Escape‐related behaviour of Atlantic cod,Gadus morhua L., in a simulated farm situation     

Linda A Hansen  Trine Dale  Børge Damsgård  Ingebrigt Uglem  Kåre Aas  Pål‐Arne Bjørn 《Aquaculture Research》2008,40(1):26-34

Cultured fish escaping from farms represent an economic loss as well as a potential problem for wild fish populations. This study investigated the escape‐related behaviour of farmed Norwegian coastal and northeast Arctic cod (NEAC), Gadus morhua L. Six groups of fish were observed during three replicate trials in a large tank that was split into two equal parts by a net wall. The fish could move freely through an opening in the net during the trials. Three groups were not fed during the trials. The first escape occurred shortly after producing the net opening (11±10.5 min; mean±standard deviation). Norwegian coastal cod were more prone to escape than the NEAC. A starvation period of 9 days increased the number of fish on the escape side of the tank. Net biting and net inspection by the fish were frequently observed, irrespective of whether the fish were fed or not. The same fish were repeatedly found on the escape side of the tank, but the propensity for recurrent escape behaviour was not related to genotype, feeding status or size. The results suggest that other factors, such as individual variation in boldness or exploration behaviour, could affect the willingness to escape.  相似文献   

Screening for pollen tolerance to high temperatures in tomato     

Marine J. Paupière  Pauline van Haperen  Ivo Rieu  Richard G. F. Visser  Yury M. Tikunov  Arnaud G. Bovy 《Euphytica》2017,213(6):130

Among the abiotic stresses affecting plant reproduction, high temperature is one of the most prominent ones because it directly affects fruit set. So far, little attention has been paid to the investigation of the variation in high temperature tolerance among wild tomato (Solanum lycopersicum) germplasm. The objective of this study was to determine the tolerance of 17 different cultivated and wild tomato accessions to high temperature, using a pollen viability screening approach. Each of the 17 genotypes of tomato was analysed for their pollen quality under a 32 °C (day)/26 °C (night) regime. The total number of pollen per flower and the fraction of viable pollen were recorded. The number of pollen per flower varied between 35,547 and 109,490 whereas the fraction of viable pollen varied between 0.03 and 0.71. No correlation was found between these two traits. However, the combination of these traits could provide the best reproductive capability under high temperature. In this study, thermo-tolerant (LA2854, LA1478 and LA0417) as well as thermo-sensitive (LA1719, LA1580, and SWEET4) genotypes have been identified. Those genotypes can be used as novel genetic resources to get more insight into pollen thermo-tolerance mechanisms and be included in breeding programs.  相似文献   

Ethephon: a tool to boost gum arabic production from Acacia senegal and to enhance gummosis processes     

Chimène Fanta Abib  Mama Ntoupka  Régis Peltier  Jean-Michel Harmand  Philippe Thaler 《Agroforestry Systems》2013,87(2):427-438

Gum arabic production from Acacia senegal is lower in sub-humid areas than arid areas. Water stress is thought to be the reason for higher yields in arid areas. The application of ethephon is thought to mimic the effect of water stress in other plants. The objective of this study was to determine if the application of ethephon would increase the gum yields of Acacia senegal under sub-humid conditions in Cameroon. Trees receiving 40 or 120 mg ethephon were compared to controls in field experiments at a semi-arid and a sub-humid location in Northern Cameroon, over two seasons. Two provenances from drier areas (Sudan) were compared to the local one. In the first season, gum yield of the local provenance treated with ethephon was increased by 400–600 % compared to the untreated trees. Gum yield at the semi-arid location was 77, 313 and 214 g/tree with 0, 40 and 120 mg ethephon/tree, respectively, while at the sub-humid location, it was 30, 186 and 114 g/tree with 0, 40 and 120 mg ethephon/tree. However, in the second season, the effect of ethephon was not significant in the semi-arid area, whereas it was evident in the sub-humid area (up to 478 g/tree). Moreover, ethephon did not affect gum yield of provenances from drier areas (Sudan). This showed that the water-stress hypothesis has to be refined. The development of ethephon-based tapping systems is promising, but requires further studies with a wider range of environmental conditions and A. senegal provenances.  相似文献   

Acoustic characteristics of two feeding modes used by brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss) and turbot (Scophthalmus maximus)     

J. P. Lagardre  R. Mallekh  A. Mariani 《Aquaculture (Amsterdam, Netherlands)》2004,240(1-4):607-616

Under conditions of intensive culture, the acoustic signals produced by fish during feeding depend on their feeding mode. Exclusive suction, as used by turbot, is characterised by a maximum acoustic energy in the frequency range 7–9 kHz and a sound duration of about one minute depending of time duration of pellet distribution. Suction feeding in conjunction with forward swimming, as employed by brown trout and rainbow trout, had a maximum acoustic energy in the frequency range 4–6 kHz and feeding sounds were measurable only for short periods (less than 1 s) in between two pellet distributions by hand. The brevity of these feeding sounds (ca. 1000 ms) requires adapting the turbot acoustic-detection systems to actively feeding fish for developing automated feed distribution systems feasible in trout aquaculture.  相似文献   

