Small rivers,great importance: Refuge and growth sites of juvenile migratory fishes in the upper São Francisco Basin,Brazil     

Marina Ferreira Moreira  Alexandre Peressin  Paulo Santos Pompeu 《Fisheries Management and Ecology》2023,30(1):1-10

Studies of migratory fish species in Neotropical Basins have generally focused on adult fishes, especially on their reproductive migration, whereas sites of growth and refuge of juveniles remain poorly investigated. We aimed to evaluate if smaller rivers play a role in the life cycle of these species. We used 13 rivers of different sizes in the upper São Francisco Basin, Brazil. We found that smaller rivers, especially when draining regions close to floodplains, were the first places where juveniles moved after leaving floodplain lakes. We also found that individuals moved downstream as they grew, and were found in increasingly larger rivers that were more distant from floodplains. Currently, the best-known strategy for conservation of neotropical migratory fishes is the maintenance of free-flowing stretches encompassing necessary habitats for life cycle completion. We conclude that small tributaries near floodplain regions are also needed in these protected free-flowing river systems.  相似文献   

Autoantigenic nuclear proteins of a clinically atypical renal vasculitis     

Julio Avila  Elisa Acosta  María-del-Valle Machargo  María-Francisca Arteaga  Eduardo Gallego  Haridian Cañete  José-Javier García-Pérez  Pablo Martín-Vasallo 《Journal of Autoimmune Diseases》2008,5(1):3

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Activities of antioxidant enzymes and photosynthetic responses in tomato pre-treated by plant activators and inoculated by Xanthomonas vesicatoria     

Fabio Rossi Cavalcanti  Mario Lucio Vilela Resende  Joo Paulo Matos Santos Lima  Joaquim Albenisio Gomes Silveira  Jos Tadeu Abreu Oliveira 《Physiological and Molecular Plant Pathology》2006,68(4-6):198-208

The activities of antioxidant enzymes and photosynthetic responses were investigated in tomato (Lycopersicon esculentum L. var.) pre-treated by plant activators and inoculated by Xanthomonas vesicatoria. Plants were sprayed with acibenzolar-S-methyl, ASM [Bion^® 50 WG (0.2 g l⁻¹)] and aqueous extract from dry necrotic tissue flour (VLA) of ‘Lobeira’ (Solanum lycocarpum) bush. Four days later, the plants were challenged with a virulent strain of X. vesicatoria, under greenhouse conditions. Tomato leaves were then assessed to determine the activities of the main antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX). A reduction of bacterial leaf spot severity was observed in plants treated by ASM (49.3%) and VLA (31.4%), without any in vitro inhibitory activity over the pathogen. Controls showed decreases in CO₂ assimilation, transpiration, photosynthetic rates, and stomatal conductance. Water use efficiency and carboxylation efficiency were strongly affected in ASM- and VLA-treated, in comparison to controls and healthy plants. The tested substances induced increases in SOD and CAT activities in a delayed enzymatic response typical in compatible plant–pathogen interactions. Measured at daily intervals, activities of APX and POX were significantly (ρ0.05) higher in treated plants than in controls, except for APX in ASM-treated plants where no difference was found when compared to controls. Only POX was clearly induced at the earlier stages after spraying the tomato plants with ASM or VLA. Our results suggest that late increases in antioxidant enzyme activities may play a role in mitigating oxidative damage in restoring the photosynthetic imbalance imposed by the expansion of bacterial lesions.  相似文献   

Lessons from the Demonstration Management Improvement Program     

Eduardo Bautista  Shirley A. Rish  William E. Le Clere  Allen R. Dedrick  David B. Levine  Wayne Clyma 《Irrigation and Drainage Systems》2000,14(1-2):69-92

The Management Improvement Program,a process based on Organizational Developmentprinciples and methods, was applied to an irrigatedagricultural system in Arizona, USA. The MIP seeks toimprove management and performance of the agriculturalsystem through structured diagnosis, planning, andimplementation activities with the participation ofsystem stakeholders. An equally important objectiveof the demonstration project was to identify strengthsand shortcomings of the MIP methodology and togenerate recommendations for managing its futureapplications. The data used to analyze thedemonstration project's management were obtainedthrough formal interviews and informal conversationswith individual participants, program review andfeedback sessions, and records of meetings andindividual communications.Lessons about the project's management are categorizedin six areas: the initial exploration phase, initialplanning, participant on-boarding, formation of theprocess management team, development of the localcontrol group, and evaluation of the project. A keyaspect of conducting a change process such as the MIPfor improving the performance of agricultural systems,is that issues affecting the system may be difficultto identify early in the process or may requirelonger-term solutions, extending beyond the life ofthe formal process. Because of this uncertainty, adetailed action plan, the role of participants, andmeasures for evaluating progress or impact are alsolikely to be uncertain early in the project. Nevertheless, it is critical that the application,including these elements, be defined as concisely aspossible, especially relative to scope and funding,while still allowing the flexibility to address apotentially wider range of issues. Given the natureof the MIP, those responsible for its management needto be technically proficient, experienced with teammanagement techniques, sensitive to the localpolitical environment of natural resource management,and when necessary, willing to challenge stakeholders'initial understandings of issues.  相似文献   

