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排序方式: 共有182条查询结果,搜索用时 15 毫秒
1.
Despite the interest of meagre (Argyrosomus regius) as a fast‐growing candidate for Mediterranean aquaculture diversification, there is a lack of information on nutrition along larval development. Importance of highly unsaturated fatty acids (HUFA) and the antioxidant vitamins E and vitamin C has not been investigated yet in this species. Six diets with two levels of HUFA (0.4% and 3% dw), two of vitamin E (1500 and 3000 mg kg?1) and two of vitamin C (1800 and 3600 mg kg?1) were fed to 15 dah meagre larvae. Larval growth in total length and dry body weight was significantly lowest in larvae fed diet 0.4/150/180 and showed few lipid droplets in enterocytes and hepatocytes and lower HUFA contents than the initial larvae. Increase in dietary HUFA up to 3%, significantly improved larval growth and lipid absorption and deposition. Besides, among fish fed 3% HUFA, increase in vitamin E and vitamin C significantly improved body weight, as well as total lipid, 22:6n‐3 and n‐3 fatty acids contents in the larvae. Thus, the results showed that 0.4% dietary HUFA is not enough to cover the essential fatty acid requirements of larval meagre and a high HUFA requirement in weaning diets is foreseen for this species. Besides, the results also pointed out the importance of dietary vitamin E and C to protect these essential fatty acids from oxidation, increase their contents in the larvae and promote growth, suggesting high vitamin E and C requirements in meagre larvae (higher than 1500 and 1800 mg kg?1 for vitamin E and vitamin C respectively).  相似文献   
2.
The aim of this study was to examine effects of dietary supplementation with Aspergillus awamori and feeding canola seed on the growth and fatty acid profile in broilers. Twenty‐eight chicks (15 days old) were assigned to the following groups: (1) control, fed a basal diet; (2) awamori, fed the basal diet supplemented with 0.05% A. awamori; (3) canola, fed a diet containing 5% canola seed; and (4) canola + awamori, fed the canola diet supplemented with A. awamori (seven birds/group). Body weight gain was increased by A. awamori but not influenced by canola seed. Breast muscle weight was increased in either awamori or canola groups. Although plasma triglyceride and cholesterol were decreased by feeding A. awamori or canola seed, fat content in the breast muscle were increased, accompanied by decrease in saturated fatty acids and increase in unsaturated fatty acids. Moreover, decreased thiobarbituric acid reactive substance and increased α‐tocopherol content in the breast muscle was observed in all experimental groups. In conclusion, these results suggested that feeding canola seed and A. awamori might improve growth performance, and modified muscle fatty acid profile and α‐tocopherol content, suggesting that they may improve meat quality.  相似文献   
3.
The present work aimed to study the effects of high constant and alternating temperatures on the development and prey consumption by Dicyphus tamaninii Wagner (Het., Miridae) with Aphis gossypii Glover (Hom., Aphididae) as prey.Results showed that the predator was able to successfully develop and reach the adult stage, on average, after 20.1 () and 20.6 () days at a temperature of 30 ± 1 °C with A. gossypii as prey. On the other hand, it was not able to develop at 35 ± 1 °C, here all N1 instars used at the beginning of the experiments had died even before moulting to N2 instar. At alternating temperatures of 25/15 ± 1 °C, the predator reached the adult stage 23.7 () and 23.5 () days after egg hatching, whereas when the temperatures were increased to 35/22 ± 1 °C, it took a significantly shorter period: 20.6 () and 20.9 () days. In general, the highest mortality occurred during the first two nymphal instars. The total percentage mortality during development