Postprandial kinetics of gene expression of proteins involved in the digestive process in rainbow trout (<Emphasis Type="Italic">O. mykiss</Emphasis>) and impact of diet composition     

Marion Borey  Stephane Panserat  Anne Surget  Marianne Cluzeaud  Elisabeth Plagnes-Juan  Alexandre Herman  Viviana Lazzarotto  Geneviève Corraze  Françoise Médale  Beatrice Lauga  Christine Burel 《Fish physiology and biochemistry》2016,42(4):1187-1202

The impact of increased incorporation of plant ingredients on diets for rainbow trout was evaluated in terms of gene expression of gastric (gastric lipase, pepsinogen) and intestinal (prolidase, maltase, phospholipase A2) digestive enzymes and nutrient transporters (peptide and glucose transporters), as well as of postprandial levels of plasma glucose, triglycerides and total free amino acids. For that purpose, trout alevins were fed from the start of exogenous feeding one of three different experimental diets: a diet rich in fish meal and fish oil (FM–FO), a plant-based diet (noFM–noFO) totally free from fish meal and fish oil, but containing plant ingredients and a Mixed diet (Mixed) intermediate between the FM–FO and noFM–noFO diets. After 16 months of rearing, all fish were left unfed for 72 h and then given a single meal to satiation. Blood, stomach and anterior intestine were sampled before the meal and at 2, 6 and 12 h after this meal. The postprandial kinetics of gene expression of gastric and intestinal digestive enzymes and nutrient transporters were then followed in trout fed the FM–FO diet. The postprandial profiles showed that the expression of almost all genes studied was stimulated by the presence of nutrients in the digestive tract of trout, but the timing (appearance of peaks) varied between genes. Based on these data, we have focused on the molecular response to dietary factors in the stomach and the intestine at 6 and 12 h after feeding, respectively. The reduction in FM and FO levels of dietary incorporation induced a significant decrease in the gene expression of gastric lipase, GLUT2 and PEPT1. The plasma glucose and triglycerides levels were also reduced in trout fed the noFM–noFO diet. Consequently, the present study suggests a decrease in digestive capacities in trout fed a diet rich in plant ingredients.  相似文献   

Biomaterials and Bioactive Natural Products from Marine Invertebrates: From Basic Research to Innovative Applications     

Giovanna Romano  Mariana Almeida  Ana Varela Coelho  Adele Cutignano  Luis G Gonalves  Espen Hansen  Denis Khnykin  Tali Mass  Andreja Ram&#x;ak  Miguel S. Rocha  Tiago H. Silva  Michela Sugni  Loriano Ballarin  Anne-Marie Genevire 《Marine drugs》2022,20(4)

Aquatic invertebrates are a major source of biomaterials and bioactive natural products that can find applications as pharmaceutics, nutraceutics, cosmetics, antibiotics, antifouling products and biomaterials. Symbiotic microorganisms are often the real producers of many secondary metabolites initially isolated from marine invertebrates; however, a certain number of them are actually synthesized by the macro-organisms. In this review, we analysed the literature of the years 2010–2019 on natural products (bioactive molecules and biomaterials) from the main phyla of marine invertebrates explored so far, including sponges, cnidarians, molluscs, echinoderms and ascidians, and present relevant examples of natural products of interest to public and private stakeholders. We also describe omics tools that have been more relevant in identifying and understanding mechanisms and processes underlying the biosynthesis of secondary metabolites in marine invertebrates. Since there is increasing attention on finding new solutions for a sustainable large-scale supply of bioactive compounds, we propose that a possible improvement in the biodiscovery pipeline might also come from the study and utilization of aquatic invertebrate stem cells.  相似文献   

Development stage-dependent susceptibility of cocoa fruit to pod rot caused by Phytophthora megakarya     

P. Takam Soh  M. Ndoumbè-Nkeng  I. Sache  E. P. Ndong Nguema  H. Gwet  J. Chadœuf 《European journal of plant pathology / European Foundation for Plant Pathology》2013,135(2):363-370

