94 results on '"Eleni Mente"'
Search Results
2. Growth performance of gilthead sea bream (Sparus aurata) fed a mixture of single cell ingredients for organic diets
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Anna Tampou, Styliani Andreopoulou, Antigoni Vasilaki, Ioannis Nengas, Panagiotis Berillis, Enric Gisbert, Ioannis T. Karapanagiotidis, Efthimia Antonopoulou, and Eleni Mente
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Gilthead sea bream ,Organic ,Fishmeal trimmings ,Bacterial protein ,Yeast meal ,Aquaculture. Fisheries. Angling ,SH1-691 - Abstract
The aim of this study was to investigate the growth performance of gilthead sea bream (Sparus aurata) fed with a mixture of a single cell ingredient (SCI) (bacterial protein, yeast protein and algae) for organic aquaculture. Sea bream with an initial mean body weight of 6.87±0.07 g were randomly allocated to 250-litre tanks. Four isonitrogenous, isolipidic and isoenergetic diets were formulated by replacing organic fishmeal trimmings with 0% (control), 12% (SCI12), 15% (SCI15) and 18% (SCI18) of the SCI mixture. Each diet was distributed to the groups in triplicate. The fish were fed three times daily until satiation and the experimental period was 60 days. Survival rates and voluntary feed intake were similar in the fish with the different feed treatments (p > 0.05). Similar (p > 0.05) growth performance (final weight, SGR) and feed conversion ratio (FCR) were observed in fish fed all SCI-based diets, which was superior to the control diet treatment. Apparent protein digestibility was similar among treatments, but lipid digestibility was significantly reduced in the SCI15 and SCI18 groups compared to the SCI12 group. The specific activities of trypsin, total alkaline protease and lipase were increased in fish fed the SCI15 diet (p < 0.05). The protein content in the fillet was significantly increased and the lipid content was decreased in the SCI12 and SCI18 groups compared to the other groups. No adverse effects on liver and intestinal histology were observed in the different groups. The results suggest that organic fishmeal trimmings can be successfully replaced by innovative SCIs based on microbial protein, yeast meal and algae, and that this SCI mixture could be a candidate for organic aqua feed for gilthead sea bream.
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- 2024
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3. Basil functional and growth responses when cultivated via different aquaponic and hydroponics systems
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Anastasia Mourantian, Maria Aslanidou, Eleni Mente, Nikolaos Katsoulas, and Efi Levizou
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Photosynthesis ,Leaf nutrients ,Soilless cultivation ,Ocinum basilicum ,Red tilapia ,PRI index ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
Background Aquaponics is an innovative farming system that combines hydroponics and aquaculture, resulting in the production of both crops and fish. Decoupled aquaponics is a new approach introduced in aquaponics research for the elimination of certain system bottlenecks, specifically targeting the optimization of crops and fish production conditions. The aquaponics-related literature predominantly examines the system’s effects on crop productivity, largely overlooking the plant functional responses which underlie growth and yield performance. The aim of the study was the integrated evaluation of basil performance cultivated under coupled and decoupled aquaponic systems compared with a hydroponic one, in terms of growth and functional parameters in a pilot-scale aquaponics greenhouse. Methods We focused on the efficiency of the photosynthetic process and the state of the photosynthetic machinery, assessed by instantaneous gas exchange measurements as well as photosynthetic light response curves, and in vivo chlorophyll a fluorescence. Light use efficiency was estimated through leaf reflectance determination. Photosynthetic pigments content and leaf nutritional state assessments completed the picture of basil functional responses to the three different treatments/systems. The plant’s functional parameters were assessed at 15-day intervals. The experiment lasted for two months and included an intermediate and a final harvest during which several basil growth parameters were determined. Results Coupled aquaponics resulted in reduced growth, which was mainly ascribed to sub-sufficient leaf nutrient levels, a fact that triggered a series of negative feedbacks on all aspects of their photosynthetic performance. These plants experienced a down-regulation of PSII activity as reflected in the significant decreases of quantum yield and efficiency of electron transport, along with decreased photosynthetic pigments content. On the contrary, decoupled aquaponics favored both growth and photochemistry leading to higher light use efficiency compared with coupled system and hydroponics, yet without significant differences from the latter. Photosynthetic light curves indicated constantly higher photosynthetic capacity of the decoupled aquaponics-treated basil, while also enhanced pigment concentrations were evident. Basil functional responses to the three tested production systems provided insights on the underlying mechanisms of plant performance highlighting key-points for systems optimization. We propose decoupled aquaponics as an effective system that may replace hydroponics supporting high crops productivity. We suggest that future works should focus on the mechanisms involved in crop and fish species function, the elucidation of which would greatly contribute to the optimization of the aquaponics productivity.
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- 2023
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4. Tenebrio molitor larvae meal inclusion affects hepatic proteome and apoptosis and/or autophagy of three farmed fish species
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Eleni Mente, Thomas Bousdras, Konstantinos Feidantsis, Nikolas Panteli, Maria Mastoraki, Konstantinos Ar. Kormas, Stavros Chatzifotis, Giovanni Piccolo, Laura Gasco, Francesco Gai, Samuel A. M. Martin, and Efthimia Antonopoulou
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Medicine ,Science - Abstract
Abstract Herein, the effect of dietary inclusion of insect (Tenebrio molitor) meal on hepatic pathways of apoptosis and autophagy in three farmed fish species, gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax) and rainbow trout (Oncorhynchus mykiss), fed diets at 25%, 50% and 60% insect meal inclusion levels respectively, was investigated. Hepatic proteome was examined by liver protein profiles from the three fish species, obtained by two-dimensional gel electrophoresis. Although cellular stress was evident in the three teleost species following insect meal, inclusion by T. molitor, D. labrax and O. mykiss suppressed apoptosis through induction of hepatic autophagy, while in S. aurata both cellular procedures were activated. Protein abundance showed that a total of 30, 81 and 74 spots were altered significantly in seabream, European seabass and rainbow trout, respectively. Insect meal inclusion resulted in individual protein abundance changes, with less number of proteins altered in gilthead seabream compared to European seabass and rainbow trout. This is the first study demonstrating that insect meal in fish diets is causing changes in liver protein abundances. However, a species-specific response both in the above mentioned bioindicators, indicates the need to strategically manage fish meal replacement in fish diets per species.
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- 2022
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5. Nutrients Use Efficiency in Coupled and Decoupled Aquaponic Systems
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Maria Aslanidou, Angeliki Elvanidi, Anastasia Mourantian, Efi Levizou, Eleni Mente, and Nikolaos Katsoulas
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aquaponics ,nutrient solution ,basil ,parsley ,cucumber ,tomato ,Plant culture ,SB1-1110 - Abstract
Aquaponics is currently undergoing a transformation into an intensive food production system. The initially applied systems focused on small-scale, fish-centric coupled (CAP, the aquaculture, and the hydroponic units are arranged in a single loop, and the water flows continuously from the fish tanks to the plant unit and back) aquaponics. More recently, the primary area of research interest has shifted toward larger-scale, plant-centric decoupled (aquaculture and hydroponics units are arranged in a multi-loop setup as separate functional units that can be controlled independently) systems, aiming to achieve greater economic benefits and employ more environmentally friendly practices. The objective of this study was to address gaps in the expansion of decoupled larger-scale aquaponics and to provide a comprehensive understanding of the water and nutrient flow in the system. For this purpose, experiments were performed in a greenhouse on CAP and DCAP systems, while this study also included measurements in a pure hydroponic system (HP). This study presents an assessment of the water and nutrient flow in four different crops: basil; cucumber; parsley; and tomato, all co-cultivated with a tilapia aquaculture system. Significant nutrient deficiencies and imbalances were identified in the CAP solution, leading to pronounced impacts on nutrient assimilation, particularly for fruiting vegetables. However, the average nutrient use efficiency (NUE) for nitrogen, phosphorous, potassium, and calcium was found to be 42% higher in the CAP treatment compared to HP and DCAP treatments. The nutrient solution in the DCAP treatment did not exhibit differences in water quality parameters and nutrient efficiency when compared to HP, resulting in similar effects on nutrient assimilation. Nonetheless, it was observed that DCAP plants exhibited superior NUE compared to HP plants.
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- 2023
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6. Toward Sustainable and Healthy Fish Products—The Role of Feeding and Preservation Techniques
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Giorgia Antonelli, Elena Chiarello, Gianfranco Picone, Silvia Tappi, Giulia Baldi, Mattia Di Nunzio, Eleni Mente, Stelios Karapanagiotis, Phelly Vasilaki, Massimiliano Petracci, Pietro Rocculi, Alessandra Bordoni, and Francesco Capozzi
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feed ,PEF ,brine ,in vitro digestion ,lipolysis ,protein hydrolysis ,Chemical technology ,TP1-1185 - Abstract
Fish is a fundamental component of the human diet, and in the near future the proportion of aquatic foods originating from aquaculture production is expected to increase to over 56%. The sustainable growth of the aquaculture sector involves the use of new sustainable raw materials as substitutes for traditional fishmeal and fish oil ingredients, but it is crucial that the substitution maintains the nutritional value of the fish meat. In addition, the preservation of the nutritional value should be a mandatory requirement of new technologies that extend the shelf life of fish. In this context, we evaluated the impact of a newly formulated feed and three preservation treatments (brine, pulsed electric field (PEF), and PEF plus brine) on the fatty acid composition and protein and lipid digestibility of sea bass fillets. In non-digested fillets, although slightly reduced by the newly formulated feed (standard = 2.49 ± 0.14; newly formulated = 2.03 ± 0.10) the n-3/n-6 PUFA ratio indicated good nutritional value. The preservation treatments did not modify the fatty acid content and profile of non-digested fillets. Conversely, protein and lipid digestibility were not affected by the different diets but were significantly reduced by brine, with or without PEF, while PEF alone had no effect. Overall, our results indicated that the newly formulated feed containing 50% less fishmeal is a good compromise between the sustainability and nutritional value of cultivated seabass, and PEF is a promising preservation technology deserving of further study.
