Colonizing Islands of water on dry land—on the passive dispersal of fish eggs by birds          下载免费PDF全文

Philipp Emanuel Hirsch  Anouk N'Guyen  Roxane Muller  Irene Adrian‐Kalchhauser  Patricia Burkhardt‐Holm 《Fish and Fisheries》2018,19(3):502-510

The vast majority of global freshwater ecosystems are small lakes with less than 100 m² surface area. These lakes are often unconnected to other water bodies but frequently host fish populations. Existing explanations for how fish colonize such remote habitats often involve birds as vectors transporting fish eggs as propagules. In this study, we aim to quantify the prevalence of these explanations among relevant societal groups as well as their scientific knowledge basis. We analyzed entries in online blogs and forums and surveyed the opinions of local stakeholders and decision makers using a questionnaire. To collect published scientific knowledge, we conducted a structured literature review. Our results reveal a discrepancy between commonly found beliefs and the empirical knowledge supporting those beliefs: Dispersal of fish eggs by water birds was overall the most frequent explanation online and in the questionnaire. In the scientific literature, however, we found hardly any empirical research on passive fish egg dispersal. We propose research directions for how to close this gap of knowledge and suggest that future empirical studies on passive fish egg dispersal may be inspired by existing work on passive dispersal in aquatic invertebrates. Mitigating the belief‐evidence discrepancy on fish dispersal will be essential to better understand the patterns of fish biodiversity across landscapes, to counteract its losses, and inform management strategies for invasive fish species.  相似文献   

Changes in some blood parameters,milk composition and yield of buffaloes (Bubalus bubalis) during the transition period          下载免费PDF全文

Enrico Fiore  Sonia Giambelluca  Massimo Morgante  Barbara Contiero  Elisa Mazzotta  Domenico Vecchio  Irene Vazzana  Pasquale Rossi  Francesca Arfuso  Giuseppe Piccione  Matteo Gianesella 《Animal Science Journal》2017,88(12):2025-2032

In this study changes in hematochemical parameters, milk composition and yield were investigated in buffaloes during the transition period. A total of 93 buffaloes 113.9 ± 8.03 months old and 535 ± 50 kg average body weight were used. Parity was recorded, blood samples were collected from 80 days pre‐partum until 70 days post‐partum; milk samples were collected from 5 days to 70 days post‐partum. On serum samples, the values of non‐esterified fatty acids, β‐hydroxybutyrate, glucose, cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, gamma‐glutamyltransferase, urea, total proteins were evaluated. On milk, percentage of fat, protein and lactose, along with the somatic cell count (SCC), milk yield and daily milk production (DMP) were assessed. The peripartum period significantly (P ≤ 0.01) influenced all studied parameters with the exception of glucose. Milk fat percentage showed decreasing trend from 10 until 40 days post‐partum; DMP significantly (P ≤ 0.01) increased from 1 day post‐partum until 40 days post‐partum. Milk yield significantly (P ≤ 0.01) decreased in animals over the sixth lactation. Our results confirmed the importance of transit period in buffaloes. Blood parameters and milk composition alterations are crucial to predict the energy balance status of buffaloes in order to improve their management and feed intake during the transition period.  相似文献   

Inoculation of tomato plants with selected PGPR represents a feasible alternative to chemical fertilization under salt stress          下载免费PDF全文

Irene Cordero  Ana Rincón  José J. Pueyo 《植物养料与土壤学杂志》2018,181(5):694-703

Plant growth‐promoting rhizobacteria (PGPR) are soil bacteria that colonize the rhizosphere of plants, enhance plant growth, and may alleviate environmental stress, thus constituting a powerful tool in sustainable agriculture. Here, we compared the capacity of chemical fertilization to selected PGPR strains to promote growth and alleviate salinity stress in tomato plants (Solanum lycopersicum L.). A pot experiment was designed with two main factors: fertilization (chemical fertilization, bacterial inoculation with seven PGPR, or a non‐fertilized non‐inoculated control) and salt stress (0 or 100 mM NaCl). In the absence of stress, a clear promotion of growth, a positive effect on plant physiology (elevated F_v/F_m), and enhanced N, P, and K concentrations were observed in inoculated plants compared to non‐fertilized controls. Salinity negatively affected most variables analyzed, but inoculation with certain strains reduced some of the negative effects on growth parameters and plant physiology (water loss and K⁺ depletion) in a moderate but significant manner. Chemical fertilization clearly exceeded the positive effects of inoculation under non‐stressed conditions, but conversely, biofertilization with some strains outperformed chemical fertilization under salt stress. The results point at inoculation with selected PGPR as a viable economical and environment‐friendly alternative to chemical fertilization in salinity‐affected soils.  相似文献   

