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This study investigated the physicochemical properties, functionalities, and antioxidant capacities of protein extracts from wild sea cucumber Australostichopus mollis collected from four distinct locations in New Zealand. Protein was extracted from sea cucumber body walls using trypsin enzymatic extraction, followed by cold acetone precipitation. The amino acid analysis revealed high glycine (189.08 mg/g), glutamic acid (119.45 mg/g), and aspartic acid (91.91 mg/g) concentrations in all samples. The essential amino acid indexes of the protein extracts (62.96, average) were higher than the WHO/FAO standard references, indicating the excellent protein quality of A. mollis. Furthermore, protein extracts from A. mollis demonstrated superior emulsifying activity (202.3–349.5 m2/g average) compared to commercial soy and whey protein isolates under all tested pH conditions, and enhanced foaming capacity (109.9–126.4%) and stability (52.7–72%) in neutral and acidic conditions. The extracts also exhibited good solubility, exceeding 70% across pH 3–11. Antioxidant capacities (ABTS and DPPH free radical scavenging activity and ferric reducing antioxidant power) were identified in A. mollis protein extracts for the first time, with clear variations observed among different locations. These findings elucidate the advantageous functional properties of protein extracts from wild New Zealand A. mollis and highlight their potential application as high-quality antioxidant food ingredients. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine the reproductive cycle and spawning frequency of the sea cucumber Holothuria tubulosa in the northeastern Aegean Sea. Methods: The study covered a period of 12 months, beginning in October 2018 and concluding in September 2019. During this period, sea cucumber samples were collected monthly. Macroscopic and histological examinations of gonadal tubules were conducted to provide credible information for fishery management and aquaculture. Result: The sex ratio of the sampled population was 1:1.3, with 95 males and 130 females. The drained body weights at 50% maturity were 70.90 g for females and 70.80 g for males. The total length at 50% maturity was estimated at 18.58 cm for females and 18.05 cm for males. Gonad maturation was initiated in March and progressed to spawning stages between July and August. From September to February, the gonads were in postspawning and recovery stages. A strong linear correlation was determined between the gonad index and the seawater temperature in the area. Conclusion: The information provided is expected to improve stock management, enforce fishery regulations, and support controlled breeding programs. These measures aim to preserve the natural populations of Holothuria tubulosa and guarantee the long‐term viability of the species in the wild. Impact statementThe Holothuria tubulosa is the most abundant commercial sea cucumber species found in the Mediterranean Sea, particularly in the Aegean Sea. This species plays an important ecological role in nutrient regeneration and surface sediment mineralization in the benthic zone; however, there is significant catch pressure on natural stocks. This study revealed the reproductive cycle of this Mediterranean Sea cucumber species, offering crucial data for sustainable fisheries and aquaculture. By understanding their breeding patterns, we can better manage wild populations and develop controlled breeding programs, ensuring the long‐term survival of the species and supporting healthy marine ecosystems. [ABSTRACT FROM AUTHOR]

Sea cucumbers are well demarcated for their valuable role in the food, pharmaceutical, nutraceutical, and cosmeceutical sectors. The demand for well-processed dried sea cucumber retaining quality is prioritized by local markets and industries. There are several techniques for the pre-processing of fresh sea cucumbers, including traditional and modern methods, such as salting, boiling, high-pressure processing, high-pressure steaming, and vacuum cooking, among others, in order to inactivate enzymes and microbial attacks. Further, pre-treated sea cucumbers require post-processing before human consumption, transportation, or industry uses such as hot air, freeze, cabinet, sun, or smoke drying. However, despite the ease, traditional processing is associated with several challenges hampering the quality of processed products. For instance, due to high temperatures in boiling and drying, there is a higher chance of disrupting valuable nutrients, resulting in low-quality products. Therefore, the integration of traditional and modern methods is a crucial approach to optimizing sea cucumber processing to obtain valuable products with high nutritional values and retain bioactive compounds. The value of dried sea cucumbers relies not only on species and nutritional value but also on the processing methods in terms of retaining sensory attributes, including colour, appearance, texture, taste, and odour. Therefore, this review, for the first time, provides insight into different pre- and post-treatments, their perspective, challenges, and how these methods can be optimized for industry use to obtain better-quality products and achieve economic gains from sea cucumber. [ABSTRACT FROM AUTHOR]

