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排序方式: 共有710条查询结果,搜索用时 390 毫秒
81.
Natalia RAMIREZ‐OTAROLA Janyra ESPINOZA Alexis M. KALERGIS Pablo SABAT 《Integrative zoology》2019,14(3):235-247
During vertebrate development, the immune function is inefficient and is mainly controlled by innate defense. While there have been detailed studies of various aspects of innate immune function, the effects of this function in the growth of vertebrates is still not well known. Similarly, there is little information regarding how early endotoxin exposure would affect juvenile phenotypes, specifically in a non‐model mammal like a precocial rodent. We evaluated the response to an antigen and its cost in offspring of the rodent Octodon degus. We inoculated pups at 4 different ages (8, 15, 22 and 30 days after birth) with an antigen to determine the ontogeny and costs of the response to an endotoxin. We assessed changes in body mass, body temperature, sickness behavior and the levels of a key mediator of the inflammatory response, the cytokine interleukin‐1β. We also determined the effects of early endotoxin exposure on the resting metabolic rate of juvenile animals (i.e. 90 days after birth). The cytokine levels, body mass and body temperature were unaffected by time of inoculation and treatment. However, pups subjected to inoculation at 22 days after birth with the antigen showed reduced locomotion. Juvenile resting metabolic rate was not affected by early endotoxin exposure. These results suggest that the magnitude of O. degus responses would not change with age. We discuss whether the lack of effect of the response on body mass or body condition is caused by environmental variables or by the precocial characteristics of O. degus. 相似文献
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Daniel E. Goszczynski Anna C. Denicol Pablo J. Ross 《Reproduction in domestic animals》2019,54(Z4):22-31
In vitro gamete differentiation could revolutionize animal production by decreasing generation intervals, increasing the number of gametes per animal and facilitating the dissemination of elite genetics. In addition, it could help to develop new strategies for the conservation of endangered species. The recent in vitro reconstitution of germ cell development in mice has inspired researchers to invest their best efforts into reproducing this achievement in livestock species. With this goal in mind, multiple differentiation approaches and cell sources have been evaluated. The degree of success in these evaluations varies according to the species and the stage of development studied, but, in general, partially positive results have been obtained. Evidence suggests that although functional gametes with true reproductive potential are still to be obtained, it is a matter of time before this goal is achieved. 相似文献
86.
Rosina Soler Pablo Luis Peri Héctor Bahamonde Verónica Gargaglione Sebastián Ormaechea Alejandro Huertas Herrera Laura Sánchez Jardón Cristian Lorenzo Guillermo Martínez Pastur 《Strength and Conditioning Journal》2018,71(5):637-645
In recent decades agroforestry has undergone significant development in Latin America. South America generates the most scientific research on the topic in the region. We conducted a comprehensive review and analysis of knowledge production for South American agroforestry that includes livestock grazing, known as agrosilvopastoralism (AS), examining how different sociopolitical factors such as sources of funding, institutional priorities, and international cooperation can bias the direction and objectives of scientific research. We assessed the major attributes of scientific publications on the topic (25 articles per country; overall n = 210) and the potential factors underlying the processes of research and development in the region. The tree component was the most studied, while the livestock component received less attention. Studies were mainly focused on the production of goods and services (monetary or nonmonetary approaches), except in Brazil, where conservation was the major study objective. Stakeholders were involved in more than half of the studies (60%), and they were mostly ranchers and local producers. More than half (70%) of the studies offered recommendations based on their results, and such recommendations were mostly concerned with the management of agrosilvopastoral system components. In general, studies were led just as often by local as foreign first authors and coauthored by more than three people as part of interinstitutional working groups. Brazil, Argentina, Colombia, and Chile had more frequent cooperation among institutions and countries but mainly used their own funding. In contrast, Bolivia, Ecuador, and Peru had almost 100% of their studies supported by foreign countries (North America and Europe). Countries with greater internal funding of research generated more long-term studies. Besides this, two clear trends were detected: 1) conservation and social aspects were mainly supported by sources from external countries led by foreign principal investigators, and 2) production issues were supported from sources within countries and supported high levels of cooperation among institutions. 相似文献
87.
