EpiStress - Epigenetic mechanisms of stress tolerance in Nereis diversicolor

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Organizational Unit

Publications

Swimming behaviour as an alternative endpoint to assess differences in abiotic stress sensitivities between strains of Brachionus koreanus (Rotifera: Monogononta)

Publication . Granada, Luana; Lemos, Marco F.L.; Bossier, Peter; Novais, Sara C.

Brachionus plicatilis is a cosmopolitan rotifer used as a model organism in several research areas and as live food in aquaculture. Being a species complex, responses to stressors vary even among strains of the same species and, thus, the responses of one species are not representative of the whole complex. This study aimed to address the effects of extreme salinity ranges, and different concentrations of hydrogen peroxide, copper, cadmium, and chloramphenicol, in two strains of B. koreanus (MRS10 and IBA3) from B. plicatilis species complex, by assessing effects on their survival and swimming capacity. Neonates (0–4 h old) were exposed to the stressors in 48 well-microplates, for 24 and 6 h, to evaluate lethal and behavioural effects, respectively. Tested conditions of chloramphenicol did not show any effects on rotifers. The behavioural endpoint showed to be particularly sensitive to assess the effects of high salinity, hydrogen peroxide, and copper sulfate, as swimming capacity impairment was observed for both strains in the lowest concentrations used in lethal tests. Overall, results showed that IBA3 was more tolerant to the majority of stressors, comparing to MRS10, which may be due to differences in physiological characteristics, highlighting the importance of performing multiclonal experiments. Also, swimming capacity inhibition proved to be a good alternative to the classical lethality tests, being sensitive to lower concentrations and with shorter exposure periods.

2023Journal article

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Modelling integrated multi-trophic aquaculture: Optimizing a three trophic level system

Publication . Granada, Luana; Lopes, Sofia; Novais, Sara C.; Lemos, Marco F. L.

As a fast-growing food production industry, aquaculture is dealing with the need for intensification due to the global increasing demand for fish products. However, this also implies the use of more sustainable practices to reduce negative environmental impacts currently associated with this industry, including the use of wild resources, destruction of natural ecosystems, eutrophication of effluent receiving bodies, impacts due to inadequate medication practices, among others. Using multi-species systems, such as integrated multi-trophic aquaculture, allows to produce economically important species while reducing some of these aquaculture concerns, through biomitigation of aquaculture wastes and reduction of diseases outbreaks, for example. Applying mathematical models to these systems is crucial to control and understand the interactions between species, maximizing productivity, with important environmental and economic benefits. Here, the application of some equations and models available in the literature, regarding basic parameters, is discussed – population dynamics, growth, waste production, and filtering rate – when considering the description and optimization of a theoretical integrated multi-trophic aquaculture operation composed by three trophic levels.

2018-10Journal article

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Epigenetics in aquaculture: the last frontier

Publication . Granada, Luana; Lemos, Marco F.L.; Cabral, Henrique N.; Bossier, Peter; Novais, Sara C.

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.

2018Journal article

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Genetic identification and comparative study on life history parameters of two strains belonging to Brachionus plicatilis species complex (Rotifera: Monogononta)

Publication . Granada, Luana; Lemos, Marco F.L.; Bossier, Peter; Novais, Sara C.

The rotifer Brachionus plicatilis is an important species for aquaculture, due to its use as food for bivalves, and fish and crustaceans larvae in hatcheries. However, being a species complex, it has become increasingly important to catalogue and describe the species and biotypes that constitute this complex. Therefore, the purpose of this study was to genetically identify two morphologically identical strains and evaluate their suitability to be used in aquaculture under the studied conditions. A correct identification and knowledge of life history characteristics of the biotypes and isolated strains is vital to avoid mass mortalities in aquaculture and to better interpret the responses of the organisms when these are used as a bioindicator and model for ecotoxicology. Strains MRS10 and IBA3 were identified as B. koreanus and, even though they have been maintained under the same laboratory conditions for several years, significant differences in several life history parameters were observed. A life table assay showed IBA3 rotifers to be larger at first reproduction, and to have longer post-reproductive period and mean lifespan. On the other hand, MRS10 rotifers produced less non-viable eggs and had higher population growth rate. Both strains showed to be a potential model for ecotoxicological and molecular studies, mainly due to the ease of maintenance, short generation time, and reproduction via parthenogenesis. However, MRS10 might present better characteristics than IBA3 to be reared in aquaculture as live food.

2022Journal article

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Changes in fatty acid profile and chemical composition of meagre (Argyrosomus regius) fed with different lipid and selenium levels

Publication . Simões, Tiago; Fonseca, Sthelio B.; Augusto, Ana; Granada, Luana; Ozório, Rodrigo O. A.; Gonçalves, Jose F. M.; Pascoal, Leonardo A. F.; Silva, José H. V.; Lemos, Marco F. L.

This studyaimed to evaluatechangesin body composition, speciallymuscleandliver fatty acid profileinmeagre (Argyrosomus regius) fed with different dietary lipid sources and levels, with or without selenium supplementation. Six hundred meagre were fed twice a day, 6 days per week, with eight experimental diets for 60 days. Diets were a combination of fish oil or a vegetable blend (45% linseedþ 35% rapeseedþ 20% soybean oil), at 12 or 17% of oil and 0 or 1 mg/kg of organic selenium, in a 2 2 2 factorial design. The whole body protein and lipid content were affected by the dietary oil source. Fish oil diets increased long-chain (LC) PUFAs content in the edible tissues, while vegetable oil-based diets increased short-chain (SC) PUFAs. Vegetable oil diet tended to decrease thefish proteincontent.A higherlipidlivercontentwas observedinmeagre fed the vegetable oil blend. The results also suggested the ability of meagre to convert SC-PUFA to LC-PUFA when the vegetable oilisincludedin their diet. The possibility for partial substitution offish oil by vegetable oilin meagre diets, resulting in lower dependence of fish oil in meagre farming, is also demonstrated here

2017Journal article

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