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Camila Almeida dos Santos Rafael Cassador Monteiro Bruno Grossi Costa Homem Lucero Sarabia Salgado Daniel Rume Casagrande José Marques Pereira Cláudia de Paula Rezende Bruno José Rodrigues Alves Robert Michael Boddey 《Grass and Forage Science》2023,78(1):147-160
The use of forage legumes to contribute biologically fixed nitrogen (N) to pastures is an alternative to increase beef cattle production in tropical regions. The objective was to compare the impact of the introduction of a legume with that of N fertilizer application on forage and animal production in Brachiaria pastures. This two-year study assessed three pasture treatments: (1) mixed Marandu palisadegrass (Brachiaria brizantha [syn. Urochloa brizantha] cv. Marandu) and the legume “ovalifolium” (Desmodium ovalifolium) cv. Itabela (Mixed), (2) Marandu palisadegrass pastures with 150 kg N ha−1 (Fertilized), and (3) Marandu palisadegrass without N fertilizer (Unfertilized). Rotational stocking with a variable stocking rate was used with a target herbage allowance of 1.0 kg forage kg body weight−1. The pre-grazing green herbage mass was similar for Fertilized and Mixed pastures, with 54% and 63% more mass than Unfertilized pasture, respectively (p < .001). Cattle that grazed the fertilized pasture had the greatest average daily gain (ADG; p = .017). The stocking rate and liveweight gain per area were greatest for the Fertilized and Mixed pastures (p < .001 and p < .001, respectively). No differences between treatments were found for DM forage intake (p = .555). Organic matter digestibility was lowest (p < .001) for the Mixed pasture. The inclusion of the ovalifolium legume in the Marandu pasture had the same impact on beef cattle production as annual fertilization with 150 kg N ha−1. The potential and environmental benefits of ovalifolium are discussed. 相似文献
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Paulo Cezar Rezende Fontes Camila Borges Antonio Tufik Marialva Alvarenga Moreira André Malacarne Milanez 《Communications in Soil Science and Plant Analysis》2020,51(10):1357-1369
ABSTRACT Potato is one of the most economically important crops in Brazil. In this crop, potassium (K) is the most accumulated nutrient and has significant and positive effect on potato plant growth and tuber yield. Thus, the aim of this work was to determine the effects of K doses on nutrients accumulation, biometric, chlorophyll, and K indexes in potato plants grown. Two experiments were installed simultaneously in an unheated greenhouse with Agata cultivar. The experiment 1 was carried out in pot with commercial organic substrate with five K doses (0, 0.66, 1.32, 1.98, and 2.64 g dm3?1). The experiment 2, nominated hydroponic system, with washed sand above a layer of expanded clay pebbles where the plants received daily nutrient solution application. The treatments were five K doses (0.0, 2.5, 5.0, 7.5 e 10.0 mmol L?1). The biometrics data were collected 21 days after emergence and at harvest. Both experiments were set at a randomized block design with four replications. In both experiments, no visual symptoms of deficiency or excess were observed but only in plants at 0 mmol L?1 of K. In both experiments, K doses interacted with some biometric and chlorophyll indexes measured in the fourth completely expanded leaf with portable SPAD and Dualex devices, commonly used as a guide to in-season fertilizer N management, leading to recommend their use only in plants properly nourished in K. K critical concentration in the fourth fully expanded leaf was 61.7 g kg?1. 相似文献
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Camila Q. V. Costa Inês I. Afonso Sandra Lage Pedro Reis Costa Adelino V. M. Canrio Jos P. Da Silva 《Marine drugs》2022,20(2)
The analysis of marine lipophilic toxins in shellfish products still represents a challenging task due to the complexity and diversity of the sample matrix. Liquid chromatography coupled with mass spectrometry (LC-MS) is the technique of choice for accurate quantitative measurements in complex samples. By combining unambiguous identification with the high selectivity of tandem MS, it provides the required high sensitivity and specificity. However, LC-MS is prone to matrix effects (ME) that need to be evaluated during the development and validation of methods. Furthermore, the large sample-to-sample variability, even between samples of the same species and geographic origin, needs a procedure to evaluate and control ME continuously. Here, we analyzed the toxins okadaic acid (OA), dinophysistoxins (DTX-1 and DTX-2), pectenotoxin (PTX-2), yessotoxin (YTX) and azaspiracid-1 (AZA-1). Samples were mussels (Mytilus galloprovincialis), both fresh and processed, and a toxin-free mussel reference material. We developed an accurate mass-extracted ion chromatogram (AM-XIC) based quantitation method using an Orbitrap instrument, evaluated the ME for different types and extracts of mussel samples, characterized the main compounds co-eluting with the targeted molecules and quantified toxins in samples by following a standard addition method (SAM). An AM-XIC based quantitation of lipophilic toxins in mussel samples using high resolution and accuracy full scan profiles (LC-HR-MS) is a good alternative to multi reaction monitoring (MRM) for instruments with HR capabilities. ME depend on the starting sample matrix and the sample preparation. ME are particularly strong for OA and related toxins, showing values below 50% for fresh mussel samples. Results for other toxins (AZA-1, YTX and PTX-2) are between 75% and 110%. ME in unknown matrices can be evaluated by comparing their full scan LC-HR-MS profiles with those of known samples with known ME. ME can be corrected by following SAM with AM-XIC quantitation if necessary. 相似文献
