Effect of Density at Harvest on the Growth Performance and Profitability of Hatchery‐reared Spotted Rose Snapper,Lutjanus guttatus,Cultured in Floating Net Cages          下载免费PDF全文

Carlos Humberto Hernández  Crisantema Hernández  Francisco Javier Martínez‐Cordero  Nicolás Castañeda‐Lomas  Guillermo Rodríguez‐Domínguez  Albert G. J. Tacon  Eugenio Alberto Aragón‐Noriega 《Journal of the World Aquaculture Society》2016,47(1):51-60

This study evaluated the effect of the density at harvest on the performance and profitability of hatchery‐reared spotted rose snapper cultured in cages. The fish were stocked at harvest densities of 15, 20, and 22 kg/m³ in cages of 222 and 286 m³. More than 39,000 snapper fingerlings with an initial weight of 14 g were stocked. The fish were fed an extruded diet and cultured over a 360 d period. The thermal growth coefficient ranged from 0.04 to 0.05 and survival was 95% for all treatments, with the highest final weight (436.8 g) observed for fish reared at a density of 20 kg/m³. The allometric value b indicated that hatchery‐raised, cage‐cultured snapper were heavier than their wild counterparts. The major costs were feed (ranging from 44.7–45.9%), labor (22.4–32.6%), and seed costs (20.2–26.1%). The total production cost ranged from US$ 6.5 to US$ 7.5/kg. The baseline scenario was not economically feasible. However, a 10% increase in the sales price resulted in increases in the internal rate of return (183%) and net present value (US$ 97,628.9). These results suggest that L. guttatus has the potential for commercial production in cages.  相似文献   

Short-term baths with essential oils of Lippia sidoides,Ocimum gratissimum and Zingiber officinale influence blood parameters and survival of tambaqui (Colossoma macropomum) after infection with Aeromonas hydrophila     

Patrícia Castro Monteiro  Maria Inês Braga de Oliveira  Franmir Rodrigues Brando  Caio Francisco Santana Farias  Cludia Majolo  Francisco Clio Maia Chaves  Humberto Ribeiro Bizzo  Fernanda Loureiro de Almeida O&#x;Sullivan  Maurício Latera Martins  Edsandra Campos Chagas 《Aquaculture Research》2022,53(1):265-275

This study evaluated the effect of short-term baths with the essential oils (EOs) of Lippia sidoides, Ocimum gratissimum and Zingiber officinale on the survival, haematological, biochemical and histopathological parameters of native fish tambaqui (Colossoma macropomum), challenged with Aeromonas hydrophila. After challenge, the fish infected with A. hydrophila received therapeutic baths of 60 min, for five consecutive days. Treatments were as follows: challenged and not treated; challenged and treated with 10 mg L^?1 of gentamicin; challenged and treated with EO of L. sidoides (2.5 and 5.0 mg L^?1); challenged and treated with EO of O. gratissimum (5.0 and 10.0 mg L^?1); challenged and treated with Z. officinale EO (5.0 and 10.0 mg L^?1). The highest survival rates were 89.5% (fish treated with 5.0 mg L^?1 of O. gratissimum EO) and 75.0% (fish treated with 5.0 mg L^?1 of L. sidoides EO). Reductions in the haematocrit percentage, haemoglobin and erythrocyte number were observed in fish treated with L. sidoides and Z. officinale EOs compared with control fish. Mild to moderate damage to the liver tissue of fish after challenge and EO treatments were observed. It is suggested that baths containing O. gratissimum and L. sidoides EOs consist in a viable treatment to increase survival rates of C. macropomum infected with A. hydrophila.  相似文献   

A review of extracellular virulence product of Vibrio species important in diseases of cultivated shrimp   总被引：2，自引：0，他引：2  

Gabriel Aguirre-Guzmán  Humberto Mejia Ruíz  & Felipe Ascencio 《Aquaculture Research》2004,35(15):1395-1404

