Effect of the dusk photoperiod change from light to dark on the incubation period of eggs of the spotted rose snapper, Lutjanus guttatus (Steindachner)     

Neil J Duncan  Leonardo Ibarra-Castro  & Ricardo Alvarez-Villaseñor 《Aquaculture Research》2008,39(4):427-433

Spotted rose snapper, Lutjanus guttatus (Steindachner), eggs were incubated under different photoperiods to examine the effect of photoperiod on incubation. The eggs from two fish were incubated under five artificial photoperiods: constant dark (D), constant light (L) from 06:00 hours and 6, 10 and 14 h of light from 06:00 hours. The eggs from seven other fish were incubated under a natural photoperiod. Different spawning times (21:00 – 01:00 hours) and different photoperiods combined to give the start of the dusk photoperiod change after 11–23 h of incubation. Constant light or applying the dusk photoperiod change after ≥20 h of incubation appeared to extend the hatching period. The mean hatching period for groups of eggs incubated in darkness or that received the dusk photoperiod change after ≤19 h of incubation (n=8 different groups) was 2 h 15±10 min, which was significantly lower (P<0.05) than the mean hatching period of 4 h±37 min for groups that did not receive the dusk photoperiod change or that received the dusk photoperiod change after ≥20 h of incubation (n=9 groups). However, despite these differences, the majority of the eggs hatched during a 2–3 h period from 17 to 20 h of incubation, and a sigmoid regression (r²=0.9) explained the relationship between percentage hatch and hours of incubation for all photoperiod groups.  相似文献   

Nutrient Digestibility of Cereal Grain Products and By‐products in Extruded Diets for Nile Tilapia     

Igo G. Guimarães  Luiz E. Pezzato  Margarida M. Barros  Leonardo Tachibana 《Journal of the World Aquaculture Society》2008,39(6):781-789

Apparent digestibility coefficients (ADCs) provide estimates of nutrient availability in feedstuffs and can be used as a tool for selecting ingredients to compound cost‐effective diets for fish. Extrusion process is one factor that could influence ADC values. Thus, a digestibility trial was undertaken to evaluate ADC of protein, energy, and dry matter, and apparent amino acid availability (AAAA) in five cereal grain products/by‐products (corn, wheat middlings, broken rice, rice bran, and sorghum) in compounded diets for Nile tilapia. Chromic oxide was used as an external inert marker. The digestibility values of energy and dry matter in ingredients, in decreasing order, were highest for broken rice (95.34 and 96.45%), sorghum (82.37 and 87.29%), corn (67.34 and 82.21%), rice bran (57.58 and 55.59%), and wheat middlings (48.94 and 45.88%). Protein digestibility value was higher for corn (72.86%) and the lowest value was observed for sorghum (56.77%), while broken rice, wheat middlings, and rice bran presented values ranging from 63.01 to 66.88%. AAAA values were higher for corn (70.05%) and the lowest methionine and cystine availability values were recorded for wheat middlings and broken rice, respectively. Broken rice appears as one of the most indicated ingredient for using in Nile tilapia diets because of its highest values of nutrient digestibility when compared to the other energetic sources. The use of this information should aid more precise and economic diet formulation for Nile tilapia.  相似文献   

The ‘pole-hooking’ method: A novel and economical technique for in situ tagging small to medium-sized fishes     

Alejo J. Irigoyen  Leonardo A. Venerus 《Fisheries Research》2008,91(2-3):349-353

We describe a new manual procedure for catching and tagging fish underwater, the ‘pole-hooking’ method, and demonstrate and discuss its advantages over standard tagging techniques (i.e. hook-and-line fishing). The new technique was designed for tagging Acanthistius brasilianus [Cuvier, M., Valenciennes, L.B., 1828. Histoire Naturelle des Poissons. Museau de Histoire Naturelle, Paris], a small to medium-sized fish inhabiting rocky reefs of the Argentine coast. The pole-hooking method minimizes injuries, avoids fast depressurization of fish and allows registration of the precise location of capture and release. In addition, the equipment needed is very simple and economical. The mean number of fish tagged per minute using this methodology on shallow rocky reefs (up to 25-m depth) was similar to that obtained during hook-and-line fishing sessions (ca. one tagged fish every 3 min), given similar densities of A. brasilianus in the fished reefs.  相似文献   

