Particulate matter dynamics and transformations in a recirculating aquaculture system: application of stable isotope tracers in seabass rearing     

Miguel-Angel Franco-Nava  Jean-Paul Blancheton  Genevi  ve Deviller  Jean-Yves Le-Gall 《Aquacultural Engineering》2004,31(3-4):135-155

The control of adverse effects and the possibility of removing suspended solids from recirculating aquaculture systems (RAS) are the principal challenges facing aquaculture engineers. However, their dynamics and transformations are not yet well known. In this study, carbon and nitrogen stable isotopes values (δ¹³C and δ¹⁵N) were used as tracers of particulate matter in a seabass RAS. An isotopic mixing model was employed to estimate the contributions of particulate sources. Feed (−22.1‰ for δ¹³C and 11.9‰ for δ¹⁵N), feces (−24.0‰ for δ¹³C and 6.4‰ for δ¹⁵N) and biofilm (−25.1‰ for δ¹³C and 12.9‰ for δ¹⁵N) were identified as main sources of particulate matter. The particle traps collected a mixing of 29% of uneaten feed and 71% of feces, when drum filter eliminated all remaining uneaten feed, shifting the isotopic signatures of suspended solids from −23.8 and 7.9‰ to −24.9 and 8.3‰ for δ¹³C and δ¹⁵N, respectively. The fish muscle (−18.6‰ for δ¹³C and 15.4‰ for δ¹⁵N) could reflect the isotopic variability of feed ingredients accumulated over time. The isotopic shifts indicate that the contribution of three sources depends on: (1) fish metabolism; (2) water treatment devices; and (3) bacterial bio-fouling into biofilter.  相似文献   

Pyrethroid resistance monitoring in European populations of pollen beetle (Meligethes spp.): a coordinated approach through the Insecticide Resistance Action Committee (IRAC)     

Slater R  Ellis S  Genay JP  Heimbach U  Huart G  Sarazin M  Longhurst C  Müller A  Nauen R  Rison JL  Robin F 《Pest management science》2011,67(6):633-638

BACKGROUND: Pollen beetle (Meligethes spp.) is a major pest of European oilseed rape crops. Its resistance to pyrethroid insecticides has been recorded in samples of beetles collected in Europe since at least 1999, and problems with the control of the beetle in the field have been widely reported. In 2007, a Pollen Beetle Working Group was formed through the Insecticide Resistance Action Committee (IRAC) in order to coordinate efforts for surveying pyrethroid resistance development. RESULTS: The results of the first 3 years of the pollen beetle pyrethroid susceptibility survey using a laboratory test are presented in this paper. Resistant beetle samples were collected from 20 of the 21 countries surveyed, with a general trend of increasing frequency and spread of resistant samples in European oilseed‐rape‐growing regions. CONCLUSION: Pyrethroid‐resistant beetles dominate in Western and Central Europe and are becoming established in the North and East, the main oilseed‐rape‐growing areas of Europe. The development and spread of pyrethroid‐resistant pollen beetles highlights the need for effective management strategies for oilseed rape insect pests. Copyright © 2011 Society of Chemical Industry  相似文献   

Effects of Hyptis spicigera Lam. (Labiatae) on the behaviour and development of Callosobruchus maculatus F. (Coleoptera: Bruchidae), a pest of stored cowpeas     

Antoine Sanon  Zakaria Ilboudo  Clementine L. B. Dabire  Roger C. H. Nebie  Idrissa O. Dicko  Jean-Paul Monge 《国际虫害防治杂志》2013,59(2):117-123

Abstract

The use of beni seed, Hyptis spicigera Lam. (Labiatae), to protect stored cowpeas from bruchid attacks is a widespread practice in West Africa. More knowledge about its actual effects on storage pests is needed to enhance its effectiveness. In this laboratory study, repellent and lethal effects of powder and essential oil from H. spicigera on Callosobruchus maculatus, the main pest of stored cowpeas, were studied. Repellency tests undertaken with a Y-tube olfactometer showed that powder was repulsive for C. maculatus adults. On the other hand, this product had no insecticidal activity. Essential oil had a dose-dependent insecticidal effect while sublethal doses repelled the adults. Both products reduced oviposition by 15 – 19 and 7 – 78% according to the doses of powder and essential oil, respectively, tested. Similarly, egg viability decreased with increasing doses of powder and essential oil used in a range of 40 – 75 and 24 – 86%, respectively. Only essential oil was lethal to C. maculatus larvae developing within cowpea seeds; however, oil activity was age-dependent, younger instars being more susceptible. These results are discussed with a view of controlling C. maculatus populations in stored cowpeas.  相似文献   

Effect of oxidation–reduction potential on performance of European sea bass (Dicentrarchus labrax) in recirculating aquaculture systems     

Xian Li  Jean-Paul Blancheton  Ying Liu  Sebastien Triplet  Luigi Michaud 《Aquaculture International》2014,22(4):1263-1282

The direct impact of oxidation–reduction potential (ORP) on fish welfare and water quality in marine recirculating aquaculture systems (RAS) is poorly documented. In this study, the effects of the fish size (S₁, S₂, S₃) and ORP level (normal, four successive levels) on the performance of European sea bass (Dicentrarchus labrax) were investigated. Three size fish were distributed into two RAS (RAS and RAS O₃). Ozone was injected into RAS O₃ to increase the ORP level. The ORP was stabilized to four successive levels: 260–300, 300–320, 320–350, and 300–320 mV in fish tanks during four periods (P_1–4). At the last day of each period, the hematological parameters, plasma protein and mortality of sea bass were analyzed. Two-way ANOVA revealed that several hematological parameters, including pH, hematocrit, concentrations of oxygen, carbon dioxide, glucose (Glu), ionized calcium, kalium, and hemoglobin, were significantly influenced by the increased ORP levels over the experimental period. The alteration in blood Glu and plasma protein concentration showed that ORP around 300–320 mV started to stress sea bass. Once the ORP exceeded 320 mV in the tanks during the P₃ period, mortality occurred even when total residual oxidants/ozone-produced oxidants was only 0.03–0.05 mg L^?1 in the fish tanks. At the same time, plasma protein decreased notably due to appetite depression. After the decrease in ORP during the P₄ period, mortality continued. In conclusion, the results strongly suggest that for European sea bass in RAS, the ORP should not exceed 320 mV in the tanks. Once ozonation damaged fish, the effect seemed to be irreversible. However, how ORP affected related hematological parameters still need the further investigations.  相似文献   

