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The food we consume and its interactions with the host and their gut microbiota affect normal gut function and health. Functional gut disorders (FGDs), including irritable bowel syndrome (IBS), can result from negative effects of these interactions, leading to a reduced quality of life. Certain foods exacerbate or reduce the severity and prevalence of FGD symptoms. IBS can be used as a model of perturbation from normal gut function with which to study the impact of foods and diets on the severity and symptoms of FGDs and understand how critical processes and biochemical mechanisms contribute to this impact. Analyzing the complex interactions between food, host, and microbial metabolites gives insights into the pathways and processes occurring in the gut which contribute to FGDs. The following review is a critical discussion of the literature regarding metabolic pathways and dietary interventions relevant to FGDs. Many metabolites, for example bile acids, SCFAs, vitamins, amino acids, and neurotransmitters, can be altered by dietary intake, and could be valuable for identifying perturbations in metabolic pathways that distinguish a “normal, healthy” gut from a “dysfunctional, unhealthy” gut. Dietary interventions for reducing symptoms of FGDs are becoming more prevalent, but studies investigating the underlying mechanisms linked to host, microbiome, and metabolite interactions are less common. Therefore, we aim to evaluate the recent literature to assist with further progression of research in this field.

Background Human health depends on a population of microorganisms that inhabit the gut and contribute to homeostasis of the host, including nutrition, immunity and metabolism. Many of the organisms are interactive and mutually dependent, where the end-products for one organism become the fuel for another through substrate and metabolic cross-feeding. To optimise the gut microbiota using diet, the composition and functionality of the gut microbiota, including these interacting networks, must be understood. Microbial composition and functionality is affected by the structure of the energy input, which is primarily dietary fibre for the gut microbiota. The structure of dietary fibre has been reviewed by carbohydrate chemists, but knowledge of how dietary fibre structure affects the gut microbiota is limited. Scope and approach The hierarchical structures of dietary fibre are reviewed, encompassing macrostructure, mesostructure and molecular structure, and how they are affected by food processing and digestion. These factors are considered in relation to their affects on microbial composition and functionality, to provide insight on the interactions between diet, the microbiota, and human health. Key findings and conclusions Food processing and digestion affect food structure, primarily through the removal of some soluble fractions and increased solubilisation of insoluble fractions. The provision of insoluble carbohydrates to the colon appears important for the sustenance of ‘keystone’ species that play a crucial role in stabilising the gut community. Further work is needed at the microbial strain level to understand the impact of increasing fibre solubility. This should be done in studies using well-characterised carbohydrates that consider the impact of food processing and digestion.

'Go Slow myopathy' (GSM) is a suspected toxic myopathy in dogs that primarily occurs in the North Island of New Zealand, and affected dogs usually have a history of consuming meat, offal or bones from wild pigs (including previously frozen and/or cooked meat). Previous epidemiological and pathological studies on GSM have demonstrated that changes in mitochondrial structure and function are most likely caused by an environmental toxin that dogs are exposed to through the ingestion of wild pig. The disease has clinical, histological and biochemical similarities to poisoning in people and animals from the plant Ageratina altissima (white snakeroot). Aqueous and lipid extracts were prepared from liver samples of 24 clinically normal dogs and 15 dogs with GSM for untargeted liquid chromatography-mass spectrometry. Group-wise comparisons of mass spectral data revealed 38 features that were significantly different (FDR

