Reiss H.,University of Nordland |
Birchenough S.,Center for Environment |
Borja A.,Tecnalia |
Buhl-Mortensen L.,Norwegian Institute of Marine Research |
And 11 more authors.
ICES Journal of Marine Science | Year: 2015
Marine benthic ecosystems are difficult to monitor and assess, which is in contrast to modern ecosystem-based management requiring detailed information at all important ecological and anthropogenic impact levels. Ecosystem management needs to ensure a sustainable exploitation of marine resources as well as the protection of sensitive habitats, taking account of potential multiple-use conicts and impacts over large spatial scales. The urgent need for large-scale spatial data on benthic species and communities resulted in an increasing application of distribution modelling (DM). The use of DM techniques enables to employ full spatial coverage data of environmental variables to predict benthic spatial distribution patterns. Especially, statistical DMs have opened new possibilities for ecosystem management applications, since they are straightforward and the outputs are easy to interpret and communicate. Mechanistic modelling techniques, targeting the fundamental niche of species, and Bayesian belief networks are the most promising to further improve DM performance in the marine realm. There are many actual and potential management applications of DMs in the marine benthic environment, these are (i) early warning systems for species invasion and pest control, (ii) to assess distribution probabilities of species to be protected, (iii) uses in monitoring design and spatial management frameworks (e.g. MPA designations), and (iv) establishing long-term ecosystem management measures (accounting for future climate-driven changes in the ecosystem). It is important to acknowledge also the limitations associated with DM applications in a marine management context as well as considering new areas for future DM developments. The knowledge of explanatory variables, for example, setting the basis for DM, will continue to be further developed: this includes both the abiotic (natural and anthropogenic) and the more pressing biotic (e.g. species interactions) aspects of the ecosystem. While the response variables on the other hand are often focused on species presence and some work undertaken on species abundances, it is equally important to consider, e.g. biological traits or benthic ecosystem functions in DM applications. Tools such as DMs are suitable to forecast the possible effects of climate change on benthic species distribution patterns and hence could help to steer present-day ecosystem management. © 2014 International Council for the Exploration of the Sea.
Moeskops B.,Ghent University |
Buchan D.,Ghent University |
Van Beneden S.,Ghent University |
Van Beneden S.,University College Ghent |
And 5 more authors.
Pedobiologia | Year: 2012
Eight fertilization strategies were compared in a field trial on Alfisol in Belgium (humid temperate climate): cattle slurry (CSL); farmyard manure (FYM); vegetable, fruit and garden waste compost (VFG); high C/N farm compost (FCP1); low C/N farm compost (FCP2); exclusively mineral fertilizer (MIN N); no fertilization (NF+), no fertilization and no crop (NF-). After five growing seasons, VFG resulted in the highest soil organic C (1.46% SOC) and total N contents (0.117%TN). SOC and TN contents of the MIN N plots, on the other hand, remained unchanged and were even similar to those of NF+ plots, despite greater biomass production on the MIN N plots than on the NF+ plots. Application of organic matter mostly increased dehydrogenase, β-glucosidase and β-glucosaminidase activity, but only FYM raised the activity of all three enzymes significantly compared to MIN N. Of the five organic amendments tested, only VFG suppressed Rhizoctonia solani (65% suppressiveness). Plots treated with FCP1, on the other hand, were highly conducive to R. solani (28.3% suppressiveness). Suppressiveness against R. solani probably depended on the maturity and cellulose content of the organic amendments. Highest microbial biomass C contents were found in the VFG plots. PLFA 16:1ω5c contents sensitively reacted to the different treatments and were significantly higher in VFG than in MIN N plots (3.84 and 2.20nmolg -1 dry soil, respectively). Finally, a soil quality index was developed using stepwise canonical discriminant analysis. β-glucosaminidase and β-glucosidase activity, and TN content were the most important parameters of the index. According to this index, FYM resulted in a significantly higher soil quality than the other treatments. We conclude that farmyard manure seems to be the preferred organic amendment for maintaining soil quality in arable fields under temperate climatic conditions. © 2012 Elsevier GmbH.
