Legumes as a Strategy for Reducing Greenhouse Gas Emissions of Forage-Livestock Systems

Incorporation of legumes into forage systems has been a widely adopted strategy to increase pasture productivity and forage nutritive value, while reducing N inputs. Considering the population growth, and the diminishing land resources for food production, the need to increase the food supply will have to be balanced with the environmental impact of these systems, particularly their carbon footprint. Enteric methane production represents the largest source of greenhouse gas emissions from livestock. Certain forage legumes have evolved plant secondary compounds, such as tannins and other polyphenols, which have been associated with reductions in enteric methane emissions. Studies were conducted at Utah State University (USU), and at the University of Florida, North Florida Research and Education Center (UF-NFREC) to assess in vivo methane emissions in grazing cattle, using the SF6 tracer technique. At USU, cattle grazing pastures of Birdsfoot trefoil (Lotus corniculatus; BFT) emitted less methane per unit of dry matter consumed when compared with cattle fed a totally mixed ration (50% barley grain, 25% alfalfa hay, and 25% corn silage) in ad libitum amounts. However, emissions in cattle grazing BFT did not differ from those grazing the legume Cicer milkvetch (Astragalus cicer), or a traditional pasture-finishing system based on Meadow brome (Bromus riparius). At UF-NFREC, three livestock-forage systems were tested during three consecutive years to determine the effects of including the legume Rhizoma peanut (Arachis glabrata Benth.; BHR) in bahiagrass pastures (Paspalum notatum Flügge) fertilized (BH) or not (BHF) with N during the warm season. No differences were observed in methane emissions (g d-1), or in methane emission intensity. From the legumes grazed in these experiments, only BFT contains significant concentrations of tannins. Thus, the potential to mitigate livestock enteric methane emissions by grazing legumes appears to be directly related to the presence of tannins

Nutrient Return from Plant Litter and Cattle Excretion Grazing on N-Fertilized Grass or Grass-Legume Pastures in North Florida

Nutrient recycling via plant litter and livestock excreta is an important ecosystem service provided by grasslands. This study determined nutrient return via these pathways in three grazing systems. The experiment was conducted from May to October (2016 and 2017) and treatments were: 1) Nitrogen fertilized bahiagrass (Paspalum notatum Flügge) pastures (112 kg N ha-1) during the warm-season, overseeded with a mixture (56 kg ha-1 of each) of ‘FL 401’ cereal rye (Secale cereale, L.) and ‘RAM’ oat (Avena sativa, L.) during the cool-season (BGN); 2) Ecoturf Rhizoma peanut (Arachis glabrata Benth.)/bahiagrass pastures during the warm-season, overseeded with similar rye/oat mixture fertilized with 34 kg N ha-1 plus a mixture of clovers (Trifolium incarnatum L., T. pretense L., and T. nigrescens L.) during the cool-season (BGRP); 3) unfertilized bahiagrass pastures during the warm-season, overseeded with similar rye/oat grass/clover mixture + 34 kg N ha-1 during the cool-season (BG). Litter mass was evaluated every 5wk. Litter decomposition was evaluated with incubation periods of 0, 2, 4, 8, 16, 32, 64, 128, and 256 days. Urine and fecal samples were collected for N concentration analysis. There was a net return of 47 kg N ha-1 season-1 via litter in all three systems without differing among them. In addition, litter decomposition rates were not different in the three systems. Conversely, N returned via excreta (urine and feces) was greater (63, 27, and 51 kg N ha-1 season-1) than that returned via litter (58.6, 41.6, and 41.2 kg ha-1 season-1). When assessing the proportions of N returning to the system via litter or excreta, no differences were observed among treatments, and on average 65.1 % of the N returned via excreta vs. 34.9 % returning via litter. The introduction of legumes could reduce the inputs from N fertilizers in grazing systems and keep the productivity similar because of more efficient N cycling

