An investigation of gram-negative tannin-protein complex degrading bacteria in fecal flora of various mammals

Dietary choices in a generalist herbivore, the eastern cottontail Sylvilagus floridanus, in urban landscapes

We tested for dietary choices of foods varying in nutrient composition by cottontail rabbits on two college campuses in midwestern USA. We quantified choices among pellets of varying nutritional quality at artificial food patches. Dietary choices differed between seasons and locations. Spring giving-up densities (GUDs: food left behind) did not show differences in food choices and were lower than summer GUDs. In Appleton, the cottontails favoured both high protein and fibre pellets, whereas the medium protein and fibre pellets were favoured in Chicago. The cottontails maintained their choice of high protein, high fibre pellets at three spatial scales. The cottontails varied food intake to balance their protein, salt and fibre needs at different times and locations. Studying dietary choices and the effect of resource quality on foraging responses by urban wildlife provides a useful tool to study ecological interactions and can help minimize damage in urban environments such as parks.

Comparative aspects of plant tannins on digestive physiology, nutrition and microbial community changes in sheep and goats: A review

Comparative aspects of plant tannins on digestive physiology, nutrition and microbial community in sheep and goats are discussed in the context of differences due to feed intake, digestibility, utilization of nutrients and microbial community. The purpose of this review was to present an overview of the potential benefits of tannin-containing diets for sheep and goats and specie differences in their response to tannins. It is well established that moderate level of tannins in the diet (3%-4% tannins DM) can precipitate with soluble proteins and increase protein supply to the sheep, but comparative aspects of tannin-containing diets in sheep and goats on animal performance, digestive physiology, rumen microbial changes and potential benefits to sustainable animal production by those compounds have received little attention. In addition, developing plant-based tannin-containing diets for control of rumen microbiota and rumen fermentation (e.g., methane gas) would be expected to have a greater impact on the ruminant health, productivity and emission of greenhouse gasses. The positive impacts of the plant tannin compounds mainly depend on their influence on the gut microbiome diversity and ability to generate fermentation end products (short-chain fatty acids) that have diverse biological roles. Diets which contain optimal levels of tannins have potential benefits for sustainability of small ruminant production systems. However, there is a need for an improved understanding of the utilization of tannin-containing forages to improve their management. This implies investigations of animal responses to tannin-containing forages or browse species and, in particular, a better understanding of the interactions that can arise between sheep and goats on digestion, DMD, rumen fermentation and microbial community changes. This knowledge could help to improve current feeding systems in terms of efficiency of feed use and environmental impacts (reduce methane gas production) and thus contribute to the development of a sustainable sheep and goat production.

Effects of tannins on population dynamics of sympatric seed-eating rodents: the potential role of gut tannin-degrading bacteria

Chemical compounds in seeds exert negative and even lethal effects on seed-consuming animals. Tannin-degrading bacteria in the guts of small mammals have been associated with the ability to digest seeds high in tannins. At the population level, it is not known if tannins influence rodent species differently according to the composition of their gut microbiota. Here, we test the hypothesis that sympatric tree species with different tannins exert contrasting effects on population fluctuations of seed-eating rodents. We collected a 10-year dataset of seed crops and rodent population sizes and sequenced 16S rRNA of gut microbes. The abundance of Apodemus peninsulae was not correlated with seed crop of either high-tannin Quercus mongolica or low-tannin Corylus mandshurica, but positively correlated with their total seed crops. Abundance of Tamias sibiricus was negatively correlated with seed crop of Q. mongolica but positively correlated with C. mandshurica. Body masses of A. peninsulae and T. sibiricus decreased when given high-tannin food; however, only the survival of T. sibiricus was reduced. The abundance of microbial genus Lactobacillus exhibiting potential tannin-degrading activity was significantly higher in A. peninsulae than in T. sibiricus. Our results suggest that masting tree species with different tannin concentrations may differentially influence population fluctuations of seed predators hosting different gut microbial communities. Although the conclusion is based on just correlational analysis of a short time-series, seeds with different chemical composition may influence rodent populations differently. Future work should examine these questions further to understand the complex interactions among seeds, gut microbes, and animal populations.