Caudal fin abnormalities in Gilthead seabream (Sparus aurata L.) have a strong genetic variance component     

Stefanos Fragkoulis  Irene Economou  Gabriel Moukas  George Koumoundouros  Costas Batargias 《Journal of fish diseases》2020,43(7):825-828

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Effects of dietary cholesterol on hepatopancreas associated with morphotypic differentiation in male Amazon River Prawns,Macrobrachium amazonicum (Heller, 1862)     

Thalles Fernando Rocha Ruiz  Karina Ribeiro  Carlos Alberto Vicentini  Irene Bastos Franceschini Vicentini  Luciene Patrici Papa 《Aquaculture Research》2019,50(3):862-870

Cholesterol is a necessary element in the diet of prawns and it is involved in the metabolic processes of sexual maturation and synthesis of the molting hormone. Freshwater prawns are not able to synthesise cholesterol from specialised metabolic pathways. The aim of this study was to describe changes in structural and morphometric patterns of hepatopancreas associated with morphotypic differentiation of males Macrobrachium amazonicum when fed with different levels of cholesterol. Considering the four morphotypes of this species, Translucent Claw morphotype specimens were split into experimental units and divided into four groups, fed with different levels of cholesterol (0%, 0.5%, 1%, 2%) for 50 days. They were collected as they reached Green Claw (GC) morphotype, weighed to determine the hepatosomatic index, and the hepatopancreas was processed in histological routine for morphologic and morphometric analysis. In this study, it was possible to observe that the 2% cholesterol treatment exhibited more animals that reached the GC morphotype, and there was no significant weight gain in all treatments. Histologically, B‐cell abundance and hypervacuolized as well as F‐ and R‐cells shortages were observed as the percentage of cholesterol increased. This alteration in cellular profile correlates with the morphometric analyses that exhibited an increase in epithelial area and alterations in the lumen shape. This imbalance observed in the lumen‐epithelium relationship may be associated with a low digestive performance and possibly congested the functions of hepatopancreas. Thus, high doses of cholesterol promoted morphotypic differentiation without weight gain, due to alterations on hepatopancreas.  相似文献   

The urogenital papillae as an indicator of sexual maturity in male African catfish,Clarias gariepinus, (Burchell, 1822)     

Jamie‐Lee Das Neves  Helene Coetzee  Irene Barnhoorn  Ina Wagenaar 《Aquaculture Research》2019,50(12):3519-3527

The present study investigated a non‐invasive method based on macroscopic morphological features of male Clarias gariepinus for the assessment of sexual maturity stage. As African catfish cannot be stripped for semen as in most other fish species; they have to be killed to obtain semen from the testes. This method could be used to ensure that males used to obtain sperm are sexually mature to increase the concentration and quality of mature sperm for egg fertilization in the production of C. gariepinus. Morphological features including the length and width of the urogenital papillae (UGP), an external secondary sexual characteristic of C. gariepinus (n = 89) were measured and calculated as a percentage of total body length. The urogenital papillae length (L_UGP) and width (W_UGP) index of each fish were used and compared with the macroscopic and microscopic maturity stage of the testes. The results revealed that although positive, a significant correlation does not exist between the L_UGP or W_UGP and maturity stage of the testes. Therefore, although this procedure would be valuable as an initial non‐invasive assessment of maturity, it does not provide an accurate or reliable indication of the maturity stage of the fish.  相似文献   

