Search Results (119)

Anesthetic agents are widely used in aquaculture to facilitate handling, transport, surgery, vaccination, tagging, and other husbandry procedures. However, most previous reviews have primarily focused on induction time, recovery duration, and welfare outcomes, with comparatively limited emphasis on blood physiology as an indicator of systemic anesthetic safety. The present review synthesizes current evidence regarding hematological, hemato-biochemical, blood gas, and immunohematological alterations induced by major anesthetic classes in aquaculture species. Literature published between 2000 and 2026 was retrieved from Scopus, Web of Science, Google Scholar, PubMed, ScienceDirect, and Springer Nature databases, with approximately 150 studies included following structured screening. Available evidence indicates that anesthetic exposure frequently alters erythrocyte and leukocyte profiles, cortisol secretion, glucose and lactate metabolism, hepatic enzyme activity, electrolyte balance, acid–base regulation, and blood oxygen transport. Respiratory depression, hypercapnia, hypoxemia, and transient metabolic acidosis were recurrent consequences of deep anesthesia, particularly during prolonged exposure or unfavorable environmental conditions. Several anesthetics also modulated innate immune responses through alterations in complement activity, respiratory burst function, cytokine signaling, and leukocyte redistribution. Collectively, the review highlights blood physiology as an essential framework for evaluating anesthetic safety and improving welfare-oriented aquaculture practices. Full article

Two growth trials were conducted to evaluate the effects of solvent-extracted soybean meal (SBM), low-oligosaccharide soybean meal (LO-SBM), and enzyme-treated soybean meal (ET-SBM) on the growth performance, feed utilization, and gut microbiome of the Pacific white shrimp (Litopenaeus vannamei). Nine diets were tested, including a basal diet using solvent-extracted soybean meal as the main protein source. The solvent-extracted soybean meal was then replaced with LO-SBM or ET-SBM at 40%, 60%, 80%, and 100% on an isonitrogenous and isolipidic basis. In the 8-week outdoor green water trial, all growth metrics, FCR and apparent net protein retention (ANPR) showed no significant differences among diets (p > 0.05). However, there was a significant effect of LO-SBM on phosphorus retention. In the clear water trial, intermediate inclusion levels of LO-SBM (60–80%) slightly improved growth metrics and phosphorus retention (p < 0.05) without affecting protein utilization, while 100% LO-SBM did not provide additional benefits. Diets with ET-SBM showed similar performance; however, phosphorus retention was reduced. Diets did not affect whole-body composition (p > 0.05), except for phosphorus and moisture. Gut microbiota analysis revealed that shrimp fed 100% ET-SBM had notably higher alpha diversity (Shannon index = 5.45, observed species = 326.41) compared to those fed 100% LO-SBM (Shannon index = 4.59, observed species = 242.69), indicating improved microbial stability with ET-SBM. Nonetheless, there were no significant differences in beta diversity or taxonomic composition between treatments (p > 0.05). This study demonstrates that incorporating 60–80% LO-SBM into the diet improves shrimp growth and nutrient utilization. Additionally, ET-SBM may also support shrimp growth, nutrient efficiency, and microbial diversity, suggesting that both LO-SBM and ET-SBM can be beneficial for shrimp nutrition. Full article

Digestibility is a fundamental concept in animal nutrition and is widely used to evaluate feed ingredients. Although digestibility values are generally expected to be positive, negative values are occasionally reported. Negative values are not analytical or calculation errors; rather, they often convey critical information about feed ingredients. Negative digestibility is most commonly observed for minerals, which readily interact with other components in compound feeds and within the gut lumen. A proper understanding of negative digestibility is therefore essential for formulating nutritionally complete diets. This paper introduces Mellanby’s toxamin theory to illustrate the mechanisms underlying negative digestibility. It also explains the rationale behind digestibility calculations, which sometimes yield mathematically extreme and biologically unrealistic negative values. Finally, the paper proposes in vivo mineral-binding capacity as an alternative metric for expressing ingredient interactions, as negative digestibility values themselves can lead to confusion and misinterpretation. By reinterpreting the biological significance of negative digestibility, this paper seeks to translate an often-confusing observation into a more practical and informative nutritional index. Full article

