Fish Processing Research Articles

Exploring the physicochemical properties, fatty acids composition, and nutritional quality indices of oil derived from Chrysichthys nigrodigitatus of different sizes: Impact of processing

Fish oil, known for its health benefits due to its abundant omega-3 fatty acids, can vary in quality and nutritional value depending on the size of the fish and the processing methods used. This study focused on oil derived from Chrysichthys nigrodigitatus of varying sizes, specifically smaller fish (about 12.0 cm) and larger fish (about 26.1 cm), processed through smoking, boiling, or roasting. It was found that larger fish contained more lipids (5.74 g/100 g fresh matter) than their smaller counterparts (2.67 g/100 g fresh matter). However, all processing methods led to a decrease in lipid content per dry matter (2.3–7.4 %), with smoking causing the most significant reduction. In terms of physicochemical properties, smoking had the most impact, followed by roasting, while boiling had the least. Oxidation levels, as indicated by thiobarbituric acid, peroxide, and anisidine values, increased across all processing methods compared to fresh samples (2.0–168.0 % for larger fish and 9.3–191.1 % for smaller fish). Conversely, iodine value decreased, ranging from 14.8 % to 27.4 % for larger fish and 10.8–39.9 % for smaller fish. Boiling exhibited the smallest variation in these values, while smoking showed the highest variation. Otherwise, infrared spectroscopy revealed a consistent oil structure across samples, but unsaturation and oxidation were altered by processing. Interestingly, larger fish yielded healthier oils with a higher concentration of polyunsaturated fatty acids (26.40 %) compared to smaller fish (21.87 %). Smoking and roasting methods diminished these beneficial fatty acids, whereas boiling preserved the nutritional value. Understanding the relationship between fish size and processing methods is crucial to maintaining fish oil’s health benefits. Future research should explore these effects in different fish species, considering consumer preferences and environmental impacts.

Prevention of Lipid Oxidation in Kilka Fillet (Clupeonella Cultriventris) using Biodegradable Packaging in the Refrigerator (3°C)

Kilka Fish is classified in the fatty fish group and is more perishable than other aquatics. It is very sensitive to oxidation during cold storage. Fat oxidation reduces the quality of Kilka, a decrease in shelf life and economic losses. Because it leads to color change (yellow) of Kilka. Therefore, the present study aimed to evaluate the effects of sodium alginate and whey protein coating on the prevention of fat oxidation of Kilka fillets during 12 days of refrigerated storage. Whey protein 15% and sodium alginate 1% were used at time= 5 min. Uncovered samples were considered as controls. Humidity, peroxide, FFA, TBA, pH, and fat were not significant in the samples covered with whey protein (73.62%, 0.08 meq kg oil-1, 1.01 g 100-1, 0.06 mg kg-1, 6.37 and 4.45%) compared with those covered by sodium alginate (73.91%, 0.05 meq kgoil-1, 1.09 g 100-1, 0.01 mg kg-1, 6.49, and 4.00%) (P>0.05). However, the index chemicals were lower in these samples compared with the control (59.16%, 3.07 meq kgoil-1, 5.73 g 100-1, 2.14 mg kg-1, 6.81 and 3.99%. Unlike fat, the other chemical tests were significant between control and covered samples (p<0.05). Covered samples had good quality at the end of the storage period. However, the control samples lost their quality after 6 days. Fish soaked with sodium alginate had better quality compared with the other samples. The use of sodium alginate is recommended by the seafood processing industry to maintain the quality of kilka during refrigeration.

Efficacy Evaluation of Chlorine Dioxide and Hypochlorous Acid as Sanitisers on Quality and Shelf Life of Atlantic Salmon (Salmo salar) Fillets.