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- 2023
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7. The Probiotic Phaeobacter inhibens Provokes Hypertrophic Growth via Activation of the IGF-1/Akt Pathway during the Process of Metamorphosis of Greater Amberjack (Seriola dumerili, Risso 1810)
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Nikolas Panteli, Konstantinos Feidantsis, Maria Demertzioglou, Vasiliki Paralika, Stelios Karapanagiotis, Constantinos C. Mylonas, Konstantinos Ar. Kormas, Eleni Mente, Pavlos Makridis, and Efthimia Antonopoulou
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insulin-like growth factor type 1 receptor (IGF-1R) ,cellular signaling ,hypertrophy ,cell death ,post-embryonic development ,teleost ,Veterinary medicine ,SF600-1100 ,Zoology ,QL1-991 - Abstract
Metamorphosis entails hormonally regulated morphological and physiological changes requiring high energy levels. Probiotics as feed supplements generate ameliorative effects on host nutrient digestion and absorption. Thereby, the aim of the present research was to investigate the impact of the probiotic Phaeobacter inhibens as a water additive on cellular signaling pathways in the metamorphosis of greater amberjack (Seriola dumerili). Activation of insulin-like growth factor type 1 receptor (IGF-1R), protein kinase B (Akt), mitogen-activated protein kinases (MAPKs) and AMP-activated protein kinase (AMPK), induction of heat shock proteins (Hsps), and programmed cell death were assessed through SDS-Page/immunoblot analysis, while energy metabolism was determined through enzymatic activities. According to the results, greater amberjack reared in P. inhibens-enriched water entered the metamorphic phase with greater body length, while protein synthesis was triggered to facilitate the hypertrophic growth as indicated by IGF-1/Akt activation and AMPK inhibition. Contrarily, MAPKs levels were reduced, whereas variations in Hsps response were evident in the probiotic treatment. Apoptosis and autophagy were mobilized potentially for the structural remodeling processes. Furthermore, the elevated enzymatic activities of intermediary metabolism highlighted the excess energy demands of metamorphosis. Collectively, the present findings demonstrate that P. inhibens may reinforce nutrient utilization, thus leading greater amberjack to an advanced growth and developmental state.
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- 2023
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8. Investigating Salinity Effects in Brackish Aquaponics Systems: Evidencing the Co-Cultivation of the Halophyte Crithmum maritimum with the Euryhaline Sparus aurata
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Nikolaos Vlahos, Panagiotis Berillis, Efi Levizou, Efstathia Patsea, Nikolas Panteli, Maria Demertzioglou, Konstantinos Morfesis, Georgia Voudouri, Nikos Krigas, Kostantinos Kormas, Efthimia Antonopoulou, and Eleni Mente
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growth performance ,rock samphire ,gilthead sea bream ,MAPKs ,HSPs stress ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The possibility of simultaneous production of halophyte and euryhaline fish creates huge interest in both commercial aquaponics systems and in research. The aim of the present study was to investigate the effect of three different salinities (8, 14, and 20 ppt) on the growth performance and survival rate of sea bream (Sparus aurata) and rock samphire (Crithmum maritimum) in an experimental brackish aquaponic system. Furthermore, induction of heat shock proteins (Hsps) and phosphorylation of mitogen-activated protein kinases (MAPKs) were assessed through the sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot analysis. A total number of 234 sea bream individuals were divided into nine autonomous aquaponic systems. The experiment lasted 45 days. In total, 54 individuals of rock samphire were used and were distributed into groups of six individuals per hydroponic tank using the raft method. Water quality showed stable fluctuation throughout the experiment, strongly supporting fish and plant growth performance and survival in both treatments. The results show that better growth performance for both sea bream and rock samphire (height increase) was evident in salinity 8 ppt compared to salinities 14 ppt and 20 ppt. Minimal or mild histopathological alterations were detected in gills, midgut, and liver for all three salinity groups. Exposure to different salinities modified Hsp60 and MAPKs expression in a tissue- and time-specific manner. During exposure to 8 ppt, constant Hsp60 levels and phosphorylation of MAPKs at 15 days may indicate a prominent protective role in the gills. The results show that sea bream and rock samphire can be used in brackish aquaponics systems with satisfactory growth performances, thus allowing for a range of commercial applications generating interest in their production.
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- 2023
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9. Spinach Responds to Minimal Nutrient Supplementation in Aquaponics by Up-Regulating Light Use Efficiency, Photochemistry, and Carboxylation
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Evangelia Tsoumalakou, Eleni Mente, Nikolaos Vlahos, and Efi Levizou
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red tilapia ,PRI ,chlorophyll content ,gas exchange ,light response curves ,chlorophyll fluorescence ,Plant culture ,SB1-1110 - Abstract
Aquaponics is a promising cultivation technique for combined production of crops and fish, on the condition of tackling certain nutrients deficiencies. The aim of the present study was to examine the limitations imposed by the system on spinach (Spinacia oleracea) growth and functional performance and to identify the minimum nutrient supplementation for their optimization. Spinach was co-cultivated with red tilapia under three treatments; iron (Fe) and iron with potassium (Fe+K) enrichment was compared with the no-external input control. During a 45-day experiment, the photosynthetic performance, photosynthetic machinery efficiency, total chlorophylls content, and leaf reflectance were monitored, along with leaf nutritional state, antioxidant activity, and growth responses of fish and crops. Control plants showed symptoms of Fe deficiency, extensive chlorosis, stunted growth, and functional impairment already from day 10. The latter consisted of a coordinated down-regulation of photochemistry, carboxylation, and light-use efficiency. Fe-treated plants exhibited similar growth and functional performance with Fe+K-treated plants but outperformed them in chlorophyll content, photosynthetic rates, and photochemical efficiency, mainly due to higher quantum yield of electron transport. Fish growth remained unaffected. Fe-deficiency was identified as the major bottleneck for spinach cultivation in closed-loop aquaponics, and our results demonstrate that only Fe supplementation may sufficiently improve spinach function and yield.
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- 2023
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10. Evaluation of various commodities for the development of the yellow mealworm, Tenebrio molitor
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Christos I. Rumbos, Ioannis T. Karapanagiotidis, Eleni Mente, Pier Psofakis, and Christos G. Athanassiou
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Medicine ,Science - Abstract
Abstract We evaluated the suitability of forty-four commodities (i.e., cereal flours and meals, non-flour, cereal commodities, legumes and various commodities of vegetative and animal origin) as oviposition and feeding substrates for the yellow mealworm, Tenebrio molitor. Τen T. molitor adults were introduced in plastic vials containing 30 g of each commodity. At the end of the 1 week period, all adults were removed, and mortality was determined; then the vials were further incubated for additional 9 weeks. After this time, the vials were opened, and the larvae of each vial were separated from the feeding substrate, counted and weighed as a group. The efficiency of ingested food conversion was calculated for each substrate. Finally, proximate composition was calculated to determine the nutrient components of the feeding substrates tested and the T. molitor larvae that fed on various selected substrates. In general, adult reproduction was clearly favoured by most amylaceous substrates tested, which was in contrast to the tested legumes on which fewer offspring were produced. Similar effects were observed for larval development. Feeding on selected substrates exerted an impact on the nutrient composition of T. molitor larvae, with a high protein content of the substrate usually resulting in a high protein content of the larvae.
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- 2020
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11. Aqua-Ento-Ponics: Effect of Insect Meal on the Development of Sea Bass, Dicentrarchus labrax, in Co-Culture with Lettuce
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Paraskevi Stathopoulou, Adamantia Asimaki, Panagiotis Berillis, Nikolaos Vlahos, Efi Levizou, Nikolaos Katsoulas, Ioannis T. Karapanagiotidis, Christos I. Rumbos, Christos G. Athanassiou, and Eleni Mente
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sea bass ,lettuce ,aquaponics ,Zophobas morio ,fishmeal replacement ,Biology (General) ,QH301-705.5 ,Genetics ,QH426-470 - Abstract
The aim of this study is to investigate the effect of 10 and 20% replacement of fishmeal (FM dietary group) with the superworm Zophobas morio larvae meal (ZM10 and ZM20 dietary groups) on the growth performance of sea bass (Dicentrarchus labrax) and lettuce plants (Lactuca sativa) reared in aquaponics. Ninety juvenile sea bass with an average body weight of 21.55 g/individual were placed in aquaponic fish tanks, together with 24 lettuce plants with an average initial height of 8.90 cm/plant and an average number of leaves of 5.75/plant over a 45-day trial period. At the end of that period, all feeding groups exhibited high survival. In fact, ΖΜ10 and ZM20 groups showed similar fish weight gain and specific growth rate (SGR) (p > 0.05), but significantly lower SGR (p < 0.05) than the FM group. Nevertheless, final fish body weight and length were similar (p > 0.05) for all feeding groups. No plant mortality was observed during the 45-day study period. All three aquaponic systems resulted in similar leaf fresh weight, as well as fresh and dry aerial biomass. At the end of the experimental period, plants in the third system showed higher fresh leaf weight, total weight of fresh leaves, total dry aerial biomass, and total produced biomass compared to the other two systems. The results of the present study show that fish fed with the ZM10 diet had higher weight gain (WG) than fish fed with the ZM20 diet, while the SGRs for ZM10 and ZM20 were similar. Both ZM10 and ZM20 diets result in efficient lettuce production. This study also provides data that enlighten the feasibility of integrating insect meals as fish feeds for aquaponics which helps towards the development of an ento-aquaponic approach.
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- 2022
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12. Precise Monitoring of Lettuce Functional Responses to Minimal Nutrient Supplementation Identifies Aquaponic System’s Nutrient Limitations and Their Time-Course
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Evangelia Tsoumalakou, Eleni Mente, Konstantinos A. Kormas, Nikolaos Katsoulas, Nikolaos Vlahos, Panagiotis Kapsis, and Efi Levizou
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aquaponics ,lettuce ,nutrient supplementation ,photosynthesis ,functional response ,red tilapia ,Agriculture (General) ,S1-972 - Abstract
In aquaponics, a closed-loop system which combines fish and crop production, essential nutrients for plant growth are often at sub-optimal concentrations. The aim of the present study was to identify system limitations and thoroughly examine the integrated response of its components to minimal external inputs, notably crop’s functional parameters, fish performance, and microorganism profile. Lettuce and red tilapia were co-cultivated under only Fe and Fe with K supplementation and their performance was evaluated against the control of no nutrient addition. Photosynthesis, the photosynthetic apparatus state, and efficiency, pigments, leaf elemental composition, and antioxidant activity of lettuce were monitored throughout the growth period, along with several parameters related to water quality, fish growth, plant productivity and bacterial community composition. Nutrient deficiency in control plants severely impacted gas exchange, PSII efficiency, and chlorophyll a content, from day 14 of the experiment, causing a significant increase in dissipation energy and signs of photoinhibition. Fe+K input resulted in 50% and two-fold increase in lettuce production compared with Fe and control groups respectively. Nutrient supplementation resulted in higher specific growth rate of tilapias, but did not affect root microbiota which was distinct from the water bacterial community. Collectively, the results emphasize the importance of monitoring crop’s functional responses for identifying the system’s limitations and designing effective nutrient management to sustain the reduced environmental footprint of aquaponics.