Background: The holothurians, commonly known as sea cucumbers, are marine organisms that possess significant dietary, nutritional, and medicinal value. However, the National Center for Biotechnology Information (NCBI) currently possesses only approximately 70 complete mitochondrial genome datasets of Holothurioidea, which poses limitations on conducting comprehensive research on their genetic resources and evolutionary patterns. In this study, a novel species of sea cucumber belonging to the genus Benthodytes, was discovered in the western Pacific Ocean. The genomic DNA of the novel sea cucumber was extracted, sequenced, assembled and subjected to thorough analysis. Results: The mtDNA of Benthodytes sp. Gxx-2023 (GenBank No. OR992091) exhibits a circular structure spanning 17,386 bp, comprising of 13 protein-coding genes (PCGs), 24 non-coding RNAs (2 rRNA genes and 22 tRNA genes), along with two putative control regions measuring 882 bp and 1153 bp, respectively. It exhibits a high AT% content and negative AT-skew, which distinguishing it from the majority of sea cucumbers in terms of environmental adaptability evolution. The mitochondrial gene homology between Gxx-2023 and other sea cucumbers is significantly low, with less than 91% similarity to Benthodytes marianensis, which exhibits the highest level of homology. Additionally, its homology with other sea cucumbers is below 80%. The mitogenome of this species exhibits a unique pattern in terms of start and stop codons, featuring only two types of start codons (ATG and ATT) and three types of stop codons including the incomplete T. Notably, the abundance of AT in the Second position of the codons surpasses that of the First and Third position. The gene arrangement of PCGs exhibits a relatively conserved pattern, while there exists substantial variability in tRNA. Evolutionary analysis revealed that it formed a distinct cluster with B. marianensis and exhibited relatively distant phylogenetic relationships with other sea cucumbers. Conclusions: These findings contribute to the taxonomic diversity of sea cucumbers in the Elasipodida order, thereby holding significant implications for the conservation of biological genetic resources, evolutionary advancements, and the exploration of novel sea cucumber resources. [ABSTRACT FROM AUTHOR]

Sea cucumbers have become a highly valuable fishery product, and therefore the determination of their proximate compositions and fatty acid profiles are useful indicators of their physiological status and nutritional value. Thus, various raw and processed products, such as raw, dried, frozen, boiled, and salted Holothuria polii and Holothuria tubulosa that were collected from the Aegean Sea were analyzed. Although there were some notable differences in the proximate and fatty acid profiles between the two species and among the various processing forms, both H. polii and H. tubulosa had a high nutritional value. They were rich in proteins (up to 68.5% in the dried form), and although their lipid fraction was low (0.3–3.9%), it was characterized by very high levels of arachidonic acid (19.1–30.9% of total fatty acids) and eicosapentaenoic acid (8.5–15.7) that play vital roles in human growth, development, and health. In addition, their n-3/n-6 fatty acid ratios were within the recommended ranges, while their low Atherogenic and Thrombogenic indices and high Hypocholesterolemic index denote their high protective role against coronary artery disease. The provided information sheds light on the high nutritional value of this important marine fishery resource and provides valuable information for its preservation and processing. This information could also help policy makers, stakeholders, and the public to recognize the importance of this valuable fishery resource for human nutrition and to adopt preventative measures toward its sustainable exploitation. [ABSTRACT FROM AUTHOR]

Sea cucumber has emerged as a crucial economic species in aquaculture in China because of its remarkable nutritional and medicinal value. However, wild sea cucumber populations have experienced a decline due to overfishing and environmental factors, underscoring the urgent need for genetic resource conservation and biotechnology innovation within the sea cucumber aquaculture and breeding industry. The development of the sea cucumber industry is still impeded by challenges and difficulties. Nevertheless, significant progress has been made through the utilization of molecular markers, which have effectively addressed a number of fisheries and aquaculture issues. In recent years, diverse types of molecular markers including mitochondrial DNA, microsatellites, and SNP markers have been developed and extensively applied in various aspects of sea cucumber research. These markers play vital roles in genetic sex identification, germplasm resource evaluation, population structure assessment, as well as marker-assisted breeding in marine ranching and sea cucumber aquaculture and breeding industry. This review provides an overview of the fundamental principles, functions, and characteristics associated with various markers employed across various sea cucumber species while also discussing their applications within different aspects of the sea cucumber fisheries, aquaculture, and breeding industry. [ABSTRACT FROM AUTHOR]