Microbial contamination during seafood processing can often lead to a reduction in shelf life and the possibility of food-borne illnesses. Sanitisation with chlorine-based products during seafood processing is therefore sometimes undertaken. This study compared the effects of two sanitisers, chlorine dioxide (ClO2) and hypochlorous acid (HOCl) at their suggested concentration (5 ppm and 10 ppm; 50 ppm and 100 ppm respectively), on physical, chemical, and microbial qualities of Atlantic salmon (Salmo salar) fillets throughout 7 days of simulated retail display refrigeration. Parameters used for assessment included quality index (QI), drip loss, colour, texture, histology, total volatile base nitrogen (TVB-N), lipid oxidation (malonaldehyde, MDA), pH, and total viable count changes. Results indicated that whilst drip loss increased over the storage time, day 4 and 7 drip loss in both sanitisers decreased significantly compared with the control. There was a linear relationship (R > 0.70) between QI and storage time in all treatments, particularly in regard to skin brightness, flesh odour, and gaping parameters, but treatment differences were not present. Texture parameters including gumminess, chewiness, and hardness increased over time in the control whilst both sanitiser treatments seemed to provide protective effects against texture hardening during storage. The observed softening effects from the sanitiser treatments were aligned with microstructural and cytological changes in the histology results, as evidenced by a reduced fibre-fibre adhesion, myodigeneration, and an increase in interfibrillar space over storage time. Colour, especially chroma (C*), was shown to decrease over time in control, whereas insignificant protective effects were observed in both sanitiser treatments at day 7. Irrespective of treatment and storage time, MDA levels exceeded the acceptable limit on all days, whilst TVB-N levels were below the critical limit. Although pH was influenced by treatment and storage time, the pH was within the normal range. Microbiological results showed that with sanitiser addition, TVC was below the permissible level (106 CFU/g) until day 4 but ClO2 ice (5 ppm), ClO2 (10 ppm), and HOCl (100 ppm) treated fillets all exceeded the limit on day 7. The mixed results on the effect of sanitiser addition on fillet quality and shelf life suggested that further investigation on pathogen reduction, sanitiser introductory method, as well as testing the same treatments in low-fat fish models would be recommended.

Validation of gut transit rate assessment methodology and the mitigation of sampling stress in Atlantic salmon, Salmo salar

Gut transit rate is an important component of the digestive process in fish, particularly in the context of aquaculture, where factors such as rearing temperature and dietary formulation impact on-farm performance. As such, developing and validating research methodologies that explore these critical physiological responses in fish is vital in the context of precision aquaculture practices. However, there are inherent methodological constraints of gut transit rate assessments, particularly when assessing the effect of sampling on the stress response of fish. In light of this, the present study aimed to assess the gut transit rate and plasma cortisol levels of Atlantic salmon (Salmo salar) subjected to the more commonly applied, repeated sampling model that results in multiple tanks disturbances (e.g., 2, 4, 8, 16 and 24 h post-feed) in comparison to one requiring only a singular tank disturbance at one of the designated time points. An inert beaded marker was integrated into diet formulations to determine the transit rate of digesta in three major gastrointestinal tract regions: the stomach, mid-intestine, and distal intestine over a period of 48 h following the provision of food. A significantly higher plasma cortisol concentration was recorded in fish subjected to a repeated disturbance, particularly at 16 h post feed (22.99 ± 6.88 ng mL−1), compared to fish sampled from tanks subjected to a single sampling event (11.35 ± 0.92 ng mL−1). Despite this, gut transit rate was generally unaffected by sampling design over the duration of the study with both groups of fish displaying a similar rate of gut transit. This suggests that repeated tank sampling (i.e. sampling multiple fish from the same tank at multiple timepoints) is suitable to assess gut transit rate in fish as it does not significantly confound gut transit rate assessments. It is envisioned that this data will contribute to the growing understanding of the digestive process of Atlantic salmon and the relationship with stress response in fish and experimental design. Moreover, it should strengthen future studies aimed at assessing key digestive processes in cultured species.

A robotic fish processing line enhanced by machine learning

This paper presents the design of a comprehensive automatic fish processing line utilizing machine learning algorithms. The processing line encompasses several essential steps, including fish identification by type, fish sorting by size, fish orientation based on shape, and fish cutting at the optimal chopping points. The primary objective of this design is not just automation but also maximizing economic benefits by preserving the maximum amount of fish meat during the cutting process, achieved through the application of machine learning algorithms. To accomplish these goals, we employ a combination of transfer learning and convolutional neural networks to establish criteria for actions across all stages of automatic fish processing. At the heart of the processing station is a conveyor belt equipped with numerous sensors and lenses. Positioned along this conveyor belt are two robotic arms, responsible for precise positioning and cutting operations, all guided by the machine learning algorithms. To provide a visual representation of these design concepts, we have created a 3D SolidWorks model.