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- 2022
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13. Freshwater-adapted sea bass Dicentrarchus labrax feeding frequency impact in a lettuce Lactuca sativa aquaponics system
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Paraskevi Stathopoulou, Panagiotis Berillis, Nikolaos Vlahos, Eleni Nikouli, Konstantinos A. Kormas, Efi Levizou, Nikolaos Katsoulas, and Eleni Mente
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Aquaponics ,Feeding frequency ,Juvenile sea bass ,Lettuce ,Water reuse ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
The aim of this study is to investigate the effect of three daily fish feeding frequencies, two, four and eight times per day (FF2, FF4, and FF8, respectively) on growth performance of sea bass (Dicentrarchus labrax)and lettuce plants (Lactuca sativa) reared in aquaponics. 171 juvenile sea bass with an average body weight of 6.80 ± 0.095 g were used, together with 24 lettuce plants with an average initial height of 11.78 ± 0.074 cm over a 45-day trial period. FF2 fish group showed a significantly lower final weight, weight gain and specific growth rate than the FF4 and FF8 groups. Voluntary feed intake was similar for all the three feeding frequencies treatmens (p > 0.05). No plant mortality was observed during the 45-day study period. All three aquaponic systems resulted in a similar leaf fresh weight and fresh and dry aerial biomass. The results of the present study showed that the FF4 or FF8 feeding frequency contributes to the more efficient utilization of nutrients for better growth of sea bass adapted to fresh water while successfully supporting plant growth to a marketable biomass.
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- 2021
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14. The Protective Role of Melatonin in Sperm Cryopreservation of Farm Animals and Human: Lessons for Male Fish Cryopreservation
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Alexandra I. Alevra, Athanasios Exadactylos, Eleni Mente, and Serafeim Papadopoulos
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cryopreservation ,fish ,farm animals ,human ,semen ,melatonin ,Veterinary medicine ,SF600-1100 ,Zoology ,QL1-991 - Abstract
Cryopreservation is a technique that offers various advantages, especially in fish, among others, that makes the reproduction of species easier through a constant supply of sperm, synchronization of the gamete availability of both sexes, storage of semen for genetic improvement programs, reduction in the cost by eliminating the need to maintain male broodstock, and conserving the gametes of endangered species. However, freezing and warming procedures for cryopreservation lead to a reduction in the quality and viability of cryopreserved sperm because of oxidative stress. For this reason, the enrichment of extender media with antioxidants is a common method of cryopreservation of the semen of several fish species. Recently, many studies have been published for the protective role of antioxidants and especially of melatonin on male fertility preservation both in farm animals and humans, demonstrating the beneficial effects of melatonin as a sperm cryoprotectant. On the other hand, very few studies were conducted using melatonin as an antioxidant in different male fish species for semen cryopreservation. We conclude that the use of moderate concentrations of melatonin are beneficial to semen preservation, and the mechanisms through which melatonin acts positively on spermatozoa need to be further investigated to establish improvement protocols for cryopreservation in fish species.
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- 2022
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15. Effects of Dietary Fishmeal Replacement by Poultry By-Product Meal and Hydrolyzed Feather Meal on Liver and Intestinal Histomorphology and on Intestinal Microbiota of Gilthead Seabream (Sparus aurata)
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Pier Psofakis, Alexandra Meziti, Panagiotis Berillis, Eleni Mente, Konstantinos A. Kormas, and Ioannis T. Karapanagiotidis
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nutrition ,aquaculture ,fishmeal replacement ,land animal proteins ,histology ,intestinal microbiota ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The effects on liver and intestinal histomorphology and on intestinal microbiota in gilthead seabream (Sparus aurata) fed diets that contained poultry by-product meal (PBM) and hydrolyzed feather meal (HFM) as fishmeal replacements were studied. Fish fed on a series of isonitrogenous and isoenergetic diets, where fishmeal protein of the control diet (FM diet) was replaced by either PBM or by HFM at 25%, 50% and 100% without amino acid supplementation (PBM25, PBM50, PBM100, HFM25, HFM50 and HFM100 diets) or supplemented with lysine and methionine (PBM25+, PBM50+, HFM25+ and HFM50+ diets). The use of PBM and HFM at 25% fishmeal replacement generated a similar hepatic histomorphology to FM-fed fish, indicating that both land animal proteins are highly digestible at low FM replacement levels. However, 50% and 100% FM replacement levels by either PBM or HFM resulted in pronounced hepatic alterations in fish with the latter causing more severe degradation of the liver. Dietary amino acid supplementation delivered an improved tissue histology signifying their importance at high FM replacement levels. Intestinal microbiota was dominated by Proteobacteria (58.8%) and Actinobacteria (32.4%) in all dietary groups, but no specific pattern was observed among them at any taxonomic level. This finding was probably driven by the high inter-individual variability observed.
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- 2021
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16. Post-Prandial Amino Acid Changes in Gilthead Sea Bream
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Eleni Mente, Chris G. Carter, Robin S. (Katersky) Barnes, Nikolaos Vlahos, and Ioannis Nengas
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amino acids ,aquafeeds ,fish ,single meal ,aquaculture ,digestion ,Veterinary medicine ,SF600-1100 ,Zoology ,QL1-991 - Abstract
Following a meal, a series of physiological changes occurs in fish as they digest, absorb and assimilate ingested nutrients. This study aims to assess post-prandial free amino acid (FAA) activity in gilthead sea bream consuming a partial marine protein (fishmeal) replacement. Sea bream were fed diets where 16 and 27% of the fishmeal protein was replaced by plant protein. The essential amino acid (EAA) composition of the white muscle, liver and gut of sea bream was strongly correlated with the EAA composition of the 16% protein replacement diet compared to the 27% protein replacement diet. The mean FAA concentration in the white muscle and liver changed at 4 to 8 h after a meal and was not different to pre-feeding (0 h) and at 24 h after feeding. It was confirmed in this study that 16% replacement of marine protein with plant protein meets the amino acid needs of sea bream. Overall, the present study contributes towards understanding post-prandial amino acid profiles during uptake, tissue assimilation and immediate metabolic processing of amino acids in sea bream consuming a partial marine protein replacement. This study suggests the need to further investigate the magnitude of the post-prandial tissue-specific amino acid activity in relation to species-specific abilities to regulate metabolism due to dietary nutrient utilization.
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- 2021
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17. Insect-Based Feed Ingredients for Aquaculture: A Case Study for Their Acceptance in Greece
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Christos I. Rumbos, Eleni Mente, Ioannis T. Karapanagiotidis, Georgios Vlontzos, and Christos G. Athanassiou
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aquaculture ,insect-based aquafeeds ,survey ,public perceptions ,Science - Abstract
Although the inclusion of insects in fish diets is officially allowed in the EU since 2017, insect-based aquafeeds have not been widely adopted by the European aquaculture sector. In order to investigate the perceptions related with adoption trends, it is critical to explore the beliefs of people associated with the aquaculture sector on the use of insects in farmed fish diets. A survey was conducted among 228 participants of an aquaculture conference to explore their perceptions on the inclusion of insect meal in fish diets. Additionally, we investigated the attitudes of nine companies operating in the aquaculture and aquafeed sector in Greece that attended the conference towards this direction. The findings of the conference survey provide evidence that there is a wide-range awareness and acceptance regarding the use of insect-based feeds in farmed fish diets among the respondents. This is mainly driven by the expectations for the decline in fishing pressure on wild fish stocks, the reduction of the ecological footprint and the enhancement of the sustainability of the aquaculture sector. The results of the stakeholder survey show that six out of the nine companies that participated in the survey are favorably disposed towards the use of insect-based feeds. Specifically, four of them stated that they would produce or use aquafeeds based on insects. However, the results highlight the need for further research on the implementation of the wider adoption of insect-based feeds in aquaculture. The present study provides some first insights into the use of insect-based aquafeeds in Greece, for which there are no data available.
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- 2021
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18. Postprandial hepatic protein expression in trout Oncorhynchus mykiss a proteomics examination
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Eleni Mente, Graham J. Pierce, Efthimia Antonopoulou, David Stead, and Samuel A.M. Martin
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Postprandial ,Hepatic proteins ,Trout ,Proteomics ,Diet ,Meal ,Nutrition ,Biology (General) ,QH301-705.5 ,Biochemistry ,QD415-436 - Abstract
Following a meal, a series of physiological changes occurs in animals as they digest, absorb and assimilate ingested nutrients, the kinetics of these responses depends on metabolic rate and nutrient quality. Here we investigated the hepatic proteome in the ectothermic teleost, the rainbow trout, following a single meal to define the postprandial expression of hepatic proteins. The fish were fed a high marine fishmeal/fish oil single meal following a period of 24 h without feeding. Liver protein profiles were examined by 2D gel electrophoresis just before feeding (time 0 h) and at 6 and 12 h after feeding. Of a total of 588 protein spots analysed in a temporal fashion, 49 differed significantly in abundance between the three time groups (ANOVA, p
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- 2017
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19. Configuration of Gut Microbiota Structure and Potential Functionality in Two Teleosts under the Influence of Dietary Insect Meals
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Nikolas Panteli, Maria Mastoraki, Maria Lazarina, Stavros Chatzifotis, Eleni Mente, Konstantinos Ar. Kormas, and Efthimia Antonopoulou
- Subjects
gut microbiota ,Sparus aurata ,Dicentrarchus labrax ,metagenomics ,16S rRNA ,sustainable aquaculture ,Biology (General) ,QH301-705.5 - Abstract
Insect meals are considered promising, eco-friendly, alternative ingredients for aquafeed. Considering the dietary influence on establishment of functioning gut microbiota, the effect of the insect meal diets on the microbial ecology should be addressed. The present study assessed diet- and species-specific shifts in gut resident bacterial communities of juvenile reared Dicentrarchus labrax and Sparus aurata in response to three experimental diets with insect meals from three insects (Hermetia illucens, Tenebrio molitor, Musca domestica), using high-throughput Illumina sequencing of the V3–V4 region of the 16S rRNA gene. The dominant phyla were Firmicutes, Proteobacteria and Actinobacteria in all dietary treatments. Anaerococcus sp., Cutibacterium sp. and Pseudomonas sp. in D. labrax, and Staphylococcus sp., Hafnia sp. and Aeromonas sp. in S. aurata were the most enriched shared species, following insect-meal inclusion. Network analysis of the dietary treatments highlighted diet-induced changes in the microbial community assemblies and revealed unique and shared microbe-to-microbe interactions. PICRUSt-predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly differentiated, including genes associated with metabolic pathways. The present findings strengthen the importance of diet in microbiota configuration and underline that different insects as fish feed ingredients elicit species-specific differential responses of structural and functional dynamics in gut microbial communities.