The sea cucumber is an essential nutrient source and a significant economic marine resource associated with successful aquaculture. However, sea cucumbers are highly susceptible to autolysis induced by endogenous protease after postmortem, and the phenomenon of body wall “melting” occurs, which seriously affects the food quality of products and the degree of acceptance by consumers. To satisfy the growing demand for fresh or processed sea cucumbers, we must clarify the autolysis mechanism of sea cucumbers and the methods to achieve autolysis regulation. In this paper, the factors leading to the quality deterioration and texture softening of sea cucumbers are reviewed, with emphasis on enzymatic characteristics, the autolysis mechanism, the effects of autolysis on the physicochemical properties of the body wall of the sea cucumber, and the development of potential natural protease inhibitors. We aim to provide some reference in future preservation and processing processes for sea cucumbers, promote new processing and preservation technologies, and advance the sea cucumber industry’s development. [ABSTRACT FROM AUTHOR]

Eight sulfated triterpene glycosides, peronioside A (1) and psolusosides A (2), B (3), G (4), I (5), L (6), N (7) and P (8), were isolated from the sea cucumber Psolus peronii. Peronioside A (1) is a new glycoside, while compounds 2–8 were found previously in Psolus fabricii, indicating the phylogenetic and systematic closeness of these species of sea cucumbers. The activity of 1–8 against human erythrocytes and their cytotoxicity against the breast cancer cell lines MCF-7, T-47D and triple-negative MDA-MB-231 were tested. The most active against cancer cell compounds, psolusosides A (2) and L (6), which were not cytotoxic to the non-transformed cells of the mammary gland, were chosen to study the inhibition of the migration, formation and growth of colonies of the cancer cell lines. Glycoside 2 effectively inhibited the growth of colonies and the migration of the MDA-MB-231 cell line. Compound 6 blocked the growth of colonies of T-47D cells and showed a pronounced antimigration effect on MDA-MB-231 cells. The quantitative structure–activity relationships (QSAR) indicated the strong impact on the activity of the form and size of the molecules, which is connected to the length and architecture of the carbohydrate chain, the distribution of charge on the molecules' surface and various aspects of hydrogen bond formation, depending on the quantity and positions of the sulfate groups. The QSAR calculations were in good accordance with the observed SAR tendencies. [ABSTRACT FROM AUTHOR]

Abstract Background Complementary medicine is an interesting field for extracting bioactive compounds from various plant and animal sources. The hepatoprotective effect of the methanolic extract of a species of sea cucumber called Holothuria leucospilota in an animal model of liver cancer caused by dimethyl nitrosamine (DMN) was studied. Methods Wistar female rats were randomly divided into five groups (n = 12): control (intact), positive control (received 1% DMN [10 mg/kg/week, intraperitoneally] for 12 weeks), and three treatment groups (received 50, 100, and 200 mg/kg/day H. leucospilota extract orally for 12 weeks along with intraperitoneal administration of 1% DMN [10 mg/kg/week]). In all groups, ultrasound was performed on the liver every week to check its density. Blood sampling and liver isolation were performed on three occasions, at 4, 8, and 12 weeks, to check liver enzymes and the histopathological condition of the liver tissue (every week, four animals from each group were randomly selected). Results Liver density changes were evident from the eighth week onward in the positive control group. Histopathological results indicated pathologic changes in the positive control group after 4 weeks. The increase in liver enzymes in the positive control group was significantly different from that in the treatment and control groups. Conclusions We demonstrated the hepatoprotective effect of H. leucospilota on DMN‐induced liver damage in rats using biochemical and histological parameters and ultrasonography. More additional research (in silico or in vitro) is needed to find the exact mechanism and the main biological compound in H. leucospilota.

Abstract Background The holothurians, commonly known as sea cucumbers, are marine organisms that possess significant dietary, nutritional, and medicinal value. However, the National Center for Biotechnology Information (NCBI) currently possesses only approximately 70 complete mitochondrial genome datasets of Holothurioidea, which poses limitations on conducting comprehensive research on their genetic resources and evolutionary patterns. In this study, a novel species of sea cucumber belonging to the genus Benthodytes, was discovered in the western Pacific Ocean. The genomic DNA of the novel sea cucumber was extracted, sequenced, assembled and subjected to thorough analysis. Results The mtDNA of Benthodytes sp. Gxx-2023 (GenBank No. OR992091) exhibits a circular structure spanning 17,386 bp, comprising of 13 protein-coding genes (PCGs), 24 non-coding RNAs (2 rRNA genes and 22 tRNA genes), along with two putative control regions measuring 882 bp and 1153 bp, respectively. It exhibits a high AT% content and negative AT-skew, which distinguishing it from the majority of sea cucumbers in terms of environmental adaptability evolution. The mitochondrial gene homology between Gxx-2023 and other sea cucumbers is significantly low, with less than 91% similarity to Benthodytes marianensis, which exhibits the highest level of homology. Additionally, its homology with other sea cucumbers is below 80%. The mitogenome of this species exhibits a unique pattern in terms of start and stop codons, featuring only two types of start codons (ATG and ATT) and three types of stop codons including the incomplete T. Notably, the abundance of AT in the Second position of the codons surpasses that of the First and Third position. The gene arrangement of PCGs exhibits a relatively conserved pattern, while there exists substantial variability in tRNA. Evolutionary analysis revealed that it formed a distinct cluster with B. marianensis and exhibited relatively distant phylogenetic relationships with other sea cucumbers. Conclusions These findings contribute to the taxonomic diversity of sea cucumbers in the Elasipodida order, thereby holding significant implications for the conservation of biological genetic resources, evolutionary advancements, and the exploration of novel sea cucumber resources.