from N1 to adult stage was 30 % and 100 % at the constant temperatures 30 ± 1 °C and 35 ± 1 °C, respectively. At the alternating temperatures of 25/15 ± 1 °C, it was lowest with 16.5 %, while at 35/22 ± 1 °C, it was 20 %.The results of the experiments on prey consumption showed that an individual D. tamaninii consumed during its development to adult stage at 30 ± 1 °C an average of 442.2 (), 433.6 () aphids. At the constant temperature of 35 ± 1 °C, the average daily prey consumption started with 4 aphids and decreased continuously till it approached nil on the 9th day, where all predatory nymphs died. At the alternating temperatures of 25/15 ± 1 °C, the total prey consumption during development was, on average, 359.3 () and 297.0 () aphids, while at 35/22 ± 1 °C it was 348.5 () and 334.0 () aphids. The effect of the four temperatures on the prey consumption by D. tamaninii during the first 10 days after emergence was also studied. At a constant temperature of 30 ± 1 °C, a total of 446.4 () and 372.0 () aphids were consumed, compared to 40.6 () and 39.0 () at 35 ± 1 °C. At alternating temperatures of 25/15 ± 1 °C, the predatory adult consumed, on average, a total of 267.0 () and 207.0 () aphids. Increasing the temperature to 35/22 ± 1 °C resulted in a higher prey consumption by the adult predator, reaching 351.5 () and 267.7 () aphids over the same period.In conclusion, results indicated that D. tamaninii is a promising predator of the melon aphid at a temperature spectrum ranging from 15 ± 1 °C up to 35 ± 1 °C.  相似文献   
4.
Two new flavones were isolated from the aerial parts of Retama raetam subsp. raetam. Their structures were established as luteolin 4'-O-neohesperidoside (1) and 5,4'-dihydroxy-(3",4"-dihydro-3", 4"-dihydroxy)-2",2"-dimethylpyrano-(5",6":7,8)-flavone (2) by means of spectroscopic methods. Also present was ephedroidin (4',5, 7-trihydroxy-8-(2-hydroxy-3-butenyl)-flavone).  相似文献   
5.
Changes in land-use or management practices may affect water outflow, sediment, nutrients and pesticides loads. Thus, there is an increasing demand for quantitative information at the watershed scale that would help decision makers or planners to take appropriate decisions. This paper evaluates by a modeling approach the impact of farming practices and land-use changes on water discharge, sediment and NO3-N loads at the outlet of a 51.29 km2 watershed of central Iowa (Walnut Creek watershed). This intensively farmed (corn-soybean rotation) watershed is characterized by a flat topography with tiles and potholes. Nine scenarios of management practices (nitrogen application rates: increase of current rate by 20, 40%, decrease of current rate by 20, 40 and 60%; no tillage) and land-use changes (from corn-soybean rotation to winter wheat and pasture) were tested over a 30 yr simulated period. The selected model (Soil and Water Assessment Tool, SWAT) was first validated using observed flow, sediment and nutrient loads from 1991 to 1998. Scenarios of N application rates did not affect water and sediment annual budgets but did so for NO3-N loads. Lessening the N rate by 20, 40 and 60% in corn-soybean fields decreased mean NO3-N annual loads by 22, 50 and 95%, respectively, with greatest differences during late spring. On the other hand, increasing input N by 20 and 40% enhanced NO3-N loads by 25 and 49%, respectively. When replacing corn-soybean rotation by winter wheat, NO3-N loads increased in early fall, immediately after harvest. Pasture installation with or without fertilization lessened flow discharge, NO3-N and sediment delivery by 58, 97 and 50%, respectively. No-tillage practices did not significantly affect the water resource and sediment loads. Finally, such realistic predictions of the impact of farming systems scenarios over a long period are discussed regarding environmental processes involved.  相似文献   
6.
