Browsing by Author "Peter Bossier"

Now showing 1 - 4 of 4
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    Drinking activity and microparticle size selection in early post-hatching axenic European sea bass (Dicentrarchus labrax L.) larvae
    (Aquaculture, 2016) Eamy Nursaliza Yaacob; Davy Vandenbosch; TomCoenye; Aline Bajek; Daisy Vanrompay; Kristof Dierckens; Peter Bossier
    Marine fish larvae are known to drink water and to feed selectively.We studied water and microparticle ingestion of axenic sea bass larvae at the early post-hatching stage. Knowledge on these physiological processes is crucial for designing effective feeding, particle delivery schemes for marine fish larvae and for the understanding of the interaction and/or association between larval fish and smaller microparticles such as bacteria in aquaculture systems. We found that the fluorescence intensity of accumulated FITC-labelled dextran in the gut of laboratoryreared axenic European sea bass larvae (Dicentrarchus labrax), at day after hatching 7 (DAH7), correlated to a drinking rate of 4.1 ± 0.1 nL h−1 larva−1. Additionally, by providing microparticles of 2, 10 or 45 μm, each time in combination with reference microparticles of 20 μm at an equal particle volume, feed size selection was examined. Feeding bigger particles (a combination of 45 and 20 μm) resulted in a statistically higher mean ingested volume (105 ± 104 μm3 larva−1) than feeding particle combinations of 2 and 20 μm or 10 and 20 μm, (104 ± 103 μm3 larva−1). Based on Jacobs' selectivity index (D-values), fish larvae always selected for the bigger particles. In addition, larvae showed significantly positive selection towards 45 μm particles after 12 h of feeding.We conclude that axenic European sea bass larvae at DAH7 fed selectively on larger microparticles and unintentionally ingested smallmicroparticles through drinking. Thus, both active and unintentional uptake of microparticles can be useful for microparticle delivery in early post-hatching marine fish larviculture. These results produce insight into the possibility of feeding with an appropriate particle size for future studies using early post-hatching axenic European sea bass larvae as model animal.
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    Epigenetics in aquaculture – the last frontier
    (Wiley Publishing Asia Pty Ltd, 2017-08) Luana Granada; Marco F.L. Lemos; Henrique N. Cabral; Peter Bossier; Sara C. Novais
    Aquaculture production is expanding rapidly around the world. To tackle rising production and species diversity issues, innovations in the field of aquaculture feeds, breeding, disease management and other improvements must be addressed. In this framework, the study of epigenetic mechanisms behind different aquaculture rearing processes presents great opportunities. The transcriptional impact of epigenetic modifications, triggered by environmental stimuli, has been shown to influence the organism’s phenotype. Therefore, understanding the environmental- induced epigenetic markers related to disease resistance or other economically important traits will allow the establishment of favourable breeding conditions with increased economical revenue. Several studies have shown epigenetic effects in various species, induced by different rearing conditions, with benefits for the organisms and evidences for heritability of the acquired adaptive phenotypic traits across generations, making these studies even more relevant in a production context. These studies have demonstrated the great potential of epigenetics to positively induce disease resistance, stress tolerance and attain better sex ratios in the aquatic organism. Also, in the field of nutritional epigenetics, the possibility of early nutritional programming to improve the performance of broodstock or even the long-term performance of their progeny has been suggested. In sum, an increased understanding of epigenetic mechanisms in economically important species, and the epigenetic markers leading to the most favourable phenotypic traits, will contribute to the expansion of economically viable commercial aquaculture industries. The major epigenetic mechanisms and respective analysis methods, as well as the state of the art and potential applications in aquaculture, are addressed in this review.
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    Significance of microalgal–bacterial interactions for aquaculture
    (Wiley Publishing Asia Pty Ltd, 2013-01) Fatin M. I. Natrah; Peter Bossier; Patrick Sorgeloos; Fatimah Md. Yusoff; Tom Defoirdt
    Knowledge on the importance of associations between bacteria and microalgae in aquatic ecosystems is rather limited at the moment, mostly due to a lack of studies at the molecular and biochemical level of microorganisms. This paper discusses the current knowledge on microalgae–bacteria interactions and their potential impacts on the productivity, efficiency and sustainability of aquaculture. Current findings suggest that the interactions are complex and specific. The release of stimulatory products by bacteria that enhance the growth of microalgae, and vice versa, indicates the existence of mutualistic relations. Other factors, such as signalling between bacteria and microalgae, may also play an important role. Although these interactions may be of significant importance, to date, only a few findings have been reported on the use of consortia consisting of microalgae and bacteria for practical purposes. Interestingly, these results pointed out that a combination of microalgae and bacteria is often better than using either of them alone. Further research is needed to obtain a thorough understanding of the mechanisms behind the interactions between these microorganisms, including the identification of active compounds. This knowledge will enable the selection of appropriate consortia for different applications in aquaculture, including disease control and high and sustainable production of feed.
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    Stress response for disease control in aquaculture
    (Blackwell Publishing Asia Pty Ltd, 2011) Yeong Yik Sung; Thomas H. MacRae; Patrick Sorgeloos; Peter Bossier
    Heat shock proteins (Hsps) are robustly induced by diverse stressors that denature proteins. In addition to stress resistance, Hsps are involved in the folding of nascent proteins, plant and animal development, aging, environmental adaptation and the immune response, demonstrating the fundamental importance of these proteins to cell survival. Heat shock proteins are induced in aquatic organisms by perturbations of temperature and salinity, environmental contaminants, handling, hormones and biotic stressors. Exposure to sublethal stress may enhance tolerance to a subsequent stress, a process termed induced thermotolerance, and provide protection to stressors other than the initial stress, known as cross-tolerance. In the present review, we briefly describe the established approaches that are used to control disease during aquaculture. This is followed by documentation of Hsp induction after exposure to stressors commonly encountered by aquatic organisms. Induced thermotolerance, cross-tolerance and immune enhancement by Hsps are also considered. Although physiological stress is known to decrease disease resistance it is now becoming clear that stress-induced Hsps enhance the tolerance of aquatic organisms to disease. Potential applications for Hsps in the commercial production of fish, crustaceans and molluscs are indicated, an issue of significance when the importance of aquaculture in feeding the world’s population is realized.