What is your diagnosis? Pulmonary hypertension     

Hearon K  Petrie JP;American College of Veterinary Radiology 《Journal of the American Veterinary Medical Association》2006,228(10):1495-1496

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Saprotrophic versus symbiotic strategy during truffle ascocarp development under holm oak. A response based on 13C and 15N natural abundance     

Bernd Zeller  Claude Bréchet  Jean-Paul Maurice  François Le Tacon 《Annals of Forest Science》2008,65(6):607-607

? The development of truffles in the soil is not well understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing ascocarps through ectomycorrhizal structures or whether sporophores become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon (C) and nitrogen (N) sources.

? To study saprophytic or symbiotic capacities of truffle ascocarps the natural abundance of ¹⁵N and ¹³C in foliage, wood, fine roots, mycorrhizae, fungal sporophores and soil were determined in a truffle orchard.

? The processes of carbon and nitrogen allocation remained unchanged during the entire period of ascocarp development of Tuber melanosporum. From ¹³C and ¹⁵N natural abundance measurements, T. melanosporum, T. brumale and T. rufum did not exhibit saprotophic strategy during ascocarp development, which is contradictory to common statements found in handbooks regarding truffle cultivation.

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An assessment of caprine tuberculosis prevalence in Lubumbashi slaughterhouse,Democratic Republic of Congo     

Luboya  Luboya Wa  Malangu  Mposhy  Kaleka  Mwenyi  Ngulu  Nsasi  Nkokele  Bimwala  Maryabo  Kazembe  Pourrut  Xavier  Vincent  Tom  Gonzalez  Jean-Paul 《Tropical animal health and production》2017,49(4):875-878

Tropical Animal Health and Production - Caprine tuberculosis is a major health problem for goats and a major zoonosis of veterinary public health interest. In order to prepare a response to and...  相似文献   

Applying ecological insights to increase productivity in tropical plantations     

Dan Binkley  Jean-Paul Laclau  José Luiz Stape  Michael G. Ryan 《Forest Ecology and Management》2010

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Enrichment of anhydrous milk fat in polyunsaturated fatty acid residues from linseed and rapeseed oils through enzymatic interesterification   总被引：1，自引：0，他引：1  

Aguedo M  Hanon E  Danthine S  Paquot M  Lognay G  Thomas A  Vandenbol M  Thonart P  Wathelet JP  Blecker C 《Journal of agricultural and food chemistry》2008,56(5):1757-1765

Lipozyme TL IM was used in a solvent-free batch and microaqueous system for enzymatic interesterification of anhydrous milkfat (AMF) with linseed oil (LO) in binary blends and with rapeseed oil (RO) in one ternary blend. The aim was to obtain and characterize physicochemically fats enriched with unsaturated C 18 fatty acids (oleic, linoleic, and, especially, linolenic acids) from natural vegetable oils. Binary blends of AMF/LO 100/0, 90/10, 80/20, 70/30, and 60/40 (w/w) were interesterified. The change in triacylglycerol (TAG) profiles showed that quasi-equilibrium conditions were reached after 4-6 h of reaction. Free fatty acid contents <1%. The decrease in solid fat content and in dropping point temperature obtained with increasing content of LO and interesterification resulted in good plastic properties for the products originating from the blends 70/30 and 60/40. This was confirmed by textural measurements. Melting profiles determined by differential scanning calorimetry showed complete disappearance of low-melting TAGs from LO and the formation of intermediary species with a lower melting temperature. Oxidative stability of the interesterified products was diminished with increasing LO content, resulting in low oxidation induction times. A ternary blend composed of AMF/RO/LO 70/20/10 gave satisfactory rheological and oxidative properties, fulfilling the requirements for a marketable spread and, moreover, offering increased potential health benefits due to the enriched content in polyunsaturated fatty acid residues.  相似文献   

Penetration and insecticidal activity of diflubenzuron in Tenebrio molitor pupae     

Noureddine Soltani  Jean-Paul Delbecque  Jean Delachambre 《Pest management science》1983,14(6):615-622

Diflubenzuron was found to be effective on the pupae of Tenebrio molitor L. (Coleoptera, Tenebrionidae) when applied topically, by dipping, or by injection. Death occurred before or at adult ecdysis, or during the first few days after emergence. Its effectiveness decreases with increasing age of the pupa. Diflubenzuron delays adult ecdysis and decreases the longevity of normally ecdysed adults. After diflubenzuron had been applied topically or by dipping, the compound was determined, on the pupal cuticle, in the body and on the rearing tray, by highperformance liquid chromatography. The results showed that diflubenzuron penetrated rapidly into the body and was not degraded during the pupal life. The level of incorporation of the insecticide, in dipping experiments on pupae at the same stage, varied from one individual to another. Moreover, the mean amount of insecticide incorporated was lower after dipping of older pupae than of younger pupae. It is suggested that the lower efficacy of diflubenzuron on older pupae may be caused by the decrease both in the permeability of the cuticle and in the sensitivity of the target cells.  相似文献