The influence of route of administration on the pharmacokinetics and efficacy of macrocyclic lactone anthelmintics has been a subject of interest due to its potential to influence the development of anthelmintic resistance. For most parasite species studied so far, oral administration results in the highest concentrations of drug in the parasites and the highest efficacy against resistant genotypes. However, a recent study in cattle measured the highest levels of ivermectin in the abomasal Ostertagia ostertagi following subcutaneous injection, but it was not possible to correlate these elevated levels with efficacy. Therefore, the current study was initiated to determine whether injectable delivery might be optimal for attaining high efficacy against this important group of parasites. Three on-farm trials were conducted to measure the efficacy of moxidectin administered by the oral, injectable, and pour-on routes against Ostertagiinae parasites in farmed red deer. Groups of rising 1-year old stags (red or red-wapiti crossbreds) in the 84−104 kg weight range were randomised on liveweight into treatment groups of 6 (1 farm) or 8 (2 farms). Animals were treated to individual liveweight with moxidectin oral (0.2 mg/kg), injectable (0.2 mg/kg), pour-on (0.5 mg/kg) or remained untreated. Twelve days later all animals were euthanised and abomasa recovered for worm count. Adult worms were counted in a 2% aliquot of abomasal washings, and adult and fourth stage larvae in a 10 % aliquot following mucosal incubation in physiological saline. In addition, blood was collected from the same 5 animals in each of the treatment groups on days 0, 1, 2, 3, 5, 7 and 12 after treatment and moxidectin levels in plasma were determined using a mass spectrometer. The number of Ostertagiinae surviving treatment was significantly different for each of the treatment groups with injectable administration being most effective, oral administration being the next most effective and pour-on administration the least effective. This applied to both adult worms and fourth stage larvae. A similar pattern was seen in the levels of moxidectin in plasma with both the peak value and area under the concentration curve being highest following injectable administration and lowest following pour-on treatment. Although undertaken in a different host species, the results support the proposition that injectable administration of macrocyclic lactone anthelmintics is likely to be optimal for efficacy against Ostertagiinae parasites and potentially useful in slowing the emergence of resistance in these parasites.

Seasonal variation of milk composition poses a challenge for maintaining dairy product quality. Multivariate statistical techniques were used here to identify seasonal patterns in mineral levels, fatty acid profiles and selected metabolites for New Zealand raw milk collected from 24 individual cows in early-season (November), mid-season (January/February) and late-season (March). Partial least-squares discriminant analysis (PLS-DA) showed clear seasonal differences in mineral and fatty acid profiles that may have been related to supplementary feeding, dilution effects (higher total solids in late-season milk) and the lactation cycle. Fatty acid profiles showed an inverse relationship between the C6–C12 fatty acids and the branched- or long-chain fatty acids, which was thought to be related to feeding of maize in mid- and late-season. Targeted metabolite analysis suggested elevated phosphatase activity in March, and this warrants further investigation as an indicator of metabolic changes related to declining milk quality at the end of the milking season.

Summary: This protocol describes the application of breath testing and ex vivo fermentations to study the association between breath methane and the composition and functionality of the gut microbiome. The protocol provides a useful systems biology approach for studying the gut microbiome in humans, which combines standardized methods in human breath testing and fecal sampling. The model described is accessible and easy to repeat, but its relative simplicity means that it can deviate from human physiological conditions.

Meat colour is one of the cues available to the consumer to gauge overall meat quality and wholesomeness. Colour stability of meat is determined by several factors both inherent to the animal and post-slaughter conditions, including ageing, storage/packaging and display times. A hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) based metabolomics study was undertaken to identify and compare polar metabolites between ovine meat samples that were exposed to different durations of ageing, storage conditions, and display times. Primary metabolites comprising amino acids, sugars, nucleotides, nucleosides, organic acids and their breakdown products were mainly identified as discriminating factors. For the first time, boron complexes of sugar and malic acid were also tentatively identified. As expected, most compounds identified were related to myoglobin chemistry, and compounds with antioxidant properties were found in higher levels in colour stable samples. Supplementary studies identifying semi-polar, non-polar and volatile compounds will provide a holistic understanding of the chemical basis of colour stability in ovine meat.

OBJECTIVES: The rapid diversification of foods introduced during complementary feeding coincides with profound changes in the infant gut microbiome, with potential effects on immediate and long-term health outcomes. The objective of this study is to elucidate dietary modulators of the infant gut microbiome by characterising dietary intake by food groups, nutrient composition, and nutrient source, followed by multivariate integration with faecal microbiome data. METHODS: Three-day food records were collected from a cohort of 40 infants recruited from the Auckland metropolitan area in New Zealand, who participated in a 6-month dietary intervention clinical pilot study. Thirty infants were provided kumara as an additional food to include in the daily diet, while 10 infants were provided commercially available probiotic drops (Bifidobacterium lactis) as a daily supplement. Faecal samples were collected on the final day of the 3-day food record at approximately 6, 9, and 12 months of age, and analysed using shotgun metagenomics and global metabolite profiling. Multivariate approaches have been used to integrate diet, microbiome, and metabolomic data. RESULTS: Preliminary results indicated that at 9 months of age some B-vitamins and minerals from meat products were strongly correlated (coefficient of ≥.6 using canonical correlations) with increased microbiome amino acid metabolism and biosynthesis, whereas a strong inverse correlation (≤–.6) was observed between breastmilk and dietary fibre consumption. At 12 months of age, the significance of associations throughout the network were diminished, and food intake data suggested that legumes, eggs, dairy products, breastmilk, and infant formula were the predominant modulators of metabolic pathways. CONCLUSIONS: While specific nutrients and food groups correlate independently with significant alterations in the microbiome, merging these metrics to encompass nutrient source provides a more complete understanding of dietary modulators from the perspective of the gut microbiome. The immature gut microbiome of younger infants may be more profoundly influenced by dietary factors than increasingly mature microbiomes. FUNDING SOURCES: This study was funded by the New Zealand Ministry of Business, Innovation, & Employment High-Value Nutrition National Science Challenge.