This work aimed to explore the difference of quality among commercial ready-to-eat sea cucumber products. The sensory, texture, chemical composition, nutritional quality and digestibility of four common commercial sea cucumber from Dalian (sea cucumber with high moisture content (HW-DLS), seasoned sea cucumber with low moisture content (FLW-DLS), sea cucumber with low moisture content (LW-DLS)) or Fujian (sea cucumber with high moisture content (HW-FJS)) were determined. Furthermore, principal component analysis (PCA) was applied to evaluate comprehensive quality of products. The results from sensory analysis revealed that the colour appearance of all sample were good. FLW-DLS had the most acceptable taste characteristics. There was a difference of texture characteristics in samples. The ash, total carbohydrate, and salt contents of FLW-DLS were significantly higher than those of other sea cucumbers (P

The sandfish Holothuria (Metriatyla) scabra, is a high-value tropical sea cucumber harvested from wild stocks for over four centuries in multi-species fisheries across its Indo-Pacific distribution, for the global bê che-de-mer (BDM) trade. Within Southeast Asia, the Philippines is an important centre of the BDM trade, however overharvesting and largely open fishery management have resulted in declining catch volumes. Sandfish mariculture has been developed to supplement BDM supply and assist restocking efforts; however, it is heavily reliant on wild populations for broodstock supply. Consequently, to inform fishery, mariculture, germplasm and translocation management policies for both wild and captive resources, a high-resolution genomic audit of 16 wild sandfish populations was conducted, employing a proven genotyping-bysequencing approach for this species (DArTseq). Genomic data (8,266 selectively-neutral and 117 putatively-adaptive SNPs) were used to assess finescale genetic structure, diversity, relatedness, population connectivity and local adaptation at both broad (biogeographic region) and local (within-biogeographic region) scales. An independent hydrodynamic particle dispersal model was also used to assess population connectivity. The overall pattern of population differentiation at the country level for H. scabra in the Philippines is complex, with nine genetic stocks and respective management units delineated across 5 biogeographic regions: (1) Celebes Sea, (2) North and (3) South Philippine Seas, (4) South China and Internal Seas and (5) Sulu Sea. Genetic connectivity is highest within proximate marine biogeographic regions (mean Fst=0.016), with greater separation evident between geographically distant sites (Fst range=0.041-0.045). Signatures of local adaptation were detected among six biogeographic regions, with genetic bottlenecks at 5 sites, particularly within historically heavilyexploited locations in the western and central Philippines. Genetic structure is influenced by geographic distance, larval dispersal capacity, species-specific larval development and settlement attributes, variable ocean current-mediated gene flow, source and sink location geography and habitat heterogeneity across the archipelago. Data reported here will inform accurate and sustainable fishery regulation, conservation of genetic diversity, direct broodstock sourcing for mariculture and guide restocking interventions across the Philippines. [ABSTRACT FROM AUTHOR]

Artificial reefs have been advocated and implemented as management tools for aquaculture, species conservation and habitat replacement. However, the shelter capacity of artificial reefs and its influencing factors are still not well understood. In this study, we identified factors that may limit the shelter capacity of artificial reefs for sea cucumber (Apostichopus japonicas) with a laboratory experiment. We investigated how water flow and food availability affect the shelter capacity and conducted shelter utilization experiments to determine whether sea cucumber sheltering behavior was density dependent. The results revealed that shelter capacity of artificial reefs in high velocity is significantly higher than that of artificial reefs in low velocity or no velocity. The artificial reefs that were provided food had significantly higher shelter capacity than those that did not have food. The densities did not affect the sheltering capacity of artificial reefs in the laboratory experiment. There was a logarithmic relationship between the shelter capacity and shelter availability assessed by the exposed surface area of the artificial reefs. In conclusion, abundant food resources and high water flow may have a positive effect on the shelter capacity of artificial reefs. [ABSTRACT FROM AUTHOR]