Utilization of Nile tilapia viscera oil and lipase as a novel and potential feedstock and catalyst for sustainable biodiesel production

The viscera of Nile tilapia, fish processing industry waste, was utilized to extract oil and lipase and used as a low-cost feedstock and catalyst, respectively, for producing biodiesel. The investigation aimed to improve the process of extracting oil from Nile tilapia viscera (NTVO) by a wet rendering method, and to use it for manufacturing biodiesel using Nile tilapia viscera lipase (NTVL)-based catalyst. Heating Nile tilapia viscera waste at 80 °C for 60 min was the best condition for oil separation, with 51.49 % oil recovery and 6.30 % yield. NTVO characteristics suggested the suitability for biodiesel production. Optimizing the synthesis of biodiesel from NTVO utilizing NTVL catalyst was also studied. The catalyst dose of 20 kUnits, reaction temperature of 35 °C, water content of 1 %, reaction period of 18 h, and methanol to oil molar ratio of 4:1 were found to provide the greatest biodiesel yield (96.9 %) (p < 0.05). ATR-FTIR analysis confirmed the conversion of NTVO to biodiesel. The physicochemical properties of biodiesel obtained met the requirement specified by international standards, namely EN 14214 and ASTM D 6751. These findings highlighted the potential of NTVO and NTVL as a substrate and catalyst for biodiesel synthesis, which might alleviate environmental pollution and disposal issues.

Capture Fish Value Chain Study in Yobe State, Northeast Nigeria: A panacea for sustainable development

The study examined fish value chain in Yobe state Northeast Nigeria. Value addition, profitability, efficiency in marketing and structure of the fish markets were assessed using data elicited in 2023 from 640 respondents. Four Local Government Areas in the state (Bade, Geidam, Jakusko and Nguru) prominent in capture fish production were purposively selected for the study. Six major value chain actors were identified and value added per Kg of catfish (Clarias gariepinus) was higher for fish processors (319.3/Kg) while, processed fish marketers had highest marketing efficiency (321.8%). Similarly, raw fish marketers received the highest marketing margin (20.63%) and the gross margin for artisanal fishermen was 272.5/Kg and on average a total 22,891.8 per day. The study revealed that, products flow was less complex from fishing points to consumption and that the values of Gini Coefficient indicated a monopolistic completion in both fresh/raw fish and processor markets. Based on the above findings, it was concluded that fisheries sub sector in Yobe state had the potential of creating more employment opportunities, increase per capital income/GDP and sustained economic development. It was therefore recommended that, more effort should be intensified by relevant stakeholders to enhance the value addition at every node of the chain and there should be policy to maintain the existing fishing sites (rivers) and to also explore other potential areas

Modernization of small-sized drying plant for searching optimal modes with thermovision control

The climatic features of the Murmansk region (low average annual temperature; insignificant number of sunny days) do not contribute to the effective use of natural methods of drying aquatic organisms and determine the use of artificial dehydration methods using appropriate equipment. The capabilities of ship fish processing complexes are limited; highly productive coastal fish processing plants are required to supply the population with fish products. The development and testing of new drying modes has been carried out using a small-sized drying unit UPOR-M2. In the course of the study, a drying unit modernization project has been developed, equipment has been selected (thermal imaging system; damper and fan control modules), the system has been modernized and a number of experiments has been conducted to determine the effectiveness of the work performed. The modernization of the drying unit has made it possible to increase the accuracy of the data obtained by 25 % (temperature), 20 % (relative humidity), 18 % (weight), to implement remote control of the processes and to ensure reliable operation of the drying system. Further research of different drying modes for aquatic organisms should include upgrading the air supply control system and improving communication equipment.

The association of certain lipid metabolism indicators and light regimes in salmonids and cyprinids in aquaculture

Purpose of the review: analysis of the effect of the photoperiodic factor based on indicators of lipid metabolism in Salmonid and Cyprinid fish species.Methods used: comparative analysis of literature and own experimental data.Results: The length of daylight (photoperiod) is one of the most important abiotic factors affecting the behavior, reproduction, metabolism, growth and development of fish. The changes in the lipids and fatty acid constituents execute a significant role in the adaptation of aquatic organisms to new light conditions. Certain parameters of lipidogenesis can serve as a reliable indicator of the normal route of metabolic processes in the organism. It is widely known that photoperiod regimes are used in aquaculture to optimize the cultivation of various species of aquatic organisms, including the most common Cyprinids and Salmonids. The specificity of the reaction of lipid metabolism to the effects of various lighting modes is shown: in cyprinids, the reaction can be multidirectional depending on the species (including its absence), while in Salmonids on example of Atlantic salmon, a change in the lipid profile in the direction of smoltification is observed. The role of combining the photoperiod with other factors, such as feeding and climatic features of the region, are discussed.Significance: The results can contribute to a better understanding of the adaptive processes in fish and optimize the conditions for their artificial rearing.

