Multi-trophic Aquaculture System Research Articles

Screening of Chaetomorpha linum Lipidic Extract as A New Potential Source of Bioactive Compounds.

Recent studies have shown that marine algae represent a great source of natural compounds with several properties. The lipidic extract of the seaweed Chaetomorpha linum (Chlorophyta, Cladophorales), one of the dominant species in the Mar Piccolo of Taranto (Mediterranean, Ionian Sea), revealed an antibacterial activity against Vibrio ordalii and Vibrio vulnificus, common pathogens in aquaculture, suggesting its potential employment to control fish and shellfish diseases due to vibriosis and to reduce the public health hazards related to antibiotic use in aquaculture. This extract showed also an antioxidant activity, corresponding to 170.960 ± 16. mmol Trolox equivalent/g (oxygen radical absorbance capacity assay—ORAC) and to 30.554 ± 2.30 mmol Trolox equivalent/g (Trolox equivalent antioxidant capacity assay—TEAC). The chemical characterization of the extract, performed by 1D and 2D NMR spectroscopy, highlighted the presence of free, saturated (SAFAs), unsaturated (UFAs) and polyunsaturated (PUFAs) fatty acids. The high content of ω-6 and ω-3 PUFAs confirmed also by gas chromatography indicates the potentiality of this algal species in the production of fortified food. The antibacterial activity seems related to the presence of linolenic acid present at high density, while the antioxidant activity could be likely ascribable to molecules such as carotenoids and chlorophylls (characterized also by thin-layer chromatography), known for this property. The presence of polyhydroxybutyrate, a biopolymer with potentiality in the field of biodegradable bioplastics was also detected. The exploitation of C. linum for a future biotechnological application is also encouraged by the results from a first attempt of cultivating this species in an integrated multi-trophic aquaculture (IMTA) system.

Application of polychaetes in (de)coupled integrated aquaculture: production of a high-quality marine resource

Capitella sp. and Ophryotrocha craigsmithi received a diet of salmon feces to evaluatetheir potential to convert fish waste into valuable marine products, e.g. ingredients for fishfeed formulation. Production rate and body composition (focusing on fatty acid [FA] profiles)were determined for polychaetes fed fresh, acid-preserved or oven-dried salmon feces to evaluatetheir application in (de)coupled integrated multi-trophic aquaculture (IMTA) systems. Coupledproduction refers to direct integration of fish and polychaetes within the same (eco)system,while in decoupled production, units can be spatially or functionally separated. For decoupledproduction, preservation of fish waste is recommended. Although diets contained relatively lowpolyunsaturated FA (PUFA) levels (5−9% of total FAs), both species were rich in PUFAs (>30%of total FAs) and contained the essential FAs for fish. Feeding Capitella sp. the acid-preserveddiet enriched its FA profile. Accumulation of PUFAs, de novo synthesis and/or transfer via bacterialbiomass could have played a role in the upregulation of PUFA content. Amino acid profilesindicated that these polychaetes contained the amino acids essential for fish. Highest growth forboth species was observed when fed fresh feces, whereas preserved diets resulted in negativegrowth rates for O. craigsmithi, suggesting an important role of microbes in polychaete diets.Our results indicate that both species are potential valuable marine products. Given growth rateswith different diets, O. craigsmithi seems more suitable for integration in coupled systems, whileCapitella sp. is interesting for both coupled and decoupled integrated systems

Stress tolerance and photoadaptation to solar radiation in Rhodymenia pseudopalmata (Rhodophyta) through mycosporine-like amino acids, phenolic compounds, and pigments in an Integrated Multi-Trophic Aquaculture system