Links between Natural Variation in the Microbiome and Host Fitness in Wild Mammals

Recent studies in model organisms have shown that compositional variation in the microbiome can affect a variety of host phenotypes including those related to digestion, development, immunity, and behavior. Natural variation in the microbiome within and between natural populations and species may also affect host phenotypes and thus fitness in the wild. Here, I review recent evidence that compositional variation in the microbiome may affect host phenotypes and fitness in wild mammals. Studies over the last decade indicate that natural variation in the mammalian microbiome may be important in the assistance of energy uptake from different diet types, detoxification of plant secondary compounds, protection from pathogens, chemical communication, and behavior. I discuss the importance of combining both field observations and manipulative experiments in a single system to fully characterize the functions and fitness effects of the microbiome. Finally, I discuss the evolutionary consequences of mammal-microbiome associations by proposing a framework to test how natural selection on hosts is mediated by the microbiome.

Antibacterial activities of tannic acid against isolated ruminal bacteria from sheep

This present study was conducted to evaluate the antimicrobial effects of tannic acid (TA) against isolated ruminal bacteria from adult sheep. Rumen samples were collected from two (2) adults sheep, and a total of nine (9) ruminal bacteria were isolated from the sample. The sensitivity of the ruminal bacteria isolates to 0.63, 1.25, 2.50, 5.00 and 10.00 mg TA/mL of growth medium was determined using clearance zone (CZ) of Kirby-Bauer disc diffusion susceptibility test. There was observable increase in the sensitivity of all bacterial isolates as the level of TA increases. Not all bacterial isolates have the capacity to tolerate more than 1.25 mg TA/mL. The result shows that only 20% of the bacterial isolates had the capacity to tolerate 0.63 and 1.25 mg of tannic acid per liter. This concentration of tannic acid would be equivalent to 2% tannin in the diet of ruminant. Our findings shows that increase in concentration of tannic acid completely inhibited the ruminal bacteria from the sheep rumen.

Multifarious activities of cellulose degrading bacteria from Koala (Phascolarctos cinereus) faeces

Cellulose degrading bacteria from koala faeces were isolated using caboxymethylcellulose-Congo red agar, screened in vitro for different hydrolytic enzyme activities and phylogenetically characterized using molecular tools. Bacillus sp. and Pseudomonas sp. were the most prominent bacteria from koala faeces. The isolates demonstrated good xylanase, amylase, lipase, protease, tannase and lignin peroxidase activities apart from endoglucanase activity. Furthermore many isolates grew in the presence of phenanthrene, indicating their probable application for bioremediation. Potential isolates can be exploited further for industrial enzyme production or in bioremediation of contaminated sites.

Tannin-degrading bacteria with cellulase activity isolated from the cecum of the Qinghai-Tibet plateau zokor (Myospalax baileyi)

Tannins, which are polyphenols present in various plants, have anti-nutritional activity; however, their negative effects are mitigated by the presence of tannin-degrading microorganisms in the gastrointestinal tract of animals. This has never been investigated in the plateau zokor (Myospalax baileyi) – the predominant small herbivore in the alpine meadow ecosystem of Qinghai Province, China – which consumes tannin-rich herbaceous plants. Tannase activity in the feces of the plateau zokor increased from June to August corresponding to the increase in hydrolyzable tannin concentrations in plants during this period, and three tannin-degrading facultative anaerobic strains (designated as E1, E2, and E3) were isolated from the cecum of these animals. Sequencing of the 16S rDNA gene identified isolates of strain E1 as belonging to the genusEnterococcus, and E2 and E3 to the genusBacillus. All of the bacteria had cellulose-degrading capacity. This study provides the first evidence of symbiotic bacterial strains that degrade tannic acid and cellulose in the cecum of plateau zokor.