- Published
- 2021
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20. Core versus diet-associated and postprandial bacterial communities of the rainbow trout (Oncorhynchus mykiss) midgut and faeces
- Author
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Eleni Mente, Eleni Nikouli, Efthimia Antonopoulou, Samuel A. M. Martin, and Konstantinos A. Kormas
- Subjects
Oncorhynchus mykiss ,Rainbow trout ,Gut ,Faeces ,Bacteria ,Diet ,Science ,Biology (General) ,QH301-705.5 - Abstract
This study investigated the impact of different dietary ingredients, with different protein/lipid sources, on midgut and faeces bacteria community structures just before feeding and 3 h after feeding a single meal to individual rainbow trout (Oncorhynchus mykiss). Fish were kept in experimental rearing facilities and fed ad libitum twice daily for 5 weeks. Fish were fed three different commercial diets, which contained variations of high or low marine fishmeal/fish oil content. DNA was extracted from midgut and faeces samples for analysis of their bacterial 16S rRNA gene diversity by targeting the V3-V4 region with 454 pyrosequencing. A total of 332 unique bacterial operational taxonomic units (OTUs) were revealed in all samples. However, each sample was dominated (>80% relative abundance) by 2–14 OTUs, with the single most dominant OTU having >30% dominance, indicating that only a few bacteria were fundamental in terms of relative abundance in each treatment. Fifteen OTUs occurred in all samples (core microbiota). The majority of these OTUs belonged to the Proteobacteria, Firmicutes or Tenericutes, and were associated with other animal gut environments. The faecal material and the midgut samples had few overlaps in their shared OTUs. A postprandial response in the gut bacterial community structure 3 h after feeding highlights how dietary stimulation induces structural changes in the microbiota profiles in the established gut bacteria. This study showed that feeding O. mykiss different diets and even single meals lead to perturbations in the established gut bacteria of O. mykiss.
- Published
- 2018
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21. Host-Associated Bacterial Succession during the Early Embryonic Stages and First Feeding in Farmed Gilthead Sea Bream (Sparus aurata)
- Author
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Eleni Nikouli, Alexandra Meziti, Efthimia Antonopoulou, Eleni Mente, and Konstantinos Ar. Kormas
- Subjects
sea bream ,development ,larvae ,symbionts ,bacteria ,Genetics ,QH426-470 - Abstract
One of the most widely reared fish in the Mediterranean Sea is Sparus aurata. The succession of S. aurata whole-body microbiota in fertilized eggs, five, 15, 21 and 71 days post hatch (dph) larvae and the contribution of the rearing water and the provided feed (rotifers, Artemia sp. and commercial diet) to the host’s microbiota was investigated by 454 pyrosequencing of the 16S rRNA gene diversity. In total, 1917 bacterial operational taxonomic units (OTUs) were found in all samples. On average, between 93 ± 2.1 and 366 ± 9.2 bacterial OTUs per sample were found, with most of them belonging to Proteobacteria and Bacteroidetes. Ten OTUs were shared between all S. aurata stages and were also detected in the rearing water or diet. The highest OTU richness occurred at the egg stage and the lowest at the yolk sac stage (5 dph). The rearing water and diet microbial communities contributed in S. aurata microbiota without overlaps in their microbial composition and structure. The commercial diet showed higher contribution to the S. aurata microbiota than the rearing water. After stage D71 the observed microbiota showed similarities with that of adult S. aurata as indicated by the increased number of OTUs associated with γ-Proteobacteria and Firmicutes.
- Published
- 2019
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22. Skeletal Deformity of Scoliosis in Gilthead Seabreams (Sparus aurata): Association with Changes to Calcium-Phosphor Hydroxyapatite Salts and Collagen Fibers
- Author
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Vaia Boursiaki, Charitini Theochari, Stefanos P. Zaoutsos, Eleni Mente, Dimitris Vafidis, Chrisoula Apostologamvrou, and Panagiotis Berillis
- Subjects
Sparus aurata ,scoliosis ,vertebra column ,collagen ,calcium ,phosphor ,Hydraulic engineering ,TC1-978 ,Water supply for domestic and industrial purposes ,TD201-500 - Abstract
The development of skeletal deformities in seabream farming affects fish growth, survival, and production costs. Collagen distribution in different fish tissues might be correlated with swimming behavior. This study investigates whether scoliosis in seabreams is associated with changes to calcium-phosphor hydroxyapatite salts and collagen fibril morphology. Samples of decalcified vertebrae of scoliotic and non-scoliotic seabreams were examined with transmission electron microscopy and collagen micrographs were taken and analyzed. The mineral content, modulus of elasticity, and morphology of the vertebrae were also determined. The results indicated that fish with scoliosis had significant smaller mean vertebral collagen fibril diameters than the controls. Vertebrae in abdominal and caudal regions of the scoliotic seabreams appeared to be smaller than the respective vertebrae of the non-deformed seabreams. The calcium (Ca) and phosphorus (P) amounts of vertebrae of both scoliotic and non-scoliotic seabreams were not affected by the scoliosis deformity. The modulus of elasticity showed that the vertebrae from seabreams with scoliosis were more flexible than the vertebrae from seabreams without any skeletal deformity. The mechanical properties of bone are crucially dependent on collagen structure. Hence, how the vertebral column collagen of juvenile fish is related to the mechanism of deformities requires further investigation in order to provide a risk-reducing strategy to increase fish performance in aquaculture.
- Published
- 2019
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23. The effect of organic and conventional production methods on sea bream growth, health and body composition: a field experiment
- Author
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Eleni Mente, Alexandros Stratakos, Ioannis S. Boziaris, Konstantinos A. Kormas, Vasileios Karalazos, Ioannis T. Karapanagiotidis, Vassiliki A. Catsiki, and Leondios Leondiadis
- Subjects
sustainable ,organic ,sea bream aquaculture ,Aquaculture. Fisheries. Angling ,SH1-691 - Abstract
This study aimed to develop a better understanding of organic sea bream aquaculture production in Greece, in particular its consequences for fish growth, health and body composition, and to propose and update standards for sustainable organic sea bream farming. Gilthead sea bream were kept in sea cages at densities of 4 kg m–3 (organic) and 15 kg m–3 (conventional), and were fed organically produced feed (45% crude protein, 14% fat) or conventional feed (46% crude protein, 17% fat). The amino acid profile of the conventional diet, particularly the lysine content, which is one of most important dietary amino acids for sea bream, appeared to be unsatisfactory. “Organic” sea bream stored less fat content in their white muscle than the conventional sea bream. The liver lipid content was lower and the hepatosomatic index was higher for the organic sea bream. The microbiological analysis showed that both Enterobacteriaceae and Escherichia coli on the skin were below the enumeration detection limit in both the organic and conventional sea bream. Total viable counts on the skin and muscle of both the organically and conventionally cultured sea bream were approximately 3 log cfu g –1, which is well below the acceptable limit (7 log cfu g–1) for marine species. The results showed that the combination of a low stocking density and feed with a different ingredient composition but similar nutritional value resulted in similar growth rates and nutrient profiles of the final product. Further research on nutrition is required to provide information on setting the appropriate standards for organic sea bream aquaculture to ensure that the final product is in line with the consumers’ preferences.
- Published
- 2012
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24. Collagen Fibrils in Cultured and Wild Sea Bream (Sparus aurata) Liver. An Electron Microscopy and Image Analysis Study
- Author
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Panagiotis Berillis, Eleni Mente, and Ioannis Nengas
- Subjects
Technology ,Medicine ,Science - Abstract
This study aims to measure liver collagen fibril diameter in cultured and wild sea breams (Sparus aurata). Cultured sea breams were fed three isonitrogenous diets. The organically produced feed contained sustainable certified fish meal (45%), fish oil (14%), and organic certified wheat; the laboratory feed contained fish meal (45%), fish oil (14%), wheat meal, and soya meal; and the commercial feed included fish meal (46%), fish oil (17%), soya meal, wheat meal, and corn gluten meal. The organic diet had higher amounts of vitamins A, C, and E; specific amino acids; and minerals that enhanced the biosynthesis of collagen. This study shows that fish fed the organic feed had significantly bigger collagen fibril diameters than the fish fed the conventional feed. Furthermore, the organically fed fish had similarly sized collagen fibril diameters as wild fish. More research is needed to understand the long-term effects and the mechanism and function of fish collagen peptide intake on lipid absorption and metabolism; and to identify dietary regimes that are able to improve whole body lipid profiles and suppress the transient increase of plasma triglycerides.
- Published
- 2011
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25. Gut Bacterial Communities in Geographically Distant Populations of Farmed Sea Bream (Sparus aurata) and Sea Bass (Dicentrarchus labrax)
- Author
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Eleni Nikouli, Alexandra Meziti, Efthimia Antonopoulou, Eleni Mente, and Konstantinos A. Kormas
- Subjects
teleosts ,intestine ,bacteria ,microbiota ,aquaculture ,Biology (General) ,QH301-705.5 - Abstract
This study investigated the profile of the autochthonous gut bacterial communities in adult individuals of Sparus aurata and Dicentrarchus labrax reared in sea cages in five distantly located aquaculture farms in Greece and determine the impact of geographic location on them in order to detect the core gut microbiota of these commercially important fish species. Data analyses resulted in no significant geographic impact in the gut microbial communities within the two host species, while strong similarities between them were also present. Our survey revealed the existence of a core gut microbiota within and between the two host species independent of diet and geographic location consisting of the Delftia, Pseudomonas, Pelomonas, Propionibacterium, and Atopostipes genera.
