaking (12h), sun-drying (5d), shade-drying (5d), chopping and chopping and water soaking of locally collected fresh leaves were done, taking fresh leaves as control. The composition of fresh leaves remained comparable to that of different processed leaves except a small decrease (P<0.05) in total carbohydrate content due to water-soaking and chopping and water-soaking. All the physical treatments were effective in reducing all the polyphenols. Reduction was the maximum for hydrolysable tannins (87.54%), followed by total tannins (70.35%), total phenolics (58.17%), condensed tannins (24.39%) and non-tannin phenolics (1.85%). Maximum reduction in hydrolysable tannin (87.54%) and condensed tannin (24.39%) levels were achieved by chopping combined with water soaking, and least reduction was by shade-drying. On the basis of results, it may be concluded that chopping followed by water soaking would be the best nutrient protective processing technique for detoxification and detannification of Q. leucotrichophora leaves.

Differences in Vole Preference, Secondary Chemistry and Nutrient Levels Between Naturally Regenerated and Planted Norway Spruce Seedlings

Field voles (Microtus agrestis) cause severe damage to young Norway spruce (Picea abies) plantations during wintertime in Fennoscandia. We experimentally investigated vole preference for winter-dormant, naturally regenerated seedlings; spring-planted seedlings; or autumn-planted seedlings; and how preference corresponds with seedling chemistry. Voles showed the highest preference for autumn-planted seedlings and the second highest for spring-planted seedlings, while naturally regenerated seedlings were avoided. The stems of the autumn-planted seedlings contained higher concentrations of nitrogen and piperidine alkaloids and lower concentrations of stilbenes than did the other groups. In addition to differences between naturally regenerated and planted seedlings, we investigated seasonal differences in naturally regenerated P. abies needle and bark secondary chemistry. While piperidine alkaloid concentrations did not vary with season, the soluble non-tannin phenolics of needles and the condensed tannins of bark were lower in May than in November or January. At the time of planting, the concentration of bark piperidine alkaloids was higher in autumn-planted than in spring-planted seedlings. We detected two alkaloids not previously found in P. abies, 2-methyl-6-propyl-1,6-piperideine and a tentatively identified pinidine-isomer. Our results demonstrate that vole choice of spruce seedlings is promoted by high nitrogen and low stilbene content, both associated with seedlings planted late in the season. As vole damage is linked to seedling chemistry, damage potentially could be mitigated by advancing planting or by manipulating plant chemistry in nurseries.

In vitroindications for favourable non-additive effects on ruminal methane mitigation between high-phenolic and high-quality forages

Feeding plants containing elevated levels of polyphenols may reduce ruminal CH₄ emissions, but at the expense of nutrient utilisation. There might, however, be non-additive effects when combining high-phenolic plants with well-digestible, high-nutrient feeds. To test whether non-additive effects exist, the leaves of Carica papaya (high in dietary quality, low in polyphenols), Clidemia hirta (high in hydrolysable tannins), Swietenia mahagoni (high in condensed tannins) and Eugenia aquea (high in non-tannin phenolics) were tested alone and in all possible mixtures (n 15 treatments). An amount of 200 mg DM of samples was incubated in vitro (24 h; 39°C) with buffered rumen fluid using the Hohenheim gas test apparatus. After the incubation, total gas production, CH₄ concentration and fermentation profiles were determined. The levels of absolute CH₄, and CH₄:SCFA and CH₄:total gas ratios were lower (P< 0·05) when incubating a combination of C. papaya and any high-phenolic plants (C. hirta, S. mahagoni and E. aquea) than when incubating C. papaya alone. Additionally, mixtures resulted in non-additive effects for all CH₄-related parameters of the order of 2-15 % deviation from the expected value (P< 0·01). This means that, by combining these plants, CH₄ in relation to the fermentative capacity was lower than that predicted when assuming the linearity of the effects. Similar non-additive effects of combining C. papaya with the other plants were found for NH₃ concentrations but not for SCFA concentrations. In conclusion, using mixtures of high-quality plants and high-phenolic plants could be one approach to CH₄ mitigation; however, this awaits in vivo confirmation.

Ruminal disappearance of polyunsaturated fatty acids and appearance of biohydrogenation products when incubating linseed oil with alpine forage plant species in vitro