Shrimp aquaculture is an important industry that experiences significant losses from Vibrio species, especially at the larval and juvenile stages. Proteinaceous virulence factors, including alkaline proteases, metalloproteases, cysteine proteases and alkaline serine proteases, have been identified as important elements in Vibrio pathogenesis. This review summarizes current knowledge regarding the principal pathogenic Vibrio species in shrimp, with emphasis on relevant exotoxins and their modes of action, principal characteristics and molecular database. This pathogenic factors and their relation with other molecules produced by microorganisms may be help to understand the virulence mechanisms present in Vibrio strain.  相似文献   

Effect of salinity on growth, survival and oxygen consumption of juvenile brown shrimp, Farfantepenaeus californiensis (Holmes)     

H Villarreal  A Hernandez-Llamas  & R Hewitt 《Aquaculture Research》2003,34(2):187-193

The brown shrimp, Farfantepenaeus californiensis (Holmes), is a species native to north‐west Mexico, where its culture potential is presently being addressed. Because of the climatic conditions prevailing in the region, salinities over 40 g L^?1 is a commonly encountered problem. In the present study, the effect of salinity on the growth and mortality of juvenile F. californiensis is described. The change in short‐term routine metabolism at different salinities was also evaluated in order to define the adaptive capacity of the shrimp and to provide insight into the changes in the pathways of energy distribution. Groups of shrimp were exposed to increasing salinity (25, 35, 45 and 55 g L^?1), and growth and survival rates after 75 days were determined in duplicate 1.8‐m³ tanks for each salinity level. Significant differences were found in final weight, growth rate and mortality of shrimp as a result of salinity level. Final mean shrimp weights at increasing salinity levels were 10.0, 9.4, 8.6 and 7.8 g. Corresponding mortality was 24.4%, 15.1%, 33.6% and 55.7%. Oxygen consumption was found to depend significantly on salinity and was equivalent to 0.0027, 0.0037, 0.0043 and 0.0053 mg g^?1 min^?1 respectively for the increasing salinities. The increased rate of oxygen consumption at high salinities reflects the response of the organism to osmoregulatory and ionic imbalances. Increased energy requirements to fulfil basic metabolic function as salinity increased resulted in a reduction in the energy that could be diverted to growth. Consequently, the culture of the brown shrimp at salinities over 35 g L^?1 would probably result in reduced yields.  相似文献   

Identification of sex in Carica papaya L. using RAPD markers     

Eliana Gertrudes Macedo Lemos  Cristina Lacerda Soares Petrarolha Silva  Humberto Actis Zaidan 《Euphytica》2002,127(2):179-184

Brazil is currently the worlds largest producer of papaya (Carica papayaL.), producing fruits for both the domestic market and export. Only fruits from hermaphrodite plants are marketed because they have the necessary commercial characteristics, i.e. they are pear-shaped and have thicker flesh and a smaller internal cavity. Increased papaya yield has been limited mainly by the ratio of female to hermaphrodite (1: 2) plants normally occurring in orchards. This ratio causes great losses to papaya producers and the identification of the sex of seedlings during the nursery stage would be an important advance. In our study random amplified polymorphic DNA (RAPD) analysis was used to differentiate between the sexual forms of three commercial C. papaya cultivars belonging to the Solo group. RAPD assays using the BC210 primer were able to detect hermaphrodites in all of the cultivars tested. The BC210₄₃₈molecular marker was much better at papaya sex differentiation than other markers described in the literature. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Shocks in ion sputtering sharpen steep surface features   总被引：1，自引：0，他引：1  

Chen HH  Urquidez OA  Ichim S  Rodriquez LH  Brenner MP  Aziz MJ 《Science (New York, N.Y.)》2005,310(5746):294-297