- Published
- 2018
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26. Advances in understanding the mitogenic, metabolic, and cell death signaling in teleost development: the case of greater amberjack (Seriola dumerili, Risso 1810)
- Author
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Nikolas Panteli, Maria Demertzioglou, Konstantinos Feidantsis, Stelios Karapanagiotis, Nikoletta Tsele, Kalliopi Tsakoniti, Konstantinos Gkagkavouzis, Constantinos C. Mylonas, Konstantinos Ar. Kormas, Eleni Mente, and Efthimia Antonopoulou
- Subjects
Physiology ,General Medicine ,Aquatic Science ,Biochemistry - Abstract
Cell growth and differentiation signals of insulin-like growth factor-1 (IGF-1), a key regulator in embryonic and postnatal development, are mediated through the IGF-1 receptor (IGF-1R), which activates several downstream pathways. The present study aims to address crucial organogenesis and development pathways including Akt, MAPKs, heat shock response, apoptotic and autophagic machinery, and energy metabolism in relation to IGF-1R activation during five developmental stages of reared Seriola dumerili: 1 day prior to hatching fertilized eggs (D-1), hatching day (D0), 3 days post-hatching larvae (D3), 33 (D33) and 46 (D46) days post-hatching juveniles. During both the fertilized eggs stage and larval-to-juvenile transition, IGF-1R/Akt pathway activation may mediate the hypertrophic signaling, while p44/42 MAPK phosphorylation was apparent at S. dumerili post-hatching processes and juvenile organs completion. On the contrary, apoptosis was induced during embryogenesis and autophagy at hatching day indicating a potential involvement in morphogenetic rearrangements and yolk-sac reserves depletion. Larvae morphogenesis was accompanied by a metabolic turnover with increased substantial energy consumption. The findings of the present study demonstrate the developmental stages-specific shift in critical signaling pathways during the ontogeny of reared S. dumerili.
- Published
- 2022
27. The Probiotic Phaeobacter inhibens Provokes Hypertrophic Growth via Activation of the IGF-1/Akt Pathway during the Process of Metamorphosis of Greater Amberjack (Seriola dumerili, Risso 1810)
- Author
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Antonopoulou, Nikolas Panteli, Konstantinos Feidantsis, Maria Demertzioglou, Vasiliki Paralika, Stelios Karapanagiotis, Constantinos C. Mylonas, Konstantinos Ar. Kormas, Eleni Mente, Pavlos Makridis, and Efthimia
- Subjects
insulin-like growth factor type 1 receptor (IGF-1R) ,cellular signaling ,hypertrophy ,cell death ,post-embryonic development ,teleost ,probiotics ,aquaculture - Abstract
Metamorphosis entails hormonally regulated morphological and physiological changes requiring high energy levels. Probiotics as feed supplements generate ameliorative effects on host nutrient digestion and absorption. Thereby, the aim of the present research was to investigate the impact of the probiotic Phaeobacter inhibens as a water additive on cellular signaling pathways in the metamorphosis of greater amberjack (Seriola dumerili). Activation of insulin-like growth factor type 1 receptor (IGF-1R), protein kinase B (Akt), mitogen-activated protein kinases (MAPKs) and AMP-activated protein kinase (AMPK), induction of heat shock proteins (Hsps), and programmed cell death were assessed through SDS-Page/immunoblot analysis, while energy metabolism was determined through enzymatic activities. According to the results, greater amberjack reared in P. inhibens-enriched water entered the metamorphic phase with greater body length, while protein synthesis was triggered to facilitate the hypertrophic growth as indicated by IGF-1/Akt activation and AMPK inhibition. Contrarily, MAPKs levels were reduced, whereas variations in Hsps response were evident in the probiotic treatment. Apoptosis and autophagy were mobilized potentially for the structural remodeling processes. Furthermore, the elevated enzymatic activities of intermediary metabolism highlighted the excess energy demands of metamorphosis. Collectively, the present findings demonstrate that P. inhibens may reinforce nutrient utilization, thus leading greater amberjack to an advanced growth and developmental state.
- Published
- 2023
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28. Cultivating the Mediterranean Wild Edible Species Cichorium spinosum L. in Aquaponics: Functional and Growth Responses to Minimal Nutrient Supplementation
- Author
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Evangelia Tsoumalakou, Eleni Mente, Nikolaos Vlahos, and Efi Levizou
- Subjects
Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,Building and Construction ,Management, Monitoring, Policy and Law ,red tilapia ,antioxidants ,DPPH assay ,leaf nutritional state ,PRI ,in vivo chlorophyll a fluorescence ,spiny chicory ,circular economy framework - Abstract
Aquaponics is a plant and fish co-cultivation system with high sustainability, yet sub-optimal concentrations of Fe and K often compromise crop yields. We cultivated the Mediterranean wild edible Cichorium spinosum L. (Greek name: stamnagathi) in an aquaponics setup following a minimal supplementation approach that focused on Fe and K. Stamnagathi and tilapia fish were co-cultivated under (i) solely Fe, (ii) Fe+K input and (iii) no-input Control treatments. We aimed to evaluate the feasibility of aquaponics for stamnagathi cultivation, identify the system’s bottlenecks, and propose optimization measures. Several plant’s growth and functional parameters were monitored throughout the 35-day experimental period, notably instantaneous gas exchange and photosynthetic capacity via light response curves, state and efficiency of the photosynthetic machinery, pigment content, and yield and morphometric assessments. Fish growth characteristics and survival rates remained unaffected. Fe deficiency was crucial in shaping the responses of Control stamnagathi, which showed inferior performance in terms of photochemistry, chlorophylls content, light use efficiency and, subsequently, photosynthetic activity. Fe and Fe+K-treated plants exhibited similarly high performance in all studied parameters and achieved 4.5- and 4-fold increased yields, respectively, compared to Control. The results demonstrate that aquaponics is an advantageous cropping system for stamnagathi and solely Fe supplementation is adequate to promote excellent performance and yield of this oligotrophic species.
- Published
- 2023
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- View/download PDF
29. Fishmeal Replacement by Full-Fat and Defatted Hermetia illucens Prepupae Meal in the Diet of Gilthead Seabream (Sparus aurata)
- Author
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Ioannis T. Karapanagiotidis, Marina C. Neofytou, Adamantia Asimaki, Evanthia Daskalopoulou, Pier Psofakis, Eleni Mente, Christos I. Rumbos, and Christos G. Athanassiou
- Subjects
Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,insects ,sustainable aquaculture ,aquafeeds ,growth performance ,feed utilization ,proximate composition ,Building and Construction ,Management, Monitoring, Policy and Law - Abstract
Insect proteins are considered as suitable low environmental impact alternatives to fishmeal for sustainable aquafeeds. Among the different insect species, Hermetia illucens has attracted research and industrial interest due to its ability to grow well on organic side streams, its high protein content and favorable amino acid profiles. Its lipid content although high is characterized by a lack of EPA and DHA that are essential to fish nutrition and thus a defatted form of Hermetia meal might be of better use in fish diets. Hence, two feeding trials were conducted to investigate the effects of the partial fishmeal replacement by increasing levels of a full-fat (up to 276 g/kg) and a defatted (up to 174 g/kg) H. illucens meal on feed intake, growth, feed utilization and nutrient compositions of gilthead seabream (Sparus aurata). Results showed that both the fat content and the inclusion level of H. illucens meal are critical for the success of fishmeal replacement in the diets of S. aurata as they strongly affect feed consumption. A lower palatability of H. illucens meal was observed when included at high dietary levels with the defatted form being more readily accepted by fish. The defatted H. illucens meal is more suitable than the full-fat type to replace fishmeal, with a dietary level of about 81–104 g/kg supporting the highest feed consumption, the highest growth, an unaffected proximate composition and a better feed utilization by S. aurata.
- Published
- 2023
- Full Text
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30. The effect of different dietary protein levels on growth performance and nutrient utilization of snarpsnout sea bream ( Diplodus puntazzo )
- Author
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Ioannis T. Karapanagiotidis, Stavroula Kyritsi, Georgia Dretaki‐Stamou, Pier Psofakis, Marina C. Neofytou, Eleni Mente, Nikolaos Vlahos, and Vasileios Karalazos
- Subjects
Aquatic Science - Published
- 2021
31. The effect of insect meal as a feed ingredient on survival, growth, and metabolic and antioxidant response of juvenile prawn Palaemon adspersus (Rathke, 1837)
- Author
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Stavros Chatzifotis, Maria Mastoraki, Efthimia Antonopoulou, Nikolaos Vlahos, Efstathia Patsea, and Eleni Mente
- Subjects
Meal ,Hermetia illucens ,biology ,business.industry ,media_common.quotation_subject ,Zoology ,Insect ,Aquatic Science ,biology.organism_classification ,Ingredient ,Aquaculture ,Palaemon adspersus ,Prawn ,Juvenile ,business ,media_common - Published
- 2020
32. The benthic environmental footprint of aquaculture in the Eastern Mediterranean: Organic vs conventional fish farming
- Author
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Rafailia Syvri, Lamprini Tziantziou, Eleni Mente, Dimitris Vafidis, and Nikos Neofitou
- Subjects
Fishery ,Eastern mediterranean ,Ecological footprint ,Aquaculture ,Benthic zone ,business.industry ,Macrobenthos ,Fish farming ,Aquatic Science ,Biology ,business - Published
- 2020
33. Effects of Dietary Fishmeal Replacement by Poultry By-Product Meal and Hydrolyzed Feather Meal on Liver and Intestinal Histomorphology and on Intestinal Microbiota of Gilthead Seabream (Sparus aurata)
- Author
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Ioannis T. Karapanagiotidis, Panagiotis Berillis, Pier Psofakis, Konstantinos Ar. Kormas, Eleni Mente, and Alexandra Meziti
- Subjects
intestinal microbiota ,Technology ,QH301-705.5 ,QC1-999 ,Lysine ,Actinobacteria ,histology ,chemistry.chemical_compound ,Fish meal ,Aquaculture ,Sparus aurata ,Poultry by-product meal ,General Materials Science ,Food science ,Biology (General) ,Instrumentation ,QD1-999 ,Fluid Flow and Transfer Processes ,Meal ,Methionine ,biology ,business.industry ,Feather meal ,Process Chemistry and Technology ,Physics ,General Engineering ,biology.organism_classification ,Engineering (General). Civil engineering (General) ,Computer Science Applications ,Chemistry ,nutrition ,fishmeal replacement ,chemistry ,aquaculture ,land animal proteins ,TA1-2040 ,business - Abstract
The effects on liver and intestinal histomorphology and on intestinal microbiota in gilthead seabream (Sparus aurata) fed diets that contained poultry by-product meal (PBM) and hydrolyzed feather meal (HFM) as fishmeal replacements were studied. Fish fed on a series of isonitrogenous and isoenergetic diets, where fishmeal protein of the control diet (FM diet) was replaced by either PBM or by HFM at 25%, 50% and 100% without amino acid supplementation (PBM25, PBM50, PBM100, HFM25, HFM50 and HFM100 diets) or supplemented with lysine and methionine (PBM25+, PBM50+, HFM25+ and HFM50+ diets). The use of PBM and HFM at 25% fishmeal replacement generated a similar hepatic histomorphology to FM-fed fish, indicating that both land animal proteins are highly digestible at low FM replacement levels. However, 50% and 100% FM replacement levels by either PBM or HFM resulted in pronounced hepatic alterations in fish with the latter causing more severe degradation of the liver. Dietary amino acid supplementation delivered an improved tissue histology signifying their importance at high FM replacement levels. Intestinal microbiota was dominated by Proteobacteria (58.8%) and Actinobacteria (32.4%) in all dietary groups, but no specific pattern was observed among them at any taxonomic level. This finding was probably driven by the high inter-individual variability observed.