Aeromonas salmonicida is the causative agent of furunculosis, a disease that affects both salmonid and non‐salmonid fish. Detection of A. salmonicida can be labour intensive and time consuming because of the difficulties in distinguishing the bacterium from other species given the wide variety of existing biochemical profiles and the slow growth characteristics which allow other organisms to overgrow the A. salmonicida. Herein, we report the development of a specific immunoassay using gold‐conjugated polyclonal antibodies for the rapid detection of A. salmonicida in fish tissues. Monodispersible 13‐nm gold nanoparticles were coated with polyclonal antibodies specific to A. salmonicida. Reddish purple agglutination of gold particles indicated the presence of A. salmonicida in samples. Positive reactions were detected visually with the naked eye. No agglutination was observed when A. salmonicida antibodycoated gold nanoparticles were tested with other common bacterial fish pathogens, thereby verifying the specificity of the assay. The assay could detect A. salmonicida in fish tissues down to 1 × 104 CFU mL?1, and results were obtained within 45 min. The antibody‐coated gold nanoparticles were stable for at least 2 months at 4°C. The immunoassay using antibody‐coated gold nanoparticles represents a promising tool for the rapid and specific detection of A. salmonicida in fish tissues.  相似文献   
7.
Research was conducted in northern Colorado in 2011 to estimate the crop water stress index (CWSI) and actual transpiration (T a) of maize under a range of irrigation regimes. The main goal was to obtain these parameters with minimum instrumentation and measurements. The results confirmed that empirical baselines required for CWSI calculation are transferable within regions with similar climatic conditions, eliminating the need to develop them for each irrigation scheme. This means that maize CWSI can be determined using only two instruments: an infrared thermometer and an air temperature/relative humidity sensor. Reference evapotranspiration data obtained from a modified atmometer were similar to those estimated at a standard weather station, suggesting that maize T a can be calculated based on CWSI and by adding one additional instrument: a modified atmometer. Estimated CWSI during four hourly periods centered on solar noon was largest during the 2 h after solar noon. Hence, this time window is recommended for once-a-day data acquisition if the goal is to capture maximum stress level. Maize T a based on CWSI during the first hourly period (10:00–11:00) was closest to T a estimates from a widely used crop coefficient model. Thus, this time window is recommended if the goal is to monitor maize water use. Average CWSI over the 2 h after solar noon and during the study period (early August to late September, 2011) was 0.19, 0.57, and 0.20 for plots under full, low-frequency deficit, and high-frequency deficit irrigation regimes, respectively. During the same period (50 days), total maize T a based on the 10:00–11:00 CWSI was 218, 141, and 208 mm for the same treatments, respectively. These values were within 3 % of the results of the crop coefficient approach.  相似文献   
8.
European Journal of Plant Pathology - Tea (Camellia sinensis) is a popular and extensively consumed beverage in Malaysia along with many other countries around the world. Grey blight is one of the...  相似文献   
9.
Continuing a previous study, the leaves and barks of thirty one plants collected from the botanical gardens in Cairo, were subjected to detailed studies with the aim of identifying the type of tannins present in each plant. The study included colour tests and paper chromatography of both the free sugars and phenolic aglycones. The plants recorded here are those ranging fromAceraceae toFlacourtiaceae.
Zusammenfassung In Fortsetzung dieser Reihe wurden die Blätter- und Rindermaterialien von 31 Pflanzen, gesammelt aus den botanischen Gärten in Kairo, auf ihre Gerbstoffe untersucht. Mit Hilfe der Papierchromatographie wurden sowohl die freien Zucker als auch die phenolischen Komponenten dieser Pflanzen identifiziert.In dieser Mitteilung wurden die Untersuchungsergebnisse der Pflanzen der Familien Aceraceae bis Flacourtiaceae gegeben.

Résumé En poursuivant nos études précédentes, les feuilles et les écorses de 31 plantes cueillies dans les jardins de Caire, ont été soumises à des études détaillées. En vue d'identifier le type des tannins présent dans chaque plante, les études contenaient des expériments par chromatographie sur papier concernant les sucres natifs et les aglycones phénoliques. Les plantes qui ont été rapportées ici sont celles des familles Aceraceae à Flacourtiaceae.
  相似文献   
10.
Genetic Resources and Crop Evolution - Mangosteen (Garcinia mangostana var. mangostana) is an obligate apomictic species which does not require a fertilization process to produce seeds. The absence...  相似文献   
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