Pod rot causes up to 30 % losses in world cocoa production. In order to predict the risk evolution of disease, it is important to take into consideration the developmental stage of fruits. In fact, it has been shown that the risk of attack by pod rot depends amongst others on the developmental stage of fruits. We proposed here to estimate the susceptibility at different stages. Susceptibility of fruit to disease was investigated at three fruit developmental stages (cherelle, young pod and adult pod); disease severity was assessed in laboratory conditions, on detached, artificially inoculated fruits, while disease incidence was assessed in the field, under natural inoculum pressure. In both assessment fruits at the cherelle stage were the most susceptible whereas the young and adult fruits were equally susceptible. The vertical position of the fruits on the tree did not influence their susceptibility. Estimates of the fruit susceptibility and of the infectious potential were derived from the severity and incidence measurements, using a model assuming that the number of spores on a fruit follows a Poisson distribution with the mean, the density of spores per fruit as the parameter. The estimated parameter values allowed the evaluation of the probability of attack of a fruit by the disease, which could be implemented in a disease warning system.  相似文献   

Effects of management regimes and extreme climatic events on plant population viability in Eryngium alpinum     

Marco Andrello  Jean-Philippe Bizoux  Morgane Barbet-Massin  Myriam Gaudeul  Florence Nicolè  Irène Till-Bottraud 《Biological conservation》2012,147(1):99-106

Extreme climatic events like the 2003 summer heatwave and inappropriate land management can threaten the existence of rare plants. We studied the response of Eryngium alpinum, a vulnerable species, to this extreme climatic event and different agricultural practices. A demographic study was conducted in seven field sites between 2001 and 2010. Stage-specific vital rates were used to parameterize matrix population models and perform stochastic projections to calculate population growth rates and estimate extinction probabilities. Among management regimes, spring grazing and land abandonment decreased vital rates and population growth, while autumn grazing and late mowing had positive effects on population viability. The 2003 heatwave reduced fecundity rates and survival rates. Only spring grazed sites presented considerable extinction risk. Stochastic projections showed that an increased frequency of 2003-like events may exacerbate extinction risk, but extinction probability depends mainly on land management regimes. To better conserve E. alpinum populations, we recommend conversion of presently spring grazed and abandoned sites to late mowing or autumn grazing.  相似文献   

Modifications of Interfacial Proteins in Oil-in-Water Emulsions Prior to and During Lipid Oxidation     

C Berton  MH Ropers  D Guibert  V Solé  C Genot 《Journal of agricultural and food chemistry》2012,60(35):8659-8671

Lipid oxidation is a major cause for the degradation of biological systems and foods, but the intricate relationship between lipid oxidation and protein modifications in these complex multiphase systems remains unclear. The objective of this work was to have a spatial and temporal insight of the modifications undergone by the interfacial or the unadsorbed proteins in oil-in-water emulsions during lipid oxidation. Tryptophan fluorescence and oxygen uptake were monitored simultaneously during incubation in different conditions of protein-stabilized oil-in-water emulsions. Kinetic parameters demonstrated that protein modifications, highlighted by decrease of protein fluorescence, occurred as an early event in the sequence of the reactions. They concerned more specifically the proteins adsorbed at the oil/water interface. The reactions led in a latter stage to protein aggregation, carbonylation, and loss of protein solubility.  相似文献   

Prediction of soil organic and inorganic carbon contents at a national scale (France) using mid‐infrared reflectance spectroscopy (MIRS)     

C. Grinand  B. G. Barthès  D. Brunet  E. Kouakoua  D. Arrouays  C. Jolivet  G. Caria  M. Bernoux 《European Journal of Soil Science》2012,63(2):141-151

This work aimed to evaluate the potential of mid‐infrared reflectance spectroscopy (MIRS) to predict soil organic and inorganic carbon contents with a 2086‐sample set representative of French topsoils (0–30 cm). Ground air‐dried samples collected regularly using a 16 × 16‐km grid were analysed for total (dry combustion) and inorganic (calcimeter) carbon; organic carbon was calculated by difference. Calibrations of MIR spectra with partial least square regressions were developed with 10–80% of the set and five random selections of samples. Comparisons between samples with contrasting organic or inorganic carbon content and regression coefficients of calibration equations both showed that organic carbon was firstly associated with a wide spectral region around 2500–3500 cm^?1 (which was a reflection of its complex nature), and inorganic carbon with narrow spectral bands, especially around 2520 cm^?1. Optimal calibrations for both organic and inorganic carbon were achieved by using 20% of the total set: predictions were not improved much by including more of the set and were less stable, probably because of atypical samples. At the 20% rate, organic carbon predictions over the validation set (80% of the total) yielded mean R², standard error of prediction (SEP) and RPD (ratio of standard deviation to SEP) of 0.89, 6.7 g kg^?1 and 3.0, respectively; inorganic carbon predictions yielded 0.97, 2.8 g kg^?1 and 5.6, respectively. This seemed appropriate for large‐scale soil inventories and mapping studies but not for accurate carbon monitoring, possibly because carbonate soils were included. More work is needed on organic carbon calibrations for large‐scale soil libraries.  相似文献