Sustainable Aquaculture Production Research Articles

New perspectives on metagenomic analysis for pathogen monitoring in sustainable freshwater aquaculture production: a systematic review

The freshwater and saltwater aquatic food sector has experienced the most significant growth in recent years and is increasingly recognized as a sustainable alternative for fostering prosperous societies self-sufficiently and ecologically. One primary economic and health risk factor in aquaculture production is health control, with potentially more severe impacts observed in tropical and developing countries. While metagenomics holds great promise for application in agro-industrial fields like aquaculture, its adoption remains limited. Consequently, this study aimed to assess the prospects for developing and applying metagenomics in identifying pathogens in freshwater aquaculture. The WIPO database was used to search for patents developed using metagenomics to monitoring pathogens in freshwater aquaculture. Metagenomics methods have been extensively employed in different fields, such as, medicine, veterinary, biotechnology, agriculture, particularly in studies focusing on microbial communities in different ecosystems. In aquaculture, the utilization of metagenomics has predominantly revolved around investigating antibiotic resistance genes, primarily in saltwater farms. Despite this, freshwater aquaculture, particularly in fish and crustacean farming, aligns closely with sustainable development goals, notably (SDGs) 2, 3, 6, and 13. Countries such as the United States of America, South Korea, and Canada stand at the forefront of utilizing metagenomics for disease monitoring in freshwater aquaculture, evidenced by their active patent developments. The metagenomic analysis, coupled with bioinformatics tools and databases, represents a rapid, secure, and non-invasive approach to environmental monitoring for preventive purposes.Systematic review registrationhttps://osf.io/srpyz/, identifier 10.17605/OSF.IO/SRPYZ.

Genetic improvement and genomic resources of important cyprinid species: status and future perspectives for sustainable production.

Cyprinid species are the most cultured aquatic species around the world in terms of quantity and total value. They account for 25% of global aquaculture production and significantly contribute to fulfilling the demand for fish food. The aquaculture of these species is facing severe concerns in terms of seed quality, rising feed costs, disease outbreaks, introgression of exotic species, environmental impacts, and anthropogenic activities. Numerous researchers have explored biological issues and potential methods to enhance cyprinid aquaculture. Selective breeding is extensively employed in cyprinid species to enhance specific traits like growth and disease resistance. In this context, we have discussed the efforts made to improve important cyprinid aquaculture practices through genetic and genomic approaches. The recent advances in DNA sequencing technologies and genomic tools have revolutionized the understanding of biological research. The generation of a complete genome and other genomic resources in cyprinid species has significantly strengthened molecular-level investigations into disease resistance, growth, reproduction, and adaptation to changing environments. We conducted a comprehensive review of genomic research in important cyprinid species, encompassing genome, transcriptome, proteome, metagenome, epigenome, etc. This review reveals that considerable data has been generated for cyprinid species. However, the seamless integration of this valuable data into genetic selection programs has yet to be achieved. In the upcoming years, genomic techniques, gene transfer, genome editing tools are expected to bring a paradigm shift in sustainable cyprinid aquaculture production. The comprehensive information presented here will offer insights for the cyprinid aquaculture research community.

Biochemical profile of the native seaweed fly Fucellia maritima (Haliday, 1838) (Diptera: Anthomyiidae) reared on five different substrates