In this study, total ammonia nitrogen (TAN) excretion rates were quantified in juvenile (mean weight: 1.79 ± 0.17 g) and adult (mean weight: 15.91 ± 0.63 g) prawns (Macrobrachium caementarius) reared under recirculating aquaculture system (RAS) conditions representative of small-scale farming operations. Prawns were fed a commercial dry pelleted diet (48.5% crude protein) at a daily ration equivalent to 5% of total biomass. Water quality parameters were maintained within species-specific tolerance ranges to ensure normal physiological and metabolic function. TAN excretion rates were estimated using a mass balance approach under closed-flow batch conditions. A significant difference in TAN excretion was observed between life stages (p = 0.008): juveniles excreted 0.009 ± 0.006 mg TAN g⁻¹ h⁻¹ (0.22 ± 0.18 mg TAN g⁻¹ day⁻¹), whereas adults excreted 0.03 ± 0.01 mg TAN g⁻¹ h⁻¹ (0.73 ± 0.06 mg TAN g⁻¹ day⁻¹). Distinct diel postprandial patterns were evident in both life stages, with peak TAN release occurring 1–2 h after each feeding event, followed by a gradual decline. These life-stage differences have direct implications for RAS design and biofilter management and should be interpreted in the context of the dietary conditions used. The quantified excretion rates provide baseline bioengineering parameters for sizing biofilters, estimating nitrogen loading, and optimizing water quality management for this emerging aquaculture species. Full article

This study evaluated trace element bioaccumulation in Nile tilapia (Oreochromis niloticus) marketed in Brazil and assessed potential implications for food safety and human health. A total of 120 farmed fish samples, including whole fish and tissues (gills, kidneys, liver, and muscle), were analyzed. Concentrations of Al, As, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and compared with ANVISA and FAO/WHO guideline values. Arsenic concentrations complied with ANVISA limits, whereas Pb in whole Nile tilapia exceeded the permissible threshold. Nickel and Se concentrations in muscle and whole fish also surpassed FAO/WHO guidelines. Estimated Se intake from consumption of whole tilapia and muscle (fillet) reached 188.01% of the Recommended Dietary Allowance (RDA) for children aged 8 years. Contamination index values (CI) indicated bioaccumulation of Ni in multiple tissues and Se in edible portions. Human health risk assessment identified carcinogenic risks associated with As, Cr, Ni, and Pb, while non-carcinogenic risk (HI > 1) was primarily driven by As exposure. These findings highlight the need for continuous monitoring of trace elements in aquaculture products. Full article

Global food production systems are increasingly challenged by population growth, climate change, water scarcity, and environmental degradation, necessitating the adoption of sustainable, resource-efficient food production strategies. Aquaponic systems integrate recirculating aquaculture with hydroponic crop cultivation, enabling nutrient recycling and improved water-use efficiency. Simultaneously, CRISPR/Cas9 genome-editing technology has emerged as a powerful tool for precise genetic improvement of economically important aquaculture traits. This review critically evaluates current progress in CRISPR/Cas9 applications in aquaculture, with emphasis on Nile tilapia (Oreochromis niloticus). Evidence from peer-reviewed studies indicates that targeted modification of genes associated with growth regulation, disease resistance, nutrient metabolism, feed efficiency, and stress tolerance can significantly enhance fish productivity and physiological resilience. Genes involved in hypoxia adaptation and nitrogen metabolism may further improve environmental performance in intensive recirculating systems by reducing ammonia accumulation and enhancing nutrient utilization. However, most genome-editing studies have been conducted under laboratory or conventional aquaculture conditions, with limited information available regarding the long-term performance, ecological interactions, microbial dynamics, and biosafety of genome-edited fish in aquaponic environments. Technical limitations including off-target effects, mosaicism, delivery efficiency, regulatory uncertainty, and public acceptance continue to constrain large-scale implementation. In the short term, CRISPR/Cas9 applications are likely to focus on practical trait enhancement under controlled aquaculture systems, whereas longer-term research may explore fish lines specifically optimized for nutrient cycling, environmental resilience, and integrated aquaponic sustainability. Overall, CRISPR/Cas9-mediated genome editing represents a promising but still emerging strategy for improving sustainable aquaculture and aquaponic food production systems. Full article