Biodegradation of gallotannins and ellagitannins

Nowadays, many researches have been made on gallotannin biodegradation and have gained great success in further utilization. Some of industrial applications of these findings are in the production of tannase, the biotransformation of tannic acid to gallic acid or pyrogallol and detannification of food and fodder. Although ellagitannins have the typical C-C bound which is more difficult to be degraded than gallotannins, concerted efforts are still in progress to improve ellagitannin degradation and utilization. Currently, more attention is mainly focused on intestinal microflora biodegradation of tannins especially ellagitannins which can contribute to the definition of their bioavailability for both human beings and ruminants. Also there have been endeavours to utilize the tannin-degrading activity of different fungi for ellagitannin-rich biomass, which will facilitate application of tannin-degrading enzymes in strategies for improving industrial and livestock production. Due to the complicated structures of complex tannins and condensed tannins, the biodegradation of them is much more difficult and there are fewer researches on them. Therefore, the researches on the mechanisms of gallotannin and ellagitannin biodegradation can result in the overall understanding to the biodegradation of complex tannins and condensed tannins. Biodegradation of tannins is in an incipient stage and further studies have to be carried out to exploit the potential of various tannins for largescale applications in food, fodder, medicine and tannery effluent treatment.

Interaction of gut microflora with tannins in feeds

Tannins (hydrolyzable and condensed) are water-soluble polyphenolic compounds that exert antinutritional effects on ruminants by forming complexes with dietary proteins. They limit nitrogen supply to animals, besides inhibiting the growth and activity of ruminal microflora. However, some gastrointestinal microbes are able to break tannin-protein complexes while preferentially degrading hydrolyzable tannins (HTs). Streptococcus gallolyticus, Lonepinella koalarum and Selenomonas ruminantium are the dominant bacterial species that have the ability to degrade HTs. These tanninolytic microorganisms possess tannin-degrading ability and have developed certain mechanisms to tolerate tannins in feeds. Hence, selection of efficient tanninolytic microbes and transinoculation among animals for long-term benefits become areas of intensive interest. Here, we review the effects of tannins on ruminants, the existence and significance of tannin-degrading microorganisms in diverse groups of animals and the mechanisms that tannin-degrading microorganisms have developed to counter the toxic effects of tannin.

Isolation of tannin-degrading bacteria isolated from feces of the Japanese large wood mouse, Apodemus speciosus, feeding on tannin-rich acorns

Bacteria with tannase activity were isolated from the feces of the Japanese large wood mouse, Apodemus speciosus. They were largely classified into two groups: Gram-positive cocci and Gram-positive bacilli. Genotypic analysis using a species-specific PCR assay as well as biochemical tests identified all cocci as Streptococcus gallolyticus. A PCR assay targeting a genus-specific sequence in the 16S/23S rDNA spacer region and additional 16S rDNA sequencing indicated that the bacilli belong to the genus Lactobacillus, with L. animalis and L. murinus being closely related taxa. Subsequent estimation of guanine-plus-cytosine content, amplified ribosomal DNA restriction analysis, and DNA/ DNA hybridization assay confirmed that the bacilli are homologous to each other but different from L. animalis or L. murinus. Consequently, a novel species of the genus Lactobacillus may be proposed. To date, this study is the first to report on the isolation of tannase-positive bacteria from the feces of a rodent species. These bacteria may play an essential role for the host organism in digesting tannin-rich acorns available in their natural habitats, thereby endowing them with a greater ecological advantage.