Abstract The sustainability of aquaculture production is crucial for the industry’s long-term viability. Diversification of feed ingredients is a key component in achieving this sustainability. Considered a promising alternative to traditional feed ingredients, terrestrial insect meals often lack sufficient n-3 polyunsaturated fatty acids (PUFA). This study explores the potential of marine insect species, specifically evaluating the influence of five different substrates on the growth and composition of the European native seaweed fly, Fucellia maritima. The substrates tested include a brown seaweed (Fucus sp.), a green seaweed (Ulva sp.), a red seaweed (the invasive Agarophyton vermiculophyllum), the invasive freshwater hyacinth (Eichhornia crassipes), and fish processing waste (codfish Gadus morhua frames). Results show no significant difference in the number of individuals per substrate, although Fucus sp. had a higher total number of individuals completing their life cycle. In contrast, feeding on codfish frames resulted in a lower number of completed life cycles, while E. crassipes led to no survival. Protein content in adult flies ranged from 55.2% to 56.7%, and in pupae, it ranged from 46.1% to 48.7% across different feeding substrates. Notably, pupae fed with Ulva sp., exhibited the highest protein content at 48.7%. Lipid content in adult flies ranged from 10.0% to 13.0%, while in pupae, it ranged from 8.8% to 11.4%. Codfish frames had the highest lipid content in both pupae (11.4%) and adults (13%). The most abundant fatty acid in Fucus sp. – fed pupae and adult flies was oleic acid (18:1 n-9), while palmitoleic acid (16:1 n-7) dominated in other treatments. It is worth highlighting that docosahexaenoic acid (22:6 n-3) was reported for the first time in a seaweed fly, namely when supplied with fish processing waste. These findings suggest that Fucellia maritima may be a promising complementary ingredient for formulating marine aquafeeds.

Utilization of Aquatic Plants and Microalgae for Sustainable Aquaculture Production and Potential Biotechnological Applications

Locally available feedstuffs, such as grain seed cakes, oilseeds, and vegetable waste, hold immense potential as alternative feed sources in fish farming. However, these plant-based ingredients have low crude protein content and lack essential fatty acids, which lowers palatability and feed conversion efficiencies, leading to suboptimal fish growth. Traditional feedstuffs like fishmeal and soybean meal face sustainability challenges such as local unavailability, the presence of anti-nutritional factors, and energy-intensive processing. The rising costs of commercial aqua-feeds and feed scarcity necessitate exploring alternative fish feed options. Aquatic plants like Ipomoea aquatica, Lemna minor, and Azolla pinnata, along with green and blue-green microalgae such as Chlorella spp. and Arthrospira spp. (Spirulina), are promising alternatives due to their high protein content, availability of essential omega-3 fatty acids such as EPA (Eicosapentaenoic acid) and DHA (Docosahexaenoic acid), and beneficial bioactive compounds. These plants and microalgae, with crude protein content ranging from 25% to 65%, can significantly enhance fish growth, health, and product quality by partially or entirely replacing fishmeal. Their nitrogen-fixing abilities contribute to their high protein levels. Additionally, these organisms have various biotechnological applications, including phytoremediation, Integrated Multi-trophic Aquaculture (IMTA), aquaponics, biofloc technology, and constructed wetlands. Despite their potential, challenges in scaling up and integrating these alternatives into existing systems remain. Collaborative efforts and advocacy among farmer groups are crucial for knowledge sharing and fostering sustainable biotechnological solutions. Long-term strategies should focus on upscaling local feed production and research and development to achieve self-sufficiency and cost-effective natural feed production systems in fish farming.

Discovering a model Pacific oyster for sustainable aquaculture production and sales optimisation in southern Australia

The Pacific oyster is prominent in global food security and the blue economy. As an unfed aquaculture species, the oyster offers substantial potential to contribute to United Nations Sustainable Development Goals related to hunger, health, and employment. By capitalising on its biophysical attributes, the industry can enhance production efficiency and economic sustainability. This study advances critical insights into commercially important biophysical traits of the Pacific oyster across its supply chains in southern Australia (South Australia and Tasmania). Applying quantitative analysis to qualitative data using proportional odds logit modelling, reflexive thematic analysis (with theme salience), Fleiss’ Kappa analyses, and a novel Industry-Acclaimed Trait Importance (IATI) Index, we identify non-specific survival, uniform growth, and shell integrity (hard, dense, and less chalky) as primary determinants of production success. The meat quality, shell appearance, and size consistency are also of prime importance for marketability. Notably, we discover the shell, which is not eaten and often overlooked in the oyster production economy, as a critical factor impacting 78% of identified biophysical traits, revealing a potential avenue for production and sales optimisation. By delineating the characteristics of a model oyster, we provide a blueprint for selective breeding and farm management practices to enhance product quality and foster sustainable Pacific oyster aquaculture.