Spezifisches Gewicht neuer Apfelsorten     

Irene Höller  Walter Guerra  Karin Gummerer 《Erwerbs-Obstbau》2017,59(2):85-91

At the Research Centre for Agriculture and Forestry Laimburg the specific weight of 121 apple varieties from the own variety collection was measured by a hydrostatic method (Archimedes principle) from 2007 to 2013. For this purpose samples of 10 apples per cultivar were collected mainly from the sites of Laimburg (220?m asl) and Laces (700 meters asl) and were examined annually at the same period with uniform fruits equal in size. The cultivars could be classified in specific weight classes from 0.75 to 0.91?g/cm³. 76% of the varieties were assigned to the middle classes since they had specific weights ranging from 0.80 to 0.86?g/cm³. ‘Golden Delicious’ was included within the specific “very light” varieties while ‘Braeburn’, ‘Nicoter Kanzi®’ and ‘Scifresh Jazz®’ were classified as “very heavy” varieties. The year and location do not significantly influence the specific weight, since this parameter depends rather on genetically caused factors such as the intercellular volume and the dry matter content of the fruit. The specific gravity can be an interesting complementary information to describe an apple variety.  相似文献   

Distribution of trichothecenes, zearalenone, and ergosterol in a fractionated wheat harvest lot     

Neuhof T  Koch M  Rasenko T  Nehls I 《Journal of agricultural and food chemistry》2008,56(16):7566-7571

To investigate possible co-occurrences of type B trichothecenes and zearalenone within a Fusarium culmorum-infected wheat harvest lot, kernels were fractionated into six groups by visual criteria. The Fusarium-damaged kernels were subdivided into white, shrunken, and red kernel groups, and the remaining kernels were sorted into healthy, black spotted, and nonspecific groups. The distribution patterns of nivalenol, deoxynivalenol, zearalenone, and ergosterol were determined for possible correlations. Significant correlations between the distribution patterns were found for the mycotoxins and ergosterol for the grouped kernels (r = 0.997-0.999, p < 0.0001). Additionally, remarkably outstanding levels of nivalenol (24-fold more than the mean at 1.16 mg/kg), deoxynivalenol (27-fold more than the mean at 0.16 mg/kg), zearalenone (25-fold more than the mean at 77 microg/kg), and ergosterol (17-fold more than the mean at 13.4 mg/kg) were found in the red kernel group. Further, detailed mycotoxin and ergosterol analyses were carried out on various segments (kernel surface, conidia, bran, and flour) of the red kernels. However, the mycotoxin and ergosterol distribution profiles revealed nonsignificant correlations for these kernel segments, with the exception of deoxynivalenol and nivalenol, which were moderately correlated (r = 0.948, p = 0.035).  相似文献   

Pan‐continental invasion of Pseudorasbora parva: towards a better understanding of freshwater fish invasions     

Rodolphe E Gozlan  Demetra Andreou  Takashi Asaeda  Kathleen Beyer  Rachid Bouhadad  Dean Burnard  Nuno Caiola  Predrag Cakic  Vesna Djikanovic  Hamid R Esmaeili  Istvan Falka  Duncan Golicher  Akos Harka  Galina Jeney  Vladimír Kováč  Jiří Musil  Annamaria Nocita  Meta Povz  Nicolas Poulet  Tomas Virbickas  Christian Wolter  A Serhan Tarkan  Elena Tricarico  Teodora Trichkova  Hugo Verreycken  Andrzej Witkowski  Chun Guang Zhang  Irene Zweimueller  J Robert Britton 《Fish and Fisheries》2010,11(4):315-340

In recent years, policy‐makers have sought the development of appropriate tools to prevent and manage introductions of invasive species. However, these tools are not well suited for introductions of non‐target species that are unknowingly released alongside intentionally‐introduced species. The most compelling example of such invasion is arguably the topmouth gudgeon Pseudorasbora parva, a small cyprinid species originating from East Asia. A combination of sociological, economical and biological factors has fuelled their rapid invasion since the 1960s; 32 countries (from Central Asia to North Africa) have been invaded in less than 50 years. Based on a combination of monitoring surveys (2535 populations sampled) and literature reviews, this paper aims to quantify and characterise important invasion parameters, such as pathways of introduction, time between introduction and detection, lag phase and plasticity of life history traits. Every decade, five new countries have reported P. parva introduction, mainly resulting from the movement of Chinese carps for fish farming. The mean detection period after first introduction was 4 years, a duration insufficient to prevent their pan‐continental invasion. High phenotypic plasticity in fitness related traits such as growth, early maturity, fecundity, reproductive behaviour and the ability to cope with novel pathogens has predisposed P. parva to being a strong invader. The Pseudorasbora parva invasion has provided quantitative data for the development of 1) early warning systems across different spatial scales; 2) rapid eradication programmes prior to natural spread in open systems and 3) sound risk assessments with emphasis on plasticity of life history traits.  相似文献