Temporal and spatial progress of the diseases caused by the crinivirus tomato chlorosis virus and the begomovirus tomato severe rugose virus in tomatoes in Brazil     

M. A. Macedo  A. K. Inoue-Nagata  T. N. Z. Silva  D. M. S. Freitas  J. A. M. Rezende  J. C. Barbosa  M. Michereff-Filho  A. R. Nascimento  A. L. Lourenção  A. Bergamin Filho 《Plant pathology》2019,68(1):72-84

Efficient management of whitefly-borne diseases remains a challenge due to the lack of a comprehensive understanding of their epidemiology, particularly of the diseases tomato golden mosaic and tomato yellowing. Here, by monitoring 16 plots in four commercial fields, the temporal and spatial distribution of these two diseases were studied in tomato fields in Brazil. In the experimental plots these diseases were caused by tomato severe rugose virus (ToSRV) and tomato chlorosis virus (ToCV), respectively. The incidence of each virus was similar in the plots within a field but varied greatly among fields. Plants with symptoms for both diseases were randomly distributed in three of four spatial analyses. The curves representing the progress of both diseases were similar and contained small fluctuations, indicating that the spread of both viruses was similar under field conditions. In transmission experiments of ToSRV and ToCV by Bemisia tabaci MEAM1 (former biotype B), these viruses had a similar transmission rate in single or mixed infections. It was then shown that primary and secondary spread of ToCV were not efficiently controlled by insecticide applications. Finally, in a typical monomolecular model of disease progress, simulation of the primary dissemination of ToSRV and ToCV showed that infected plants were predominantly randomly distributed. It is concluded that, although the manner of vector transmission differs between ToSRV (persistent) and ToCV (semipersistent), the main dispersal mechanisms are most probably similar for these two diseases: primary spread is the predominant mechanism, and epidemics of these diseases have been caused by several influxes of viruliferous whiteflies.  相似文献   

Association of zein nanoparticles with botanical compounds for effective pest control systems     

Jhones L de Oliveira  Estefnia V R Campos  Taís Germano‐Costa  Renata Lima  Jaqueline Franciosi Della Vechia  Sidneia Terezinha Soares  Daniel Junior de Andrade  Kelly Cristina Gonalves  Joacir do Nascimento  Ricardo Antonio Polanczyk  Leonardo Fernandes Fraceto 《Pest management science》2019,75(7):1855-1865

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Mediterranean versus Atlantic monk parakeets Myiopsitta monachus: towards differentiated management at the European scale     

Jose‐Luis Postigo  Diederik Strubbe  Emiliano Mori  Leonardo Ancillotto  Inês Carneiro  Panagiotis Latsoudis  Mattia Menchetti  Liviu G Pru  Dave Parrott  Luís Reino  Anne Weiserbs  Juan Carlos Senar 《Pest management science》2019,75(4):915-922

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Tolerance to nymphs and adults of Mahanarva spectabilis (Hemiptera: Cercopidae) by forage plants in fertilized soils     

Roberta Alvarenga  Alexander Machado Auad  Jair Campos Moraes  Sandra Elisa Barbosa da Silva  Brunno Santos Rodrigues 《Pest management science》2019,75(8):2242-2250

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Synthesis and herbicidal activity of 2alpha, 4alpha-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one derivatives.     

A V Costa  L C Barbosa  A J Demuner  A A Silva 《Journal of agricultural and food chemistry》1999,47(11):4807-4814