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Vitrification of ovarian tissue of Brazilian North‐eastern donkeys (Equus asinus) using different cryoprotectants 
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下载免费PDF全文 Kátia Regina F. Lopes Erica Camila G. Praxedes Livia B. Campos Marcelo B. Bezerra Gabriela L. Lima Márcia Viviane A. Saraiva Alexandre R. Silva 《Reproduction in domestic animals》2018,53(5):1060-1067
The aim of this study was to assess a vitrification protocol for asinine ovarian tissue, to preserve preantral follicles using different cryoprotectant solutions, composed of various concentrations (EG 3 M or 6 M) of dimethyl sulfoxide or ethylene glycol isolate, or as a combination (DMSO 3 M + EG 3 M). Ten pairs of ovaries from Brazilian north‐eastern breed jennies were obtained through videolaparoscopy, and cortical fragments were submitted to a solid‐surface vitrification (SSV) using each cryoprotectant solution. The ovarian tissue was evaluated for follicular morphology and viability, DNA integrity (TUNEL technique) and the presence of nucleolar organizing regions in granulosa cells (AgNOR technique). After thawing, the percentage of normal preantral follicles was significantly reduced in the vitrified ovarian tissue fragments compared to the fresh control (p < 0.05). When comparing treatments, the use of DMSO 3 M (81.7 ± 37.5%), EG 3 M (83.7 ± 27.4%) and the combination of both DMSO 3 M + EG 3 M (81.8 ± 46.8%) allowed a greater percentage of follicular survival in contrast to DMSO 6 M (69.8 ± 16.5%) and EG 6 M (72.3 ± 18.0%; p < 0.05). When vitrified using the DMSO + EG combination, a higher percentage (62.5 ± 29.1%) of viable follicles (trypan blue) was observed in relation to the other vitrification treatments (p < 0.05). The TUNEL technique identified that all treatments tested showed DNA fragmentation in the follicular cells, except in the case of the DMSO 3 M + EG 3 M treatment. When evaluating the presence of NORs, no significant differences were observed in the amount of NORs between the fresh and vitrified groups using DMSO 3 M + EG 3 M (p > 0.05). We concluded that the combination DMSO 3 M + EG was more efficient for the vitrification of ovarian tissue taken from Equus asinus, allowing adequate preservation of PAFs morphology, viability, DNA integrity and cell proliferative capacity. 相似文献
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Camila Fernandes Pedro Albuquerque Nuno Mariz-Ponte Leonor Cruz Fernando Tavares 《Plant pathology》2021,70(4):943-958
Xanthomonas arboricola pv. juglandis (Xaj) is the aetiological agent of walnut diseases causing economic losses on walnut production worldwide. This phytopathogen is spread around the world where walnuts are produced and has a considerable genetic diversity. Using a comprehensive sampling methodology, focusing on factors that could influence the diversity of walnut-colonizing Xaj in Portugal, this work provides new insights on xanthomonad populations on walnut. Genetic diversity was assessed by multilocus sequence analysis (MLSA) and dot blot hybridization patterns on 131 Xanthomonas isolates obtained from 64 walnut trees considering epidemiological metadata such as year of isolation, distinct bioclimatic regions, production regimes, and host-related features. The results showed that the majority of isolates were split into 17 lineages of Xaj, while the other isolates clustered in four MLSA groups that did not include Xaj strains. These four groups were represented by three lineages of X. arboricola, and 11 lineages of Xanthomonas spp., including strains assigned to the recently proposed new species Xanthomonas euroxanthea. Furthermore, distinct Xaj, X. arboricola, and Xanthomonas spp. were isolated from the same walnut tree, suggesting possible genetic admixture within the same host. Phylogenetic analysis through geoBurst revealed the high diversity of these Xanthomonas spp. populations. Assessment of type III effector genes gave the indication that some Xanthomonas spp. strains were nonpathogenic on walnut, with the exception for X. euroxanthea CPBF 424. Altogether, these findings add to the thorough characterization of walnut-associated xanthomonads in Portugal, providing a comprehensive snapshot of the current diversity that could contribute to risk assessment analysis and improve phytosanitary control. 相似文献
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