Rhodymenia pseudopalmata lives in the intertidal zone receiving high doses of solar radiation, including the potentially harmful UVR. Previous studies proved it ability to adapt to different artificial light intensities and salinity concentrations. The aim of this study was to describe the differences on the Mycosporine-like amino acids (MAAs), phenolic compounds, and pigments of R. pseudopalmata due to exposure to high solar radiation. Vegetative thalli were exposed to solar radiation using a Solar Exposure Chambers System (SECS) under an Integrated Multi-Trophic Aquaculture (IMTA) approach with marine fish culture. Samples from natural populations in Playa de Carmen, Mexico were included as reference. The biosynthesis of MAAs, and phenolic compounds were stimulated as a response to the stress caused by the exposure to high solar irradiation. Liquid Chromatography-Mass Spectrometry (LC-MS) revealed seven MAAs and their precursor deoxygadusol. Five MAAs were partially characterized through MS2 and fragmentation patterns suggested a common fragmentation pattern pathway. After seven days (D7), the MAAs total content was significant five-fold higher compared to wild populations (0.26 ± 0.1 mg g−1 DW). The Individual composition increased from four MAAs at D0, up to eight at D7, including deoxygadusol, palythene and usujirene, MAAs with high antioxidant activity. At D7, phenolic compounds increased up to 20%, and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity reduced the IC50 to 4.0 ± 0.6 mg mL−1. The pigment content, Phycoerythrin (PE):Chl-a, and MAAs:Chl-a ratios might confer a unique photoprotection role from PE and MAAs to Chl-a. Similarly, Fv/Fm which was adapted to the variations of Photosynthetic Active Radiation (PAR) indicated a process of dynamic photoinhibition. Overall, our results evidenced the ability of this species to tolerate the stress to high solar irradiance and suggested the photoadaptation of the thalli. Farming possibilities, expected MAAs productivity, potential applications of MAAs and ecological considerations are also discussed.

Bio mitigation based on integrated multi trophic aquaculture in temperate coastal waters: practice, assessment, and challenges

In general, aquaculture wastes from traditional aquatic organism cultivation rapidly deteriorate the water quality of the surrounding ecosystems, endangering animals living in the area. The integrated multi-trophic aquaculture (IMTA) system is a bio-mitigation strategy to alleviate the adverse impacts caused by aquafarming pollutants on the environment and aquatic species. This study provides an overview of the IMTA system, explains the interactive processes among the different trophic levels, summarizes the major practices being followed around the temperate coastal waters with a field case study in Japan, and discusses the assessment of IMTA bio-mitigation efficiency through experimental greatly dependent on the customs and market values in the local IMTA practice. Bio-mitigation efficiency acquired in a land-based experiment exhibits its limitation in approach and conducts a comprehensive analysis on the possibility of applying numerical models to evaluate IMTA effectiveness. The selection of a suitable candidate organism is estimating that in the same or different culture conditions with various biomasses of extractive species. However, in open water experiments, it is difficult to evaluate the bio-mitigation effect of extractive species because the initial biomass ratio (IBR) of the extractive to target species is too small. Alternatively, the possibility of applying existing numerical models to assess IMTA is relatively low. In conclusion, an optimally designed large-scale IMTA experiment is required, in which the IBR of the extractive to target species is adequately considered, and a full-scale IMTA model should be further improved with a database of individual-based submodels for IMTA candidate organisms. Normal 0 7.8 磅 0 2 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:普通表格; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;}

Implementation of lyapunov method to analyze the stability of pompano, cantang growth and nutrition dynamical systems

This study aims to determine the analysis stability of dynamical model of pompano, cantang growth, and nutrition on the Integrated Multi-Trophic Aquaculture (IMTA) systems by using the Lyapunov method. The analytical analysis was given to discuss the dynamic behavior of this model. Global stability analysis was performed based on the Lyapunov theory, i.e., construction the function V (x) that is a definite positive scalar function and the derivative of V (x) is defa inite negative. As a verification of the Lyapunov method, we conducted numerical simulations with data taken from IMTA systems in Sea Farming region, Kepulauan Seribu, Indonesia.