Van Ranst G.,Ghent University |
Vandewalle M.,Institute for Agriculture and Fisheries Research |
Gadeyne F.,Ghent University |
De Riek J.,Institute for Agriculture and Fisheries Research |
Fievez V.,Ghent University
Animal | Year: 2013
Most often, farmers consider red clover an unattractive forage because of its low ensilability. Nevertheless, several in vivo and in vitro experiments also showed advantages of red clover silages such as decreased rumen biohydrogenation of polyunsaturated fatty acids. This has been attributed to a possible protective role of protein-bound phenols, with polyphenol oxidase playing a key role in their formation. This enzyme is active in red clover, but not in other green forages, such as, for example, perennial ryegrass. Therefore, the aim was to study the lipid metabolism within red clover/ryegrass mixtures in lab scale silages and during in vitro rumen batch incubations. Ensilability of red clover increased with higher proportions of ryegrass in the silage mixture. However, the lipid-protecting mechanism of red clover does not seem to occur in the co-ensiled ryegrass as lipolysis of polar lipids linearly increased with increasing proportions of ryegrass (86.0%, 91.6%, 89.9%, 93.1% and 95.6% in 60-day-old silages with 100/0, 75/25, 50/50, 25/75 and 0/100 red clover/ryegrass, respectively). Rumen lipolysis and biohydrogenation of C18:3n-3 and C18:2n-6 were negatively related to red clover proportions in the silage mixtures. The lipid-protective mechanism in red clover silages is confirmed, but it seems not to be transferred to lipids in co-ensiled forages. © 2013 The Animal Consortium.
Beeckman A.,Ghent University |
Vicca J.,KaHo St. Lieven Polytechnic |
Van Ranst G.,Institute for Agriculture and Fisheries Research |
Janssens G.P.J.,Ghent University |
Fievez V.,Ghent University
Journal of Animal Physiology and Animal Nutrition | Year: 2010
Analysis of blood plasma of 60 cows selected on six Flemish organic dairy farms revealed that on average 12% of all samples and on one farm up to 28% of the organic cows showed plasma vitamin E concentrations less than 3.0 μg/ml, which is considered the minimum level to avoid health risks due to vitamin E shortages. Furthermore, this study showed early lactating and dry cows to be more at risk in relation to animals in mid-late lactation. In European organic farming, vitamin supplements are only allowed if granted by the local authority to satisfy daily requirements. Therefore, the vitamin E content of the feedstuffs used on the farms was determined. Grass clover silage (GCS) and mixed silage had significantly more vitamin E than hay, maize or grain (p < 0.05) [mean (SD): 52 (35), 29 (20), 4.5 (1.7), 4.9 (4.4) and 7.1 (3.8) mg/kg DM, respectively]. Apparently, variation in the vitamin E content in the silage samples was huge. Hence, the vitamin E content of ryegrass, white and red clover was determined in a second lab scale experiment and the effects of wilting, DM content and supplementation of ensiling additives were investigated. Fresh ryegrass had a higher vitamin E content than white and red clover (p < 0.05) [156 (11.3), 49.3 (0.67) and 74.3 (5.73) μg/g DM, respectively]. These differences remained after the wilting or ensiling. Supplementation of formic acid or lactic acid bacteria at ensiling had no significant effect on the vitamin E content. Overall, it can be concluded that GCS is the most important source of vitamin E in organic dairy farming. A legal possibility for case-related supplementation should be retained in organic dairy farming as approximately 18% of all dry and early lactating cows were at risk of vitamin E shortage. © 2009 Blackwell Verlag GmbH.
Aerts J.,Institute for Agriculture and Fisheries Research |
Aerts J.,Ghent University |
Metz J.R.,Radboud University Nijmegen |
Ampe B.,Institute for Agriculture and Fisheries Research |
And 3 more authors.