The catalytic oxidation of 2alpha,4alpha-dimethyl-8-oxabicyclo[3.2. 1]oct-6-en-3-one with osmium tetraoxide and excess hydrogen peroxide resulted in the formation of 2alpha,4alpha-dimethyl-6, 7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3-one (2), with 91% yield. Addition of aryllithium reagents to this compound resulted in the formation of the aromatic alcohols (6a-h) with 48-76% yield. These alcohols were treated with thionyl chloride in pyridine, and the corresponding alkenes (7a-h) were obtained with 46-80% yield. The effect of compounds 6a-h and 7a-h on the root growth of Sorghum bicolor was evaluated at a concentration of 6.6 microg g(-)(1). The alcohols 6a-h caused an inhibitory effect (8-100%) on the S. bicolor radicle growth. The three most active compounds were 6e (aryl = p-methylphenyl), 6g (aryl = p-chlorophenyl), and 6h (aryl = p-fluorophenyl) and caused 100% inhibition. The effect of alkenes 7a-h was less pronounced and varied from 15% to 46% inhibition. Another experiment was carried out in a greenhouse to evaluate the effect of alcohols 6e, 6g, and 6h, at a 6.6 microg g(-)(1) dose, against Cucumis sativus, S. bicolor and the weeds Bidens pilosa, Desmodiumtortuosum, and Pennisetum setosum. All three compounds showed an inhibitory effect on the development of the aerial parts (26-73%) and roots (13-79%) of the weeds and crops.  相似文献   

Primary and secondary metabolite composition of kernels from three cultivars of Portuguese chestnut (Castanea sativa Mill.) at different stages of industrial transformation     

Do Carmo Barbosa Mendes De Vasconcelos M  Bennett RN  Rosa EA  Ferreira Cardoso JV 《Journal of agricultural and food chemistry》2007,55(9):3508-3516

Chestnut (Castanea sativa) is an important basic food in rural diets and a major starch crop used in a similar way to potatoes. Chestnuts are a fundamental economic resource in the "chestnut regions" not only for the fruit but also for the chestnut wood. Chestnuts have become increasingly important with respect to human health, for example, as an alternative gluten-free flour source. Chestnuts are also a rich source of other beneficial compounds, but there have been few studies on the composition during processing. In this study, we analyzed the chemical composition of three Portuguese cultivars at different stages of industrial processing. The chestnut cultivars were Longal, Judia, and Martaínha. All three cultivars had high moisture contents but were low in ash, crude fat, and crude protein contents, with high starch and low fiber contents. The free amino acid contents, including various essential amino acids, varied depending on the cultivar. All three cultivars also had a significant content of polyphenolics with gallic acid; ellagic acid was predominant among hydrolyzable and condensed tannins. Many of these compounds are known to exert significant positive effects on human health. The one-way analysis of variance for fresh chestnut shows significant differences among the three cultivars for most of the studied parameters. The same statistical analysis applied to each one of the two cultivars (Judia and Longal) sampled for the four processing steps analyzed indicates a significant effect of this factor in practically all of the constituents. On the other hand, the two-way analysis of variance shows that, besides the residual, the processing step and the interaction cultivar x processing step were the factors that more contributed for the total variation observed in the constituents analyzed, while the contribution of cultivar was much less significant.  相似文献   

Growth and production of the Amazonian tambaqui in fixed cages under different feeding regimes     

S. Chellappa  N. T. Chellappa  W. B. Barbosa  F. A. Huntingford  M. C. M. Beveridge 《Aquaculture International》1995,3(1):11-21

Experimental culture of the native Amazonian fish tambaqui, Colossoma macropomum, in fixed cages was carried out over a period of 8 months, in Lake Urubu (Rio Grande do Norte, Brazil), to assess the viability of fixed cage culture of tambaqui and to test the influence of diet on growth rates. Nine synthetic net cages (1 m³) were each stocked with 45-day-old fish (mean weight 3 g; mean total body length 51 mm) at a density of 34 fry m^–3. During the first 2 months of culture, fish were fed a balanced formulated feed on an as-fed basis at the rate of 5% body weight day^–1. During months 3–8 this continued for fish in treatment 1 while those in treatment 2 were fed tropical regional fruits, on a wet weight basis at the rate of 5% body wt day^–1. Fish in treatment 3 were given no supplementary feed. Monthly biometric measurements were made on all fish. Fixed cage fish culture was shown to be a viable and simple technique. Survival in all treatments was 100%. With balanced supplementary feed, production was 14.4 kg m^–3, compared with 4.9 kg m^–3 and 2.1 kg m^–3, respectively, in the treatments where fish were fed with fruits and were not given any supplementary feed.  相似文献