Microplastic assessment in aquaculture feeds: Analyzing polymer variability across commercial fishfeeds from three continents

This study analysed ten widely used commercial fishfeeds in aquaculture from six countries spanning three continents to assess microplastic (MP) contamination. MPs with an average abundance of 1130 ± 259.07 particles/kg and an average length of 2.64 ± 0.62 mm ( ± SE) were found in aquaculture feeds, with fibres (85 %) and fragments (15 %). The majority of these MPs were black. The abundance of MPs varied among the samples, with the highest in feed SP (26 %), followed by IF, GA, ELS, NT, EW, TB, GR, VR, and the least in HCF (3 %). Polymers identified consisted of Polyethylene terephthalates (PET, 20 %), Polyamide (PA, 30 %), Polymethyl methacrylate (PMMA), Polyurethane (PU), and Polystyrene (PS) with 15 % each, and Polypropylene (PP, 5 %). SEM-EDX analysis of fibres showed flakes, cracks, and pits and the presence of heavy metals Ni, Cu, Zn, Cr, Au, Hg, Cd, Ti, and Pb. Additionally, some fragments contained Nb (Niobium) alongside the naturally occurring elements. The Polymer Hazard Index (PHI) for the polymers in ten feeds was calculated, and nine were in the highly hazardous category (IV and V) with PHI values ranging from 400–394825. The work showcases the graveness of MPs in fishfeeds and advocates control measures to curtail MPs in fishfeeds for sustainable aquaculture production.

A Holistic Approach to Producing Anti-Vibrio Metabolites by an Endosymbiotic Dinoflagellate Using Wastewater from Shrimp Rearing.

The aquaculture industry requires green solutions to solve several environmental challenges, including adequate wastewater remediation and natural drug applications to treat bacteria- and virus-related diseases. This study investigated the feasibility of cultivating the dinoflagellate Durusdinium glynnii in aquaculture wastewater from shrimp rearing in a synbiotic system (AWW-SS), with different dilutions of f/2 medium (FM). Interestingly, D. glynnii demonstrated enhanced growth in all AWW-SS treatments compared to the control (FM). The highest growth rates were achieved at AWW-SS:FM dilutions of 75:25 and 50:50. The removal of total nitrogen and total phosphorus reached 50.1 and 71.7%, respectively, of the crude AWW-SS. Biomass extracts of D. glynnii grown with AWW-SS were able to inhibit the growth of the bacteria Vibrio parahaemolyticus (inhibition zone of 10.0 ± 1.7 mm) and V. vulnificus (inhibition zone of 11.7 ± 1.5 mm). The presented results demonstrate that the dinoflagellate D. glynnii is a potential candidate for the development of circularity for sustainable aquaculture production, particularly by producing anti-Vibrio compounds at a near-zero cost.

European consumers' intention to buy sustainable aquaculture products: An exploratory study

Given the increasing global importance of low trophic level aquaculture (LTA) products (e.g. seaweed and mussels) for sustainable and healthy seafood supply, this study examined consumer intentions towards LTA products among European consumers. This study performed an extended theory of planned behaviour to focus on the influence of health consciousness, subjective knowledge, food neophobia, and sociodemographic and lifestyle factors on consumers' intentions to buy LTA products. We conducted an online questionnaire survey in Denmark, the United Kingdom and France (~500 respondents per country). Consumer segmentation analysis, based on food-related lifestyles, employing K-means clustering techniques, revealed five distinct segments, namely ‘Adventurous’, ‘Uninvolved’, ‘Foodies’, ‘Rational’, and ‘Conservative’, each reflecting unique consumer behavioural patterns. Furthermore, partial least squares structural equation modelling analysis revealed that subjective norms are the main predictor of LTA product buying intention, followed by attitude, food neophobia, subjective knowledge, and health consciousness. Furthermore, food neophobia seems to moderate the influence of subjective norms and subjective knowledge on LTA product buying intention. This dual approach explains the predictive power of the model while identifying targeted segments for sustainable aquaculture product marketing, ensuring that the distinction between the model's test and the subsequent segmentation analysis is clearly articulated. To enhance the adoption of LTA products, marketers should primarily target the ‘Foodies’ segment, characterised by high involvement and innovation, by emphasizing attitudes, health consciousness, subjective knowledge, and food quality attributes, while mitigating food neophobia and leveraging subjective norms.