OBJECTIVES: Dietary fibre supplementation is recognised as important for functional gastrointestinal disorders (FGID). The exact role of the microbiome in this relationship remains unclear. We explored differences in dietary fibre intake, GI symptoms and the fecal microbiome in those with FGID. METHODS: The COMFORT cohort is an observational case control study examining FGID, particularly irritable bowel syndrome (IBS) aetiology (Ethics 16/NTA/21). Participants prospectively completed a food and GI symptoms diary over 3 days. Severity of GI symptoms and mood disorders were assessed using clinical questionnaires; SAGIS and PROMIS for GI symptoms and HADS for anxiety and depression. Fecal samples were analysed by shotgun sequencing; 95 healthy controls (HC), 22 constipation IBS (IBS-C) and 50 diarrhea IBS (IBS-D). Taxonomic classifications were assigned by aligning sequences against the NCBI non-redundant database using DIAMOND. RESULTS: Diet diaries were completed by 292 participants (176 cases, 71.2% female). Average daily fibre intake was higher in HC compared to FGID (23.99g, 95% CI = –2.06-0.55; 20.28g, 95% CI = -1.96-0.45; P |0.5|). At the genus level, Blautia were correlated with diarrhea and faecal incontinence (canonical r > 0.5). CONCLUSIONS: Higher fibre consumption was associated with decreased bloating, anxiety and depression in different FGID subgroups. IBS was also associated with altered fecal microbiome composition including some taxa linked to carbohydrate and hydrogen metabolism. FUNDING SOURCES: Funded by the Ministry of Business, Innovation and Employment through the High-Value Nutrition National Science Challenge.

OBJECTIVES: Vitamin deficiencies are prevalent in the elderly. Common diseases of aging are characterized by alterations of one-carbon (1C) metabolites, namely homocysteine. Despite the importance of diet-derived nutrients and interconversion to active coenzymes for regulation of 1C metabolism, little is known about age-related alterations in 1C metabolism in response to meals. This study aimed to identify whether postprandial 1C metabolite regulation is impaired in older adults, and determine the influence of meal type. We hypothesized that older adults would have altered 1C metabolite responses, and that these would differ between energy dense and nutrient dense meals. METHODS: In a double-blinded randomized crossover design, healthy younger (n = 15) and older (n = 15) adults consumed mixed-meal breakfasts on separate occasions: an energy-dense (ED) meal (sausage and egg sandwich) and a nutrient-dense (ND) meal (oats, toast, cottage cheese and fruit). Plasma collected at fasting and hourly for 5 h was analysed for 12 1C metabolites using high-performance liquid chromatography with tandem mass spectrometry. RESULTS: Postprandial concentrations of five 1C metabolites differed between older and younger subjects, dependent on meal type. Unlike younger subjects, older subjects had similar meal responses for betaine, choline, taurine, and glycine concentrations (meal × age interactions P 0.05 each, respectively). Younger subjects had higher homocysteine concentrations than older after the ED meal (meal × age interaction P

OBJECTIVES: The nutritional composition of human milk is affected by many factors, including stage of lactation and time of day. Metabolomic profiling of milk provides a biochemical fingerprint of hundreds of metabolites being consumed by the infant, which may help to understand potential factors affecting infant health, growth and nutritional status. We hypothesized that frequency of daily lactations would alter the profile of metabolites and lipids in the milk. METHODS: Human milk samples from 630 individuals [378 mothers exclusively breast feeding and 252 mothers partially breast feeding (i.e., infant supplemented with formula feeding)] from a single sample (infant aged 3 months) were subjected to biphasic extraction and metabolite profiling performed using two separate untargeted liquid chromatography high resolution mass spectrometry analysis methods (polar metabolites and the lipidome). RESULTS: Univariate statistical analysis of the lipidome data matrix revealed considerable differences in lipid concentrations between partial or exclusive feeding. Of the 241 lipids measured in the non-polar extracts, 203 were significantly different between the two groups after multiple testing correction (FDR corrected p-value