- Published
- 2021
- Full Text
- View/download PDF
34. Freshwater-adapted sea bass Dicentrarchus labrax feeding frequency impact in a lettuce Lactuca sativa aquaponics system
- Author
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Eleni Nikouli, Efi Levizou, Panagiotis Berillis, Nikolaos Katsoulas, Konstantinos Ar. Kormas, Paraskevi Stathopoulou, Eleni Mente, and Nikolaos Vlahos
- Subjects
Lactuca ,Feeding frequency ,General Biochemistry, Genetics and Molecular Biology ,Juvenile sea bass ,03 medical and health sciences ,Water reuse ,Nutrient ,Animal science ,medicine ,Juvenile ,Aquaponics ,Sea bass ,030304 developmental biology ,0303 health sciences ,Biomass (ecology) ,biology ,General Neuroscience ,food and beverages ,04 agricultural and veterinary sciences ,General Medicine ,Lettuce ,biology.organism_classification ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Medicine ,Dicentrarchus ,medicine.symptom ,General Agricultural and Biological Sciences ,Weight gain - Abstract
The aim of this study is to investigate the effect of three daily fish feeding frequencies, two, four and eight times per day (FF2, FF4, and FF8, respectively) on growth performance of sea bass (Dicentrarchus labrax)and lettuce plants (Lactuca sativa) reared in aquaponics. 171 juvenile sea bass with an average body weight of 6.80 ± 0.095 g were used, together with 24 lettuce plants with an average initial height of 11.78 ± 0.074 cm over a 45-day trial period. FF2 fish group showed a significantly lower final weight, weight gain and specific growth rate than the FF4 and FF8 groups. Voluntary feed intake was similar for all the three feeding frequencies treatmens (p > 0.05). No plant mortality was observed during the 45-day study period. All three aquaponic systems resulted in a similar leaf fresh weight and fresh and dry aerial biomass. The results of the present study showed that the FF4 or FF8 feeding frequency contributes to the more efficient utilization of nutrients for better growth of sea bass adapted to fresh water while successfully supporting plant growth to a marketable biomass.
- Published
- 2021
35. Reshaping gut bacterial communities after dietary Tenebrio molitor larvae meal supplementation in three fish species
- Author
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Efthimia Antonopoulou, Giovanni Piccolo, Francesco Gai, Laura Gasco, Konstantinos Ar. Kormas, Eleni Mente, Eleni Nikouli, Stavros Chatzifotis, Antonopoulou, Efthimia, Nikouli, Eleni, Piccolo, Giovanni, Gasco, Laura, Gai, Francesco, Chatzifotis, Stavro, Mente, Eleni, and Kormas, Konstantinos Ar
- Subjects
Mealworm ,Firmicutes ,insect meal ,Fish farming ,Zoology ,Aquatic Science ,Gut flora ,replacement ,Bacteria, Diet, FishGut, Insect meal, Replacement, Aquaculture ,03 medical and health sciences ,Fish meal ,Sea bass ,030304 developmental biology ,fish ,0303 health sciences ,Bacteria ,biology ,Bacteroidetes ,04 agricultural and veterinary sciences ,biology.organism_classification ,aquaculture ,040102 fisheries ,gut ,0401 agriculture, forestry, and fisheries ,Dicentrarchus ,diet ,FishGut - Abstract
The aquaculture industry is currently looking for alternative, sustainable diets that provide similar or better growth for the reared species. We investigated whether replacing fishmeal with yellow mealworm (Tenebrio molitor) meal in the supplied diets of the gilthead sea bream (Sparus aurata), European sea bass (Dicentrarchus labrax) and rainbow trout (Oncorhynchus mykiss) causes similar shifts in the bacterial gut communities of these farmed fish species. The diversity of the gut bacterial 16S rRNA gene revealed the presence of 598 operational taxonomic units (OTUs) belonging to all of the major phyla known to exist in the gut of these three fish species, such as Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria. Although no statistically significant differences of diversity indices in all three species was found, there was a differential shift in the dominant bacteria in the gut of each species before and after the dietary meal replacement. In S. aurata and D. labrax diversity indices remained practically unchanged before and after the replacement, while for O. mykiss the five-fold increase of the Simpson dominance D index and the almost two-fold decrease of the Shannon H index, suggested that a more specialized gut bacterial community was favoured for this species after the replacement. Also, this replacement resulted in the occurrence of higher number of OTUs which were absent before the replacement in the gut of S. aurata (62.2% of all its OTUs) and D. labrax (60.0% of all its OTUs) compared to O. mykiss (33.0% of all its OTUs) suggesting that insect meal replacement resulted in novel nutritional niches in the gut of S. aurata and D. labrax compared to O. mykiss. Our results indicate that the most desirable fish diet substitution differentially affects the gut microbiota in different hosts, implying that a species-specific tailor-made approach in diet manipulations should be considered in the future.
- Published
- 2019
36. The lesser mealworm Alphitobius diaperinus : a noxious pest or a promising nutrient source?
- Author
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Ioannis T. Karapanagiotidis, Eleni Mente, Christos I. Rumbos, and Christos G. Athanassiou
- Subjects
0106 biological sciences ,Mealworm ,Ecology ,biology ,business.industry ,Alphitobius diaperinus ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,Management, Monitoring, Policy and Law ,Aquatic Science ,biology.organism_classification ,040201 dairy & animal science ,01 natural sciences ,Toxicology ,010602 entomology ,Nutrient ,Aquaculture ,PEST analysis ,business - Published
- 2018
37. Configuration of Gut Microbiota Structure and Potential Functionality in Two Teleosts under the Influence of Dietary Insect Meals
- Author
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Efthimia Antonopoulou, Eleni Mente, Maria Lazarina, Stavros Chatzifotis, Nikolas Panteli, Maria Mastoraki, and Konstantinos Ar. Kormas
- Subjects
0301 basic medicine ,Microbiology (medical) ,Hermetia illucens ,Firmicutes ,alternative animal feeds ,Zoology ,Gut flora ,Microbiology ,Article ,03 medical and health sciences ,sustainable aquaculture ,Microbial ecology ,Sparus aurata ,Virology ,Dicentrarchus labrax ,KEGG ,16S rRNA ,lcsh:QH301-705.5 ,Illumina dye sequencing ,Tenebrio molitor ,metagenomics ,biology ,gut microbiota ,04 agricultural and veterinary sciences ,biology.organism_classification ,030104 developmental biology ,lcsh:Biology (General) ,Metagenomics ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Musca domestica ,Proteobacteria - Abstract
Insect meals are considered promising, eco-friendly, alternative ingredients for aquafeed. Considering the dietary influence on establishment of functioning gut microbiota, the effect of the insect meal diets on the microbial ecology should be addressed. The present study assessed diet- and species-specific shifts in gut resident bacterial communities of juvenile reared Dicentrarchus labrax and Sparus aurata in response to three experimental diets with insect meals from three insects (Hermetia illucens, Tenebrio molitor,Musca domestica), using high-throughput Illumina sequencing of the V3–V4 region of the 16S rRNA gene. The dominant phyla were Firmicutes, Proteobacteria and Actinobacteria in all dietary treatments. Anaerococcus sp., Cutibacterium sp. and Pseudomonas sp. in D. labrax, and Staphylococcus sp., Hafnia sp. and Aeromonas sp. in S. aurata were the most enriched shared species, following insect-meal inclusion. Network analysis of the dietary treatments highlighted diet-induced changes in the microbial community assemblies and revealed unique and shared microbe-to-microbe interactions. PICRUSt-predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly differentiated, including genes associated with metabolic pathways. The present findings strengthen the importance of diet in microbiota configuration and underline that different insects as fish feed ingredients elicit species-specific differential responses of structural and functional dynamics in gut microbial communities.
- Published
- 2021
- Full Text
- View/download PDF
38. Post-Prandial Amino Acid Changes in Gilthead Sea Bream
- Author
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Nikolaos Vlahos, Eleni Mente, R Barnes, Chris G. Carter, and I. Nengas
- Subjects
Veterinary medicine ,digestion ,Article ,03 medical and health sciences ,Nutrient ,Fish meal ,SF600-1100 ,Food science ,Essential amino acid ,030304 developmental biology ,chemistry.chemical_classification ,fish ,0303 health sciences ,Meal ,amino acids ,aquafeeds ,General Veterinary ,Chemistry ,digestive, oral, and skin physiology ,04 agricultural and veterinary sciences ,Metabolism ,Amino acid ,single meal ,QL1-991 ,aquaculture ,Plant protein ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Animal Science and Zoology ,Digestion ,Zoology - Abstract
Simple Summary Using combinations of plant protein concentrates and EAA supplementation, high levels of replacement (50–75% of fishmeal protein) have been achieved in gilthead sea bream without affecting the growth performance or quality traits. It was confirmed in this study that 16% replacement of marine protein with plant protein meets the amino acid needs of sea bream. The results of the present study suggest the need to further investigate tissue-specific and species-specific responses in the timing and ability to regulate metabolism due to dietary nutrient utilization. Abstract Following a meal, a series of physiological changes occurs in fish as they digest, absorb and assimilate ingested nutrients. This study aims to assess post-prandial free amino acid (FAA) activity in gilthead sea bream consuming a partial marine protein (fishmeal) replacement. Sea bream were fed diets where 16 and 27% of the fishmeal protein was replaced by plant protein. The essential amino acid (EAA) composition of the white muscle, liver and gut of sea bream was strongly correlated with the EAA composition of the 16% protein replacement diet compared to the 27% protein replacement diet. The mean FAA concentration in the white muscle and liver changed at 4 to 8 h after a meal and was not different to pre-feeding (0 h) and at 24 h after feeding. It was confirmed in this study that 16% replacement of marine protein with plant protein meets the amino acid needs of sea bream. Overall, the present study contributes towards understanding post-prandial amino acid profiles during uptake, tissue assimilation and immediate metabolic processing of amino acids in sea bream consuming a partial marine protein replacement. This study suggests the need to further investigate the magnitude of the post-prandial tissue-specific amino acid activity in relation to species-specific abilities to regulate metabolism due to dietary nutrient utilization.
