Estrategias para la prevención y el control de intoxicaciones naturales por plantas fotosensibilizantes en bovinos Strategies for the prevention and control of natural intoxication by photosensitizing plants in cattle
The study was conducted at the Livestock Production Enterprise Bacuranao, of the Habana del Este municipality (La Habana province, Cuba), in order to establish a strategy for the prevention and control of natural intoxications by photosensitizing plants in cattle. For such purpose, a presumptive diagnosis on photosensitization was carried out, through the floristic inventory of the plants present in grazing and with the use of the clinical method. Diverse plants which cause hepatogenous photosensitization in the animals were identified, with Ageratum houstonianum Mill., Lantana camara L., Crotalaria retusa L. Crotalaria incana L. and Crotalaria spectabilis Roth standing out. The density of cattle per quadrant, the areas with higher incidence of this type of plants and the animals with dermatitis were determined through the Epidemiological Surveillance System (SIVE), by quadrants and grids. In the evaluation of the relative risk (RR) with and without the presence of the sun and with regards to the green forage intake, it was found that the animals exposed to sunlight and those that consumed forage had 1,85 and 3,17 times more incidence, respectively, of clinical signs associated to the hepatogenous photodynamic dermatitis, with higher levels for the ones that ingested the toxic plant A. houstonianum Mill along with the forage. From these results a plan of general and specific measures was elaborated for the control of toxicosis in the areas contaminated with these plants. It is concluded that the use of SIVE, the botanical census, the support treatments to animals with severe symptoms and the management and feeding measures can improve the efficacy in the control of toxicosis and, in turn, the protection of the animals at risk.
Feasibility of vermicomposting for the management of terrestrial weed Ageratum conyzoides using earthworm species Eisenia fetida
Abstract This study illustrates the feasibility of vermicomposting of an invasive terrestrial weed Ageratum conyzoides for environment and economic benefits. This study presents the different mix proportion of substrate and cow dung as blending material in the vermicomposting process. It also advocates the potential of earthworm species Eisenia fetida for the bioconversion of A. conyzoides into a valuable end product. The work is based on biochemical characterization along with earthworm growth and cocoon production to evaluate the properties of the final product. The vermicompost obtained from all the reactors attained stabilization with increase in nutrients and decrease in total organic carbon (TOC), CO2 evolution rate after the end of the process. The pH was obtained in the range of 6.7–7.4 during vermicomposting. The final C/N ratio falls within 12–17 in all the reactors. The highest Total Kjeldahl Nitrogen (TKN) value observed in the final vermicompost was 2.67% which was higher than the initial value 1.83%. TOC decreased up to 30.05% at the end of the process. The earthworm biomass increased in a similar trend in all the reactors with highest biomass change of 25.75%. The results indicate that the biomass of A. conyzoides can be efficiently utilized to produce a mature vermicompost with the potential of further applications. It may be inferred from the findings that vermicomposting can be an alternative environment friendly option for the management of A. conyzoides and recommendable for on site management of the weed in an economical way.
Inhibition of Root Growth and Polyamine Metabolism in Sunflower (Helianthus annuus) Seedlings Under Cadmium and Copper Stress
Although sunflower is usually regarded as a highly tolerant crop, impairment of root growth at initial stages of plant development may result in poor crop establishment and higher susceptibility to pathogen attack. In order to evaluate if Cd2+ and Cu2+ may impact on sunflower germination and initial root development, a pot experiment under controlled conditions was carried out. Possible involvement of polyamine metabolism in sunflower response to these stressors was also investigated. Although Cd2+ and Cu2+ treatments affect neither seed germination nor radicle emergence, sunflower seedlings grown in the presence of these heavy metals showed significant inhibition of root growth, being this inhibition greater for Cd2+. Both metals caused significant increases in proline contents at the highest concentrations tested (0.5 and 1 mM), and these increments were more pronounced for Cd2+ treatments, especially between days 3 and 10. Metals also increased putrescine (Put) contents at all concentrations assayed from the seventh day onward, causing no variations on this polyamine time-course pattern. Spermine and spermidine contents, however, were increased only by 1 mM Cd2+. Arginine decarboxylase seems to have been the enzyme responsible for Put increases under both metal treatments. This work demonstrates that initial root growth of sunflower seedlings may be significantly impaired in Cd2+ or Cu2+ contaminated soils. It also shows that polyamines are key biological compounds, which are probably involved in signaling pathways triggered under stress environmental conditions.