Fungal endophytes belonging to the genus Epichloë form associations with temperate grasses belonging to the sub-family Poöideae that range from mutualistic through to pathogenic. We previously identified a novel endophyte gene (designated gigA for grass induced gene) that is one of the most abundantly expressed fungal transcripts in endophyte-infected grasses and which is distributed and highly expressed in a wide range of Epichloë grass associations. Molecular and biochemical analyses indicate that gigA encodes a small secreted protein containing an imperfect 27 amino acid repeat that includes a kexin protease cleavage site. Kexin processing of GigA liberates within the plant multiple related products, named here as epichloëcyclins, which we have demonstrated by MS/MS to be cyclic peptidic in nature. Gene deletion of gigA leads to the elimination of all epichloëcyclins with no conspicuous phenotypic impact on the host grass, suggesting a possible bioactive role. This is a further example of a ribosomal peptide synthetic (RiPS) pathway operating within the Ascomycetes, and is the first description of such a pathway from a mutualistic symbiotic fungus from this Phylum.

Administration of long-acting anthelmintics to pregnant ewes prior to lambing is a common practice in New Zealand. Today, most of these products contain macrocyclic lactone (ML) actives, which because of their lipophilic nature, are detectable in the milk of treated animals and in the plasma of their suckling offspring. This study was conducted to confirm the transfer of ML actives to lambs in the ewe's milk, and to assess whether this could result in selection for ML resistant nematodes in the lamb. Ninety, twin bearing Romney ewes were treated before lambing with a long-acting injectable formulation of moxidectin, a 100-day controlled release capsule (CRC) containing abamectin and albendazole, or remained untreated. After lambing, seven ewes from each treatment group were selected for uniformity of lambing date and, along with their twin lambs, relocated indoors. At intervals, all ewes and lambs were bled, and samples of ewe's milk were collected, for determination of drug concentrations. Commencing 4 weeks after birth all lambs were dosed weekly with 250 infective larvae (L3) of either an ML-susceptible or –resistant isolate of Teladorsagia circumcinta. At 12 weeks of age all lambs were slaughtered and their abomasa recovered for worm counts. Moxidectin was detected in the plasma of moxidectin-treated ewes until about 50 days after treatment and in their lambs until about day 60. Abamectin was detected in the plasma of CRC-treated ewes until the last sample on day 80 and in the plasma of their lambs until about day 60. Both actives were detectable in milk of treated ewes until day 80 after treatment. Establishment of resistant L3 was not different between the treatment groups but treatment of ewes with moxidectin reduced establishment of susceptible L3 by 70%, confirming the potential of drug transfer in milk to screen for ML-resistance in the suckling lamb., Graphical abstract, Highlights • Long-acting anthelmintics were administered to pregnant ewes. • Moxidectin and abamectin were detected in ewe's milk for >60 days. • Moxidectin and abamectin were detected in plasma of lambs for >60 days. • Abamectin treatment had not effect on establishment of larvae in the lambs. • Moxidectin treatment reduced establishment of susceptible, but not resistant larvae.

OBJECTIVES: Irritable Bowel Syndrome (IBS) is a functional gastrointestinal (GI) disorder featuring chronic or recurrent abdominal discomfort, usually with changes in GI habit. To improve our understanding of links between the microbiome and IBS, and how these links can be manipulated through diet, we undertook shotgun metagenomic sequencing of fecal samples from a case-control study. METHODS: Fecal samples from 172 individuals were analyzed by shotgun sequencing using the Illumina NextSeq platform. Of these, 77 were classified as controls, 16 were constipation-predominant IBS (IBS-C), 39 were diarrhea-predominant IBS (IBS-D), 29 were diagnosed with functional constipation (FC), and 11 had functional diarrhea (FD). Taxonomic classifications were determined using Metaxa2 and the SILVA 128 database. Gene functions were assigned by alignment of sequences against a protein reference database using DIAMOND. Mean relative abundance of bacterial taxa and functional genes were compared using permutation ANOVA. Ethical approval was obtained from the University of Otago Human Ethics Committee (Health) (Reference H16/094). RESULTS: Bacterial genera that discriminated case-controls (P