Efficacy of adding chemical and microbial additives to silage on beef cattle performance: Systematic review and meta-analysis     

Guilherme Lobato Menezes  Alan Figueiredo de Oliveira  Frederico Patrus Ananias de Assis Pires  Lúcio Carlos Gonçalves  Rafael Araújo de Menezes  Pamella Grossi de Sousa  Paulo Henrique Arruda de Medeiros  Matheus Morais de Pinho  Ângela Maria Quintão Lana  Vânia Eloisa de Araújo  Diogo Gonzaga Jayme 《Grass and Forage Science》2023,78(1):1-22

The effects of different additives on farm-scale silage quality and beef cattle performance are inconsistent. This study aimed to carry out a systematic review and meta-analysis to evaluate the efficacy of chemical and microbial additives to silage on beef cattle performance. Systematic searches were performed using databases and scientific journals, and 42 articles were selected. Data for all variables were grouped into subgroups according to the additive type. For dry matter intake and average daily gain, the data were also grouped by forage type due to greater comparison numbers. The treatment mean differences and 95% confidence intervals (p < 0.05) were analysed using a random-effects model. The use of homo- and heterofermentative microbial inoculant mixtures and chemical additives (Ch) increased the average daily gain of beef cattle fed maize/sorghum silage. Homofermentative microbial inoculant (Ho), Ch, and a mixture of microbial inoculant and chemical additives also increased the average daily gain of beef cattle fed temperate grasses. Only Ch increased dry matter intake. Ch increased feed efficiency, and Ch and Ho increased carcass weight. The evaluated additives improved the silage fermentation process mainly via pH and ammonia nitrogen reduction. Overall, this meta-analysis demonstrated that silage additives improved the ensiling process and beef cattle performance, with better results with Ch use. Due to the aerobic stability and microbiological profile analyses being carried out more in laboratory-scale silos, more studies are needed to determine these silage parameters after opening the silo at the farm scale.  相似文献   

Growth,water quality and oxidative stress of Nile tilapia Oreochromis niloticus (L.) in biofloc technology system at different pH     

Gabriel Bernardes Martins  Carlos Eduardo da Rosa  Fbio de Melo Tarouco  Ricardo Berteaux Robaldo 《Aquaculture Research》2019,50(4):1030-1039

The objective of this study was to demonstrate the pH effects on growth, survival, water quality, proximal composition of bioflocs and oxidative stress of Nile tilapia in biofloc technology (BFT) system. Twenty‐five fish (3.68 ± 0.93 g) were distributed in each tank (useful vol. 37.5 L), utilizing treatments with pH 8.3, 7.5 and 6.5 at 60 days. During the experiment, the oxidation of total ammonia was similar among the treatments. However, the NO₂^?‐ N oxidation was slower at pH 6.5 (10.1 ± 1.0 mg/L) compared to pH 7.5 (7.0 ± 0.6 mg/L) and 8.3 (7.1 ± 1.5 mg/L). The final weight was higher for pH 7.5 treatment (44.1 ± 0.9 g) compared to pH 8.3 (37.1 ± 3.9 g), while the pH 6.5 (40.4 ± 4.1 g) was like to the other treatments. Moreover, the survival, daily growth rate and the food conversion rate were not affected by treatments. When evaluating physiological and biochemical parameters, no alterations were detected, therefore, indicating that fish have a good health status. Thus, the present study demonstrates that BFT for a Nile tilapia nursery, utilizing pH 6.5–7.5, promotes the best results in terms of growth, net yield and efficiency.  相似文献   

Aluminum-induced oxidative stress in lymphocytes of common carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis>)     

Sandra García-Medina  Amparo Celene Razo-Estrada  Leobardo Manuel Gómez-Oliván  Araceli Amaya-Chávez  Eduardo Madrigal-Bujaidar  Marcela Galar-Martínez 《Fish physiology and biochemistry》2010,36(4):875-882

Several studies of fish have shown that aluminum may induce hypoxia, hypercapnia, metabolic acidosis, and respiratory failure. In lymphocytes, morphologic abnormalities and reduced immune activity have been observed. Nevertheless, there is little data on oxidative stress and such data are essential in order to identify its mechanism of action. The common carp Cyprinus carpio, an omnivorous fish commonly used in commercial aquaculture, has been proposed as a test organism in toxicologic assays due to its economic importance and wide geographic distribution. The aim of this work was to evaluate Al-induced oxidative stress in lymphocytes of the common carp C. carpio. Specimens were exposed to three different concentrations of Al (0.05, 120, and 239 mg/l) in a static exposure system for 96 h. At the end of the exposure period, blood was collected and lymphocytes were separated. Lipid peroxidation, oxidized protein content and the activity of superoxide dismutase, catalase, and glutathione peroxidase were measured. Results show that the tested Al concentrations modified the activity of antioxidant enzymes and elicited higher levels of lipid peroxidation and oxidized proteins. The degree of damage induced was concentration and tissue dependent.  相似文献   