Multi-functional application of octacosanol as a feed additive in animal and aquaculture: A review.

Demand for sustainable animal and aquaculture production drives the exploration of novel feed additives. We highlight octacosanol, a long-chain alcohol from plant sources, as a promising multifunctional feed additive. The review comprehensively evaluates octacosanol's applications in animal and aquaculture nutrition, including its molecular properties and mechanisms of action. It elucidates how octacosanol affects lipid metabolism, energy utilization and immune modulation. Octacosanol enhances livestock growth, efficiency, carcass quality and stress resilience. We thoroughly discuss how it enhances feed utilization, disease resistance and overall performance in finfish and shellfish in aquaculture. The review also addresses the ecological and sustainability aspects of octacosanol utilization. We identify challenges and knowledge gaps in octacosanol research, prompting suggestions for future investigations. We address regulatory considerations, dosage optimization and potential interactions with other feed additives to ensure the safe and effective use of octacosanol. In conclusion, the review highlights octacosanol's potential as a versatile feed additive in the animal and aquaculture industries and urges further research to uncover its benefits and sustainability contributions, proposing a prospective research plan for this purpose. This thorough analysis is a valuable resource for researchers, nutritionists and industry professionals looking to find innovative methods to improve production practices and advance sustainable food systems.

Improved breeding and seed production of climbing perch (Anabas testudineus) in controlled tanks and cage systems

The climbing perch (Anabas testudineus) is a valuable fish species with significant potential for aquaculture. However, a low survival rate was observed at its early development stages, requiring an optimized protocol for sustainable aquaculture production. This paper presents an improved breeding and seed production technology for climbing perch. Mature climbing perch were induced to spawn using salmon gonadotropin-releasing hormone analog (sGnRHa) at a dose of 30 µg/kg-1 body weight of the breeder. The female broodfish spawn 9–10 hours after hormone injection. Developmental stages were defined based on the morphological features of the embryos from the first cleavage to the hatching stage. The first cleavage began at approximately 18–20 minutes after fertilization. Newly hatched larvae were observed within 18–20 h at 30°C, having an average larval size of 0.389±0.042 mm (total length). Successful breeding entails a selection of suitable algal species, an optimal aquaculture environment, regular feeding rates, consistent monitoring of larval development, and effective management of water quality. Survival rates from the larval stage to fry were achieved at 84.69% and 77.60%, respectively, while the survival rate to the fingerlings stage was 72.51%. Therefore, by implementing an optimized protocol, aquaculture practitioners can maximize the production potential of climbing perch while ensuring sustainable cultivation practices. The findings from this research contribute to the advancement of climbing perch aquaculture by providing valuable insights for the successful cultivation and increased economic profitability of A. testudineus species in hatchery productions.

Biodegradation of polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics by floc-forming bacteria, Bacillus cereus strain SHBF2, isolated from a commercial aquafarm.

The ubiquitous proximity of the commonly used microplastic (MP) particles particularly polyethylene (PE), polypropylene (PP), and polystyrene (PS) poses a serious threat to the environment and human health globally. Biological treatment as an environment-friendly approach to counter MP pollution has recent interest when the bio-agent has beneficial functions in their ecosystem. This study aimed to utilize beneficial floc-forming bacteria Bacillus cereus SHBF2 isolated from an aquaculture farm in reducing the MP particles (PE, PP, and PS) from their environment. The bacteria were inoculated for 60 days in a medium containing MP particle as a sole carbon source. On different days of incubation (DOI), the bacterial growth analysis was monitored and the MP particles were harvested to examine their weight loss, surface changes, and alterations in chemical properties. After 60 DOI, the highest weight loss was recorded for PE, 6.87 ± 0.92%, which was further evaluated to daily reduction rate (k), 0.00118 day-1, and half-life (t1/2), 605.08 ± 138.52 days. The OD value (1.74 ± 0.008 Abs.) indicated the higher efficiency of bacteria for PP utilization, and so for the colony formation per define volume (1.04 × 1011 CFU/mL). Biofilm formation, erosions, cracks, and fragments were evident during the observation of the tested MPs using the scanning electron microscope (SEM). The formation of carbonyl and alcohol group due to the oxidation and hydrolysis by SHBF2 strain were confirmed using the Fourier transform infrared spectroscopic (FTIR) analysis. Additionally, the alterations of pH and CO2 evolution from each of the MP type ensures the bacterial activity and mineralization of the MP particles. The findings of this study have confirmed and indicated a higher degree of biodegradation for all of the selected MP particles. B. cereus SHBF2, the floc-forming bacteria used in aquaculture, has demonstrated a great potential for use as an efficient MP-degrading bacterium in the biofloc farming system in the near future to guarantee a sustainable green aquaculture production.

