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3 resultados encontrados para: AUTOR: Valencia Salazar, Sara Stephanie
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1.
- Artículo con arbitraje
Resumen en: Inglés |
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Incorporation of foliage and pods of tropical legumes in ruminant rations is an alternative to mitigate enteric methane emissions. The objective of this research was to evaluate the effect of adding increasing levels of ground pods of Enterolobium cyclocarpum (Jacq.) Griseb. mixed with foliage of Gliricidia sepium (Jacq.) Steud. on emissions of ruminal methane (CH4), volatile fatty acid proportions, rumen pH and microbial population in cattle. Four heifers (218 ± 18 kg LW) were fed (13 days) 0, 15, 30, and 45% of pods of E. cyclocarpum mixed with foliage of G. sepium, which were supplemented to a basal ration of Brachiaria brizantha (Hochst. ex A. Rich.) Stapf. Data were analyzed as a 4×4 Latin square. After three days of CH4 measurements in opencircuit respiration chambers, rumen fluid was collected to determine volatile fatty acid (VFA) molar proportions and quantify the microbial population. Samples of ration ingredients, refusals and feces were collected to evaluate nutrient composition. Foliage and pods of legumes provided crude protein (CP), condensed tannins (CT) and saponins, while grass was characterized by higher concentrations of neutral detergent fiber (NDF). Dry matter intake (DMI) was 5.35 kg/day on average (P=0.272). Apparent fiber digestibility was reduced (81 g/kg) and digestible CP intake (13 g/kg) increased when E. cyclocarpum mixed with G. sepium in rations were given (P < 0.05). Incorporation of legume foliage and pods had a linear effect on molar proportions of butyric acid and acetic to propionic acid ratio (P < 0.05).

Incorporation of legume foliage and pods had a linear effect on molar proportions of butyric acid and acetic to propionic acid ratio (P < 0.05). Methane production, expressed on basis to digestible dry matter intake (DDMI), ranged between 43.22 and 49.94 g/kg DDMI (P=0.131) and when CH4 was related to digestible CP (347 vs. 413 g CH4 /kg DCP) or annual weight gains (0.30 vs. 0.38 kg CH4/kg weight gain, P < 0.001) there were differences between the E. cyclocarpum mixed with G. sepium rations compared to the control treatment, respectively. Rumen population of total bacteria, methanogenic archaea, and total protozoa was not affected by the increasing levels of condensed tannins and saponins in rations (P > 0.05). Substitution of 15 and 30% of pods of E. cyclocarpum mixed with foliage of G. sepium in the ration, decreases annual methane emissions per unit product, without affecting dry matter intake or rumen microbial population, on the contrary, digestible CP intake and animal productivity increased due to supply of CP, CT and saponins.


2.
Artículo
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Resumen en: Inglés |
Resumen en inglés

Livestock production is a main source of anthropogenic greenhouse gases (GHG). The main gases are CHч 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, CHч 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 CHч. 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 information about chitosan for dietary manipulation to be considered for future studies to mitigate enteric methane and reduce the environmental impact of GHGs arising from livestock production systems. Chitosan is a promising agent with methane mitigating effects, but further research is required with in vivo models to establish effective daily doses without any detrimental effect to the animal and consider its addition in practical rations as well as the economic cost of methane mitigation.


Resumen en: Inglés |
Resumen en inglés

The objective of this study was to determine methane (CH4) yield by crossbred cattle fed tropical grasses. A total of 66 individual determinations of dry matter intake (DMI) and 42 determinations of organic matter intake (OMI) in relation to the production of enteric CH4 were carried out. Methane measurements in heifers were performed in open-circuit respiration chambers. Heifers (Bos indicus×B. taurus) with an average live weight of 288.5 ± 55.7 kg fed tropical grasses as basal ration were used. An average intake of 8.22 and 7.80 kg of DM and OM per day were recorded. An average enteric CH4 production of 88.0 g/heifer/day was determined. It was found that DMI and OMI in relation to CH4 production have a coefficient of determination (R²) of 0.73 and 0.70 respectively, to predict CH4 emissions. It is concluded that the methane yield (18.07 g CH4/kg DM intake) predicted by regressing DM intake against methane production represents a reliable value to be used for the estimation of enteric CH4 inventories for cattle grazing in the tropical regions of Mexico.