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1.
This study was conducted to investigate the effects of dietary synthetic β‐carotene on growth performance, haematological and immunological parameters, energy reserves and antioxidant status of juvenile fish Piaractus mesopotamicus. Two hundred and ten fish (12.24 ± 2.98 g) were fed with a control extruded feed (CEF) and the same diet supplemented with β‐carotene (BEF) for 90 days. A higher weight gain and specific growth rate were found in fish fed BEF in comparison with those fed CEF. In addition, BEF‐fed fish showed lower liver somatic index and a higher percentage of eosinophils. No statistical differences were found in energy reserves, except for plasma triglycerides which decreased in fish fed with BEF. Regarding oxidative stress markers, decreased activities of antioxidant enzymes were found in intestine and gills of BEF‐fed fish (SOD and GST, respectively). In the liver, both LPO levels and CAT activity decreased in fish fed with BEF. Additionally, lower brain LPO levels without changes in the antioxidant enzymes were observed in BEF‐fed fish. The inclusion of dietary synthetic β‐carotene improved growth and antioxidant status, and had a plasma triglyceride‐lowering effect in juvenile P. mesopotamicus.  相似文献   
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In this study, the effects of three diets were investigated to enhance Paracentrotus lividus production for commercial purposes. P. lividus were fed ad libitum for 80 days with: diet A—fresh Codium tomentosum Stackhouse, 1797; diet B—formulated using a jellified mix of macroalgae and vegetables, including C. tomentosum (20%), Coralina sp. Linnaeus, 1758 (17%), cabbage Brassica oleracea var. capitata Linnaeus, 1753 (30%), carrot Daucus carota Linnaeus, 1753 (30%) and agar (3%) as a gelling agent. Diet C consisted of maize Zea mays Linnaeus, 1753 (56%) and New Zealand spinach Tetragonia tetragonoides (Pallas, 1781) Kuntze, 1891 (44%). Their effects on the gonadal and somatic growths, gonadosomatic index (GI) and gametogenesis were evaluated, as well as on the total lipid content and fatty acid composition of sea urchin's gonads. Diet A provided high values of eicosapentaenoic acid (EPA). Gonads of sea urchins fed with diet A were found mostly in growth and maturation stages of gametogenesis and showed the lowest lipid content. Sea urchins fed with diet B presented their gonads in the reabsorption stage and had the highest values of omega‐3 polyunsaturated fatty acids (PUFAs). Sea urchins fed with diet C were in the early stages of gametogenesis and had the highest values of lipid content, plus omega‐6 PUFAs. Once as an ingredient in a balanced mix with vegetables, C. tomentosum can be a key factor to the development of new promising high‐quality and low‐cost feed for P. lividus roe enhancement.  相似文献   
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Evolution of flooding tolerance in weedy rice has occurred in several rice-growing regions, but the genes related to this process and the environmental effects are unknown. The objective of this study was to analyse the expression of genes related to flooding tolerance in response to temperature and flooding during the initial establishment of weedy rice. The experiments were carried out with rice cultivars IRGA 417 and Nipponbare, which are sensitive to flooding, and weedy rice ITJ03 and AV04 genotypes that have high and intermediate tolerance to flooding, respectively. The expression of genes related to reserve mobilisation, anaerobic respiration, escape and quiescence strategies was analysed at periods up to 24 days after sowing. The flooding tolerance of weedy rice genotype ITJ03 was associated with the expression of RAmy3D and OsTPP7 , which are involved in the mobilisation of carbohydrate reserves, ADH1 and ADH2, which participate in anaerobic respiration, and SNRKL1 that triggers rapid elongation of the coleoptile and emergence. Although the genes PDC1, SUS3 and SUB1 are important for flooding tolerance in cultivated rice, their expression was not directly related to flooding tolerance in weedy rice. A temperature of 20°C reduced levels of expression of the RAmy3D, ADH2 and SNRKL1 genes and low temperature had a negative effect on the establishment of weedy rice. Breeding of rice genotypes with tolerance of low temperatures and anaerobic conditions may be a viable strategy to improve the control of weedy rice in paddy fields.  相似文献   
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Landscape Ecology - Harmful effects of habitat loss and fragmentation can be detected across multiple spatial scales, yet most studies that aim to characterize these effects take place at a single...  相似文献   
7.