Present status of brood stock management and breeding operations at Carp Hatcheries in Jashore, Bangladesh

Sustainable aquaculture production depends on the proper management of brood stock. In this regard, multiple survey studies were reviewed to assess the present status of management of carp brood stock at Jashore region in Bangladesh from March 2023 to August 2023. A total of 38 hatcheries were selected in Jashore. The areas of ponds were ranged from 33.33 to 400 decimal and shape with maximum rectangular. The green color water of pond was 79% and 75% practice pond drying. Most of the farmers applied liming doses were ranged from 500- 1200 gm dec-1. Most of the farmers used rotenone (39%) to control predators in the brood stock pond. Different sorts of fertilizers both organic and inorganic were applied. Most of the brood stocks (39%) were collected from the hatcheries and the rest of them were collected from other pond, World fish, BFRI and the natural sources (Halda and Padma River). Moreover, 4 carp species (rui, catla, mrigala and kalbashu) among 13 endemic and 4 exotic carp species (silver carp, grass carp, bighead and common carp) out of 6 exotic carp’s species were used for seed production. Negative selection of brood stock was performed in few hatcheries in order to reduce the cost for collecting or purchasing good quality broods. The formulated feed which contained 20-30% protein for carp brood stock were prepared using the indigenous ingredients including mainly rice bran, mustard oil cake, vitamin and mineral premix, wheat flour, fish meal and soya bean flour and maize flour. The main problem of hatchling production is Argulosis (fish lice) diseases which causes 95% of hatchlings mortality. Finally, these survey findings indicate that proper brood stock management could be a good approach to attain the main purpose of aquaculture.

Effects of ammonia on the cellular, physiological, biochemical and genetic traits of Indian major carp (Labeo rohita) fry in artisanal Bangladeshi aquaculture

AbstractThe major carp Rohu (Labeo rohita) is a prime freshwater aquaculture species across the Indian subcontinent that faces various production‐related issues associated with water quality parameters. The present study examined the effects of three different doses of NH3 (T1 = 1 mg/L, T2 = 2 mg/L and T3 = 3 mg/L) on cellular (gill ultrastructure), physiological (growth and oxygen consumption rate), biochemical (blood cell counts, blood cortisol and glucose levels) and genetic (expression of five genes involved in growth, immunity and metabolism) traits of Rohu. The experimental ammonia dose significantly affected the tested biological parameters (p < 0.05), causing moderate‐to‐severe gill tissue damage. In general, compared with those in the control group, 16%–25% slower growth, 12%–30% lower survival and 15%–56% higher O2 consumption were observed for the treatment groups. Blood glucose and cortisol levels increased with increasing ammonia levels, but blood cell counts decreased. The five selected candidate genes showed a differential expression pattern in response to the ammonia dose, with higher expression in the control group and lower expression in the treatment groups. The results indicate that different concentrations of ammonia impose stress on different orders of magnitude in the experimental fishes. Therefore, it can be inferred that the presence of ammonia in aquatic/farming environments can adversely affect production performance; the severity of damage during production depends on the concentration of ammonia. Therefore, maintaining no or minimum ammonia levels in farming environments is urgently needed for sustainable aquaculture production of Rohu.

