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An experiment to assess the effect of different levels of Sesbania leaves on chemical composition, in vitro dry matter (DM) digestibility (IVDMD), in sacco rumen DM degradability (DMD), organic matter degradability (OMD) and crude protein (CP) degradability (CPD) of Napier grass–Sesbania mixtures was conducted. There were four Napier–Sesbania mixtures (100, 150, 200 and 250g/kg of Sesbania on a DM basis) and Napier grass only (control) in a randomised complete block design. As the proportion of Sesbania increased in the mixture, there was an increase in CP, Ca and metabolizable energy, and a reduction in P, neutral detergent fibre (NDF), acid detergent fibre (ADF), cellulose and hemicellulose contents. The DMD, OMD, CPD and IVDMD increased as the proportion of Sesbania leaves increased. Results indicate that different levels of Sesbania forages have desirable characteristics as a potential feed supplement to improve the utilization of Napier grass to ruminant animals under tropical condition. Moreover, it could be concluded that nutrient content, IVDMD and ruminal DMD, OMD and CPD can be enhanced by feeding Sesbania with Napier grass, and it can be used in diet mixtures up to 250g/kg of the DM fed. [Copyright &y& Elsevier]

The inclusion level of dried Elaeis guineense supplementation on nitrogen and energy partitioning was evaluated using 12 two-year-old West African Dwarf (WAD) sheep fed a basal hay diet. Six of the sheep were fistulated ruminally and used for rumen pH, ammonia and volatile fatty acid determination in the fluid. Dried leaves of E. guineense were offered as supplement at two levels (25 and 50% of DMI, diets D25% and D50%, respectively) to a basal hay diet. Rumen liquor was sampled 1h before feeding and 1, 3 and 5h after the morning feeding. The sheep were also subjected to nitrogen and energy balance trials. The CP content of the control, D25% and D50% diets were (131.0, 121.0 and 111.0gkg-1), respectively, and their energy digestibility amounted to (0.625, 0.533 and 0.482), respectively. In the fermentation profile trial, rumen pH decreased (P < 0.05) with level of supplementation, with diet D50% having the lowest (P < 0.05) pH value. Diet D25% had a higher (P < 0.05) ruminal ammonia concentration than both the control and D50% diets, respectively. D25% had a superior (P < 0.05) volatile fatty acid (VFA) than the controls. Nitrogen intake decreased (P < 0.05) with supplementation level. Faecal-N increased (P < 0.05) with level of supplementation while N-digestibility decreased (P < 0.05). Organic matter digestibility (OMD), decreased (P < 0.05) with supplementation. Faecal energy increased (P < 0.05) with supplementation while methane energy decreased at the higher supplementation level (P < 0.05). The lowest (P < 0.05) heat loss of 709kJday-1 was observed on diet D50% and this was about 45% of the total energy intake. Animals in diet D50% lost 8.4% of the energy retained in fat and protein. Although E. guineense had a CT, CP and a relatively high GE content of (18gkg-1, 90gkg-1 and 19.8kJg-1 DM), respectively, dried leaves of E. guineense is of low fodder value and should be used sparingly. [Copyright &y& Elsevier]

There is a knowledge gap regarding the factors that impede the ruminal digestion of plant cell walls or if rumen microbiota possess the functional activities to overcome these constraints. Innovative experimental methods were adopted to provide a high-resolution understanding of plant cell wall chemistries, identify higher-order structures that resist microbial digestion, and determine how they interact with the functional activities of the rumen microbiota. We characterized the total tract indigestible residue (TTIR) from cattle fed a low-quality straw diet using two comparative glycomic approaches: ELISA-based glycome profiling and total cell wall glycosidic linkage analysis. We successfully detected numerous and diverse cell wall glycan epitopes in barley straw (BS) and TTIR and determined their relative abundance pre- and post-total tract digestion. Of these, xyloglucans and heteroxylans were of higher abundance in TTIR. To determine if the rumen microbiota can further saccharify the residual plant polysaccharides within TTIR, rumen microbiota from cattle fed a diet containing BS were incubated with BS and TTIR ex vivo in batch cultures. Transcripts coding for carbohydrate-active enzymes (CAZymes) were identified and characterized for their contribution to cell wall digestion based on glycomic analyses, comparative gene expression profiles, and associated CAZyme families. High-resolution phylogenetic fingerprinting of these sequences encoded CAZymes with activities predicted to cleave the primary linkages within heteroxylan and arabinan. This experimental platform provides unprecedented precision in the understanding of forage structure and digestibility, which can be extended to other feed-host systems and inform next-generation solutions to improve the performance of ruminants fed low-quality forages., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 Published by Elsevier B.V. on behalf of Research Network of Computational and Structural Biotechnology.)