Sustainable Seafood Processing: Reducing Waste and Environmental Impact in Aquatic Ecosystems

The global seafood industry is crucial in food production, providing essential nutrition and contributing to food security. Beyond its traditional role, the industry holds significant potential for generating high-value products by utilizing seafood resources. This comprehensive review explores the diverse applications of seafood resources, focusing on fish, shellfish, and seaweeds, in producing high-value products. The review examines various technological processes in extracting and purifying bioactive compounds from seafood, highlighting the advancements in seafood processing areas such as nanoencapsulation, fermentation, and enzymatic hydrolysis. Furthermore, it also discusses these innovations' economic and environmental impacts, emphasizing the importance of sustainability and efficiency in utilizing seafood by-products and waste. The seafood industry can minimize environmental pollution and promote circular economy principles by repurposing these materials. The review provides a holistic view of the future directions in this field, advocating for continued research and development efforts to enhance the value and sustainability of seafood resources. Overall, this review underscores the significance of seafood-derived high-value products in addressing global challenges while fostering economic growth and environmental stewardship.

Gender Dimensions of Vulnerabilities, Adaptations and Alternative Livelihoods of the Closed Season in Elmina – Ghana: A Qualitative Study

A closed season policy has emerged as an ocean governance strategy aimed at protecting and conserving fish stocks across countries and coastal areas. Its implementation has produced traces of vulnerabilities, and forms of livelihood adaptations and alternative livelihood opportunities. However, little is known about how these occur among gender groups. This paper therefore focuses on the gender dimensions of vulnerabilities, adaptations and alternative livelihoods during the closed season in Elmina, Ghana, within the feminist political ecology framework. It employed Focus Group Discussions (FGDs) from purposively selected fishermen and fish processors. The study found significant differences in the vulnerability patterns among the gender groups, albeit some similarities. We further observed more fluid roles among the women than the men because the women were ready to undertake alternative livelihood options that were traditionally male-based during the closed season. Based on these results, we contend that political decisions toward environmental sustainability may create vulnerability and fluid adaptation patterns which may vary among gender groups in the light of their differential patterns of access, control and positionalities within the fishing industry.

Compliance of Malaysia Standard Dried Fish Crackers of Selected Fish Processor in Terengganu

Compliance of Malaysia Standard Dried Fish Crackers of Selected Fish Processor in Terengganu

Astaxanthin attenuates glucose-induced liver injury in largemouth bass: role of p38MAPK and PI3K/Akt signaling pathways

BackgroundAstaxanthin (ASX) has been documented to exert beneficial influence on various processes in fish. Largemouth bass (Micropterus salmoides) serves as a common model for studying glucose-induced liver disease, making it imperative to investigate the regulatory mechanisms underlying its liver health.MethodsLargemouth bass were fed with a control diet (CON), a high carbohydrate diet (HC), or a HC diet supplemented astaxanthin (HCA) for 8-weeks, followed by the glucose tolerance test (GTT). Primary hepatocytes were treated with low glucose and high glucose combined with different concentrations of astaxanthin for 48 h. The histopathology, enzymology, transcriptomics, molecular biology and cell biology were combined to investigate the mechanism of liver injury.ResultsThis study provides evidence for the protective effects of ASX against growth performance reduction and hepatic liver injure in largemouth bass fed HC diet. In GTT, HCA diet exhibited an improvement in glucose tolerance following glucose loading. Although HCA diet did not restore the expression of insulin resistance-related genes in livers at different time during the GTT, the addition of ASX in the long-term HC diet did improve the insulin resistance pathway by regulating the PTP1B/PI3K/Akt signaling pathway. Hepatic transcriptome analyses showed that ASX plays an essential role in the modulation of glucose homeostasis in response to treated with HC diet. In in vitro study, ASX treatment resulted in an exaltation in cell viability and a reduction in the rate of cell apoptosis and reactive oxygen species (ROS). Additionally, astaxanthin was observed to improve apoptosis induced by high-glucose via p38MAPK/bcl-2/caspase-3 signaling pathway.ConclusionsAstaxanthin exhibited a protective effect against apoptosis by regulating p38MAPK/bcl-2/caspase-3 pathway, and ameliorated insulin resistance by activating the PTP1B/PI3K/Akt pathway. This study elucidated the mechanism of astaxanthin in the liver injury of largemouth bass from a new perspective and provided a new target for the treatment of insulin resistance.Graphical

Sequence Segmentation of Nematodes in Atlantic Cod with Multispectral Imaging Data.