Broodstock nutrition in Nile tilapia and its implications on reproductive efficiency

Broodstock nutrition is the most essential constituent of sustainable aquaculture production. Its impact on the reproductive performance and profitability of commercial aquaculture has been the subject of considerable research. The present paper reviews the literature available on the subject, examining the implication of Nile tilapia broodstock nutrition on parameters including maturation, fecundity, fertilization, embryo development, larval quality, and survival rate. The provision of a nutritive diet composed of essential macro- and micronutrients including proteins, lipids, carbohydrates, vitamins, minerals, and functional additives, such as prebiotics, enzymes, hormones, and probiotics, in different proportions is discussed. Special emphasis is given to literature dealing with the effects of dietary protein and lipid on vitellogenesis and ovarian maturation, fecundity, egg hatching rate, larval quality, and fry survival number. The impact of the feeding regime on reproductive performance is described.

Do climate change, access to electricity and renewable energy consumption matter in aquaculture production in Africa?

AbstractThe contribution of aquaculture to economic development cannot be overemphasized. Several factors affect aquaculture production. However, few studies document the impact of climate change, electricity and other macroeconomic covariates on aquaculture production in Africa. The present research's objective is to examine the impact of rainfall, temperature, access to electricity, per capita national income, renewable energy consumption, employment in agriculture, and carbon emissions on aquaculture production in 32 African countries. We rely on panel data using rigorous estimation techniques involving the fixed effects and method of moment quantile regression approaches. Our fixed effects model result indicates that an increase in temperature reduces aquaculture production, while renewable energy consumption, net per capita income, employment in agriculture, and carbon emissions increase aquaculture production. Similarly, the 75th and 90th quantiles of the method of moment quantile regression results indicated that both rainfall and temperature decrease aquaculture production, while renewable energy consumption, employment in agriculture, and carbon emissions increase aquaculture production. The study provides useful insight into the climate, economic, and technological factors that might increase or decrease aquaculture production in Africa and similar contexts. Overall, our findings are important for improving aquaculture production in Africa, particularly with the current low production relative to the global north. The results have implications on the current and future climate action that calls for increased reliance on renewable energy and targeting improvements in agricultural employment, and net national income. Additional efforts are needed to achieve carbon neutrality while ensuring sustainable aquaculture production in Africa.

Genetic diversity and population structure of farmed and wild Nile tilapia (Oreochromis niloticus) in Uganda: The potential for aquaculture selection and breeding programs

Nile tilapia is one of the most important aquaculture species globally, providing high-quality animal protein for human nutrition and a source of income to sustain the livelihoods of many people in low- and middle-income countries. This species is native to Africa and nowadays farmed throughout the world. However, the genetic makeup of its native populations remains poorly characterized. Additionally, there has been important introgression and movement of farmed (as well as wild) strains connected to tilapia aquaculture in Africa, yet the relationship between wild and farmed populations is unknown in most of the continent. Genetic characterization of the species in Africa has the potential to support the conservation of the species as well as supporting selective breeding to improve the indigenous strains for sustainable and profitable aquaculture production. In the current study, a total of 382 fish were used to investigate the genetic structure, diversity, and ancestry within and between Ugandan Nile tilapia populations from three major lakes including Lake Albert (L. Albert), Lake Kyoga (L. Kyoga) and Lake Victoria (L. Victoria), and 10 hatchery farms located in the catchment regions of these lakes. Our results showed clear genetic structure of the fish sourced from the lakes, with L. Kyoga and L. Albert populations showing higher genetic similarity. We also observed noticeable genetic structure among farmed populations, with most of them being genetically similar to L. Albert and L. Kyoga fish. Admixture results showed a higher (2.55–52.75%) contribution of L. Albert / L. Kyoga stocks to Uganda's farmed fish than the stock from L. Victoria (2.12–28.02%). We observed relatively high genetic diversity across both wild and farmed populations, but some farms had sizable numbers of highly inbred fish, raising concerns about management practices. In addition, we identified a genomic region on chromosome 5, harbouring the key innate immune gene BPI and the key growth gene GHRH, putatively under selection in the Ugandan Nile tilapia population. This region overlaps with the genomic region previously identified to be associated with growth rate in farmed Nile tilapia.