OBJECTIVES: Plasma levels of branched-chain amino acids (BCAA) and aromatic amino acids (AAA) phenylalanine (phe) and tyrosine (tyr) have been associated with obesity, insulin resistance and risk of type 2 diabetes. This study aimed to investigate the response of circulating plasma and tissue levels of BCAA and AAA to weight loss, and to correlate the level of these metabolites in plasma and tissue in obese women. METHODS: 28 obese (mean BMI 46.2 kg/m(2)) women underwent low energy diet (LED)-induced weight loss (−9.2 ± 4.2 kg) followed by bariatric surgery-induced weight loss (−23.6 ± 2.5 kg). Plasma at baseline (t0), post-LED/pre-surgery (t1) and 6-month post-surgery (t2) as well as biopsies of subcutaneous abdomen adipose tissue (SAfat), superficial thigh adipose tissue (Tfat) and vastus lateralis thigh muscle (Tmuscle) at both t1 and t2 were collected, and profiled using mass spectrometry-based metabolomics approach. Paired t-tests were applied to assess between-timepoint differences, and Pearson correlation used to calculate correlation coefficient of metabolite levels between plasma and tissue. RESULTS: Plasma BCAA and AAA were all significantly reduced post-LED at t1 (fold-change of 0.76–0.85 for val, leu, ile, tyr and phe, P

Tea is an infusion made from the dried leaves of Camellia sinensis L. and is the second most consumed beverage in the world. It has been shown that factors such as fermentation methods, cultivar, geographical origin and season can affect the biochemical composition of tea. In this study, the biochemical composition of green, oolong and black commercial tea samples from around the world was studied using a non-targeted method utilising reversed phase ultra high pressure liquid chromatography (UHPLC) and high resolution mass spectrometry. Principal component analysis of green, oolong and black tea extracts clearly showed that fermented tea can be resolved from non-fermented tea. When the non-targeted data were combined with the supervised multivariate technique, partial least squares discriminant analysis, the method was able to clearly distinguish ‘country of origin’ within green tea and to a lesser extent within a black tea sample set, plus provide indicative marker ions for the country of origin. Many of the significant components detected in this study are unknowns, emphasising the importance of un-biased non-targeted analytical techniques. This study highlights the potential efficacy of non-targeted UHPLC–mass spectrometry when combined with multivariate statistics to differentiate fermented from non-fermented tea and provide potential indicators of provenance of tea samples for further examination.

Tea is the second most consumed beverage in the world and its consumption has been associated with numerous potential health benefits. Factors such as fermentation methods, geographical origin and season can affect the primary and secondary metabolite composition of tea. In this study, a hydrophilic interaction liquid chromatography (HILIC) method coupled to high resolution mass spectrometry in both positive and negative ionisation modes was developed and optimised. The method when combined with principal component analysis to analyse three different types of tea, successfully distinguished samples into different categories, and provided evidence of the metabolites which differed between them. The accurate mass and high resolution attributes of the mass spectrometric data were utilised and relative quantification data were extracted post-data acquisition on 18 amino acids, showing significant differences in amino acid concentrations between tea types and countries. This study highlights the potential of HILIC chromatography combined with non-targeted mass spectrometric methods to provide a comprehensive understanding of polar metabolites in plant extracts.

Polyphenolics are an important class of biologically active compounds found in plants and are purported to have benefits for human health. To assess their significance in foods, improved methods are required for their detection and classification. In this paper, we describe a targeted MS2 approach using an ion-trap mass spectrometer for the analysis and classification of proanthocyanidins (PAs) in crude plant-derived extracts, which has been applied to compare green, oolong and black tea crude extracts and a grape seed extract. The method could separate, detect and provide qualitative information (full scan MS2 spectra) to enable chromatographic and mass spectral confirmation of PAs in the crude tea extracts. Using the developed methodology we report here for the first time the detection of PA tetramers in black tea, and PA trimers and tetramers in oolong tea.

