Relation between lipid and fatty acid composition of eggs and larval survival in white pacific shrimp (Penaeus vannamei, Boone, 1931)     

Elena Palacios  Ilie S. Racotta  Horacio Heras  Yanic Marty  Jeanne Moal  Jean-François Samain 《Aquaculture International》2001,9(6):531-543

In this study, lipid classes and fatty acid composition were determinedin eggs of P. vannamei as a function of survival to zoeaIII stage. Spawns were reared individually to zoea III and grouped, accordingtotheir final survival to this larval stage, into spawns of high and lowsurvival.Eggs of individual spawns were analyzed for lipid and fatty acid composition ofneutral and polar lipids and the results were then grouped according tosurvivalto zoea III. The lipids within each group (high and low survival to zoea III)were pooled for the separation of phospholipids and the analysis of their fattyacid composition.Higher levels of triglycerides, carotenoids, and linoleic (18:2n-6) acid ineggs were associated with improved survival to zoea III. Linoleic acid washigher in spawns from the high survival group in both neutral and polarfractions and in most of the phospholipid classes analyzed. Docosahexanoic acid(DHA) was not related to survival to zoea, probably because its content washighenough (> 15% of total fatty acids) to satisfy embryo and early larvaldevelopment needs. A high content of eicosapentaenoic acid (EPA) was found inphosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylserine, andphosphatidylinositol compared to other phospholipid classes, suggesting aspecific role of EPA in these lipids. These results describe the specificphospholipid composition of penaeid eggs and could (potentially) be used aspredictive indicators of larval quality for research and production purposes.  相似文献   

Rearing fry of South American catfish (Rhamdia sapo) on natural zooplankton populations     

Horacio E. Zagarese 《Aquaculture (Amsterdam, Netherlands)》1988,70(4):323-331

Two experiments were performed on rearing South American catfish (Rhamdia sapo) fry in 8-m² concrete tanks. Live zooplankton was found to be an adequate food for Rhamdia fry. However, fry showed a natural preference for benthic organisms when they were available. No differences in selectivity due to fry age were observed. Differences in selectivity between small and large fry were only detected for Daphnia parvula, the largest zooplanktonic item. This suggested that food partitioning may occur only when large prey items are available.  相似文献   

The potential of temporary shelters to increase survival of the endangered Mexican axolotl     

Alejandra G. Ramos  Horacio Mena-González  Luis Zambrano 《水产资源保护:海洋与淡水生态系统》2021,31(6):1535-1542

1. Amphibian populations worldwide are in decline. Proactive conservation techniques such as translocations into created and restored wetlands have gained popularity in recent years but may fail owing to high predation and low environmental adaptability.
2. The Mexican axolotl (Ambystoma mexicanum), affected by rapid urbanization, is now possibly extinct in the wild despite millions living in captivity throughout the world.
3. The aim of this study was to explore whether ponds from an artificial wetland can function as temporary shelters for a viable population of axolotls that could be re-introduced into their native ecosystem in Xochimilco once it is restored.
4. Egg-laying and hatching of 11 unique axolotl pairs placed into reproductive enclosures and larval survival to 7 weeks and up to 12 months were examined. Physicochemical and biological parameters were estimated and compared among ponds.
5. The results from this study are encouraging as they suggest that two ponds have adequate conditions for axolotls to reproduce and for larvae and juveniles to survive.