Sustainable intensification of livestock production on pastures

Growing human population and limited natural resources require a sustainable intensification of agricultural production systems. The ‘green revolution’ was successful in increasing world food production, but unintended consequences, including pollution of groundwater, soil erosion, climate change, and intensive use of agrochemicals, left a large footprint in the environment. Sustainable livestock intensification (SLI) implies greater productivity and more efficient use of natural resources, reducing the impact of livestock systems in the environment. Approaches to reach this goal include diversification of plant species and plant functional groups, multiple ruminant species, improvement in feeding techniques and grazing management, plant breeding for improved nutrient use efficiency, integrated crop-livestock systems, and silvopasture systems. Greater use of forage legumes appears to be an opportunity for SLI in extensive C4 grass-based pastureland commonly found in vast areas of Latin America. Grasslands in the 21st century will also be valued for multiple services they provide to humankind, and mechanisms of payment for these services are needed. A more ‘holistic’ approach will improve the social and economic sustainability of livestock systems. Achieving long-term sustainability must match short-term profits. Diversification of the products and services provided by grassland ecosystems is key to reach SLI in the near future

T Cells Recognizing a Peptide Contaminant Undetectable by Mass Spectrometry

Synthetic peptides are widely used in immunological research as epitopes to stimulate their cognate T cells. These preparations are never completely pure, but trace contaminants are commonly revealed by mass spectrometry quality controls. In an effort to characterize novel major histocompatibility complex (MHC) Class I-restricted β-cell epitopes in non-obese diabetic (NOD) mice, we identified islet-infiltrating CD8+ T cells recognizing a contaminating peptide. The amount of this contaminant was so small to be undetectable by direct mass spectrometry. Only after concentration by liquid chromatography, we observed a mass peak corresponding to an immunodominant islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)206-214 epitope described in the literature. Generation of CD8+ T-cell clones recognizing IGRP206-214 using a novel method confirmed the identity of the contaminant, further underlining the immunodominance of IGRP206-214. If left undetected, minute impurities in synthetic peptide preparations may thus give spurious results

Vernonia cinerea Less. supplementation and strenuous exercise reduce smoking rate: relation to oxidative stress status and beta-endorphin release in active smokers

<p>Abstract</p> <p>Purpose</p> <p>The aim of this study was to evaluate the effects of <it>Vernonia cinerea </it>Less. (VC) supplementation and exercise on oxidative stress biomarkers, beta-endorphin release, and the rate of cigarette smoking.</p> <p>Methods</p> <p>Volunteer smokers were randomly divided into four groups: group 1: VC supplement; group 2: exercise with VC supplement; group 3: exercise; and group 4: control. VC was prepared by wash and dry techniques and taken orally before smoking, matching the frequency of strenuous exercise (three times weekly). Before and after a two month period, exhaled carbon monoxide (CO), blood oxidative stress (malondialdehyde [MDA], nitric oxide [NOx], protein hydroperoxide [PrOOH] and total antioxidant capacity [TAC]), beta-endorphin and smoking rate were measured, and statistically analyzed.</p> <p>Results</p> <p>In Group 1, MDA, PrOOH, and NOx significantly decreased, whereas TAC increased (p < 0.05). In Group 2, MDA and PrOOH decreased (p < 0.05), with no other changes noted (p > 0.05). In Group 3, MDA, PrOOH, NOx, TAC, and beta-endorphin levels increased significantly (p < 0.05). Group 4 showed no change in oxidative stress variables or beta-endorphine levels (p > 0.05). All groups had lower levels of CO after the intervention. The smoking rate for light cigarette decreased in group 2(62.7%), 1(59.52%), 3 (53.57%) and 4(14.04%), whereas in self-rolled cigarettes it decreased in group 1 (54.47%), 3 (42.30%), 2 (40%) and 4 (9.2%).</p> <p>Conclusion</p> <p>Supplementation with <it>Vernonia cinerea </it>Less and exercise provided benefit related to reduced smoking rate, which may be related to oxidaive stress and beta-endorphine levels.</p