In vitro evaluation of macroalgae as unconventional ingredients in ruminant animal feeds

Macroalgae may comprise an alternative feed resource to ruminant animals contributing to a more sustainable livestock production. A wide range of effects on the ruminal fermentation parameters have been reported in short-term in vitro studies, but longer term fermentations are scarce and their effects on the rumen function remain largely unknown. Hypothesizing that ruminal fermentation might be differently affected by the extent of the in vitro fermentations, the present study investigated the effects of Ulva rigida, Gracilaria vermiculophylla, and Saccharina latissima inclusion on gas and methane production, on fermentation parameters, digestibility, and bacterial fatty acids in a RUSITEC system, after a potential adaptation of the rumen microbes to the experimental treatments. Green (U. rigida), red (G. vermiculophylla) or brown (S. latissima) macroalgae produced in an integrated multitrophic aquaculture system were included at 25% (dry matter basis) in a single total mixed ration (TMR) diet and incubated in a RUSITEC system along with a control (100% TMR) over an experimental period of 8 days, following an adaptation period of 7 days. Macroalgae inclusion did not affect gas and methane production. Volatile fatty acids production was not affected by macroalgae but its profile was; the proportion of acetic acid increased and that of propionic acid and butyric acid decreased. Compared to control, macroalgae inclusion only reduced the fermentation efficiency by 1%. The inclusion of macroalgae increased the dry matter and organic matter digestibility, decreased the crude protein digestibility, and did not affect the neutral detergent fiber digestibility. The odd- and branched-fatty acids profile of the bacteria associated to the solid or the liquid fractions was not affected by macroalgae inclusion. Overall, the absence of effects on rumen fermentation suggest U. rigida, G. vermiculophylla, and S. latissima to be suitable alternative feed ingredients to be used in ruminant nutrition up to 25% inclusion.

Oxytetracycline accumulation in the macroalgae Ulva: Potential risks for IMTA systems

Oxytetracycline (OTC) is one of the most used antibiotics in aquaculture. With the development of Integrated Multitrophic Aquaculture (IMTA) systems in order to mitigate some aquacultures' adverse effects, attention needs to be shifted to other co-cultured species that can also accumulate such pharmaceuticals and pose a risk to human consumption. Therefore, the present work evaluated the exposure of the seaweed Ulva to OTC at two realistic concentrations (0.040 and 0.120 mg L−1). Oxytetracycline degradation rates in seawater were dependent on the initial concentration but were not influenced by the presence of Ulva. The macroalgae presented good assimilation rates of OTC, with internal concentrations reaching 40.9934 ng g−1 WW for the lowest concentration tested and 108.6787 ng g−1 WW for the highest, with a steep decrease after 48 and 24 h, respectively. Nonetheless, concentrations were still half of the Maximum Residue Limit set for fish (100 μg kg−1) 48 h after C2 treatment. The highest dosage tested stimulated growth 96 h after the beginning of the trial, although some signs of decay could also be found in Ulva's fronds.

Culture of the seaweed Ulva ohnoi integrated in a Solea senegalensis recirculating system: influence of light and biomass stocking density on macroalgae productivity

A growth model was developed to optimize the management of multi-trophic aquaculture systems by analyzing the influence of light and biomass stocking density (SD) in the productivity of Ulva ohnoi fed with the effluents from Solea senegalensis culture tanks. Growth rates and productivity were determined in three flat bottom algae tanks with different incident photon irradiances (E0) (163, 280, and 886 μmol photons m−2 s−1), photoperiod 12:12 h, and with stocking densities ranging from 82 to 340 gdw m−2. The distribution of photon irradiance in the algae tanks was estimated as a function of the E0 and SD. The results obtained showed that the algae exposed to the highest E0 (886 μmol photons m−2 s−1) and SD below 170 gdw m−2 showed a strong decrease in their growth rate, together with morphological changes. The model proposed to estimate the specific growth rate (μNET), on the basis of E0 and SD, assumed that photosynthetic activity is dependent on the local photon flux density and, therefore, spatially distributed in the tank. Non-linear regression used to estimate the growth kinetic parameters showed a standard deviation of the distance between measured and fitted μNET data values equal to 0.011 day−1. In terms of biomass productivity per unit area (BPA), the model shows, for each E0 level, a trend to increase with SD, achieving a maximum BPA, where SD can be considered optimal, and decreasing for higher SD values. The optimal SD and the maximum BPA achievable can be also determined as a function of E0.

