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Veterinary Research Communications - Propofol is a widely used drug in veterinary medicine to induce anesthesia; as well as the chosen compound for protocols of intravenous anesthesia. The present...  相似文献   
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Resistance to fumigants has been frequently reported in insect pests of stored products and is one of the obstacles in controlling these pests. The authors studied phosphine resistance and its physiological basis in adult insects of 12 populations of Tribolium castaneum (Herbst) (Tenebrionidae), ten populations of Rhyzopertha dominica (F.) (Bostrichidae) and eight populations of Oryzaephilus surinamensis L. (Silvanidae) from Brazil, and the possible existence of fitness costs associated with phosphine resistance in the absence of this fumigant. The bioassays for the detection of phosphine resistance followed the FAO standard method. The production of carbon dioxide and the instantaneous rate of population increase (r(i)) of each population of each species were correlated with their resistance ratios at the LC(50). The resistance ratio at LC(50) in T. castaneum ranged from 1.0- to 186.2-fold, in R. dominica from 2.0- to 71.0-fold and in O. surinamensis from 1.9- to 32.2-fold. Ten populations of T. castaneum, nine populations of R. dominica and seven populations of O. surinamensis were resistant to phosphine. In all three species there was significant association (P < 0.05) between respiration rate and phosphine resistance. The populations with lower carbon dioxide production showed a higher resistance ratio, suggesting that the lower respiration rate is the physiological basis of phosphine resistance by reducing the fumigant uptake in the resistant insects. Conversely, populations with higher r(i) showed lower resistance ratios, which could indicate a lower rate of reproduction of the resistant populations compared with susceptible populations. Thus, management strategies based on the interruption of phosphine fumigation may result in reestablishment of susceptibility, and shows good potential for more effective management of phosphine-resistant populations.  相似文献   
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The goal of this study is to develop a larviculture protocol for Mithraculus forceps, a popular marine aquarium species. Different temperatures (25±0.5°C and 28±0.5°C), stocking densities (10, 20, 40 and 80 larvae L?1), prey densities (newly hatched Artemia of 1, 4, 7 and 12 nauplii mL?1) and metamorphosis to crab conditions (Systems A and B) were tested. The best survivorship and faster development were obtained when the larvae were reared at a density of 40 larvae L?1 for 7 days post hatching (DPH) in System A, at 28°C and fed with 7 mL?1 of newly hatched Artemia nauplii. After 7 DPH all the megalopa were moved to System B and the same temperature and prey density were maintained. At the end of the experiment, 12 DPH, survivorship of 74.1±4.8% was obtained.  相似文献   
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Ethnopedology is the study of local knowledge of soil and land management in an ecological perspective. It is an emerging hybrid discipline that is a component of ethnoecology and stands to offer much for land-based studies. This paper reviews the field of ethnopedology in Latin America and compares some of the many case studies from that region. Various literature sources are considered, including the ethnographical, ethnohistorical, archaeological, geographical, agronomic, ethnoecological, and development studies. Our review invokes the theory of ethnoecology that focuses on the linkages between kosmos (beliefs and symbolic representations), corpus (environmental knowledge), and praxis (the set of practical operations through which the material appropriation of nature takes place) of local land-users. The main topics covered are the ethnohistorical and archaeological evidence of ethnopedology, local soil and land classification, local land management systems, local perceptions and beliefs of soil and land resources, and local soil fertility management. After analysing past and present research trends, recommendations are given on how ethnopedological studies can contribute to enhance sustainable land use and management in Latin America.  相似文献   
5.