The impact of a commercial microbial population (product name “RAS Right”) on the off-flavours geosmin and 2-methylisoborneol (2-MIB) in water and fish of a recirculating aquaculture system (RAS) for Nile tilapia production was studied over five months. The “RAS Right” product contains a microbiome that is reported to reduce geosmin. In the system that received “RAS Right”, geosmin ranged from 1.6 to 171.2 ng/L, while 2.4 to 89.3 ng/L occurred in the control RAS. After fluctuations in the first two months, water in the control RAS had lower geosmin concentrations (mean of 8.8 ng/L) than the treated RAS (mean of 16.6 ng/L). 2-MIB was low (<4.3 ng/L) or undetectable in both the control and treated systems. In the fish, geosmin varied from 112 to 3683 ng/kg, with the highest levels measured in the treated RAS during three of eight samplings. 2-MIB in the fish ranged from 11.6 to 136 ng/kg and peaked in the treated RAS in one sampling. The results indicate that “RAS Right” did not produce a significant reduction of geosmin or 2-MIB in water or fish. However, optimisation of the treatment with respect to dose or addition frequency may improve its effect, though this remains to be examined. Full article

Opportunistic bacterial and fungal infections from surface wounds remain a persistent threat to aquaculture, resulting in significant economic losses and reduced stock welfare. Topical wound sealants are widely employed in recreational aquaculture applications, yet no market regulation or efficacy data exist to support their usage. The broader biological/environmental impacts of these products also remain poorly characterized. This study provides the first quantitative assessment of the antibacterial, antifungal and cellular toxicity of a panel of commercially available topical ‘carp care’ formulations. Our data highlights highly variable to no functional growth inhibition or killing of microbial pathogens, significant inherent cyprinid cellular toxicity, and lack of submerged wet adhesion in all products tested. We show for the first time that commercial propolis solutions are ineffective against the four main pathogenic microorganisms affecting carp. Propolis formulations were also found to induce apoptosis and ROS generation in cyprinid cells in vitro, and permeabilise intact carp skin, questioning the foundation of propolis formulations in topical wound-care treatments for carp rearing/angling. We show improved efficacies can be attained through natural compound implementation, with increased antibacterial and antifungal effects, inherent regenerative benefits to cyprinid fibroblasts, and improved human and environmental safety profiles. This research demonstrates the widespread lack of efficacy in currently commercially available wound sealants for carp; of those tested here, many popular formulations are in fact inherently toxic to carp cells, and also have a permeabilizing effect on intact carp skin due to carrier solvent effects, providing a route for secondary infection; most show no activity against any common carp pathogens; and all uniformly lacked wet adhesion. This work provides a framework standard for the future development of topical wound-care formulations for carp and highlights the need for better dialogue between trade and academia when designing novel wound-care products. Full article

This field study examined extant aquatic food production and marketing in the three coastal states of Lagos, Ogun, and Ondo before IMTA across 15 Local Government Areas (LGAs)/Local Council Development Areas (LCDAs). Marketing mix practices in coastal aquatic food systems were explored through a structured, qualitative assessment using a multi-value chain perspective. Monthly sales volumes most frequently fell within the range of 1–5 tonnes. The local market was dominant, with some sales in the international markets. Respondents asserted that post-harvest processing was diverse, and some were satisfied with the technology available to preserve their products. Cold storage practices across coastal states were hindered by unreliable power supply. Zero-level channel distribution dominated among traders, with over 90% relying on word-of-mouth (WOM) to promote their products. Consumers showed a strong preference for the quality of local products and expressed openness to incorporating seaweed into their purchases. Health benefits, taste, and other reasons for purchase decisions varied significantly across the state χ² (df = 8, n = 300) = 92.39, p < 0.001. These findings provide a baseline for IMTA in Nigeria, highlighting existing strengths, market dynamics, and infrastructure gaps that must be addressed to support sustainable integration. Full article