  相似文献   

Canopy structure analysis for estimating forest regeneration dynamics and growth in <Emphasis Type="Italic">Nothofagus pumilio</Emphasis> forests     

Guillermo J. Martínez Pastur  Pablo L. Peri  Juan M. Cellini  María V. Lencinas  Marcelo Barrera  Horacio Ivancich 《Annals of Forest Science》2011,68(3):587-594

•Introduction   

Silviculture systems applied in Nothofagus pumilio forests are based on opening the canopy to stimulate natural regeneration by modifying light and soil moisture. The objective is to evaluate regeneration dynamics of N. pumilio along different forest canopy and solar radiation gradients.  相似文献   

Dissolved and Particulate Heavy Metals in the Salado River (Santa FE, Argentina)     

Marcos Gallo  Alfredo Trento  Ana Alvarez  Horacio Beldoménico  Darío Campagnoli 《Water, air, and soil pollution》2006,174(1-4):367-384

The objective of this work is to analyze Fe, Mn, Cr, Cd, Cu, Pb, and Zn distributions in the water column in terms of total, dissolved, and particulate concentrations in the Salado River (Santa Fe – Argentina); their relationship with total, dissolved and suspended solids; and the impact of two pollution sources on the watercourse: a stream that collects domestic and industrial wastewater discharges of the region and a direct discharge that releases urban and industrial effluents to the river. Water samples obtained from 5 surveys were analyzed. The Salado River transported a load of heavy metals that ranged from 700 g/s to 2200 g/s of Fe, 20 g/s to 60 g/s of Mn and 1 g/s to 3 g/s of Cr. Results show that most metals were found in particulate form, that the metal input from the direct discharge may be significant at low water levels, whereas a lesser impact was produced by the stream, and that both pollution sources were negligible at high water levels.  相似文献   

Estudio micologico del aparato respiratorio de Gallus gallus     

Aída Cubillos  Horacio Prüssing 《Zoonoses and public health》1979,26(8):605-613

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Differences in body temperature, cell viability, and HSP-70 concentrations between Pelibuey and Suffolk sheep under heat stress   总被引：1，自引：0，他引：1  

Rosita Denny Romero  Arnulfo Montero Pardo  Hugo Horacio Montaldo  Ana Delia Rodríguez  Joel Hernández Cerón 《Tropical animal health and production》2013,45(8):1691-1696

Pelibuey and Suffolk sheep were compared as to their capacity to regulate body temperature under environmental hyperthermia by measuring their differences in cellular response to heat stress (HS). In a first experiment, seven Pelibuey and seven Suffolk ewes were kept in a climatic chamber for 6 h daily during 10 days (temperatures within the 18 to 39.5 °C range). As chamber temperature rose, sheep rectal temperature increased in both groups, but to a lesser extent in Pelibuey (0.3 °C) than in Suffolk sheep (0.7 °C) (P?<?0.05). In a second experiment, cellular viability was assessed using cultured blood mononuclear cells from 15 Pelibuey and 15 Suffolk sheep. They were incubated at 37 °C for 24 h (control) or 43 °C for 6 h followed by 18 h at 37 °C (HS). In a third experiment, another blood mononuclear cells culture from eight Pelibuey and eight Suffolk sheep was kept at 37 °C for 15 h; these were subsequently cultured for 6 h at 37 °C (controls) or 43 °C (HS). Next, HSP-70 concentration was determined. HS reduced the percentage of viable cells to a greater extent in Suffolk [37 °C (73.7 %) vs. 43 °C (61.9 %); P?<?0.05] than in Pelibuey sheep [37 °C (74.9 %) vs. 43 °C (66.7 %); P?>?0.05]. HS significantly increased HSP-70 average concentrations for both breeds at 43 °C. A significant effect was observed for the breed by temperature interaction (P?<?0.05) caused by a greater difference between Pelibuey and Suffolk at 43 °C (2.85 vs. 0.53 ng/mL, respectively; P?<?0.05) than at 37 °C (0.05 vs. 0.03 ng/mL, respectively; P?>?0.05). In conclusion, Pelibuey sheep show more effective body temperature regulation under conditions of environmental hyperthermia. Also, cell viability after HS was higher in Pelibuey than in Suffolk, an effect that could be mediated by an HSP-70-related mechanism.  相似文献   

Genetic variation of sweet potatoes (Ipomoea batatas L.) cultivated in Chile determined by RAPDs   总被引：1，自引：0，他引：1  