PLoS ONE | Year: 2015
Fish faced with stressful stimuli launch an endocrine stress response through activation of the hypothalamic-pituitary-interrenal (HPI-) axis to release cortisol into the blood. Scientifically validated biomarkers to capture systemic cortisol exposure over longer periods of time are of utmost importance to assess chronic stress in governmental, wildlife, aquaculture and scientific settings. Here we demonstrate that cortisol in scales of common carp (Cyprinus carpio L.) is the long-sought biomarker for chronic stress. Undisturbed (CTR) and daily stressed (STRESS) carp were compared. Dexamethasone (DEX) or cortisol (CORT) fed fish served as negative and positive controls, respectively. Scale cortisol was quantified with a validated ultra-performance liquid chromatography tandem mass spectrometry method. An increase in scale cortisol content was found in STRESS and CORT but not in CTR and DEX fish. Scale cortisol content reflects its accumulation in a stressor and time dependent manner and validates the scale cortisol content as biomarker for chronic stress. Plasma analyses confirmed that (i) CTR, DEX and CORT treatments were effective, (ii) plasma cortisol of STRESS fish showed no signs of chronic HPI-axis activation, and (iii) plasma cortisol is a poor predictor for chronic stress. The expression of HPI key genes crf, pomc, and star were up-regulated in STRESS fish in the absence of a plasma cortisol response, as was the target gene of cortisol encoding subunit α1 of the Na+/K+-ATPase in gills. When lost, scales of fish regenerate fast. Regenerated scales corroborate our findings, offering (i) unsurpassed time resolution for cortisol incorporation and as such for stressful events, and (ii) the possibility to investigate stress in a well defined and controlled environment and time frame creating novel opportunities for bone physiological research.We conclude that the cortisol content in ontogenetic and regenerated scales is an innovative biomarker for chronic stress offering ample applications in science and industry. © 2015 Aerts et al.
Trinh P.Q.,Ghent University |
Waeyenberge L.,Institute for Agriculture and Fisheries Research |
Nguyen C.N.,Institute of Ecology and Biological Resources |
Moens M.,Ghent University |
Moens M.,Institute for Agriculture and Fisheries Research
Nematology | Year: 2012
Four isolates of Radopholus arabocoffeae and one isolate of R. duriophilus were collected during a survey of plant-parasitic nematodes on coffee in Vietnam. Radopholus species only occurred in the Western Highland region. Information on the degree of variability in morphometrics, and morphological and molecular characters amongst and within these species are reported. The survey also yielded a Radopholus isolate collected from Robusta coffee roots and soil in Dak Lak, which is herein described as a new species, R. daklakensis sp. n. Within the genus, R. daklakensis sp. n. is most similar to R. arabocoffeae and R. duriophilus in morphology and morphometrics. It differs from R. arabocoffeae by the stylet knobs always directed posteriorly and the conical tail shape with rounded terminus in females. Radopholus daklakensis sp. n. differs from R. duriophilus by the stylet knobs, which are always directed posteriorly vs rounded, and dorsal knob sometimes projected anteriorly, and sperm rod-shaped vs oval and kidney-shaped. Radopholus daklakensis sp. n. differs from R. similis by the absence of a postrectal intestinal sac, four incisures of the lateral fields terminating far posterior to the position of the phasmid, the bursa in male reaching one-third of tail to half, never reaching tail terminus and smaller stylet length in females. The canonical discriminant analysis separated the Radopholus species by characters such as lip height, stylet length, b, b', c, V and ratio tail length/stylet length. Phylogenetic analysis of Radopholus species using ITS-rDNA sequences or sequences from the D2-D3 expansion region of the 28S rRNA gene also confirm R. daklakensis sp. n. to be distinct. © 2012 Koninklijke Brill NV, Leiden, The Netherlands.
Van Ranst G.,Institute for Agriculture and Fisheries Research |
Fievez V.,Ghent University |
Vandewalle M.,Institute for Agriculture and Fisheries Research |
Van Waes C.,Belgium Institute for Agricultural and Fisheries Research |
And 3 more authors.
Animal | Year: 2010
This paper describes the relationship between protein-bound phenols in red clover, induced by different degrees of damaging before wilting and varying wilting duration, and in silo lipid metabolism. The ultimate effect of these changes on rumen biohydrogenation is the second focus of this paper. For this experiment, red clover, damaged to different degrees (not damaged (ND), crushing or frozen/thawing (FT)) before wilting (4 or 24 h) was ensiled. Different degrees of damaging and wilting duration lead to differences in polyphenol oxidase (PPO) activity, measured as increase in protein-bound phenols. Treatment effects on fatty acid (FA) content and composition, lipid fractions (free FAs, membrane lipids (ML) and neutral fraction) and lipolysis were further studied in the silage. In FT, red clover lipolysis was markedly lower in the first days after ensiling, but this largely disappeared after 60 days of ensiling, regardless of wilting duration. This suggests an inhibition of plant lipases in FT silages. After 60 days of ensiling no differences in lipid fractions could be found between any of the treatments and differences in lipolysis were caused by reduced FA proportions in ML of wilted FT red clover. Fresh, wilted (24 h) after damaging (ND or FT) and ensiled (4 or 60 days; wilted 24 h; ND or FT) red clover were also incubated in rumen fluid to study the biohydrogenation of C18:3n-3 and C18:2n-6 in vitro. Silages (both 60 days and to a lower degree 4 days) showed a lower biohydrogenation compared with fresh and wilted forages, regardless of damaging. This suggests that lipids in ensiled red clover were more protected, but this protection was not enhanced by a higher amount of protein-bound phenols in wilted FT compared with ND red clover. The reduction of rumen microbial biohydrogenation with duration of red clover ensiling seems in contrast to what is expected, namely a higher biohydrogenation when a higher amount of FFA is present. This merits further investigation in relation to strategies to activate PPO toward the embedding of lipids in phenol-protein complexes. Copyright © The Animal Consortium 2010.
