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51.
Leandro Silveira Rahel Sollmann Anah T. A. Jácomo José A. F. Diniz Filho Natália M. Tôrres 《Landscape Ecology》2014,29(7):1213-1223
Most large reserves in Brazil do not hold viable populations of jaguars to guarantee the species’ long-term survival. Corridors linking populations have been identified as a potential tool to avoid negative effects of isolation, increasing population viability. Here, we performed a Brazil-wide evaluation of potential large scale corridors connecting protected jaguar populations. Six variables (human population size, dam reservoir size, number of dams, roads, railways and cities) expected to negatively impact jaguar movement were analyzed across 180 potential corridors connecting 298 protected jaguar areas. We established overall disturbance scores for the corridors using a principal components analysis and compared them among the Brazilian biomes. We further investigated which variables separated biomes using a canonical variates analysis. The Atlantic Forest and the semi-arid Caatinga have the most impacted potential corridors, whereas the Amazon and Pantanal still have the best potential corridors. Corridor quality in the Cerrado grasslands was intermediate. All variables but human population size and corridor length contributed significantly to differences in corridor variables among biomes. Our conclusions suggest that we need to plan the implementation of large scale corridors in the Amazon, Pantanal and particularly the Cerrado soon, while potential corridors might still be economically viable. In the much more impacted Atlantic Forest and Caatinga, the need for conservation actions is strongest, but logistical difficulties and costs may turn implementation of corridors unfeasible. 相似文献
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Zimbres Barbara Furtado Mariana M. Jácomo Anah T. A. Silveira Leandro Sollmann Rahel Tôrres Natália M. Machado Ricardo B. Marinho-Filho Jader 《Landscape Ecology》2013,28(2):259-269
Landscape Ecology - The impact of deforestation and fragmentation upon ecologically important and poorly known groups is currently an important issue for conservation biology. Herein we describe... 相似文献
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Sulaiman CHEABU Nat PANICHAWONG Prisana RATTANAMETTA Boonthong WASURI Poonpipope KASEMSAP Siwaret ARIKIT Apichart VANAVICHIT Chanate MALUMPONG 《水稻科学》2019,26(4):229-238
A total of 10 000 M4 individuals in Jao Hom Nil (JHN) mutant population was treated with high temperature (40 ℃ to 45 ℃) during the day time (6 h) from the booting to the harvesting stages, and ambient temperature (33 ℃ to 35℃) was used as the control. The results of screening and yield trials found that the mutant line M9962 had a high spikelet fertility of 78% under heat stress. In addition, the other mutant lines, including M3181 and M7988, had a spikelet fertility of approximately 70%. However, the JHN wild type, Sin Lek, RD15 and RD33 had very low spikelet fertility of 34%, 14%, 9% and 4%, respectively. The lower spikelet fertility at an elevated temperature resulted in a dramatic decrease of filled grain and contributed to a loss in 100-grain weight. M9962 is a potential genetic stock for use in a heat tolerance breeding programme. In addition, spikelet fertility at high temperature was representative of heat tolerance and can be used as a screening trait for heat tolerance during the reproductive phase on a large scale. 相似文献
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Behavior of sheep fed babassu cake (Orbygnia speciosa) as a substitution for elephant grass silage 
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下载免费PDF全文 Ernestina Ribeiro dos Santos Neta Kaliandra Souza Alves Rafael Mezzomo Daiany Íris Gomes Luis Rennan Sampaio Oliveira Francisco Fernando Ramos de Carvalho Janaina Barros Luz Natália Gomes Lacerda Venucia de Diniella dos Santos Bourdon 《Animal Science Journal》2017,88(8):1171-1177
This study aimed to evaluate the behavior of sheep fed babassu cake as a substitution for elephant grass silage. The experiment was conducted at the Federal Rural University of Amazonia (Universidade Federal Rural da Amazônia ‐ UFRA), Brazil, using 45 sheep housed in individual stalls, with unlimited access to feed and distributed in a completely randomized design with five treatments (0, 12.5, 25, 37.5 and 50% inclusion of babassu cake) and nine replications. All of the treatments contained a roughage‐to‐concentrate ratio of 40:60. No differences were observed in the time spent feeding (P > 0.05), regardless of the source of roughage used. However, there was a reduction in the time spent in rumination (P < 0.05) and an increase in time spent idling (P < 0.05) when babassu cake was included in the diet. Although there was a reduction in the time spent chewing the ruminal bolus (P < 0.05), the total daily chewing time was the same for all animals (P > 0.05). However, the sheep fed babassu cake showed higher feeding and rumination efficiency (P < 0.05). Therefore, the substitution of elephant grass silage with babassu cake can be performed at up to 50% without compromising the total time spent eating and chewing, which allows increased feeding and rumination efficiency. 相似文献
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Fasting and refeeding lead to more efficient growth in lean pacu (Piaractus mesopotamicus) 下载免费PDF全文
下载免费PDF全文 Gisele Cristina Favero Rodrigo Yukihiro Gimbo Luz Natália Franco Montoya Fábio Sabbadin Zanuzzo Elisabeth Criscuolo Urbinati 《Aquaculture Research》2018,49(1):359-366