Is Ulva sp. able to be an efficient biofilter for mariculture effluents?

Nitrogenous compounds such as ammonia, nitrate, and dissolved organic nitrogen (DON) are the main waste components of marine fish pond effluents. These compounds are also regarded as the primary nitrogen sources for seaweed. Aiming at designing an efficient and cost-effective extractive biofilter for fishpond effluents, Ulva lactuca performance and the dynamics of dissolved inorganic (DIN) and DON uptake by this alga grown in the effluents of a land-based integrated multi-trophic aquaculture (IMTA) system were studied. Stocking densities of 1 and 3 kg m−2 were found to be optimal for yield along with specific growth rate (SGR) and protein content, respectively. The presence of ammonia inhibited nitrate uptake by U. lactuca and carbon limitation reduced SGR and yield. However, protein levels of U. lactuca tissue in a carbon-limited situation were higher than when unlimited carbon was made available. When compared with 3 kg m−2 stocking densities, the high C/N ratio in U. lactuca tissue cultured at 1 kg m−2 likely indicated carbon limitation. Ammonia assimilation rate was density dependent. At 1 kg m−2, ammonia uptake was relatively fast, at 4.31 μmole N h−1, and nitrate uptake started only 24 h after ammonia depletion, suggesting this period to be the time required for nitrate reductase (NR) synthesis in the algae tissue. At 2 kg m−2, ammonia uptake was 2.51 μmole N h−1 and nitrate uptake started 24 h after that observed in 1 kg m−2, suggesting that the lower ammonia threshold for uptake by the U. lactuca is around 1.4 μmole L−1. Contrary to 1 and 2 kg m−2 stocking densities, in the 3 kg m−2 stocking density, ammonia uptake was as low as 1.51 μmole N h−1 and no uptake of nitrate appeared to have taken place due to the presence of ammonia in the water. The additional ammonia in the water was found to be due to DON-ammonifying bacteria on the surface of U. lactuca thalli. In the 1ow stocking density, the additional ammonia was relatively low compared to that measured at the high algae density. In the light of the better understanding of the system dynamics achieved in our study, we hypothesize that a set of similar bioreactors using U. lactuca can intensify the system purification efficiency manifold.

Bioremediation of fishpond effluent and production of microalgae for an oyster farm in an innovative recirculating integrated multi-trophic aquaculture system

Integrated multi-trophic aquaculture (IMTA) systems are a promising solution for sustainable aquaculture combining nutrient recycling with increased biomass production. An innovative land-based recirculating aquaculture system (RAS) was studied in France for a 60-day experiment. It combined a European sea bass (Dicentrarchus labrax) RAS with two other production systems: high rate algal ponds (HRAP) with natural marine polyspecific algal assemblages, and oysters in separate open tanks. The objective was the assessment of: 1) the efficiency and the stability of the microalgae bioremediation of the effluent from a fish RAS in spring and summer, 2) the abundance and the diversity patterns of the microalgae biomass for consumption in the oyster compartment of the IMTA. Silicate was added every week after the beginning of the experiment for maintaining a Si:N:P molar ratio of 10:5:1 in the HRAP to encourage the growth of diatoms. The HRAP have an overall removal efficiency of 98.6 ± 0.2% for NO3-N, 98.0 ± 0.4% for NO2-N, 97.3 ± 0.7% for NH4-N and 96.1 ± 0.6% for PO4-P, with removal rates of 335.8 ± 0.8, 23.6 ± 0.2, 30.9 ± 0.2, and 22.3 ± 0.2 mg m−2 d−1, respectively. The concentration of total suspended solid (TSS) and chlorophyll a (chl a) increased during the experiment and reached maximum values on day 46 (135.3 ± 34.7 mg TSS l−1 and 0.42 ± 0.03 mg chl a l−1) after which the microalgae collapsed due to a CO2 limitation (pH ca. 10). Sequencing analysis revealed that the microalgae community was dominated by Tetraselmis sp. from day 1 to day 16 (45.7% to 73.8% relative abundance). From day 30 to day 43 the culture was dominated by diatoms, Phaeodactylum sp. (83.4% to 98.1% relative abundance). Although the stable carbon isotope signatures confirmed that the microalgae were consumed, oysters' growth was limited in the RAS-IMTA, suggesting that oysters were under stress or not fed enough.