Nematodes pose significant challenges for the fish processing industry, particularly in white fish. Despite technological advances, the industry still depends on manual labor for the detection and extraction of nematodes. This study addresses the initial steps of automatic nematode detection and differentiation from other common defects in fish fillets, such as skin remnants and blood spots. VideometerLab 4, an advanced Multispectral Imaging (MSI) System, was used to acquire 270 images of 50 Atlantic cod fillets under controlled conditions. In total, 173 nematodes were labeled using the Segment Anything Model (SAM), which is trained to automatically segment objects of interest from only few representative pixels. With the acquired dataset, we study the potential of identifying nematodes through their spectral signature. We incorporated normalized Canonical Discriminant Analysis (nCDA) to develop segmentation models trained to distinguish between different components within the fish fillets. By incorporating multiple segmentation models, we aimed to achieve a satisfactory balance between false negatives and false positives. This resulted in 88% precision and 79% recall for our annotated test data. This approach could improve process control by accurately identifying fillets with nematodes. Using MSI minimizes unnecessary inspection of fillets in good condition and concurrently boosts product safety and quality.

Measurement of the social investment impact of the bahtera segara program using the social return on investment method (SROI)

PT Pertamina Patra Niaga Integrated Terminal Semarang conducted this study to analyze the impact of the BAHTERA SEGARA (Bahagia Sejahtera Nelayan Pesisir Semarang Utara) Program, aiming to enhance the program's quality in the future. This research employs the SROI method to measure the impact of all activities carried out by PT Pertamina Patra Niaga Integrated Terminal Semarang within the framework of the BAHTERA SEGARA (Bahagia Sejahtera Nelayan Pesisir Pesisir Semarang Utara) Program. Based on the study results of the BAHTERA SEGARA Program (Bahagia Sejahtera Nelayan Pesisir Semarang Utara), this program has proven to be effective and has a significant positive impact. The program has succeeded in improving the economic, social, and environmental welfare of the target community groups and communities that replicate it independently. Increasing SROI scores from 2020 to 2023 indicate that the program is increasingly effective in delivering benefits, particularly through the replication of food crop cultivation and increased fish processing productivity. The program also contributes to the reduction of greenhouse gas emissions and supports climate change adaptation efforts. The program's successful replication demonstrates the effectiveness of BAHTERA SEGARA as a collective learning tool, as well as its potential for replication in other areas with similar conditions.

Improving organic and nutrient removal efficiencies in seafood processing wastewater using anaerobic membrane bioreactor (AnMBR) integrates with anoxic/oxic (AO) processes

Wastewater from seafood processing is a significant source of pollution, containing many harmful organic and inorganic compounds such as proteins, lipids, carbohydrates, nitrogen and phosphorus. This study investigated the enhancement of organic and nutrient removal efficiencies in seafood processing wastewater by integrating an Anaerobic Membrane Bioreactor (AnMBR) with an anoxic/oxic (AO) processes. A pilot-scale system was constructed with a capacity of 0.5 m3/day directly at the factory operated continuously, featuring an AnMBR process with a 24-hour hydraulic retention time (HRT) and an AO process with HRT values and internal recycle changes. The AnMBR system exhibited consistent and high-performance biochemical oxygen demand (COD) elimination, approximately 80 ± 5 %. However, this system demonstrated low-efficiency removal of total nitrogen (TN) at about 20 ± 5 %, and total phosphorus (TP) 15 ± 5 %, under organic loading rates (OLR) of 0.6 to 1.3 kg-COD/(L·d). The AO process was then continually employed to improve the treatment efficacy (at HRT, 5 h in the anoxic phase, and 8.3 h in the oxic phase, at a recycling rate of 300 %) resulting in the final post-treatment concentrations of COD 27–41 mg/L (removal 98.3 ± 0.3 %), TN 12–25 mg/L (90 ± 2 %), and TP 18 ± 2 mg/L (35 ± 5 %). The performance of the integrated AnMBR-AO system met the established Vietnamese discharge standards for seafood processing wastewater, as outlined in QCVN 11-MT: 2015/BTNMT.