Malabar red snapper (Lutjanus malabaricus) is widely farmed across Asia (e.g., China, Malaysia, Singapore, Taiwan) and is highly valued in regional markets. Despite its importance to fisheries and aquaculture, population structure and genetic connectivity between wild and farmed populations across the South China Sea remain poorly understood. We analyzed 594 individuals retained after quality filtering from an initial dataset of 930 samples, representing eight wild and farmed populations spanning north-eastern Australia (Queensland) and the South China Sea region (Hong Kong, Malaysia, Singapore, Taiwan), using 18,177 SNPs to quantify genetic diversity, population structure, and effective population size (Ne). Genetic differentiation was low but significant. Wild populations from Australia were differentiated from all other populations, indicating regional genetic isolation. In contrast, farmed populations from Malaysia and Singapore clustered closely with wild populations from Hong Kong and Singapore, indicating regional connectivity. Effective population size (Ne) in farmed populations was low (Ne = 49.1–138.6). Farmed populations from Malaysia and Singapore formed a genetically connected cluster, whereas the Taiwan farm population was genetically distinct. Low Ne was observed in farmed populations from Singapore and Taiwan. These findings support aquaculture management by identifying Australian populations as a distinct unit and enabling biosecure broodstock exchange within the Malaysia–Singapore cluster to minimize inbreeding and strengthen sustainable selective breeding programs. Full article

Smolt production in freshwater is an essential component of the salmonid aquaculture production chain. But it generates sludge (feed waste and fish feces) that must be managed to meet environmental regulations. While sludge can be reused as a resource, there are limited empirical results about cost structures, market conditions, and energy implications in industrial aquaculture. This study analyzes sludge collection, processing, and utilization based on a single-case study of a Norwegian smolt producer (Sisomar AS). The analysis combines company-level production data, accounting information, and process descriptions. In 2023, the company produced approximately 9.2 million smolt (1184 tons of biomass), generating 140 tons of dried sludge. Sisomar’s value creation from production of bio-based fertilizer from sludge is relatively close to that of comparable mineral fertilizers, but a direct comparison here is difficult because of large variations in the prices of mineral fertilizers. The energy consumption is significantly lower for organic fertilizer from Sisomar compared to standard technology for mineral fertilizer production. Bio-based fertilizers are looked at as an important contribution to dealing with environmental challenges, and this study discusses the characteristics of how market structures have importance for this. Full article

Aquaculture is expanding rapidly, creating a greater need for sustainable and cost-effective feed ingredients to reduce reliance on traditional protein sources such as fishmeal (FM) and soybean meal (SBM). Insect-derived frass, which consists of insect excrement, molted exoskeletons, uneaten substrate, plus associated microbial biomass, has shown potential as a viable and sustainable ingredient in aquafeed. Although traditionally used as an organic fertilizer, its richness in essential nutrients and bioactive compounds highlights its potential as a partial substitute for conventional feedstuffs. This study synthesizes current research on insect-derived frass, focusing on its nutritional composition and effects on growth performance, immunity, health, and gut microbiota in aquaculture species, alongside environmental, economic, safety, and regulatory considerations. Although a wide range of insect species have been evaluated for use in aquafeeds, research on insect frass has primarily focused on black soldier fly and yellow mealworm, with most studies examining its application in omnivorous fish species. Despite its promise as a circular economy-aligned aquafeed ingredient, challenges remain due to nutritional and amino acid variability, largely influenced by the quality of the original insect rearing substrate, as well as species-specific responses and potential contamination risks. To promote widespread adoption of insect-derived frass in aquafeed, there is a need to optimize insect rearing substrate selection and processing, define inclusion levels by insect and target aquatic species, establish safety protocols, and develop harmonized international standards. Full article

