Diversity of Gut Methanogens and Functional Enzymes Associated With Methane Metabolism in Smallholder Dairy Cattle

Methane is a greenhouse gas with disastrous consequences when released to intolerable levels. Ruminants produce methane during gut fermentation releasing it through belching and/or flatulence. To better understand the diversity of methanogens and functional enzymes associated with methane metabolism in dairy cows, 48 samples; six rumen and 42 dung contents were collected and analyzed using a shotgun metagenomic approach. The results indicated archaea from 5 phyla, 9 classes, 16 orders, 25 families, 59 genera, and 87 species. Gut sites significantly contributed to the presence and distribution of various methanogens (P<0.01). The class Methanomicrobia was abundant in the rumen samples (~ 39%) and in dung (~44%). The most abundant (~17%) methanogen species identified was Methanocorpusculum labreanum. However, some taxonomic classes were not classified (~ 6% in the rumen and ~4% in the dung). Furthermore, five functional enzymes: Glycine/Serine hydroxy methyltransferase, Formylmethanofuran—tetrahydromethanopterin N-formyltransferase, Formate dehydrogenase, Anaerobic carbon monoxide dehydrogenase and Catalase-peroxidase were associated with methane metabolism. KO0600 module and Enzyme Commissions (1.11.1.6 & 2.1.2.1) were common for dung and rumen fluid’s enzymatic pathways. Functional analysis for the enzymes identified were significant (P<0.05) for 5 metabolism processes. Breeding for tolerable methane emitting dairy cattle for a sustainable environment should be undertaken.

The Effect of Rice vs. Wheat Ingestion on Postprandial Gastroesophageal Reflux (GER) Symptoms in Patients with Overlapping GERD-Irritable Bowel Syndrome (IBS)

A randomized crossover study in twenty-one patients (18F, age 50 ± 13 years) with overlapping GERD-IBS was conducted to evaluate the effects of rice noodles (low FODMAPs) vs. wheat noodles (high FODMAPs) on typical GER symptoms, and the correlation between GERD symptoms and intestinal gas production. Results: Heartburn and regurgitation scores were highest in most patients (19/21) during the first 15 min after meals. At 15 min after lunch, wheat was significantly associated with more regurgitation and heartburn than rice. Also, at 15 min after breakfast, wheat aggravated more regurgitation than rice. Wheat ingestion was significantly associated with higher H2 and CH4 levels after lunch compared to rice, whereas gas levels before lunch were similar (p > 0.05). The area under the curve of H2 and CH4 concentration 15 min after a lunch of wheat moderately correlated with the regurgitation severity at 15-min (r = 0.56, p < 0.05). Conclusion: Wheat induced more GERD symptoms than rice in patients with overlapping GERD-IBS. This effect, immediately developed after lunch, was associated with more intestinal gas production. Thus, a low FODMAPs diet may relieve postprandial GERD symptoms in GERD patients with overlapping IBS. Wheat inducing more regurgitation than rice after breakfast suggests other mechanism(s) besides gut fermentation.

Factors influencing Euryarchaeal gut methanogens distribution in dairy cattle in smallholding farms

Guts of ruminants contain symbiotic domains (Eubacteria, Archaea and Eukarya) that aid in the breakdown of consumed carbohydrates from plants to simple molecules that can be absorbed into the ruminant’s bloodstream. Methanogenesis occurs during the gut fermentation and methane gas is released in the final step of biomass degradation from the fermentation chambers. The Archaea that play a major role critical for methane emissions are methanogens and are found freely in the ruminants’ gut. Methane production from ruminants has attracted global attention due to their input on the Green House Gases effect, contribution to global warming and negative effects on farmers’ productivity. The objective of this study was to determine the factors contributing to the methanogens’ gut distribution in dairy cows from smallholder farms using next generation sequencing techniques. A total of 48 samples from smallholding dairy farms were used during this study and were collected from Kenya (Kiambu county) and Tanzania (Lushoto and Rungwe). The collected data samples from the experimental animals were from both the rumen fluid (6) and fecal (42). Samples were analyzed using metagenomic approaches and statistical analysis was undertaken using IBM SPSS statistics software version 28.0.0.0. Results showed that the gut site along the gastrointestinal tract and the feeding regime significantly contributed to the distribution and presence of various methanogenic species (P<0.1). The herd and the genotype had no statistical effect. A total of 12 families were identified. The family Methanobacteriaceae was identified with the leading number (8) of the methanogenic species. A third of the identified families showed presence for at least two methanogenic species with Methanobrevibacter ruminantium being abundant. For proper curbing mechanisms, efforts to reduce methane release should be channeled to the whole gastrointestinal tract and advanced studies carried out on any potential interspecies presence facilitation and/or elimination.

Bioaccessibility and Gut Metabolism of Free and Melanoidin-Bound Phenolic Compounds From Coffee and Bread

The aim of this study is to investigate the bioaccessibility and gut metabolism of free and melanoidin-bound phenolic compounds from coffee and bread. Phenolics from coffee were predominantly found in free forms (68%, mainly chlorogenic acids), whereas those from bread were mostly bound to melanoidins (61%, mainly ferulic acid). Bioacessibility of coffee total free phenolics slightly decreased during simulated digestion (87, 86, and 82% after the oral, gastric, and intestinal steps, respectively), with caffeoylquinic acids being isomerized and chlorogenic acids being partially hydrolyzed to the corresponding hydroxycinnamic acids. Bioacessibility of bread total free phenolics decreased during simulated digestion (91, 85, and 67% after the oral, gastric, and intestinal steps, respectively), probably related to complexation with the proteins in simulated gastric and intestinal fluids. Upon gut fermentation, the bioaccessibility of total free phenolics from both coffee and bread decreased, mainly after the first 4 h (56 and 50%, respectively). Caffeic and ferulic acids were the predominant metabolites found during coffee and bread gut fermentation, respectively. Melanoidin-bound phenolics from coffee and bread were progressively released after the gastric and intestinal steps, probably due to hydrolysis caused by the acidic conditions of the stomach and the action of pancreatin from the intestinal fluid. The bioaccessibilities of all phenolics from coffee and bread melanoidins after the gastric and intestinal steps were, on average, 11 and 26%, respectively. During gut fermentation, phenolics bound to both coffee and bread melanoidins were further released by the gut microbiota, whereas those from coffee were also metabolized. This difference could be related to the action of proteases on melanoproteins during gastrointestinal digestion, probably anticipating phenolics release. Nevertheless, bioaccessibilities of melanoidin-bound phenolics reached maximum values after gut fermentation for 24 h (50% for coffee and 51% for bread). In conclusion, the bioaccessibilities of coffee and bread free phenolics during simulated digestion and gut fermentation were remarkably similar, and so were the bioaccessibilities of coffee and bread melanoidin-bound phenolics.