Abstract— Most marine fish larviculture is dependent on the culture and nutritional manipulation of live prey, of which the rotifers Brachionus sp. are one of the most commonly used. The particular reproductive characteristics of gilthead seabream Spus aurata L. lead to an egg overproduction in commercial hatcheries, where the excess is normally wasted. This study was developed with the objective of testing seabream eggs as an enrichment product for Brachionus sp., using as control the commercial product Algamac 2000×. In view of the need to preserve and store the eggs produced in excess, freezedrying was examined as a possible technical solution for this purpose. The fatty acid profiles of the tested enrichment products (fresh seabream eggs, freeze-dried eggs and Algamac 2000×), as well as of the enriched rotifers at 0 h and after 3,6,12, 15, 18 and 24 h of enrichment, were analyzed. Freeze-dried eggs were stored for 14 and 58 wk prior to analysis, in order to examine a potential deterioration of the fatty acid nutritional quality. A potential use of seabream eggs as an enrichment product for Brachionus sp. was demonstrated. Rotifers enriched with eggs, fresh and freeze-dried, presented relatively high levels of polyunsaturated fatty acids (PUFA), highly unsaturated fatty acids (HUFA; × C20 and 2 double bonds), and fatty acid methyl esters (FAME), a docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) ratio of about 2 and a fairly high (n-3)/(n-6) ratio, especially during the first 3-6 h of enrichment. When freeze-dried eggs were stored in a dry atmosphere during 14 and 58 wk, only a slight and nonsignificant decrease was noted in the fatty acid content over this period of time. Therefore, freeze-drying may be an effective way of preserving the eggs in excess, at least up to 58 wk of storage.  相似文献   
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Several commercial oils of plant and animal origin were tested in order to improve the HUFA content and the DHA:EPA ratio of Artemia sp. metanauplii. The relationship between the n-3 and n-6 fatty acid series, and more recently, the DHA:EPA ratio seem to be indicators for better survival and growth of marine fish larvae. The tested plant oils were derived from linseed, peanut and sunflower, and the animal oils came from squid, sardine, cod liver and Selco emulsion. For each oil emulsion tested, four different enrichment periods (9, 24, 33 and 48 h) were evaluated in the same Artemia sp. strain (Artemia EG from Artemia Systems Inc., Baasrode, Belgium). The results show that oil emulsions of plant origin give very poor results in relation to either HUFA content or DHA:EPA ratio. All the oil emulsions from animal origin resulted in HUFA incorporation. Sardine oil was the poorest and squid oil the best. The HUFA content and the DHA:EPA ratio increased with enrichment periods up to 33 h, followed by a negligible variation up to the final 48 h.  相似文献   
8.
An assessment of the sub‐lethal effects of abamectin on queens of the leaf‐cutting ant Acromyrmex subterraneus subterraneus (Hymenoptera: Formicidae) was carried out. A concentration‐response bioassay was conducted by exposing media workers (head capsule width ranging from 1.69 to 1.83 mm) to filter paper impregnated with abamectin residue. This bioassay allowed selection of the abamectin concentrations (0, 10, 50 and 100 mg AI ml−1) to be used in the experiment in which eight queens were exposed to the insecticide. The highest concentration killed queens, but those exposed to lower concentrations survived and were placed back in their nests. Reductions in leaf consumption, fungus garden volume, and foraging activity were observed in colonies whose queens were exposed to higher abamectin concentration (50 mg AI ml−1). Colonies with queens exposed to 50 mg AI ml−1 were suppressed after 11 weeks. The dissection of queen ovaries revealed a marked decrease in the number of ovarioles per ovary and oocytes per ovariole with increased insecticide concentration. It would appear that, as abamectin‐exposed queens became reproductively impaired, producing little or no progeny, colony members were not replaced and this led to colony suppression. © 2000 Society of Chemical Industry  相似文献   
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Multiple matings occur in many species of stored-grain insect pests, such as the rice weevil Sitophilus oryzae (L.), with both female and male mating more than once and with more than one partner. Multiple female mating in S. oryzae increased lifetime fecundity by extending the period of time progeny were produced, but consequences of multiple male mating in S. oryzae were not yet studied although it is likely to increase male fitness by increasing offspring production. Here, the effects of polygynous mating on male mating behavior, success, and fitness were assessed in two strains of S. oryzae, one adapted to barley and another to wheat. Two insect strains were considered because they may differ in response depending on the host grain, which present distinct nutritional value to the insects. Mating by pairs formed between the two strains did not impact mating success, but wheat-adapted females exhibited longer mating duration, which was positively correlated with progeny production. Wheat-adapted males exhibited higher fertility than barley-adapted males. When male multiple matings were considered in successive polygynous matings, late matings led to lower non-cumulative values of progeny production, but higher cumulative performance, and wheat-adapted S. oryzae always performed better. Thus, male fitness and grain losses in wheat are higher than in barley, even when S. oryzae was adapted to the latter.  相似文献   
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