Bacterial mechanisms to overcome inhibitory effects of dietary tannins

High concentrations of tannins in fodder plants inhibit gastrointestinal bacteria and reduce ruminant performance. Increasing the proportion of tannin-resistant bacteria in the rumen protects ruminants from anti-nutritional effects. The reason for the protective effect is unclear, but could be elucidated if the mechanism(s) by which tannins inhibit bacteria and the mechanisms of tannin resistance were understood. A review of the literature indicates that the ability of tannins to complex with polymers and minerals is the basis of the inhibitory effect on gastrointestinal bacteria. Mechanisms by which bacteria can overcome inhibition include tannin modification/degradation, dissociation of tannin-substrate complexes, tannin inactivation by high-affinity binders, and membrane modification/repair and metal ion sequestration. Understanding the mechanism of action of tannins and the mechanism(s) bacteria use to overcome the inhibitory effects will allow better management of the rumen ecosystem to reduce the anti-nutritional effects of tannin-rich fodder plants and thereby improve ruminant production.

Method for analysis of tannic acid and its metabolites in biological samples: application to tannic acid metabolism in the rat

A new analytical method for measuring tannic acid (TA) using tannase was developed and applied to the investigation of TA metabolism in the rat following oral administration at a dose of 1.0 g/kg. The proposed method for TA determination was based on the enzymatic hydrolysis of TA to gallic acid (GA) and subsequent determination by HPLC. TA metabolites were determined by HPLC. 4-O-Methylgallic acid (4-OMGA), pyrogallol (PY), and resorcinol (RE) were detected in serum. TA was excreted into urine as GA (0.01%), 4-OMGA (0.10%), PY (0.24%), and RE (2.06%) and into feces as TA (62.74%), GA (0.19%), PY (0.02%), and RE (0.76%) within 54 h after oral administration. It was suggested that >60% of TA remained unchanged but that some was hydrolyzed to GA by tannase in the intestine and further metabolized to 4-OMGA, PY, and RE.

Catechins are bioavailable in men and women drinking black tea throughout the day

Tea consumption has been associated with reduced risk of both cancer and cardiovascular disease in population studies, but clinical data demonstrating bioavailability of the individual catechins and other polyphenolic components of tea are limited. This study assessed the apparent bioavailability of the prominent catechins from black tea in humans drinking tea throughout the day. After 5 d of consuming a low flavonoid diet, subjects drank a black tea preparation containing 15.48, 36.54, 16.74, and 31.14 mg of (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG), respectively, at four time points (0, 2, 4 and 6 h). Blood, urine and fecal specimens were collected over a 24- to 72-h period and catechins were quantified by HPLC with coularray detection. Plasma concentrations of EGC, EC and EGCG increased significantly relative to baseline (P < 0.05). Plasma EGC, EC and EGCG peaked after 5 h, whereas ECG peaked at 24 h. Urinary excretion of EGC and EC, which peaked at 5 h, was increased relative to baseline amounts (P < 0.05) and fecal excretion of all four catechins was increased relative to baseline (P < 0.05). Approximately 1.68% of ingested catechins were present in the plasma, urine and feces, and the apparent bioavailability of the gallated catechins was lower than the nongallated forms. Thus, catechins were bioavailable. However, unless they are rapidly metabolized or sequestered, the catechins appeared to be absorbed in amounts that were small relative to intake.

Isolation of tannin-degrading lactobacilli from humans and fermented foods

Lactobacilli with tannase activity were isolated from human feces and fermented foods. A PCR-based taxonomic assay revealed that the isolates belong to Lactobacillus plantarum, L. paraplantarum, and L. pentosus. Additional studies on a range of Lactobacillus species from established culture collections confirmed that this enzymatic activity is a phenotypic property common to these three species.