The costs of implementing anaemia reduction interventions among women fish processors in Ghana

BackgroundAnaemia among women of reproductive age (WRA) remains persistently high in Ghana, affecting 41% in 2022. Women in low-income communities in Ghana engaged in fish processing activities are at increased risk of anaemia due to inadequate diets, exposure to infectious pathogens, and pollutants. The Invisible Fishers (IFs) project was implemented among women fish processors in their reproductive age in Central and Volta regions of Ghana to mitigate anaemia. Despite the efficacy, feasibility and scalability of the intervention, the cost of implementing the intervention is unknown. The objective of this study was to estimate the costs of implementing the IFs project in Ghana.MethodsWe used micro-costing approach to analyse the costs of implementing the IFs project. Data were collected as part of a pilot randomized control trial with three interventions: Behaviour Change Communication (BCC), Strengthening Market Engagement of fish processors plus Behaviour Change Communication (SME + BCC), and Fish Smoking Technology and Practices plus Behaviour Change Communication (FST + BCC). The interventions were delivered to 60 women fish processors in the Central region and 60 in Volta region. The cost of the intervention was estimated from the societal perspective. Economic costs were categorized as direct costs (i.e. personnel, transportation, meetings, training, and monitoring) and indirect cost (i.e. value of productive time lost due to women and community volunteers’ participation in the activities of the IFs project).ResultsThe FST + BCC had the highest average cost per beneficiary (US$11898.62), followed by the SME + BCC (US8962.93). The least expensive was the BCC (US$4651.93) over the intervention period of 18 months. Recurrent costs constituted the largest component of economic costs (98%). Key drivers of direct costs were personnel (58%), administrative expenses (14%), and transportation (7%).ConclusionThere is a high cost for implementing interventions included in the IFs project. Planning and scaling -up of the interventions across larger populations could bring about economies of scale to reduce the average cost of the interventions.

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.

Fish milt and roe‐derived functional proteins and peptides: composition, bioactivities, and applications

SummaryAn expanding list of marine species has been identified and evaluated for their potential bioactivity and nutritional values. Most attention is directed toward utilising protein‐rich by‐products of fish processing for their bioactive functionalities, which can aid in minimising waste and add value to underutilised resources. Milt and roe, the reproductive constituents of fish, are known to contain a high concentration of nutritional content. Bioactive peptides derived from these constituents have shown several biological activities including antihypertensive, antibacterial, anticoagulant, anti‐inflammatory, anti‐obesity, anti‐cancer, and antioxidant activities. These peptides are commonly extracted by enzymatic hydrolysis and purified by different chromatographic methods according to their mass, molecular size, and composition. This review discusses the approaches to produce, purify, and characterise the protein hydrolysates from fish milt and roe and delves into the compositions of the nutraceutical compounds derived from milt and roe. The review also highlights the bioactive properties of the milt and roe‐derived peptides that can have potential applications in the food, nutraceutical, pharmaceutical, and cosmeceutical industries.

Single housing of juveniles accelerates early-stage growth but extends adult lifespan in African turquoise killifish.

Within the same species, individuals exhibiting faster growth tend to have shorter lifespans, even if their fast growth arises from early-life pharmacological interventions. However, in vertebrates, the impact of the early-life environment on the growth rate and lifespan has not been fully elucidated. In this study, by utilizing the short-lived African turquoise killifish, which is suitable for a comprehensive life-stage analysis in a brief timeframe, we explored the effects of housing density during the juvenile stage on holistic life traits. As a result, we found that lower housing densities resulted in faster growth, but led to longer adult lifespan, which was contrary to the common notion. Furthermore, the single-housed adult fish displayed a longer egg-laying period than did their group-housed counterparts. Our transcriptome analysis also demonstrated that, in terms of internal transcriptional programs, the life stage progression and aging process of single-housed fish were slower than those of group-housed fish. Collectively, our results suggest that sharing housing with others in early life might influence whole-life attributes, potentially leading to specific life history traits beyond the typical relationship between the growth rate and lifespan.