- Published
- 2021
39. Evaluation of various commodities for the development of the yellow mealworm, Tenebrio molitor
- Author
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Eleni Mente, Christos G. Athanassiou, Pier Psofakis, Christos I. Rumbos, and Ioannis T. Karapanagiotidis
- Subjects
0106 biological sciences ,0301 basic medicine ,Mealworm ,Farms ,Animal feed ,Science ,media_common.quotation_subject ,01 natural sciences ,Animal origin ,Article ,Protein content ,03 medical and health sciences ,Nutrient ,parasitic diseases ,Developmental biology ,Edible Insects ,Animals ,Food science ,Tenebrio ,media_common ,Larva ,Multidisciplinary ,biology ,Reproduction ,fungi ,Nutrients ,biology.organism_classification ,Animal Feed ,010602 entomology ,030104 developmental biology ,Medicine ,Composition (visual arts) ,Plant sciences - Abstract
We evaluated the suitability of forty-four commodities (i.e., cereal flours and meals, non-flour, cereal commodities, legumes and various commodities of vegetative and animal origin) as oviposition and feeding substrates for the yellow mealworm, Tenebrio molitor. Τen T. molitor adults were introduced in plastic vials containing 30 g of each commodity. At the end of the 1 week period, all adults were removed, and mortality was determined; then the vials were further incubated for additional 9 weeks. After this time, the vials were opened, and the larvae of each vial were separated from the feeding substrate, counted and weighed as a group. The efficiency of ingested food conversion was calculated for each substrate. Finally, proximate composition was calculated to determine the nutrient components of the feeding substrates tested and the T. molitor larvae that fed on various selected substrates. In general, adult reproduction was clearly favoured by most amylaceous substrates tested, which was in contrast to the tested legumes on which fewer offspring were produced. Similar effects were observed for larval development. Feeding on selected substrates exerted an impact on the nutrient composition of T. molitor larvae, with a high protein content of the substrate usually resulting in a high protein content of the larvae.
- Published
- 2019
40. Insect-Based Feed Ingredients for Aquaculture: A Case Study for Their Acceptance in Greece
- Author
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Georgios Vlontzos, Christos G. Athanassiou, Ioannis T. Karapanagiotidis, Christos I. Rumbos, and Eleni Mente
- Subjects
Ecological footprint ,business.industry ,Science ,Fish farming ,Fishing ,0402 animal and dairy science ,Stakeholder ,insect-based aquafeeds ,04 agricultural and veterinary sciences ,Biology ,Fish stock ,public perceptions ,040201 dairy & animal science ,Article ,Agricultural science ,aquaculture ,Aquaculture ,Insect Science ,Sustainability ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,%22">Fish ,survey ,business - Abstract
Simple Summary Since 2017, insects can be used as ingredients in aquafeeds in the EU. However, insect-based aquafeeds are still not broadly accepted by European aquaculture companies. Understanding the beliefs of people associated with the aquaculture sector on the use of insect-based fish diets could assist their adoption. In the present study, we ran a survey among the participants of an aquaculture conference held in Greece, in order to ask them what they think regarding the inclusion of insect meal in aquafeeds. Furthermore, we inquired nine Greek aquaculture and aquafeed companies about this issue. Greece is among the largest farmed fish producers in the EU; however, there are currently no data available on the acceptance of insect-based aquafeeds in Greece. Based on our results, the majority of the respondents were aware and in favor of the inclusion of insects in aquafeeds, mainly due to their potential to lower fishing pressure on wild fish stocks used for fishmeal production and enhance the ecological footprint and sustainability of aquaculture. Moreover, six out of nine companies were favorably disposed towards the use of insects in fish diets and four of them were willing to produce or use such diets. Further studies are warranted towards this direction. Abstract Although the inclusion of insects in fish diets is officially allowed in the EU since 2017, insect-based aquafeeds have not been widely adopted by the European aquaculture sector. In order to investigate the perceptions related with adoption trends, it is critical to explore the beliefs of people associated with the aquaculture sector on the use of insects in farmed fish diets. A survey was conducted among 228 participants of an aquaculture conference to explore their perceptions on the inclusion of insect meal in fish diets. Additionally, we investigated the attitudes of nine companies operating in the aquaculture and aquafeed sector in Greece that attended the conference towards this direction. The findings of the conference survey provide evidence that there is a wide-range awareness and acceptance regarding the use of insect-based feeds in farmed fish diets among the respondents. This is mainly driven by the expectations for the decline in fishing pressure on wild fish stocks, the reduction of the ecological footprint and the enhancement of the sustainability of the aquaculture sector. The results of the stakeholder survey show that six out of the nine companies that participated in the survey are favorably disposed towards the use of insect-based feeds. Specifically, four of them stated that they would produce or use aquafeeds based on insects. However, the results highlight the need for further research on the implementation of the wider adoption of insect-based feeds in aquaculture. The present study provides some first insights into the use of insect-based aquafeeds in Greece, for which there are no data available.
- Published
- 2021
41. Digestive Enzyme Activity during Initial Ontogeny and after Feeding Diets with Different Protein Sources in Zebra Cichlid,Archocentrus nigrofasciatus
- Author
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Nikolaos Vlahos, Enric Gisbert, Eleni Mente, Mikhail M. Solovyev, and Guiomar Rotllant
- Subjects
0301 basic medicine ,biology ,Ecology ,Hatching ,Ontogeny ,Zoology ,04 agricultural and veterinary sciences ,Aquatic Science ,biology.organism_classification ,Enzyme assay ,03 medical and health sciences ,030104 developmental biology ,Fish meal ,Cichlid ,Digestive enzyme ,040102 fisheries ,biology.protein ,Archocentrus ,0401 agriculture, forestry, and fisheries ,Digestion ,Agronomy and Crop Science - Abstract
This study aims to describe changes in the activity of digestive enzymes of the zebra cichlid, Archocentrus nigrofasciatus, from hatching until 30 d after hatch (d.a.h.), and to evaluate the effects of feeding diets with different levels of fishmeal (FM) substitution with alternative nonanimal protein sources from 30 d.a.h. up to the age of 60 d.a.h. Results indicated that the developmental patterns of digestive enzymes from the exocrine pancreas and intestine are similar to those of other phylogenetically close cichlids, although they seemed to develop faster than other species as indicated by the peaks in enzyme activity, which were detected at younger stages of development. The 100% FM replacement with different alternative nonanimal protein sources had a negative impact on the growth performance of A. nigrofasciatus juveniles, whereas fish fed the diet with a 50% FM replacement showed similar results to those fed the 100% FM diet. Fish showing the lowest growth rate had also the lowest enzyme activity, especially in relation to the intestinal brush border enzymes. This study assesses the digestive capabilities and nutritional condition of the zebra cichlid fish and provides knowledge on the potential for FM substitution in their feeds.
- Published
- 2016
42. Gut microbial communities associated with the molting stages of the giant freshwater prawn Macrobrachium rosenbergii
- Author
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Eleni Mente, Hugh S. Hammer, Eleni Nikouli, Andrew T. Gannon, and Konstantinos Ar. Kormas
- Subjects
0301 basic medicine ,Abiotic component ,biology ,Macrobrachium rosenbergii ,Ecology ,business.industry ,Aquatic animal ,Aquatic Science ,biology.organism_classification ,Crustacean ,03 medical and health sciences ,030104 developmental biology ,Aquaculture ,Prawn ,Microbiome ,business ,Shellfish - Abstract
The reciprocal interaction between host organisms' physiology and their gut microorganism community is of great interest in aquatic animal biology and aquaculture but for crustaceans, it remains understudied. This study enhances our understanding of this community of microorganisms as it changes during the molt cycle. Because crustaceans shed a major component of their gut, and the associated microbiome, with each molt this adds a level of complexity heretofore unexamined. We have identified the bacterial communities that are affected by the changing gut environment and that may in turn, exert some control over aspects of the molt cycle. We investigated the structural changes of the resident gut bacterial communities, using the diversity of the 16S rRNA gene by 454 pyrosequencing, in the freshwater prawn Macrobrachium rosenbergii during its four-stage molt cycle. The number of bacterial operational taxonomic units (OTUs) increased from stages A to C. Stage C the intermolt and longest lasting stage was different in the gut bacterial community structure having the (a) highest number of total OTUs, (b) highest number of unique and newly introduced OTUs, (c) highest percentage of estimated specialists OTUs, i.e. that are more ecologically restricted. Moreover, stage C was characterized by greater contribution of Actinobacteria-related and unaffiliated OTUs. The most dominant OTUs found in stage C of the gut of M. rosenbergii were related to microorganisms involved in fermentation and food material processing originating from similar, i.e. gut, or habitats of terrestrial and freshwater animals. Thus, the distinct gut bacterial communities found in molting stage C corroborate with the physiological significance of this molting stage. The abiotic factors and the exact role of the corresponding specific bacterial communities in the animal's physiology and growth are areas that remain to be elucidated. Statement of relevance A thorough understanding of M. rosenbergii digestive physiology is essential to achieve better growth performance when cultured. This paper provides information that could be useful for developing effective strategies to manipulate gut microbial communities to promote prawn's growth and health and improve aquaculture productivity.
- Published
- 2016
43. An Experimental Brackish Aquaponic System Using Juvenile Gilthead Sea Bream (Sparus aurata) and Rock Samphire (Crithmum maritimum)
- Author
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Vlasoula Bekiari, Eleni Mente, Paraskevi Stathopoulou, Nikolaos Vlahos, Efthimia Antonopoulou, Efi Levizou, Konstantinos Ar. Kormas, Nikos Krigas, and Panagiotis Berillis
- Subjects
HSPs ,Geography, Planning and Development ,TJ807-830 ,Management, Monitoring, Policy and Law ,water reuse ,TD194-195 ,Renewable energy sources ,03 medical and health sciences ,Animal science ,MAPKs ,Heat shock protein ,Crithmum ,Halophyte ,Juvenile ,Aquaponics ,GE1-350 ,rock samphire ,030304 developmental biology ,gilt-head juvenile sea bream ,0303 health sciences ,Brackish water ,biology ,Environmental effects of industries and plants ,Renewable Energy, Sustainability and the Environment ,04 agricultural and veterinary sciences ,Euryhaline ,biology.organism_classification ,Environmental sciences ,Food products ,040102 fisheries ,aquaponics ,0401 agriculture, forestry, and fisheries ,brackish water - Abstract
Brackish aquaponics using Mediterranean fish and plants provides an alternative opportunity for a combined production of high-quality food products with high commercial and nutritional value. This is the first study that investigates the effect of two different salinities (8 and 20 ppt) on growth and survival of Sparus aurata and Crithmum maritimum along with the cellular stress pathways using the activation of heat shock proteins (HSPs) and mitogen-activated protein kinase (MAPK) protein family members and the water bacterial abundance. In total, 156 fish were used (average initial weight of 2.55 g, length of 5.57 cm) and 36 plants (average initial height of 8.23 cm) in floating racks above the 135 L fish tanks. Survival rate for both organisms was 100%. C. crithmum grew better at 8 ppt (t-test, p <, 0.05). The growth rate of S. aurata was similar for both treatments (p >, 0.05). HSPs and MAPK were differentially expressed, showing tissue-specific responses. The average bacterial abundance at the end of the experiment was higher (p <, 0.05) in the 20 ppt (18.6 ±, 0.91 cells ×, 105/mL) compared to the 8 ppt (6.8 ±, 1.9 cells ×, 105/mL). The results suggest that the combined culture of euryhaline fish and halophytes provides good quality products in brackish aquaponics systems.