Isolation and characterization of proteolytic ruminal bacteria from sheep and goats fed the tannin-containing shrub legume Calliandra calothyrsus

Tannins in forages complex with protein and reduce the availability of nitrogen to ruminants. Ruminal bacteria that ferment protein or peptides in the presence of tannins may benefit digestion of these diets. Bacteria from the rumina of sheep and goats fed Calliandra calothyrsus (3.6% N and 6% condensed tannin) were isolated on proteinaceous agar medium overlaid with either condensed (calliandra tannin) or hydrolyzable (tannic acid) tannin. Fifteen genotypes were identified, based on 16S ribosomal DNA-restriction fragment length polymorphism analysis, and all were proteolytic and fermented peptides to ammonia. Ten of the isolates grew to high optical density (OD) on carbohydrates (glucose, cellobiose, xylose, xylan, starch, and maltose), while the other isolates did not utilize or had low growth on these substrates. In pure culture, representative isolates were unable to ferment protein that was present in calliandra or had been complexed with tannin. One isolate, Lp1284, had high protease activity (80 U), a high specific growth rate (0.28), and a high rate of ammonia production (734 nmol/min/ml/OD unit) on Casamino Acids and Trypticase Peptone. Phylogenetic analysis of the 16S ribosomal DNA sequence showed that Lp1284 was related (97. 6%) to Clostridium botulinum NCTC 7273. Purified plant protein and casein also supported growth of Lp1284 and were fermented to ammonia. This is the first report of a proteolytic, ammonia-hyperproducing bacterium from the rumen. In conclusion, a diverse group of proteolytic and peptidolytic bacteria were present in the rumen, but the isolates could not digest protein that was complexed with condensed tannin.

Purification and characterization of gallic acid decarboxylase from pantoea agglomerans T71

Oxygen-sensitive gallic acid decarboxylase from Pantoea (formerly Enterobacter) agglomerans T71 was purified from a cell extract after stabilization by reducing agents. This enzyme has a molecular mass of approximately 320 kDa and consists of six identical subunits. It is highly specific for gallic acid. Gallic acid decarboxylase is unique among similar decarboxylases in that it requires iron as a cofactor, as shown by plasma emission spectroscopy (which revealed an iron content of 0.8 mol per mol of enzyme subunit), spectrophotometric analysis (absorption shoulders at 398 and 472 nm), and inhibition of the enzyme activity by 2,2'-bipyridyl, o-phenanthroline, and EDTA. Another interesting feature of this strain is the fact that it contains a tannase, which is used together with the gallic acid decarboxylase in a two-enzyme resting cell bioconversion to synthesize valuable pyrogallol from readily available tannic acid.

Phenotypic and phylogenetic characterization of ruminal tannin-tolerant bacteria

The 16S rRNA sequences and selected phenotypic characteristics were determined for six recently isolated bacteria that can tolerate high levels of hydrolyzable and condensed tannins. Bacteria were isolated from the ruminal contents of animals in different geographic locations, including Sardinian sheep (Ovis aries), Honduran and Colombian goats (Capra hircus), white-tail deer (Odocoileus virginianus) from upstate New York, and Rocky Mountain elk (Cervus elaphus nelsoni) from Oregon. Nearly complete sequences of the small-subunit rRNA genes, which were obtained by PCR amplification, cloning, and sequencing, were used for phylogenetic characterization. Comparisons of the 16S rRNA of the six isolates showed that four of the isolates were members of the genus Streptococcus and were most closely related to ruminal strains of Streptococcus bovis and the recently described organism Streptococcus gallolyticus. One of the other isolates, a gram-positive rod, clustered with the clostridia in the low-G+C-content group of gram-positive bacteria. The sixth isolate, a gram-negative rod, was a member of the family Enterobacteriaceae in the gamma subdivision of the class Proteobacteria. None of the 16S rRNA sequences of the tannin-tolerant bacteria examined was identical to the sequence of any previously described microorganism or to the sequence of any of the other organisms examined in this study. Three phylogenetically distinct groups of ruminal bacteria were isolated from four species of ruminants in Europe, North America, and South America. The presence of tannin-tolerant bacteria is not restricted by climate, geography, or host animal, although attempts to isolate tannin-tolerant bacteria from cows on low-tannin diets failed.