This study employs a multidisciplinary methodology across natural and social sciences to examine relationships between biodiversity loss at sea and urban consumption with a focus on sea cucumber and dried seafood markets in New York City (NYC). The study identified 34 dried seafood retailers across three NYC Chinatown boroughs: Manhattan, Brooklyn, and Queens. Samples of sea cucumber were collected with Chinese-language labels indicating the commodity was from South America, a region of conservation concern. Comparison samples were taken from sea cucumbers labeled from Mexico and Japan. A mitochondrial DNA barcoding method was used to examine the taxonomic origin of 103 samples. Sequence data were successfully obtained from 74 of the samples, 8 of which were classified as brown sea cucumber (Isostichopus fuscus), an endangered species for which harvest is banned in several locations. Semi-structured interviews with dried seafood retailers and consumers (n = 64), moreover, revealed associations between consuming sea cucumber and enhancing human health and limited knowledge of product origins. Collectively, the findings reveal socio-ecological dynamics wherein endangered species on the market coupled with geographic market labeling practices and varying degrees of retailer and consumer knowledge negatively bear on marine biodiversity. Furthermore, given that brown sea cucumbers are abundant on the market, there is a need for developing genetic markers that can trace geographic origin to determine if species were legally harvested. These results indicate that more robust market labeling, training, genetic research, and public outreach are required to advance One Health in urban seafood markets. [ABSTRACT FROM AUTHOR]

Sea cucumbers are the second most diverse class among echinoderms. They are characterized by an elongated body and dermal ossicles in the body wall. Among the included groups in that class, the order Holothuriida encompasses many species of commercial interest. Faced with the threats of biodiversity loss resulting from the climate crisis and the advancement of cities, this study provides an overview of recent research involving the Holothuriida of the Brazilian Coast. Searches were carried out in the main periodical databases, using appropriate keywords, targeting publications on the subject in the period between 2000 and 2023. In total, 69 publications were found, most of them corresponding to scientific articles in international journals. Most of the studies come from the Northeast region in Brazil (56.52%). Regarding lines of research, those involving taxonomy and molecular analysis were the most prevalent. Over these 20 years, seven species constituted new occurrences. Of note are the studies focused on Holothuria (Halodeima) grisea, which makes up 39.13% of papers. Despite progress, little is known about morphological variations, genetic distance between populations, population densities, and on reproductive biology of species. Brazil has a vast, heterogeneous coastal area, with unique characteristics to which the species are adapted. The findings reinforce the importance to expand studies aiming on knowing the biodiversity, reproductive biology, and population densities of species. Such data are essential for the creation of public policies aimed at the conservation of species of Holothuriida and their habitats. [ABSTRACT FROM AUTHOR]

Sea cucumbers from unharvested areas, are underutilized resources which may have the potential to become a future food resource. The aim of this study was to evaluate protein quality and investigate the changes in antioxidant activity from frozen and freeze-dried red sea cucumber (Parastichopus tremulus) subjected to digestion, using an in vitro digestion model. P. tremulus constituted high moisture content (90%), comparable protein (4%) and ash (4%) content, and low lipid (1%) content. The biochemical components in freeze-dried samples were largely retained during the freeze-drying process. Frozen samples showed significantly higher (p < 0.05) antioxidant activity compared to freeze-dried samples (calculated on a dry weight basis). The quantity of essential amino acids was high (31%) and corresponds to the Food and Agriculture Organization of the United Nations reference protein. Frozen samples showed an increase in antioxidant activity during digestion measured by three different antioxidant assays. Freeze-dried samples only showed an increase in one of the antioxidant assays. Correlations (p < 0.05) were found between specific free amino acids and antioxidant activity. The amount of free amino acids exceeded the threshold to taste bitter, umami, sour, and sweet flavors. This study showed that P. tremulus constitutes good protein quality, performed antioxidant activity, and has the potential to be used as a flavor-enhancing ingredient. [ABSTRACT FROM AUTHOR]