Graphical abstract Epichloënin A (1) has been isolated from fungal cultures together with a minor variant epichloënin B, and ferriepichloënin A and a related peptide epichloëamide have been found in endophyte-infected plants. Highlights ► Epichloënin A has been characterized as a ferrichrome octapeptide by HRMSn and NMR. ► The minor heptapeptide variant epichloënin B has been characterized by HRMSn. ► Ferriepichloënin A was detected in guttation fluid of endophyte-infected plants. ► The related peptide epichloëamide was also detected in guttation fluid. ► Epichloëamide has been characterized as an octapeptide by HRMSn., A number of genes encoding non-ribosomal peptide synthetases (NRPSs) have been identified in fungi of Epichloë/Neotyphodium species, endophytes of Pooid grasses, including sidN, putatively encoding a ferrichrome siderophore-synthesizing NRPS. Targeted gene replacement and complementation of sidN in Epichloë festucae has established that extracellular siderophore epichloënin A is the major product of the SidN enzyme complex (Johnson et al., 2007a). We report here high resolution mass spectrometric fragmentation experiments and NMR analysis of an isolated fraction establishing that epichloënin A is a siderophore of the ferrichrome family, comprising a cyclic sequence of four glycines, a glutamine and three Nδ-trans-anhydromevalonyl–Nδ-hydroxyornithine (AMHO) moieties. Epichloënin A is unusual among ferrichrome siderophores in comprising an octapeptide rather than hexapeptide sequence, and in incorporating a glutamine residue. During this investigation we have established that desferrichrome siderophores with pendant trans-AMHO groups can be distinguished from those with pendant cis-AMHO groups by the characteristic neutral loss of an hydroxyornithine moiety in the MS/MS spectrum. A minor component, epichloënin B, has been characterized as the triglycine variant by mass spectrometry. A peptide characterized by mass spectrometry as the putative deoxygenation product, epichloëamide has been detected together with ferriepichloënin A in guttation fluid from ryegrass (Lolium perenne) plants infected with wild-type E. festucae, but not in plants infected with the ΔsidN mutant strain, and also detected at trace levels in wild-type E. festucae fungal culture.

Microarrays produce high-resolution image data that are, unfortunately, permeated with a great deal of ''noise'' that must be removed for precision purposes. This paper presents a technique for such a removal process. On completion of this non-trivial task, a new surface (devoid of gene spots) is subtracted from the original to render more precise gene expressions. The graph-cutting technique as implemented has the benefits that only the most appropriate pixels are replaced and these replacements are replicates rather than estimates. This means the influence of outliers and other artifacts are handled more appropriately (than in previous methods) as well as the variability of the final gene expressions being considerably reduced. Experiments are carried out to test the technique against commercial and previously researched reconstruction methods. Final results show that the graph-cutting inspired identification mechanism has a positive significant impact on reconstruction accuracy.

Based on direct infusion mass spectrometry we identified a novel alkaloid as a major component of perennial ryegrass (Lolium perenne). Initial mass spectral data suggested it to be a pyrrolizidine conjugate. As this class of alkaloids has not been described before from grasses, we isolated it to elucidate its structure. The isolated alkaloid proved to be a mixture of two stereoisomers. The structures of the two compounds as determined by 1D and 2D NMR spectroscopy, were E-thesinine-O-4′-α-rhamnoside (1) and Z-thesinine-O-4′-α-rhamnoside (2). These identifications were supported by the characterisation by GC-MS and optical rotation of (+)-isoretronecanol as the necine base released on alkaline hydrolysis of these alkaloids. 1 and 2 together with the aglycone and a hexoside were also detected in tall fescue (Festuca arundinacea). This is the first report of pyrrolizidine alkaloids produced by grasses (Poaceae).

An experiment was conducted for 111 days in the summer of 2002/2003 to compare the effect of grazing lambs on condensed tannin-containing Lotus corniculatus L. (cv. Grasslands Goldie; n = 12) and perennial ryegrass/white clover pasture (PRG/WC; Lolium perenne/Trifolium repens; n = 12) on the concentration of indole and skatole in rumen fluid, blood plasma and body fat and upon the odour of the fat. Rumen fluid and blood samples were obtained on days 0, 22, 58, 87 and 111 of the experiment. Fat from inter-muscular and tail-stub depots was obtained at slaughter. During the experiment the mean concentration of indole and skatole in both the rumen fluid and blood plasma was lower for lambs grazing L. corniculatus compared to PRG/WC pastures. The concentration of skatole in the tail-stub fat was lower and less variable (P