The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quarantine pest since 1998. This nematode causes severe damage in economically important crops such as potato and tomato, making agricultural products unacceptable for the fresh market and food processing. Commonly used nematicidal synthetic chemicals are often environmentally unsafe. Essential oils (EOs) may constitute safer alternatives against RKN. EOs, isolated from 56 plant samples, were tested against CRKN hatching, in direct contact bioassays. Some of the most successful EOs were fractionated and the hydrocarbon molecules (HM) and oxygen-containing molecules (OCM) fractions tested separately. 24 EOs displayed very strong hatching inhibitions (≥90 %) at 2 µL mL?1 and were further tested at lower concentrations. Dysphaniaambrosioides, Filipendula ulmaria, Ruta graveolens, Satureja montana and Thymbra capitata EOs revealed the lowest EC50 values (<0.15 µL mL?1). The main compounds of these EOs, namely 2-undecanone, ascaridol, carvacrol, isoascaridol, methyl salicylate, p-cymene and/or γ-terpinene, were putatively considered responsible for CRKN hatching inhibition. S. montana and T. capitata OCM fractions showed hatching inhibitions higher than HM fractions. The comparison of EO and corresponding fractions EC50 values suggests interactions between OCM and HM fractions against CRKN hatching. These species EOs showed to be potential environmentally friendly CRKN hatching inhibitors; nonetheless, bioactivity should be considered globally, since its HM and OCM fractions may contribute, diversely, to the full anti-hatching activity.  相似文献   
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Diacronema sp. was cultured and its sterols were separated by column chromatography on silica gel. The new sterol 24-ethyl-4alpha-methyl-cholestane-3,20-diol (1) was characterised by NMR and MS spectrometry, as well as (22E)-24-ethyl-4alpha-methyl-5alpha-cholest-22-en-3beta-ol (2) and beta-sitosterol, the major components of the sterol fractions. Neither the biosynthetic origin of the new dihydroxysterol nor its role in the biochemistry of Diacronema is known.  相似文献   
9.
The Clean Development Mechanism (CDM) of the Kyoto Protocol of the United Nations Framework Convention on Climate Change allows a country that emits C above agreed-upon limits to purchase C offsets from an entity that uses biological means to absorb or reduce greenhouse emissions. The CDM is currently offered for afforestation and reforestation projects, but may apply subsequently to sequestration in agricultural soils. Additionally, markets outside of the Protocol are developing for soil C sequestration.  相似文献   
10.
In Italy, poplar plantations represent an important source of wood products, and especially of high-quality veneer logs. These plantations offer favourable conditions to the introduction of forest mechanisation, and especially easy access and industrial management. However, owners fear that mechanised log-making may cause value losses, due to poor length measurement, log surface damage and improper grading. This study compared the performance of manual and mechanised log-making on ten commercial operations, in order to determine the occurrence and the severity of possible value losses due to product degrade. The study found that length measurement errors are smaller for mechanised processing, while the frequency and severity of log surface damage are the same for both treatments. In three cases out of five, mechanised log-making extracted the same value from the stems as manual log-making: in the remaining two, differences were very small and went opposite directions. Significant differences were found between operators, stressing the importance of operator skills and motivation. In fact, the log-making specifications and the pricing structure applied to poplar processing are relatively simple and are unlikely to challenge the ability of personnel and equipment. At present, most Italian poplar growers are unaware of the potential offered by modern technology, whose intelligent use would boost value recovery and decrease harvesting cost. Significant benefits may derive from the introduction of optimised bucking, which may help shifting to a more articulated and rewarding product strategy.  相似文献   
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