KEYNOTE TALK The importance of amphipods: from taxonomy to applications

Event Abstract Back to Event KEYNOTE TALK The importance of amphipods: from taxonomy to applications Jose Manuel Guerra-García1* 1 University of Seville, Spain During the last years the annual rate of newly described amphipod species has significantly increased, including not only taxonomical information (both morphological and molecular) but also ecological and behavioural data. The active participation of amphipodologists in WoRMS is also remarkable. Important advances using amphipods as models in proteogenomic, transcriptomic and mitogenomic studies have been achieved throughout the last decade, and detailed studies dealing with invasive species, life histories, behaviour and trophic ecology have also been conducted. The progress in the use of amphipods as bioindicators and as resource in aquaculture is especially interesting. They have been used successfully in environmental programs for monitoring TBTs, heavy metals and organic pollution. Their high nutritional content (fatty acids omega 3 and proteins) makes them suitable as food for several species of commercial interest. Taking into account that they are mainly detritivorous, they have been proposed as elements of Integrate Multitrophic Aquaculture systems. Amphipods have also attracted the attention of different media during the last few years, and two amphipods, Liropus minusculus and Epimeria quasimodo have been among the top ten new species, in 2014 and 2018 respectively, selected from a total of ca. 15,000 species described annually. Despite the increasing interest in amphipod research, there is still a long way to go to understand and convey the importance of this group. Keywords: Amphipoda, Crustacea, Taxonomy, ecology & behavior, Bioindicator, Aquaculture Conference: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019. Presentation Type: Keynote talk Topic: Keynote lecture Citation: Guerra-García J (2019). KEYNOTE TALK The importance of amphipods: from taxonomy to applications. Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00003 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Aug 2019; Published Online: 27 Sep 2019. * Correspondence: Dr. Jose Manuel Guerra-García, University of Seville, Seville, Spain, jmguerra@us.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jose Manuel Guerra-García Google Jose Manuel Guerra-García Google Scholar Jose Manuel Guerra-García PubMed Jose Manuel Guerra-García Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Optimization of integrated multi-trophic aquaculture systems for the giant freshwater prawn Macrobrachium rosenbergii

Optimization of integrated multi-trophic aquaculture systems for the giant freshwater prawn Macrobrachium rosenbergii

Environmentally Friendly Valorization of Solieria filiformis (Gigartinales, Rhodophyta) from IMTA Using a Biorefinery Concept.

Marine macroalgae (seaweed) are an excellent source of novel bioactive metabolites. The biorefinery concept applied to seaweed facilitates the extraction of many chemical constituents from the same biomass ensuring that the resource is used fully, generating few residues through a succession of extraction steps. In the present study, the biomass of the carragenophyte Solieria filiformis (Rhodophyta, Gigartinales) cultured in an integrated multi-trophic aquaculture (IMTA) system was evaluated to obtain valuable products by a biorefinery approach. Enzymatic-assisted extraction (EAE) and microwave-assisted extraction (MAE) were the eco-friendly technologies used to ensure an environmentally friendly valorization of the biomass. Three valuable products were successfully recovered: a water-soluble extract rich in proteins and sulfated polysaccharides suitable as a food supplement; a lipid fraction rich in polyunsaturated fatty acids (PUFAs) with potential to be used in the nutraceutical industry; and a pure ι-carrageenan with a powerful antiviral activity against Herpes simplex virus (EC50 = 6.3 µg mL−1) comparable to the commercial antiviral acyclovir (EC50 = 3.2–5.4 µg mL−1).