We evaluated whether body fat content affects the energetic metabolism and growth in pacu submitted to daily feeding, fasting and refeeding. For 15 days, fish were fed different diets to obtain lean and fat conditions, and then subjected, for 20 days to: (1) continuously feeding (control), or (2) fasting for 15 days and refeeding for 5 days. Blood (glucose, triglycerides, cholesterol, non‐esterified fatty acids and total protein) and tissue (liver lipid and glycogen, muscle lipid and mesenteric fat) metabolic indicators, and growth performance parameters (weight gain, specific growth rate, daily feed intake and feed conversion ratio) were measured. Fasting led both lean and fat pacu to make notable use of their energy reserves, through glycogenolysis and lipolysis, reflected in reduced blood glucose and triglycerides, liver glycogen and muscle lipid levels. Lipolysis was confirmed by the high levels of non‐esterified fatty acids, especially in fat pacu. Refeeding led to higher plasma glucose and liver lipid in lean fish. Muscle fat increased in fat fish but was not restored in lean fish, while mesenteric fat index (MFI) remained the same in fat fish and increased in lean fish. Although refeeding occurred only for 5 days, lean fish grew more and were more efficient at utilizing food (higher weight gain and better feed conversion ratio). In conclusion, our results suggest that fat pacu have higher glycogenic and lipogenic abilities, and the higher deposition of lipids in fish does not mean higher availability of energy for growth when compensatory growth is stimulated by refeeding after fasting. 相似文献
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Segalés J Domingo M Chianini F Majó N Domínguez J Darwich L Mateu E 《Veterinary microbiology》2004,98(2):151-158
The present review concentrates on the clinical, pathological and immunological aspects of pigs suffering from PMWS which strongly suggest that PCV2 may be, in particular conditions, a cause of secondary immunodeficiency in pigs. From a clinical point of view, the lack of antibiotic therapy response against the disease, the existence of a litter effect and the concurrence of other disease syndromes and well-known secondary pathogens, such as Pneumocystis carinii, Chlamydia spp. and Aspergillus spp., may account as features of immunosuppression in PMWS. Furthermore, pathologic, immunohistologic and flow cytometric studies also suggest that pigs with PMWS may be immunosuppressed. Lymphocyte depletion of follicular and interfollicular areas together with macrophage infiltration of lymphoid tissues is a unique lesion, which is the basic feature of PMWS affected pigs. These findings are highly correlated with the decrease of circulating B- and T-cells and the diminution of these cell types in lymphoid organs, and with the increase of macrophage/monocytes lineage cells both in peripheral blood and lymphoid tissues in both naturally and experimentally PMWS affected pigs. The altered populations of cells participating in the immune system response both in blood and tissues suggests, at least in those severely PMWS affected pigs, a transient inability of diseased pigs to mount an effective immune response. From these points of view, strong suspicions on the immunosuppressive status of PMWS affected pigs do exist; however, future studies are needed to characterise the exact role of PCV2 on the immune system of pigs affected with PMWS. 相似文献
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Effects of azithromycin on tilapia (Oreochromis niloticus): health status evaluation using biochemical,physiological and morphological biomarkers 下载免费PDF全文
下载免费PDF全文 Natália Sayuri Shiogiri Cynthia Venâncio Ikefuti Silvia Patricia Carraschi Claudinei da Cruz Marisa Narciso Fernandes 《Aquaculture Research》2017,48(7):3669-3683
Bacterial diseases cause tilapia's high‐mortality outbreak. This study investigated the toxicity of azithromycin (AZT), a macrolide antibiotic that has been considered a possible therapeutic drug for tilapia aquacultural use. The 48‐h acute toxicity (50% lethal concentration, LC50; 48 h) of AZT was determined for Oreochromis niloticus. Thereafter, fish were exposed to 0, 1, 50 and 100 mg L?1 AZT during 14 days (chronic exposure) and measured the haematological variables, the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione‐S‐transferase (GST) and the concentration of glutathione (GSH), protein carbonyl and lipid peroxidation in the liver; histopathology was analysed the liver, gills and kidneys. The LC50; 48 h was >100 mg L?1. No fish died during chronic exposure. Haematocrit and haemoglobin concentration increased in fish exposed to 50 and 100 mg L?1, and the total number of leucocyte and thrombocyte increased after exposure to 100 mg L?1 AZT, suggesting a stimulation of defence cell production. In the liver, the antioxidant enzyme activities did not change, but GST activity and the GSH level increased in fish exposed to 100 mg L?1 AZT. Oxidative stress did not occur. Histopathological index (HIL) indicates moderate liver damage; minor histological changes in the gill and no change in the kidneys. AZT was considered non‐toxic for O. niloticus after acute exposure and, although it causes moderated histopathology in the liver after chronic exposure, this antibiotic may be an alternative against bacterial infections, depending on its efficacy to control bacterial disease in fish. 相似文献
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Natália C. Teixeira Janete Oliveira S. Valim Maria Goreti A. Oliveira Wellington G. Campos 《Journal of Agronomy and Crop Science》2020,206(2):187-201
It was postulated that Si-mediated plant resistance to herbivory changes with soil water status, increasing when plants are under drought stress. We subjected collard (Brassica oleracea) to such soil variables and assessed plant responses and effects on the leaf-chewing larvae of Plutella xylostella and the sap-sucking aphid Brevicoryne brassicae. Silicon accumulated in collard leaves independently of soil water conditions, but it influenced mainly drought-stressed plants. Silicon suppressed harmful effects of drought on leaf and root length and raised leaf water content and stomatal size to the same conditions of well-watered plants. Drought stress reduced hemicellulose and cellulose, but Si did not influence them or lignin. Combination of drought and Si increased total and soluble leaf nitrogen. Drought decreased total glucosinolates, but Si increased such defence metabolites to similar concentrations that were found in well-watered plants. Nutritional changes mediated by drought and Si in fibre, leaf water content, soluble nitrogen and glucosinolates did not increase insect performance in any feeding guild. Instead, caterpillars performed worse in drought-stressed or Si-treated collards, mainly in plants under combined conditions. Silicon improved plant resistance to drought and herbivore stresses. 相似文献