Ruminal fermentation and enteric methane production of legumes containing condensed tannins fed in continuous culture

Abstract

A continuous-culture fermentor study was conducted to assess nutrient digestibilities, volatile fatty acid (VFA) concentrations, microbial protein synthesis, bacterial nitrogen (N) efficiency, and enteric methane (CH 4 ) production of four 50:50 grass-legume diets, randomly assigned in a 4 × 4 Latin square design. Four legumes with different concentrations of condensed tannins (CT) were tested: alfalfa [ALF; Medicago sativa L., non-CT legume]; birdsfoot trefoil [BFT; Lotus corniculatus L., low-CT legume]; crown vetch [CV; Securigera varia (L.) Lassen, moderate-CT legume]; and sericea lespedeza [SL; Lespedeza cuneata (Dum. Cours.) G. Don, high-CT legume]. Orchardgrass (Dactylis glomerata L.) was the common forage used in all diets. Four fermentors were evaluated over four 10-d periods by feeding 82 g of dry matter (DM)/d in 4 equal feedings. Methane output was recorded every 10 min. Effluent samples were collected during the last 3 d of the experiment,composited by fermentor and period, and analyzed for pH and VFA, as well as DM, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber for determination of apparent and true nutrient digestibilities. Microbial protein synthesis and bacterial efficiency were estimated by analysis of N flows and purines. The CT concentrations were 3, 21, 38 and 76 g/kg of DM for ALF, BFT, CV, and SL diets, respectively. The SL diet had decreased fiber digestibilities and total VFA concentrations compared with the other diets. This resulted in the least total CH 4 production in the SL diet. Bacterial N efficiency per kilogram of organic matter truly digested was lower in the SL diet than in the BFT and CV diets. The lowest CH 4 production per unit of digestible nutrients was also found in the SL diet. Further work should be conducted to find optimal diets (by testing other legumes, rations, and sources of CT) for reducing CH 4 emissions without negatively affecting ruminal digestion to maintain or improve productivity.

Designing Diverse Agricultural Pastures for Improving Ruminant Production Systems

“…Management efforts in the design of diverse pasturelands up to the present have been limited to combination of grasses, legumes and forbs from "traditional" species that historically have been used in grazing systems. The challenge ahead entails the design of diverse agricultural pastures by selecting species identities from a wider array of forage options, exploring "non-traditional" forage species like cicer milkvetch (Astragalus cicer L.), small burnet (Sanguisorba minor), hairy vetch (Vicia villosa Roth), forage radish (Raphanus sativus L.), safflower (Carthamus tinctorius) (Meccage et al, 2019;Stewart et al, 2019;Roca-Fernández et al, 2020) and shrubs like saltbrush (Atriplex spp.) (Pearce et al, 2010), Leucaena leucocephala, Guazuma ulmifolia (Casanova-Lugo et al, 2014, or Tricomaria usillo, and Mimosa ephedroides (Egea et al, 2016).…”

“…In vitro studies have been traditionally used for screening the potential degradability and environmental impacts (i.e., through the production of CH 4 and CO 2 ) of single forage species (e.g., Tavendale et al, 2005;Roca-Fernández et al, 2020) and medicinal effects of bioactive-containing plants (e.g., Githiori et al, 2006) given their low cost, rapid turnaround and repeatable results. After careful assessment of the outputs obtained, the most promising candidate treatments are tested in vivo.…”

Reinforcing the bulwark: unravelling the efficient applications of plant phenolics and tannins against environmental stresses

“…These contain plant species ( Bharathidhasan, 2018 ), plant part ( Hassanpour et al., 2011 ), plant maturation ( Lagrange, 2020 ), developing season ( Kumar et al . , 2020a , b ), and the fertility of soil ( Roca-Fernández et al . , 2020 ).…”

Integrating Animal Husbandry With Crops and Trees

“…Precision feeding, matching feed intake with the need of the animal (Gerber et al, 2013a), and the choice of forages can also reduce the gaseous footprint. For example, the combination of highly digestible forages (Haque, 2018;van Gastelen et al, 2019) that contain secondary compounds such as tannins (Roca-Fernández et al, 2020) can also reuce methane emissions. The multiple GHG perspective is an important strategy that can address the potential pollution swapping-a reduction in one gas can lead to emission of another (Gerber et al, 2013a).…”