Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.

Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.

Aims: To measure the impact of supplementing a forage diet with tree-based browse on the ruminal bacterial communities of Nigerian West African Dwarf (WAD) sheep. Methods and Results: Fifteen WAD sheep were fed a control diet of forage (Panicum maximum), with 12 animals shifted in groups of three to one of four browse-supplemented diets (Albizia saman, Bridelia micrantha, Ficus sur, or Gmelina arborea). These browse plants were shown in a concurrent but separate study to be reasonably nutritious (based on chemical composition and fibre constituents) and nontoxic (based on tannin, phytate, saponin, alkaloid and oxalate levels). Rumen liquids and solids for DNA extraction were collected via intubation from two animals in each group before and after dietary shift. Bacterial 16S rRNA gene regions V6-V8 were sequenced by 454 pyrosequencing. All communities were highly diverse and dominated by the phyla Firmicutes, Bacteroidetes, Tenericutes, Actinobacteria and Proteobacteria. All communities shared members of the genera Butryivibrio, Prevotella and Ruminococcus. Our analysis defined a core sets of bacteria shared by all animals, forage-fed animals and browse-fed animals. Community structure shifted dramatically in animals fed A. saman or G. arborea. Conclusions: The impact of tree-based browse on the ruminal bacterial community of Nigerian WAD sheep varies by browse species, likely due to differences in browse composition. Significance and Impact of the Study: Our study describes the first neotropical small ruminant bacterial microbiome and supports diet supplementation with specific tree-based browse for WAD sheep.

No abstract

Studies were conducted to evaluate the nutritive value of eight selected forages (Tridax procumbens, Merremia aegyptia, Aspilia africana, Tithonia diversifolia, Alchornea cordifolia, Alchornea laxiflora, Synedrella nodiflora, and Newbouldia laevis) consumed by ruminants in South-Western Nigeria. Chemical composition and qualitative analysis of saponins, phenol and steroids of the plants were determined. In vitro gas production (IVGP) was carried out for 72 hours on the plants. Metabolizable energy (ME), Organic matter digestibility (OMD) and Short chain fatty acids (SCFA) were predicted and methane (CH4) was measured. Five of the plants were subjected to acceptability study using cafeteria method. The result of the chemical composition revealed that M. aegyptia had the highest value of CP (22.09 %) while Tridax procumbens had the lowest (10.50 %). A. africana had the highest content of Calcium, Phosphorus and Zinc with values of 3.10 %, 0.93 % and 39 ppm respectively. The analysis of secondary metabolites showed that A. africana, T. diversifolia and S. nodiflora were high in saponin while A. cordifolia, A. laxiflora, T. diversifolia and A. africana were implicated for condensed Tannin. N. laevis recorded a high level of steroids. Results showed significant variations in the values of IVGP, ME, OMD, SCFA and CH4 obtained for the plants. The order of preference of the plants by the calves were M. aegyptia>A. cordifolia > N. laevis > A. axiflora> T. diversifolia. The study revealed that the forages are rich in crude protein as well as micro and macro minerals. They are also rich in highly fermentable carbohydrates which affirm them as ruminant feed resource.