Simple SummaryRuminant husbandry is one the largest contributors to greenhouse gas emissions from the agriculture sector, particularly of methane gas, which is a byproduct of the anaerobic fermentation of structural and non-structural carbohydrates in the rumen. Increasing the efficiency of production systems and decreasing its environmental burden is a global commitment, thus methane mitigation is a strategy in which to reach these goals by rechanneling metabolic hydrogen (H2) into volatile fatty acids (VFA) to reduce the loss of energy as methane in the rumen, which ranges from 2% (grain rations) to 12% (poor-quality forage rations) of gross energy intake. A strategy to achieve that goal may be through the manipulation of rumen fermentation with natural compounds such as chitosan. In this review, we describe the effects of chitosan on feed intake and rumen fermentation, and present some results on methanogenesis. The main compounds with antimethanogenic properties are the secondary metabolites, which are generally classified into five main groups: saponins, tannins, essential oils, organosulfurized compounds, and flavonoids. Novel compounds of interest include chitosan obtained by the deacetylation of chitin, with beneficial properties such as biocompatibility, biodegradability, non-toxicity, and chelation of metal ions. This compound has shown its potential to modify the rumen microbiome, improve nitrogen (N) metabolism, and mitigate enteric methane (CH4) under some circumstances. Further evaluations in vivo are necessary at different doses in ruminant species as well as the economic evaluation of its incorporation in practical rations.AbstractLivestock production is a main source of anthropogenic greenhouse gases (GHG). The main gases are CH4 with a global warming potential (GWP) 25 times and nitrous oxide (N2O) with a GWP 298 times, that of carbon dioxide (CO2) arising from enteric fermentation or from manure management, respectively. In fact, CH4 is the second most important GHG emitted globally. This current scenario has increased the concerns about global warming and encouraged the development of intensive research on different natural compounds to be used as feed additives in ruminant rations and modify the rumen ecosystem, fermentation pattern, and mitigate enteric CH4. The compounds most studied are the secondary metabolites of plants, which include a vast array of chemical substances like polyphenols and saponins that are present in plant tissues of different species, but the results are not consistent, and the extraction cost has constrained their utilization in practical animal feeding. Other new compounds of interest include polysaccharide biopolymers such as chitosan, mainly obtained as a marine co-product. As with other compounds, the effect of chitosan on the rumen microbial population depends on the source, purity, dose, process of extraction, and storage. In addition, it is important to identify compounds without adverse effects on rumen fermentation. The present review is aimed at providing in...

1The treatment of 1,4-dioxane solution by electrochemical oxidation on boron-doped 2 diamond was studied using a central composite design and the response surface 3 methodology to investigate the use of SO4 2-and HCO3

The aim of this study was to evaluate the inclusion of water hyacinth (WH) as a possible substitution of alfalfa hay (AH) in diets of beef cattle on in vitro methane production, gas kinetics and chemical composition. AH in the diets was substituted by WH at 0% (T1, as a control), 25% (T2), 50% (T3), 75% (T4) and 100% (T5). Methane, CO2 and gas production parameters were recorded after 24 and 48h of incubation. NDF, condensed tannins and total phenolic compounds increased when AH was substituted. Likewise, the net gas production decreased linearly when AH was substituted. However, gas production rate among treatments were similar. Methane and CO2 production decreased linearly with inclusion of WH. These results indicate that WH arises as a promising alternative for mitigating methane production in ruminants.

Large areas of arid and semi-arid grasslands in Mexico are severely damaged. Large areas of high-risk rainfed crops have been abandoned. These problems are the result of constant overgrazing, extraction of firewood, overutilization of valuable species, fire and the practice of subsistence agriculture. The aim of this study was to measure the initial performance of the seedlings, as well as forage production and survival in the second year of nine Bouteloua curtipendula populations native to Mexico in comparison with El Reno, a commercial variety from the US. Plant development was visually estimated and dry matter (DM) production was estimated one year after the establishment. Survival was assessed at the end of the growing season in the following year. The experiment was carried out using a complet randomized blocks experimental design, and differences in vigor between genotypes were analyzed by a permutation test. Significant differences in DM production and plant establishment (P ≤ 0.05) were observed between genotypes. The US commercial variety was the least productive population, exhibiting less vigor during the first year than the rest of the genotypes evaluated. Large diversity in seedling establishment capacity, DM yield and survival was observed in the second year. The Mexican populations 241, NdeM-303, 47 and NdeM-5 were superior for plant establishment and DM production.

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