Elevated contents of α-linolenic and rumenic acids in dairy foods originating from alpine areas have been hypothesized to be partially due to the modulatory effect of plant secondary metabolites on ruminal biohydrogenation. The objective of the present study was to investigate the effect of some representatives of typical and abundant alpine forage plant species on ruminal fatty acid (FA) biohydrogenation and its relationship to the polyphenols, a class of plant secondary compounds, in the plants. Overall, two species of grasses, nine dicotyledonous non-leguminous herbs, three herbaceous legumes and leaves or flowers from three trees were collected from sites situated in the Swiss Alps. These plants were incubated in vitro at 39°C for 24h together with linseed oil as a source rich in polyunsaturated FA (particularly α-linolenic acid) in a rumen fluid:buffer mixture using the Hohenheim gas test method (n=4 replicates per plant). The plants were analyzed for their contents of different polyphenol fractions. The FA profiles of the plants, of the linseed oil and of the fermentation fluid after incubation (total syringe content) were determined by gas chromatography. From these data, the disappearances of unsaturated FA and the appearances of rumenic, vaccenic and stearic acids as biohydrogenation products were calculated. There were no differences in the disappearance of α-linolenic and linoleic acids when incubating any of the plant species, except for Castanea sativa where the disappearance was lower than for all other plants (both at P<0.05). Even though not significantly different from the other plants, the appearance of rumenic and vaccenic acids was high with C. sativa which led also to the lowest (P<0.05) appearance of stearic acid, the ultimate biohydrogenation product. Total extractable phenols, total tannins and hydrolysable tannins were significantly negatively correlated with the disappearance of α-linolenic and linoleic acids and with the appearance of stearic acid, and positively correlated with the appearance of vaccenic acid. Only hydrolysable tannins showed a clear positive correlation with the appearance of rumenic acid (P<0.05). No significant positive or negative correlations were instead established with the non-tannin phenols and the condensed tannins. The above mentioned relationship was, however, almost exclusively the result of including C. sativa. This plant might be interesting for strategic feeding aimed at elevating the contents of some beneficial FA but these results do not explain the particularly favorable FA profile of the milk obtained from ruminants fed alpine pastures.

Nutrient composition, polyphenolic contents, and in situ protein degradation kinetics of leaves from three mulberry species

Mulberry leaves of 14 cultivars of Morus atropurpurea Roxb (MAR), 7 cultivars of Morus alba Linn (MAL) and 8 cultivars of Morus multicaulis Perr (MMP) were assessed for their differences in chemical composition and in situ ruminal degradation. The contents of acid detergent fibre (P=0.073) and ether extract (P<0.0001) ranked as: MMP>MAL>MAR. Crude protein (CP), neutral detergent fibre and polyphenolic contents of the leaves did not differ between three species. Nylon bags containing the leaves were incubated for 2, 6, 12, 24, 36, 48 and 72h in three rumen cannulated dairy cows. Soluble CP fraction and fractional degradation rate did not differ between three species, but the potential degradable CP fraction in the leaves was greater for MAR than the others (P=0.005). Effective CP degradability was consistently ranked: MAR>MAL>MMP (P=0.051). Non-tannin phenols and total tannins were negatively correlated with the soluble CP fraction (r=−0.48, P<0.01) and the potential degradable CP fraction (r=−0.36, P<0.05), respectively. In summary, the mulberry leaves with high protein, low fibre and tannin contents could be exceptional forage for use in ruminant animals.

Sorption of Tannin and Related Phenolic Compounds and Effects on Extraction of Soluble-N in Soil Amended with Several Carbon Sources

Some tannins sorb to soil and reduce soluble-N. However, we know little about how they interact with organic amendments in soil. Soil (0–5 cm) from plots, which were amended annually with various carbon substances, was treated with water (control) or solutions containing tannins or related phenolic subunits. Treatments included a proanthocyanidin, catechin, tannic acid, β-1,2,3,4,6-penta-O-galloyl-D-glucose (PGG), gallic acid, and methyl gallate. We applied solutions of each of these materials to soil and measured soluble-C and -N in supernatants after application and following extraction with hot water (16 h, 80 °C). Sorption was low for non-tannin phenolics, methyl gallate, gallic acid, and catechin, and unaffected by amendment. Sorption of tannins, proanthocyanidin, tannic acid, and PGG, was higher and greater in plots amended with biosolids or manure. Extraction of soluble-N was not affected by amendment or by catechin, proanthocyanidin, or methyl gallate, but was reduced with PGG, tannic acid and gallic acid. Soil cation exchange capacity increased following treatment with PGG but decreased with gallic acid, irrespective of amendment. Tannins entering soil may thus influence soil organic matter dynamics and nutrient cycling but their impact may be influenced by the composition of soil organic matter.

Caution against Determining Tannins in Soil using the Protein Precipitable Phenolics Assay

The aim of this study was to assess the use of the protein precipitable phenolics assay as a method for estimating tannin in soil samples. This method is more selective than general methods such as Folin assays and is used to differentiate tannin from other phenolics in plant extracts. We evaluated the role of the protein as an agent that separated tannin from nontannin phenolics in soil by running the assay in the normal mode, with protein present, and in a modified format without the protein. We tested the method using native soils and soils amended with tannic acid. We found that this assay is not suitable for determining tannin in soil samples, because the protein precipitation step is incompatible with solid soil samples. We also assessed the background color of soil samples in the assay and established that background color is so high that reliable absorbance readings cannot be obtained.