Boris Sagredo  Patricio Hinrichsen  Horacio López  Alberto Cubillos  Carlos Muñoz 《Euphytica》1998,101(2):193-198

RAPD (randomly amplified polymorphic DNA) technology was applied to analyze the genetic variability of sweet potato germplasm existing in Chile and elsewhere. Analysis of 28 cultivars from all over the world showed polymorphic bands with all 18 primers tested. A total of 124 RAPD bands were scored with an average of 6.9 polymorphic bands per primer. These results confirm that sweet potato exhibits high genetic variation. Two groups were distinguished: one containing Peruvian cultivars, and another containing cultivars from the rest of the world. Analysis of 14 accessions from Central Chile and one from Northern Chile showed polymorphic bands with 24 of 26 primers tested, but almost all of the 140 polymorphic bands merely showed the distinctness of the Northern accession. The almost complete uniformity of the other 14 accessions shows that sweet potato germplasm collected in Central Chile has very little genetic variability and may be derived from a single cultivar. Based on these results and on historical records, some hypotheses are proposed to explain the origin of sweet potatoes cultivated in Chile. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Loss of genetic variability in the captive stocks of tambaqui,Colossoma macropomum (Cuvier, 1818), at breeding centres in Brazil,and their divergence from wild populations          下载免费PDF全文

Jonas da Paz Aguiar  Paola Fabiana Fazzi Gomes  Igor Guerreiro Hamoy  Sidney Emanuel Batista dos Santos  Horacio Schneider  Iracilda Sampaio 《Aquaculture Research》2018,49(5):1914-1925

The loss of variability in farmed populations and the risks of interactions with wild populations support the need for the genetic monitoring of species farmed throughout the world. In Brazil, the tambaqui is the most widely farmed native fish species. Despite this, there are no data on the pedigree of the farmed stocks, and the potential for interactions with wild populations in the Amazon basin has raised concerns with regard to the genetic variability of these stocks. The present study analysed sequences of the mitochondrial Control Region and 12 microsatellites to characterize the genetic variability of seven historically important commercial tambaqui breeding centres located in four different regions of Brazil, and compared these sequences with those obtained from individuals collected from a wild population. High levels of genetic diversity were found in the wild population, whereas genetic diversity was reduced in both markers in most captive populations, except for the broodstock located near the Amazon River. High F_ST and D_EST indices were recorded between the wild population and most of the captive stocks analysed. The drastic reduction in genetic diversity found in most captive stocks and the difference between these stocks and the wild population may have been the result of the small size of the founding populations and the absence of breeding management. The renewal of the broodstocks and the application of breeding management techniques are recommended. In the Amazon region, in addition, the use of broodstocks that are genetically very different from local wild populations should be avoided.  相似文献   

A morphological assessment system for ‘show quality’ bovine livestock based on image analysis     

Horacio M. González-Velasco  Carlos J. García-Orellana 《Computers and Electronics in Agriculture》2011,78(1):80-87

Morphological assessment is one important parameter considered in conservation and improvement programs for bovine livestock. This assessment process consists of scoring an animal based on its morphology and is normally carried out by highly qualified staff. These animals are all of agreed ‘show quality’ and hence they are morphologically very similar.This paper presents a system designed to provide an assessment based on a lateral image of the cow. The system consists of two main parts: a feature extraction stage, to reduce the information on the cow in the image to a set of parameters, and a neural network stage to provide a score based on that set of parameters. For the image analysis section, a model of the animal is constructed by means of the point distribution model (PDM) technique. Later, that model is used in the searching process within each image, which is implemented using genetic algorithms (GAs). As a result of this stage, the vector of weights that describe the deviation of the given shape from the mean is obtained. This vector is used in the second stage, where a multilayer perceptron is trained to provide the desired assessment, using the scores given by experts for selected cows.The system has been tested with 138 images corresponding to 44 individuals of a special rustic breed, with very promising results, given that the information contained in only one view of the cow can not be considered complete.  相似文献