The value of sea urchin, Lytechinus variegatus, egesta consumed by shrimp, Litopenaeus vannamei

Sea urchins produce high‐energy, membrane‐bound fecal pellets that contain residual nutrients and large quantities of microbiota. These egesta are readily consumed by the shrimp, Litopenaeus vannamei. Egesta of the sea urchin, Lytechinus variegatus, were evaluated as a feed supplement or total replacement for a commercial shrimp diet. Shrimp were stocked at 0.49 g ± 0.06 g initial body weight and housed individually in 2.8‐L tanks in a commercial recirculating zebrafish system. Shrimp were assigned to one of six diets: commercial shrimp feed, reference sea urchin feed, collected dried sea urchin egesta, collected wet sea urchin egesta, half ration of shrimp feed and half collected wet sea urchin egesta, and egesta naturally produced by two sea urchins in polyculture. Equivalent dry matter amounts of each diet were proffered to shrimp in each treatment twice daily, except for those that had complete access to natural egesta excreted by sea urchins in polyculture. Sea urchins were proffered a reference sea urchin feed at 2% body weight daily. After 27 days, shrimp proffered collected dried or wet egesta did not differ significantly in percent weight gain and showed the lowest weight gain. The percent weight gain of shrimp fed the commercial shrimp diet did not differ significantly from that of the shrimp fed half commercial shrimp diet and half egesta. The highest weight gain was recorded for those shrimp that consumed the untouched egesta produced by sea urchins in polyculture. These data suggest that consumed egesta have noteworthy nutritional value and therefore would be beneficial to the culture of extractive species in an integrated multitrophic aquaculture system.

Lipidomic signature of the green macroalgae Ulva rigida farmed in a sustainable integrated multi-trophic aquaculture

Ulva species, green macroalgae, are widely distributed across the globe, being one of the most heavily traded edible seaweeds. Nonetheless, although this genus has been largely used in scientific studies, its lipidome remains rather unexplored. The present study sheds light over the lipid profile of Ulva rigida produced in a land-based integrated multi-trophic aquaculture (IMTA) system using liquid chromatography coupled to high-resolution mass spectrometry for molecular lipid species identification. The lipidome of U. rigida revealed the presence of distinct beneficial n-3 fatty acids for human health, namely alpha-linoleic acid (ALA) and docosapentaenoic acid (DPA). A total of 87 molecular species of glycolipids, 58 molecular species of betaine lipids, and 57 molecular species of phospholipids were identified in the lipidome of U. rigida including some species bearing PUFA and with described bioactive properties. Overall, the present study contributes to the valorization and quality validation of sustainably farmed U. rigida.

Adopt and Adapt Nature’s Design Principles to Create Sustainable Aquaculture Systems

Sustainable development of aquaculture faces many constraints. An approach that offers solutions to these challenges is emulating nature’s patterns and strategies. There are many elements of sustainability employed by nature that can be adopted for aquaculture systems through necessary adjustments (or adaptations). Analysis of empirical data generated by a series of experiments on different aquaculture systems generated new knowledge of practical importance. An outcome of the analysis pertaining to two important aspects of aquaculture, the sex control in captive stocks of commercially important protogynous hermaphrodite grouper and the operation of integrated multi-trophic aquaculture systems is presented here. Both cases serve as outstanding examples of the relevance of examining and applying nature’s principles for finding sustainable solutions to aquaculture problems.

Environmental Impacts of Experimental Production of Lactic Acid for Bioplastics from Ulva spp.

An exploratory Life Cycle Assessment (LCA) was carried out to provide insight into the environmental impacts of using the green seaweed Ulva spp. as a feedstock, for production of bioplastic. The study focused on the production of lactic acid as a precursor of polylactic acid. The study was on the production process: (1) The cultivation of Ulva spp., in an Integrated Multitrophic Aquaculture system; (2) the processing of the biomass for solubilization of sugars; (3) the fermentation of the sugars to lactic acid; (4) the isolation of lactic acid from fermentation broth. The study identified environmental hotspots and compared an experimental seaweed production chain with conventional feedstocks. The main hotspot is derived from electricity consumption during seaweed cultivation. The impact of electricity consumption can be lowered by reducing energy use and sourcing renewable energy, and by improving the material efficiency in the product chain. To improve understanding of the process of production’s environmental impacts, future studies should broaden the system boundaries and scope of sustainability issues included in the environmental assessment.