Skin ulceration syndrome of sea cucumbers is one of the most serious diseases in intensive aquaculture, and it is the most effective way of preventing the spread of this disease to detect the abnormal behavior of sea cucumbers in time and take corresponding measures. However, the detection and tracking of multi-object is a hard problem in sea cucumber behavior analysis. To solve this problem, this paper first proposes a novel one-stage algorithm SUS-YOLOv5 for multi-object detection and tracking of sea cucumbers. The proposed SUS-YOLOv5 optimizes the maximum suppression algorithm in the overlapping region of the object detection box. Next, the SE-BiFPN feature fusion structure is proposed to enhance the transmission efficiency of feature information between deep and shallow layers of the network. Then, a MO-Tracking algorithm is proposed integrated with DeepSORT to achieve real-time multi-object tracking. Experimental results show that the mAP@0.5 and mAP@0.5:0.95 of the proposed object detector reach 95.40% and 83.80%, respectively, which are 3.30% and 4.10% higher than the original YOLOv5s. Compared with the traditional SSD, YOLOv3, and YOLOv4, the mAP of SUS-YOLOv5 is improved by 5.49%, 1.57%, and 3.76%, respectively. This research can realize the multiobject detection and tracking, which lays the foundation for the prediction of skin ulceration syndrome in sea cucumbers and has a certain practical application value for improving the intelligence level of aquaculture. [ABSTRACT FROM AUTHOR]

Numerous spatiotemporal species distribution modeling frameworks are now available to the ecological practitioner. This study compared three such frameworks accessible in the R programming language: generalized additive models with spatiotemporal smooths as implemented by mgcv, spatiotemporal generalized linear mixed models based on nearest neighbor Gaussian processes as implemented by starve, and spatiotemporal generalized linear mixed models based on the stochastic partial differential equations approach as implemented by sdmTMB. The primary focus was to compare the inferences obtained from applying these frameworks to the case study of the orange‐footed sea cucumber, Cucumaria frondosa, on the Scotian Shelf off Nova Scotia, Canada. Each model was fit to catch data (2000–2019) from Fisheries and Oceans Canada's annual Research Vessel and Snow Crab surveys. Environmental covariates were sourced from high‐resolution data layers, including physical oceanographic, bathymetric, and seafloor morphometric datasets. The three models captured variability in sea cucumber distribution that would have been overlooked without a spatiotemporal approach. Although their predictions were similar, including within C. frondosa spatial reserves, the models provided different inferences regarding covariate effects. This suggests that while practitioners primarily interested in mapping species distributions need only apply the most familiar framework, those most concerned with identifying predictive environmental covariates may benefit from comparing the output from multiple approaches. Employing multiple approaches can also serve as a validation technique. [ABSTRACT FROM AUTHOR]

Image analysis is being developed to improve the efficiency of fishery and aquaculture technologies. Optical cameras are an easy and cost-effective method for monitoring fish and other species. In this study, a monitoring system that combines an underwater time-lapse camera and a deep learning-based image analysis was developed for utilization in integrated multi-trophic aquaculture (IMTA). The sea cucumber (Apostichopus japonicus) was used as a target species because the technology necessary for estimating growth, particularly in terms of weight, of caged sea cucumber using an underwater environment is still under study. Therefore, semantic segmentation was applied to classify the images into caged sea cucumbers and various underwater backgrounds. Multiple images of sea cucumbers were captured in a water tank that mimicked the box cage used in IMTA, and their body weights were measured simultaneously. For model development, approximately 1,300 images were prepared for the training and validation processes. The model then achieved an IoU (Intersection over Union) of approximately 94 % for the validation data. Next, the pixel numbers of sea cucumbers were converted into an area calculated using the size of the cage net as the background. The relationship between the area and weight of sea cucumbers yielded an approximate line for estimating body weight. As a result, the approximation line had a coefficient of determination of R2 = 0.87 for training and validation data and RMSE (Root Mean Square Error) =1.81 and 6.78 g for sea cucumbers less than 10 and 110 g, respectively. Using the model, test images in an actual IMTA situation were applied, and the estimated body weights were close to the measured values for small sea cucumbers. If we apply this model to images obtained over an extended period, the growth of sea cucumbers in a time series can be understood.