Water quality management in aquaculture

Abstract The aquaculture industry requires good water quality for its successful operation but produces wastes that can cause environmental deterioration and pose high risks to the sector. Adequate waste treatment and recycling are necessary to make aquaculture a sustainable and profitable industry and contribute to the circular economy. Polluted water sources, excess feeding, overstocking, use of antibiotics/chemicals and harmful algal blooms are major causes of water quality deterioration and low production in aquaculture systems. Discharges of untreated wastes would have serious impacts on the receiving water bodies, and eventually on the aquaculture industry itself. Possible solutions include technological innovations in environmentally friendly production systems, use of efficient processes in water quality management and improved legislation and governance. Environmentally feasible aquaculture production technologies such as recycling aquaculture system, integrated multi-trophic aquaculture and aquaponics including features of waste recycling are viable options in aquaculture schemes. Best aquaculture practices integrating advanced water quality treatment processes and technologies, supported by automation and sensors, modeling and artificial intelligence-internet of things are necessary for a sustainable aquaculture environment, production and stable value chain. In general, low-cost technologies for aquaculture waste treatment and environmental impact reduction through good governance are crucial for achieving sustainability in the aquaculture industry and natural environmental management.

Enhancing sustainable aquaculture production through Periphyton-based practices

Enhancing sustainable aquaculture production through Periphyton-based practices

Perikphyton Growth on Two Different Bamboo Substrate Models for Its Use in Aquaculture

Periphyton-based fish farming practices are considered low-cost technologies as they help in sustainable aquaculture production. The present study was designed to determine the efficiency of two different substrate models (viz. roof hut model and prism model) made from the bamboo sticks. The small-sized substrate models were constructed for invitro studies. The growth of periphyton was investigated on the 30th day of the experimental setup. This is the first time experimenting with bamboo substrate models. From the result it was found that the biomass of periphyton in terms of dry weight 0.03±0.01 g/cm2 was observed on both substrate models. There is no biomass difference and taxonomic difference between these two models. It may be due to the material used for the construction of the model being the same i.e. bamboo sticks and cotton thread. The taxonomic identification of the periphyton community showed the different genera of class Chlorophyceae and Bacillariophyceae. These models are efficient for periphyton growth and they also increase the productivity of periphyton due to increased surface area of substrate models. These models can be used for low-cost aquaculture.

Tissue Lipid Profiles of Rainbow Trout, Oncorhynchus mykiss, Cultivated under Environmental Variables on a Diet Supplemented with Dihydroquercetin and Arabinogalactan.

Reared rainbow trout are vulnerable to environmental stressors, in particular seasonal water warming, which affects fish welfare and growth and induces a temperature response, which involves modifications in tissue lipid profiles. Dietary supplements of plant origin, including the studied mix of a flavonoid, dihydroquercetin and a polysaccharide, arabinogalactan (25 and 50 mg per 1 kg of feed, respectively), extracted from larch wood waste, were shown to facilitate stress tolerance in fish and also to be beneficial for the safety of natural ecosystems and the sustainability of aquaculture production. This four-month feeding trial aimed to determine the effects of the supplement on liver and muscle lipid accumulation and the composition in rainbow trout reared under environmental variables. During periods of environmental optimum for trout, a consistent increase in energy lipid stores, particularly triacylglycerols (2.18 vs. 1.49-fold over a growing season), and an overall increase in lipid saturation due to lower levels of PUFAs, such as eicosapentaenoic (20:5n-3), docosahexaenoic (22:6n-3) and arachidonic (20:4n-6) acids, were observed in both control and supplement-fed fish, respectively. However, in fish stressed by an increase in ambient temperature, dietary supplementation with dihydroquercetin and arabinogalactan reduced mortality (3.65 in control vs. 2.88% in supplement-fed fish, p < 0.05) and alleviated the high-temperature-induced inhibition of lipid accumulation. It also stabilised the membrane phospholipid ratio and moderated the fatty acid composition of fish muscle and liver, resulting in higher levels of n-3 PUFAs and their precursors. Thus, the natural compounds tested are beneficial in accelerating fish tolerance to environmental stressors, reducing mortality and thermal response, and moderately improving fillet quality attributes by increasing the protein/lipid ratio and the abundance of fatty acids essential for human nutrition.