de Backer A.,Ghent University |
de Backer A.,Institute for Agriculture and Fisheries Research |
van Ael E.,Ghent University |
Vincx M.,Ghent University |
And 2 more authors.
Helgoland Marine Research | Year: 2010
Despite the numerous ecological and behavioural studies, relatively little is known about the behavioural dynamics of Corophium volutator during the tidal cycle. In the present study, the behaviour of C. volutator was observed in the laboratory in a tide-simulated aquarium, and time allocation of the different activities was quantified. Overall, the surface activity was low and showed a steep decline after submersion. A clear tide-based cyclic pattern was found, with a boost of activity immediately after first submersion, continuing during submersion, and shifting over a period with decreasing activity towards almost total inactivity at the end of emersion. © Springer-Verlag and AWI 2009.
PubMed | Institute for Agriculture and Fisheries Research, Ghent University and Radboud University Nijmegen
Type: Journal Article | Journal: PloS one | Year: 2015
Fish faced with stressful stimuli launch an endocrine stress response through activation of the hypothalamic-pituitary-interrenal (HPI-) axis to release cortisol into the blood. Scientifically validated biomarkers to capture systemic cortisol exposure over longer periods of time are of utmost importance to assess chronic stress in governmental, wildlife, aquaculture and scientific settings. Here we demonstrate that cortisol in scales of common carp (Cyprinus carpio L.) is the long-sought biomarker for chronic stress. Undisturbed (CTR) and daily stressed (STRESS) carp were compared. Dexamethasone (DEX) or cortisol (CORT) fed fish served as negative and positive controls, respectively. Scale cortisol was quantified with a validated ultra-performance liquid chromatography tandem mass spectrometry method. An increase in scale cortisol content was found in STRESS and CORT but not in CTR and DEX fish. Scale cortisol content reflects its accumulation in a stressor and time dependent manner and validates the scale cortisol content as biomarker for chronic stress. Plasma analyses confirmed that (i) CTR, DEX and CORT treatments were effective, (ii) plasma cortisol of STRESS fish showed no signs of chronic HPI-axis activation, and (iii) plasma cortisol is a poor predictor for chronic stress. The expression of HPI key genes crf, pomc, and star were up-regulated in STRESS fish in the absence of a plasma cortisol response, as was the target gene of cortisol encoding subunit 1 of the Na+/K+-ATPase in gills. When lost, scales of fish regenerate fast. Regenerated scales corroborate our findings, offering (i) unsurpassed time resolution for cortisol incorporation and as such for stressful events, and (ii) the possibility to investigate stress in a well defined and controlled environment and time frame creating novel opportunities for bone physiological research. We conclude that the cortisol content in ontogenetic and regenerated scales is an innovative biomarker for chronic stress offering ample applications in science and industry.
PubMed | Institute for Agriculture and Fisheries Research, Nutrition science N.V., Flemish Institute for Technological Research, Leitat Technological Center and 2 more.
Type: | Journal: Food chemistry | Year: 2016
In the present paper, 26 food waste streams were selected according to their exploitation potential and investigated in terms of pectin content. The isolated pectin, subdivided into calcium bound and alkaline extractable pectin, was fully characterized in terms of uronic acid and other sugar composition, methylation and acetylation degree. It was shown that many waste streams can be a valuable source of pectin, but also that pectin structures present a huge structural diversity, resulting in a broad range of pectin structures. These can have different physicochemical and biological properties, which are useful in a wide range of applications. Even if the data could not cover all the possible batch by batch and country variabilities, to date this represents the most complete pectin characterization from food waste streams ever reported in the literature with a homogeneous methodology.