Feasibility of pacific white shrimp Litopenaeus vannamei culture in southern Brazil: effects of stocking density and a single or a double CROP management strategy in earthen ponds     

Dariano Krummenauer  Ronaldo O Cavalli  Eduardo L C Ballester  & Wilson Wasielesky Jr 《Aquaculture Research》2010,41(2):240-248

Marine shrimp culture at southern Brazil is restricted to the warmer season (November to April). Therefore, farmers must consider culture strategies and competition with shrimp landings from artisanal fishery. The fishing season starts every 1 February; in order to obtain higher prices, farmers may consider shrimp culture in two crops, with a first harvest before the start of the fishing season, and a second harvest after the end of the landings. The present study evaluated the performance and feasibility of Litopenaeus vannamei reared at 10, 25 and 40 shrimp m⁻² either in two short consecutive culture cycles or one longer cycle (LC). The experimental design consisted of two sets of nine pens installed in a 3.8 ha earthen pond. In one set of pens, shrimp were harvested after 75 days and pens were restocked for another 75-day-long rearing period. In the second set of pens, shrimp were cultured for 150 days. Shrimp survival and final weight ranged from 79% to 91% and 6.67 to 14.53 g respectively. Feasibility analysis pointed towards culture at higher densities (25 and 40 shrimp m⁻²) in a LC as productivity (2274–4227 kg ha⁻¹) and shrimp final weight (13.05–13.21 g) resulted in higher profitability (US$7761–12 379).  相似文献   

Biological and ecological aspects of the deep‐water red crab populations inhabiting isolated seamounts to the west of the Azores (Mid‐Atlantic Ridge)     

Rgis Santos  Mrio Pinho  Octvio Melo  Joo Gonalves  Ana Leocdio  Ana Aranha  Gui Menezes  Eduardo Isidro 《Fisheries Oceanography》2019,28(6):723-734

Seamounts are common topographic features in the Mid‐Atlantic Ridge (MAR) including the Azores. However, the knowledge on the ecology of seamounts in this region remains scarce despite needs for assessment and management of seamount resources such as the developing fisheries for deep‐water crabs. We described here for the first time the biological characteristics of an unexploited virgin deep‐water red crab Chaceon affinis population on seamount areas of the MAR to test the hypothesis that its general life history characteristics are similar in different ecosystem types (coastal areas and seamounts) across Macaronesia. We used a randomly stratified design to prospect a layer between 600 and 900 m depth around the summit of two isolated seamounts off the Azores. Results were consistent with the literature information in relation to the patterns of depth distribution, size and sex structure, and reproductive aspects. On the other hand, seamounts showed higher abundances when compared to previously studied coastal areas. Abundance may be also different between seamount areas as a function of the suitable bottom type available and presence of hydrothermal vents. We recommend that the essential habitat of the species should be better mapped identifying vulnerable areas before the development of any fishery.  相似文献   

Essential oil of Lippia alba in the diet of Macrobrachium rosenbergii: Effects on antioxidant enzymes and growth parameters     

Luana Cagol  Bernardo Baldisserotto  Alexssandro Geferson Becker  Carine de Freitas Souza  Berta Maria Heinzmann  Braulio Otomar Caron  Francisco Assis Leone  Lilian Dena dos Santos  Eduardo Luis Cupertino Ballester 《Aquaculture Research》2020,51(6):2243-2251

The juveniles of Macrobrachium rosenbergii (0.060 ± 0.004 g and 2.018 ± 0.071 cm) were fed during 60 days with diets containing different doses of Lippia alba essential oil (EOLA) (0.0—control, 1.0, or 2.0 ml EOLA/kg diet; in triplicate, with 20 prawns/replicate). After the experimental period, were verified the survival, growth parameters and the antioxidant enzymes, lipid peroxidation and Na/K‐ATPase activities in hepatopancreas and gills, respectively, of the animals. There were no significant differences on survival, growth parameters and gill Na/K‐ATPase activity. However, glutathione peroxidase and glutathione‐S‐transferase activities were lower in hepatopancreas of prawns fed with 1.0 ml EOLA/kg diet compared to the control. Moreover, the activity of the enzyme superoxide dismutase was higher in hepatopancreas of prawns that received 2.0 ml EOLA/kg diet compared to those fed with 1.0 ml EOLA/kg diet. Although the addition of both EOLA doses has not improved the survival and growth parameters of M. rosenbergii, these doses contributed to decrease lipid peroxidation. Additionally, the dose of 2.0 ml EOLA/kg diet contributed for increasing the antioxidant enzymes activities in the hepatopancreas, improving antioxidant status, and therefore, it can be recommended as diet supplementation for M. rosenbergii.  相似文献