Iazbik MC Gómez Ochoa P Westendorf N Charske J Couto CG 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(6):1181-1184
BACKGROUND: Collection of 50 mL of blood (standard unit) in cats is a common procedure. There are several studies on the health status of donors, but to our knowledge there are no reports on the effects of blood collection on the feline donor. HYPOTHESIS: Collection of a standard unit of blood from cats does not significantly change arterial blood pressure (BP), mean arterial pressure (MAP), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), PCV, and heart rate (HR) in healthy blood donor cats. ANIMALS: Twenty-six healthy blood donor cats (6 spayed females and 20 castrated males). METHODS: An oscillometric method was used to measure MAP, SAP, DAP, and to quantify HR before and after blood collection; PCV was obtained before and immediately after blood collection. RESULTS: Despite a significant decrease (P < .05) in all variables (ie, BP, PCV, HR) after blood collection, no adverse events were observed. CONCLUSIONS AND CLINICAL IMPORTANCE: The collection of a unit of blood for transfusion from healthy donor cats weighing more than 5 kg appears to be safe, but this procedure leads to a decrease in arterial BP, PCV, and HR. 相似文献
88.
Juan Pablo Hualde Walter Damián Ceferino Torres Pablo Moreno Mirna Ferrada Mariela Ana Demicheli Leonardo Javier Molinari Carlos Marcelo Luquet 《Aquaculture Research》2011,42(6):754-763
An experiment was performed to evaluate the performance of Patagonian pejerrey during net cage rearing in the oligomesotrophic reservoir Exequiel Ramos Mexía. Survival, growth, nutrition and reproduction were evaluated for two lots of pejerrey, initial weights 4.0 and 2.5 g, reared in net cages for 22 and 14 months respectively. Fish were stocked at 29 and 48 individuals m?3 densities and fed with an experimental pejerrey feed. During the experiment, temperature fluctuated between 6.6 and 19.6 °C. The two lots did not show substantial differences in survival (pooled survival at the end of the experiment >80%) and the thermal‐unit growth coefficient (TGC), daily feed intake and feeding efficiency were 0.43±0.19, 1.70±0.80 and 53.6±9.9 respectively. Digestive tract analysis showed that caged pejerrey can consume substantial quantities of natural food, taking advantage of its planktivorous condition. Pejerrey showed high percentage survival, slow growth and early sexual maturation in captivity. The use of the TGC is proposed as a model for describing the growth pattern of this species and other pejerrey under culture conditions. 相似文献
89.
Pablo A. Conejeros Carlos Calderón Daniela Gómez Luis Nilo Sergio H. Marshall 《Aquaculture International》2011,19(5):999-1005
As with any other intensively farmed animal species, the Atlantic salmon has been selectively bred and cross-bred to maximize
desirable traits. Selection tends to diminish genetic diversity in target populations, which among other negative effects
is hypothesized to decrease their capacity to confront a broad variety of pathogens. We have analyzed mitochondrial (mtDNA)
as well as major histocompatibility complex (MHC) DNA sequences from individuals collected from a single aquaculture cage
in southern Chile. Interestingly, only two mtDNA haplotypes were obtained; however, several different MH alleles were detected,
with divergence values that were compared with those of natural populations of salmonids. Thus, it seems evolutionary processes
responsible of keeping MH diversity in the wild managed to retain MH variability in farmed Atlantic salmon, maintaining high
immune diversity despite the generally lower levels of observed neutral genetic diversity. 相似文献
90.
Significant improvement of shrimp growth performance by growth hormone‐releasing peptide‐6 immersion treatments
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Amílcar Arenal Juana María Lugo Reynold Morales Leonardo Martín Ramón Franco Rodríguez Jannel Acosta Antonio Morales Jorge Duconge Mario Pablo Estrada 《Aquaculture Research》2017,48(9):4632-4645
Growth hormone‐releasing peptide‐6 (GHRP‐6) is one of the earliest developed synthetic peptidyl growth hormone secretagogue receptor agonists. These compounds mimic the effect of the endogenous ligand ghrelin. In vertebrates, ghrelin is a potent circulating orexigenic hormone with functional roles in controlling food intake, energy expenditure, adiposity, growth hormone secretion and immunity. Ghrelin has been studied mainly in vertebrates; thus, little is known about its role in invertebrates, including crustaceans. We first evaluated the effect of GHRP‐6 injection over feed intake in shrimp and its effects on shrimp growth when the peptide was administrated by successive immersion baths. GHRP‐6 increased feed intake, body weight and size, the number of rostral spines and gill branches, protein concentration and haemocyte number in treated shrimps. We also evaluated the peptide uptake and clearance in a pharmacokinetics, using [H3]GHRP‐6 administered to postlarvae. Given a limited exposure and efficient clearance of the peptide‐associated radioactivity from larvae, our findings suggested that GHRP‐6‐treated Litopenaeus vannamei can be consumed safely by humans after aquaculture applications. These results propose that GHRP‐6 could be an additional tool to study growth physiology in crustaceans and also a promising candidate for development into a new biotechnology product for improving shrimp growth and quality. 相似文献