The discharge of effluents from shrimp farms into coastal lagoons can alter food availability, water quality, and pollutant load, potentially affecting the biological performance and safety of farmed bivalves. This study evaluated the influence of shrimp farm effluents on the growth, total weight, and condition index of the Pacific oyster Crassostrea (Magallana) gigas. Two oyster cultivation zones were established in the coastal lagoon of Los Melagos (Sonora, Mexico): one near a shrimp effluent zone (EZ) and the other in a reference effluent-free zone (FZ). Shell height and length, total weight, and condition index were measured monthly, along with environmental variables, including chlorophyll “a” concentration and sea surface temperature obtained from satellite imagery. Oysters cultivated in EZ showed significantly higher total weight, condition index, and growth rates compared to those in FZ. Seasonal fluctuations in chlorophyll “a” were observed, reflected in growth patterns, suggesting greater food availability in waters influenced by effluents. However, these environments pose health risks that require continuous, integrated environmental and health monitoring. Full article

This study applied time-series modeling using autoregressive integrated moving average (ARIMA) to compare the growth performance of tilapia broodfish in pond and recirculating aquaculture systems (RAS) from June 2023 to May 2024. Descriptive statistics showed a higher mean percentage weight gain under RAS (26.69%) than pond culture (23.75%), although monthly variability in the RAS dataset was influenced by an outlier, which may be attributed to influential exogenous factors rather than water-quality parameters. Normality, stationarity, and autocorrelation diagnostics confirmed that both datasets were appropriate for ARIMA modeling without differencing. Multiple ARIMA models were evaluated based on RMSE, MAPE, MAE, AIC, BIC, and residual behavior; ARIMA (1,0,1) emerged as the best fit for both systems. Forecasting up to May 2028 revealed stable long-term growth patterns, with RAS consistently showing slightly higher forecasted growth compared to pond culture, although the difference remained small in absolute terms. Predictions remained within model-generated 95% confidence intervals; however, these results indicate internal model consistency rather than independent validation of predictive accuracy. The findings highlight that RAS offers more consistent and slightly superior growth performance, supporting its potential for optimized broodfish production. Recommendations emphasize adopting RAS for enhanced growth predictability and improved management in tilapia aquaculture. Full article

Pre-fattening (also referred to as nursery culture) of Manila clam is a priority for this sector of aquaculture, as it allows hatchery-produced seed (1–3 mg) to reach sowable juvenile sizes of 30–100 mg and reduces reliance on natural juvenile recruitment. This study evaluated the efficiency of two early pre-fattening systems, both in economic terms and in product quality: conventional upwelling units (a high-density system) and flat-bottom tanks (a mid-density system), the latter tested with and without a sand layer. The 51-day trial was conducted under autumn environmental conditions (temperature 13–25.8 °C; salinity 25–28 ppt; chlorophyll-a 3–24 µg/L), starting with 1.34 mg seed maintained under a water flow rate ≥ 15–20 mL/min/g. In upwelling units, the initial density was ~216 ind./cm². Four grading events produced four size classes, with total mean weights ranging from 6.4 mg in the smallest (tails) to 46.3 mg in the largest (heads). The overall population mean size was 19.0 mg, with a specific growth rate (SGR) of 5.2%/day and mortality of 17.6%. Flat-bottom tanks, stocked at ~30 ind./cm², achieved higher growth (overall weighted mean: 28.0 mg; SGR ~6%/day), but exhibited higher mortality (26.0% on average), with no significant effect from the presence of bottom sand. Overall, flat-bottom systems showed promising growth performance with reduced labor requirements, suggesting that this system could represent a viable alternative to upwelling. However, the associated rearing protocol could still be improved by optimizing stocking density and water exchange rates. Full article