This Letter is concerned with the global asymptotic stability analysis problem for a class of uncertain stochastic Hopfield neural networks with discrete and distributed time-delays. By utilizing a Lyapunov–Krasovskii functional, using the well-known S-procedure and conducting stochastic analysis, we show that the addressed neural networks are robustly, globally, asymptotically stable if a convex optimization problem is feasible. Then, the stability criteria are derived in terms of linear matrix inequalities (LMIs), which can be effectively solved by some standard numerical packages. The main results are also extended to the multiple time-delay case. Two numerical examples are given to demonstrate the usefulness of the proposed global stability condition.

The properties of condensed tannins (CT) from Lotus corniculatus and L. pedunculatus (also known as L. uliginosus ) depend on their structure in terms of monomer units, their mean degree of polymerisation (mDP) and the linkage-type between flavan-3-ol units with a considerable range of structural variation. To ascertain the identity of the individual units that make up the CT, the polymer chains are subjected to strong acid-catalysed cleavage in the presence of phloroglucinol or benzyl mercaptan. Mass spectrometry (MS) can also be utilized to probe CT structural differences. MALDI-TOF MS has been used to study L. corniculatus cultivars. We have examined the chemical composition of Sephadex LH-20 CT fractions from both L. corniculatus and L. pedunculatus by strong acid-catalysed cleavage with benzyl mercaptan (thiolysis), and by high-performance liquid-chromatography (HPLC)-electrospray mass spectrometry (ES/MS) with detection in negative ion mode. The thiolysis study confirmed earlier findings that CT from the two species are composed of procyanidin (PC) and prodelphinidin (PD) units with the L. pedunculatus CTs (PC:PD; 19:81) having a higher proportion of prodelphinidin units than L. corniculatus CTs (PC:PD; 84:16). However, using a gradient fractionation approach eluting first with water, L. pedunculatus CT was found to include a high molecular weight polymer (mDP 44), not found in L. corniculatus . In the gradient fractionation a series of oligomer fractions were also separated for L. pedunculatus CTs (mDP 1.7, 3.6, 6.3 and 12) and L. corniculatus CTs (mDP 1.9, 6.3 and 19). Ions from oligomeric species (DP 2–10) were detected in these fractions by LC/ES/MS. Fractions with an identical mDP of 6.3 by thiolysis for the two species have shown a different compositional dispersion (range of DP) of oligomeric CTs by ES/MS with a DP range of 2–7 for L. corniculatus and 4–6 for L. pedunculatus . Chemical degradation and MS techniques have shown that dispersion of polymer size, for L. corniculatus and L. pedunculatus CTs, and not solely their concentration in the plant may influence biological activity.

The proanthocyanidin polymer fractions of the leaves of the forage legume Dorycnium rectum were analysed by acid catalysis with benzyl mercaptan, NMR and ES-MS. The results showed that D. rectum differs from other temperate proanthocyanidin-containing forage legumes in that the range of polymers extends up to very high degrees of polymerisation. Three fractions were characterised as low, medium, and high molecular weight proanthocyanidin fractions with mean degree of polymerisations of 10.3, 41 and 127, respectively. Epigallocatechin was the most abundant extension unit and the terminating flavan-3-ols comprised largely catechin and gallocatechin units in equal proportions. Formation of thiolyated dimer products showed the interflavan-linkages of the lower molecular weight proanthocyanidins to be predominantly C4-->C8 with a small amount of C4-->C6. ES-MS spectra distinguished lower from higher polymeric proanthocyanidins from M2- to M8(2)-. The antibacterial activity of proanthocyanidin fractions against pure cultures of microbes selected from the ruminal population to represent fibre degrading, proteolytic and hyper ammonia producing bacteria in broth culture was evaluated. The activity of proanthocyanidin fractions against Clostridium aminophilum, Butyrivibrio fibrisolvens and Clostridium proteoclasticum was significantly dependent on their structure but not so against Ruminococcus albus and Peptostreptococcus anaerobius. The latter observation was unique in that they were sensitive to all proanthocyanidin fractions evaluated, even at the lowest concentration (100 microg/ml). The results suggest the effects of the extractable proanthocyanidins on rumen microbes should be considered when evaluating an alternative proanthocyanidin-containing forage source for ruminants, such as D. rectum.