We report a regime of ion beam sputtering that occurs for sufficiently steep slopes. High slopes propagate over large distances without dissipating the steepest features. Both the propagation velocity and the dynamically selected slope are universal, independent of the details of the initial shape of the surface. The resulting behavior can be understood as the propagation of a shock front that self-selects a stable slope, as has been previously observed in thin-film fluid flows. Experiments confirm predictions of the theory. An important implication of the propagative behavior at high surface slopes is that a pattern can be fabricated at a large length scale and, through uniform ion irradiation, reduced to a smaller length scale while preserving, or even sharpening, the sharpest features.  相似文献   

Amazon forests green-up during 2005 drought     

Saleska SR  Didan K  Huete AR  da Rocha HR 《Science (New York, N.Y.)》2007,318(5850):612

Coupled climate-carbon cycle models suggest that Amazon forests are vulnerable to both long- and short-term droughts, but satellite observations showed a large-scale photosynthetic green-up in intact evergreen forests of the Amazon in response to a short, intense drought in 2005. These findings suggest that Amazon forests, although threatened by human-caused deforestation and fire and possibly by more severe long-term droughts, may be more resilient to climate changes than ecosystem models assume.  相似文献   

Voltammetric determination of the antioxidant capacity in wine samples using a carbon nanotube modified electrode     

Souza LP  Calegari F  Zarbin AJ  Marcolino-Junior LH  Bergamini MF 《Journal of agricultural and food chemistry》2011,59(14):7620-7625

A direct determination of gallic acid was achieved at a carbon paste electrode modified with carbon nanotubes under differential pulse voltammetry conditions. The values obtained for gallic acid were used to estimate the antioxidant properties of the wine sample based on gallic acid oxidation. The proposed method is based on the gallic acid oxidation process at a modified carbon paste electrode (MCPE) containing 30% (m/m) of carbon nanotubes monitored at 0.35 V versus Ag/AgCl (KCl 3 mol L(-1)). Using the optimized experimental conditions, the calibration curve for gallic acid was linear in the concentration range from 5.0 × 10(-7) to 1.5 × 10(-5) mol L(-1) with a detection limit of 3.0 × 10(-7) mol L(-1). The MCPE was successfully applied for the determination of the antioxidant capacity for red and white wine samples without interference of glucose and ascorbic acid, and the obtained results were compared with the standard spectrophotometric method.  相似文献   

Suicide vectors for the introduction of genetic markers into Bradyrhizobium strains by site-directed chromosomal integration between repeated sequences (RS-α)     

Humberto J.O. Ramos 《Soil biology & biochemistry》2006,38(8):2481-2486

To achieve stable expression of the heterologous and reporter genes in the Bradyrhizobium genome, we constructed suicide plasmids capable of site-directed genomic integration of the gusA, gfp and nifA genes by homologous recombination into non-essential repeated sequences (RS-α), isolated from B. japonicum strain CPAC7 (SEMIA5080). In this report, we describe the strategies to construct the vectors and their use to obtain mutants with site-specific insertions.  相似文献   

Participatory landrace selection for on-farm conservation: An example from the Central Valleys of Oaxaca, Mexico   总被引：8，自引：1，他引：8  

Mauricio R. Bellon  Julien Berthaud  Melinda Smale  José Alfonso Aguirre  Suketoshi Taba  Flavio Aragón  Jaime Díaz  Humberto Castro 《Genetic Resources and Crop Evolution》2003,50(4):401-416

On-farm conservation is recognized as a key component of a comprehensive strategy to conserve crop genetic resources. A fundamental problem faced by any on-farm conservation project is the identification of crop populations on which efforts should be focused. This paper describes a method to identify a subset of landraces for further conservation efforts from a larger collection representing the diversity found in the Central Valleys of Oaxaca, Mexico. Mexico is a center of origin and diversity for maize (Zea mays L.). The 17 landraces selected from an initial collection of 152 satisfy two criteria. First, they represent the diversity present in the larger collection. Second, they appear to serve the interests of farmers in the region. Data for applying the method were elicited through participatory as well as conventional techniques. They incorporate the complementary perspectives of both men and women members of farm households, and of plant breeders and social scientists.  相似文献