Abstract The growing interest in valorizing industrial by-products has led researchers to focus on exploring different sources and optimizing collagen extraction conditions over the past decade. While bovine hide, cattle bones, pork, and pig skins remain the most abundant collagen sources, there is a growing trend in the industrial utilization of collagen from non-mammalian species. This review explores alternative marine collagen sources and summarizes emerging trends in collagen recovery from marine sources, with a particular focus on environmentally friendly methods. Additionally, this review covers the colloidal structure-forming properties of marine collagens, including foam, film, gel, and emulsion formation. It also highlights the potential and important applications of marine collagen in various food products. Based on the currently reported marine sources, collagens extracted from fish, jellyfish, and sea cucumbers were found to have the highest yield and mostly comprised type-I collagen, while crustaceans and mollusks yielded lower percentages of collagen. Traditional extraction techniques isolate collagen based on acetic acid and pepsin treatment, but they come with drawbacks such as being time-consuming, causing sample destruction, and using solvents. Conversely, marine collagen extracted using conventional methods assisted with ultrasonication resulted in higher yields and strengthened the triple-stranded helical structures. Recently, an increasing number of new applications have been found in the food industry for marine collagens, such as biodegradable film-forming materials, colloid stabilizers, foaming agents, and micro-encapsulating agents. Furthermore, collagen is a modern foodstuff and is extensively used in the beverage, dairy, and meat industries to increase the stability, consistency, and elasticity of products. Graphical abstract

Abstract Sea cucumbers, belonging to class Holothuroidea, are marine invertebrates with substantial bioactive compounds. This study provides the first comparative metabolome profiling of Holothuria atra and Actinopyga crassa sea cucumbers in relation to their season of collection to dissect between winter and summer samples, providing several first‐time reported metabolites as well as the effect of metabolome variation on their cytotoxic activity against colon and prostate cancer cell lines. Ultrahigh‐performance liquid chromatography coupled with high‐resolution mass spectrometry and global natural products social molecular networking followed by multivariate data analysis were employed for metabolite profiling and seasonal biomarker assignment for each species. The cytotoxic activity was evaluated using in vitro assays against prostate and colon cancer cell lines. A total of 113 metabolites were annotated in both species, including 4 organic acids, 21 sulfoquinovosyl glycerol (sulfolipids), 5 alkyl sulfates, 13 sulfated/saponins, 8 sulfated/triterpene mono/di‐glycosides, 10 triterpenes, 13 sulfated/sterols, 32 phospholipids, 4 sphingolipids, and 3 glycerolipids, several of which are new or first‐time reported. Multivariate data analyses revealed lipid accumulation in summer samples versus triterpene and saponin enrichment in winter‐collected samples, particularly in H. atra, rationalizing its potent cytotoxic activity (IC50 6–12 µg/mL) as revealed using a regression model. However, winter‐collected samples of A. crassa are relatively the least abundant in antinutrient saponins, thus considered to have higher food value.

In order to provide reference for the comprehensive development and utilization, the nutritional function components of wild sea cucumbers in different sea areas were explored. This study comprehensively analyzed the nutritional composition of four wild sea cucumber species: Stichopus horrens, Stichopus chloronotus, Holothuria mammata, and Cucumaria frondosa. The basic nutritional composition, amino acid, fatty acid, and mineral element contents of the four sea cucumbers species were analyzed and evaluated. The results showed that the four species had high protein and low fat in common. Holothuria mammata exhibited the highest protein and lowest fat content. Stichopus chloronotus was rich in polysaccharides and ash content, while Cucumaria frondosa had notable saponin content. Each of the four sea cucumber types contained a consistent array of 17 amino acids, boasting substantial quantities of both delectable and medicinal amino acids. The essential amino acids accounted for a range of 13.78% to 20.27%, with Cucumaria frondosa displayed the most elevated content. Through the assessment of amino acid scores (AAS) and chemical scores (CS), lysine emerges was the predominant limiting amino acid across all four sea cucumber species. In terms of fatty acid composition, all species exhibited a spectrum of saturated fatty acids (SFA) within total fatty acids, with content varying from 23.84% to 36.24%. Palmitic acid (C16:0) and stearic acid (C18:0) constituted the primary components of this SFA makeup. Notably, polyunsaturated fatty acid (PUFA) content ranged from 56.39% to 72.93%, with Cucumaria frondosa displayed the highest proportion. Among the major elements, calcium (Ca) content was relatively higher in all four samples, except for Holothuria mammata. Among the trace elements, the highest content was iron (Fe). This comparative analysis showed that wild sea cucumbers in different sea areas were rich in various nutrients that the human body needs, and had different edible values and development utilization.