- Published
- 2019
- Full Text
- View/download PDF
44. Skeletal Deformity of Scoliosis in Gilthead Seabreams (Sparus aurata): Association with Changes to Calcium-Phosphor Hydroxyapatite Salts and Collagen Fibers
- Author
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Charitini Theochari, Eleni Mente, Panagiotis Berillis, Chrisoula Apostologamvrou, Dimitris Vafidis, Vaia Boursiaki, and Stefanos Zaoutsos
- Subjects
0106 biological sciences ,collagen ,Gilthead Seabream ,lcsh:Hydraulic engineering ,Geography, Planning and Development ,chemistry.chemical_element ,Scoliosis ,Aquatic Science ,Calcium ,01 natural sciences ,Biochemistry ,Collagen fibril ,lcsh:Water supply for domestic and industrial purposes ,lcsh:TC1-978 ,medicine ,Deformity ,Sparus aurata ,Skeletal deformity ,Water Science and Technology ,lcsh:TD201-500 ,scoliosis ,calcium ,010604 marine biology & hydrobiology ,vertebra column ,04 agricultural and veterinary sciences ,Anatomy ,medicine.disease ,musculoskeletal system ,phosphor ,medicine.anatomical_structure ,chemistry ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Fish growth ,medicine.symptom ,Vertebral column - Abstract
The development of skeletal deformities in seabream farming affects fish growth, survival, and production costs. Collagen distribution in different fish tissues might be correlated with swimming behavior. This study investigates whether scoliosis in seabreams is associated with changes to calcium-phosphor hydroxyapatite salts and collagen fibril morphology. Samples of decalcified vertebrae of scoliotic and non-scoliotic seabreams were examined with transmission electron microscopy and collagen micrographs were taken and analyzed. The mineral content, modulus of elasticity, and morphology of the vertebrae were also determined. The results indicated that fish with scoliosis had significant smaller mean vertebral collagen fibril diameters than the controls. Vertebrae in abdominal and caudal regions of the scoliotic seabreams appeared to be smaller than the respective vertebrae of the non-deformed seabreams. The calcium (Ca) and phosphorus (P) amounts of vertebrae of both scoliotic and non-scoliotic seabreams were not affected by the scoliosis deformity. The modulus of elasticity showed that the vertebrae from seabreams with scoliosis were more flexible than the vertebrae from seabreams without any skeletal deformity. The mechanical properties of bone are crucially dependent on collagen structure. Hence, how the vertebral column collagen of juvenile fish is related to the mechanism of deformities requires further investigation in order to provide a risk-reducing strategy to increase fish performance in aquaculture.
- Published
- 2019
- Full Text
- View/download PDF
45. Introduction to the special issue on 'European aquaculture development since 1993 : the benefits of aquaculture to Europe and the perspectives of European aquaculture production'
- Author
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Eleni Mente and Aad C. Smaal
- Subjects
0106 biological sciences ,Regional center Yerseke ,Regiocentrum Yerseke ,business.industry ,010604 marine biology & hydrobiology ,010501 environmental sciences ,Aquatic Science ,01 natural sciences ,Fishery ,Aquaculture ,Organic aquaculture ,Life Science ,Production (economics) ,business ,Agronomy and Crop Science ,0105 earth and related environmental sciences - Published
- 2016
46. Heat shock protein (HSP) expression and mitogen-activated protein kinase (MAPK) phosphorylation during early embryonic developmental stages of the Gilthead sea bream (Sparus aurata)
- Author
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Eleni Mente, Efthimia Antonopoulou, Elena Sarropoulou, Konstantinos Feidantsis, and Chrysoula Roufidou
- Subjects
0301 basic medicine ,Environmental Engineering ,Aquatic Science ,Oceanography ,ERKs ,03 medical and health sciences ,Sparus aurata ,Heat shock protein ,Gene expression ,HSP90 ,0501 psychology and cognitive sciences ,050102 behavioral science & comparative psychology ,Ecology, Evolution, Behavior and Systematics ,HSP70 ,Mapk phosphorylation ,JNKs ,biology ,Kinase ,05 social sciences ,Hsp90 ,Embryonic stem cell ,early development ,Hsp70 ,Cell biology ,030104 developmental biology ,Mitogen-activated protein kinase ,biology.protein ,p38MAPK - Abstract
Both heat shock proteins (HSPs), which have key roles in vital cell functions, as well as members of the mitogen-activated protein kinases (MAPKs), which adjust gene expression by transducing cellular signals to the nucleus, are necessary for normal embryonic development in vertebrates. Therefore, protein expression levels of HSP70 and HSP90 and the activation of members of the MAPK protein family, such as p38 MAPK, ERKs, and JNKs were studied in the early developmental stages of the Gilthead sea bream, Sparus aurata Linnaeus, 1758. The protein expression of HSP70 and the phosphorylation ratio of JNKs remained at equal levels at all examined developmental stages, while the other examined proteins exhibited a differential profile. HSP90 levels were mostly increased at the 16-cell stage and towards the morula stages, and the lowest values were observed at the two- to four-cell and one-half epiboly stages. While p38 MAPK phosphorylation ratio exhibited increased values mostly in the early developmental stages, the opposite was observed concerning ERK phosphorylation ratio, where increased values were observed in the later embryonic stages (high blastula to one-half epiboly stages). These differential profiles of the examined protein expression levels highlight the importance of these proteins during embryogenesis and pave the way for further research to unveil their distinct role in early development.
- Published
- 2018
47. Impact of sea lice (Caligus rogercresseyi) infection levels on skin transcriptome in Atlantic salmon (Salmo salar)
- Author
-
Samuel A.M. Martin, Eleni Mente, Alex Douglas, Elżbieta Król, and R. Zindrili
- Subjects
Transcriptome ,Caligus rogercresseyi ,Environmental Chemistry ,Zoology ,RNA-Seq ,General Medicine ,Aquatic Science ,Biology ,Salmo ,biology.organism_classification - Published
- 2019
48. Histology of Goblet Cells in the Intestine of the Rainbow Trout Can Lead to Improvement of the Feeding Management
- Author
-
Panagiotis Berillis and Eleni Mente
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,Open access publishing ,Physiology ,Rainbow trout ,Histology ,010501 environmental sciences ,Biology ,01 natural sciences ,0105 earth and related environmental sciences - Published
- 2017
49. Dietary differences are reflected on the gut prokaryotic community structure of wild and commercially reared sea bream (Sparus aurata)
- Author
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Alexandra Meziti, Athanasios Frentzos, Konstantinos Ar. Kormas, and Eleni Mente
- Subjects
Firmicutes ,Molecular Sequence Data ,Fisheries ,Zoology ,Animals, Wild ,Biology ,Gut flora ,Microbiology ,Actinobacteria ,Sparus aurata ,Animals ,16S rRNA ,Phylogeny ,Original Research ,Bacteria ,Ecology ,Microbiota ,Bacteroidetes ,biology.organism_classification ,16S ribosomal RNA ,Archaea ,Animal Feed ,Sea Bream ,Gastrointestinal Tract ,pyrosequencing ,Seafood ,gut ,Proteobacteria - Abstract
We compared the gut prokaryotic communities in wild, organically-, and conventionally reared sea bream (Sparus aurata) individuals. Gut microbial communities were identified using tag pyrosequencing of the 16S rRNA genes. There were distinct prokaryotic communities in the three different fish nutritional treatments, with the bacteria dominating over the Archaea. Most of the Bacteria belonged to the Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. The number of bacterial operational taxonomic units (OTUs) was reduced from the wild to the conventionally reared fish, implying a response of the gut microorganisms to the supplied food and possibly alterations in food assimilation. The dominant bacterial OTU in all examined fish was closely related to the genus Diaphorobacter. This is the first time that a member of the β-Proteobacteria, which dominate in freshwaters, are so important in a marine fish gut. In total the majority of the few Archaea OTUs found, were related to methane metabolism. The inferred physiological roles of the dominant prokaryotes are related to the metabolism of carbohydrates and nitrogenous compounds. This study showed the responsive feature of the sea bream gut prokaryotic communities to their diets and also the differences of the conventional in comparison to the organic and wild sea bream gut microbiota.
- Published
- 2014
50. Shift in Trophic Level of Mediterranean Mariculture Species
- Author
-
Konstantinos I. Stergiou, Athanassios C. Tsikliras, Daniel Pauly, Eleni Mente, and Nikolaos Adamopoulos
- Subjects
Ecology ,biology ,Fish farming ,Common pandora ,Pagellus ,Dentex dentex ,Pagrus ,biology.organism_classification ,Fishery ,Fish meal ,Mariculture ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Trophic level - Abstract
The mean trophic level of the farmed fish species in the Mediterranean has been increasing. We examined the farming-up hypothesis (i.e., the increase in the production of high-trophic-level species) in the Mediterranean by determining the trophic level of the aquafeeds (i.e., what the fish are fed) of 5 species of farmed marine fishes: common dentex (Dentex dentex), common pandora (Pagellus erythrinus), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and red porgy (Pagrus sp.). The mean trophic level of aquafeed used in mariculture from 1950 to 2011 was higher (3.93) than the prey farmed fish consume in the wild (3.72) and increased at a faster rate (0.48/decade) compared with that based on their diets in the wild (0.43/decade). Future expected replacement of the fishmeal and oil in aquafeeds by plant materials may reverse the farming-up trend, although there are a number of concerns regarding operational, nutritional, environmental, and economic issues. The farming-up reversal can be achieved in an ecologically friendly manner by facilitating the mariculture of low-trophic-level fishes and by promoting high efficiency in the use of living marine resources in aquafeeds.
- Published
- 2014
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