The effects of marine farm-scale sequentially integrated multi-trophic aquaculture systems on microbial community composition, prevalence of sulfonamide-resistant bacteria and sulfonamide resistance gene sul1

Aquaculture, one of the most important food production practices worldwide, faces serious challenges of mitigating the detrimental impacts of intensive farming on the environment and increased prevalence of antibiotic resistance. To develop an environment-friendly aquaculture system, a land-based and farm-scale sequentially integrated multi-trophic aquaculture (IMTA) system was established for farming Chanos chanos in southwestern Taiwan. In this system, fishes are cultured in combination with organic extractive shellfish and inorganic extractive seaweed. This study aimed to evaluate the prevalence of sulfonamide-resistant bacteria, microbial community structure, and occurrence of sulfonamide resistance genes in the IMTA and traditional aquaculture systems. Water and sediment samples were collected before raising and after harvesting C. chanos. Our results showed that the occurrence of sulfonamide-resistant phenotypes in the IMTA system was comparable with that in influent seawater, while the traditional system exhibited a high sulfonamide resistance rate. Additionally, the traditional system resulted in a deviation of the bacterial community structure from that of seawater. In the water samples from the IMTA system and influent seawater, Proteobacteria and Bacteroidetes were the two dominant phyla, representing approximately 75% and 15% of the community, respectively. In the traditional system, Actinobacteria, constituting 39% of the community, was the dominant bacterial phylum. Thirty-one sulfonamide-resistant bacterial species were isolated. In conclusion, a sequentially IMTA system showed superior ability to maintain the prevalence of antibiotic resistance and the integrity of the bacterial community structure compared to the traditional farming system, representing a potentially valuable aquaculture system for preserving the sustainability of the marine environment.

Utilization of IMTA-produced Ulva lactuca to supplement or partially replace pelleted diets in shrimp (Litopenaeus vannamei) reared in a clear water production system

Integrated multi-trophic aquaculture (IMTA) systems typically rely on macroalgae to maintain water quality for fed and extractive species. Macroalgae harvested from these systems can in turn be used as feed source for these species. This study evaluated the use of harvested Ulva lactuca from a land-based IMTA system as a partial replacement (25, 50%) or a supplement (25%) to a commercial shrimp diet for Litopenaeus vannamei juveniles. In addition to the impacts on shrimp production, the nutritional profile of the commercial diet and the macroalgae were compared. Thirty shrimp (1.17 ± 0.12 g) were stocked in 80-L tanks in a clear water system and fed either a commercial pellet (100F), a commercial diet supplemented with U. lactuca (100F:25U), or a partial replacement diet (75F:25U, 50F:50U) for 7 weeks. Survival was similar in all treatment groups; however, all growth parameters were significantly lower in the 50F:50U group, although feed conversion ratio was also lowered. The harvested Ulva contained high levels of protein (32%) and a similar amino acid profile to that of the commercial diet, although lipid levels were low (1.9%), and docosahexaenoic acid (DHA) was lacking. Shrimp in the partial replacement treatment groups had significantly lower protein levels. These results indicate that up to 25% of a commercial diet may be replaced with fresh U. lactuca without impacting shrimp production, and therefore, a cost savings in feed may be seen in an IMTA system producing both shrimp and Ulva.

Stability analysis of the phytoplankton effect model on changes in nitrogen concentration on integrated multi-trophic aquaculture systems

Integrated Multi-Trophic Aquaculture (IMTA) is a polyculture with several biotas maintained in it to optimize waste recycling as a food source. The interaction between phytoplankton and nitrogen as waste in fish cultivation including ammonia, nitrite, and nitrate studied in the form of mathematical models. The form model is non-linear systems of differential equations with the four variables. The analytical analysis was used to study the dynamic behavior of this model. Local stability analysis is performed at the equilibrium point with the first step linearized model by using Taylor series, then determined the Jacobian matrix. If all eigenvalues have negative real parts, then the equilibrium of the system is locally asymptotic stable. Some numerical simulations were also demonstrated to verify our analytical result.