Research on ecologically and economically important sea cucumbers has been focused on temperate and tropical species, leaving those from higher latitudes, such as the Canadian Arctic, understudied. This study compared the phenotypic characters of the sea cucumber Cucumaria frondosa sampled from populations of the Arctic (Hudson Bay, Nunavut) and Northwest Atlantic (Newfoundland). Organ indices and external and internal tissue pigmentation, and various biochemical metrics (proximate composition, lipids, fatty acids, amino acids, lipid-soluble vitamins, carotenoids) were assessed. All sea cucumbers had similar total body weights, but those from Newfoundland had heavier gonads and body walls, while the tissue pigmentation of Nunavut individuals was distinctive (more red and yellow trivium, darker brown pigmentation). Moisture and ash contents of sea cucumbers were similar between locations; however, protein and lipid contents in Nunavut samples were 12 and 50% lower, respectively. Inversely, Nunavut samples contained more ω-3 fatty acids, a greater degree of lipid desaturation, double the concentration of proline and vitamin A, and more carbohydrates and astaxanthin than Northwest Atlantic samples. Examining phenotypic variability across latitudes and longitudes, including into the Arctic, highlights unique physical and biochemical features attributed to this specific environment and may support the sustainable development of sea cucumber fisheries.

Abstract A challenge for evolutionary developmental (evo-devo) biology is to expand the breadth of research organisms used to investigate how animal diversity has evolved through changes in embryonic development. New experimental systems should couple a relevant phylogenetic position with available molecular tools and genomic resources. As a phylum of the sister group to chordates, echinoderms extensively contributed to our knowledge of embryonic patterning, organ development and cell-type evolution. Echinoderms display a variety of larval forms with diverse shapes, making them a suitable group to compare the evolution of embryonic developmental strategies. However, because of the laboratory accessibility and the already available techniques, most studies focus on sea urchins and sea stars mainly. As a comparative approach, the field would benefit from including information on other members of this group, like the sea cucumbers (holothuroids), for which little is known on the molecular basis of their development. Here, we review the spawning and culture methods, the available morphological and molecular information, and the current state of genomic and transcriptomic resources on sea cucumbers. With the goal of making this system accessible to the broader community, we discuss how sea cucumber embryos and larvae can be a powerful system to address the open questions in evo-devo, including understanding the origins of bilaterian structures.

Study purpose. This study aims to analyze and highlight the potential of Sea Cucumber in reducing oxidative stress and inflammation caused by exercise. Materials and methods. The study is a type of systematic review research using searches from various journal databases such as Science Direct, Pubmed and Web of Science. The inclusion criteria in this study were journals published in the last 5 years which discussed sea cucumber, oxidative stress, inflammation and exercise. Furthermore, the exclusion criteria in this research are journals that are not reputable or are not indexed by Scopus and Web of Science. A total of 1038 articles from the Science Direct, Pubmed and Web of Science databases were identified. A total of 8 articles that met the inclusion criteria were selected and analyzed for this systematic review. For standard operations, this study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) assessment. Results. The results of this systematic review research report that the strong phenolic content found in Sea Cucumber has anti-oxidant properties which may reduce oxidative stress. Furthermore, the anti-inflammatory properties of sea cucumbers have the potential to reduce uncontrolled inflammation caused by intense exercise. Conclusions. The phenolic content in sea cucumbers has strong anti-oxidant properties in reducing oxidative stress. In addition, the anti-inflammatory properties of sea cucumbers may reduce uncontrolled inflammation caused by exercise. In this case, sea cucumbers have an anti-inflammatory effect by suppressing the secretion of pro-inflammatory cytokines. Through this systematic review, we recommend that future studies should perform clinical trials on the potential effects of sea cucumber on oxidative stress biomarkers and inflammatory biomarkers after exercise.

To improve the ease of eating sea cucumbers, we investigated the impact of puffing temperature (190 °C - 250 °C) and time (1–5 min) on their quality and flavor. As temperature and time increased, sea cucumber puffing significantly enhanced. The microstructure of the puffed sea cucumber exhibited a uniform porous structure at 230 °C for 4 min. However, further puffing treatment caused the void to collapse. A total of 81 volatile organic compounds (VOCs) were identified using HS-GC-IMS, and 18 VOCs with Relative odor activity value (ROAV) ≥1 were identified. The content of fishy compounds, such as dimethyl sulfide, 1-octanal, and 1-nonanal in sea cucumbers gradually decreased with increasing temperature and time. Combined with GC–MS analysis indicating that the flavor of sea cucumbers puffed at 250 °C for 5 min was superior. Our findings suggest new avenues for sea cucumber processing and address the limited research on puffing techniques for protein-based raw materials.

Many species of sea cucumbers (Echinodermata, Holothuroidea) perform evisceration, i.e., ejection of internal organs including digestive tracts when responding to environmental stresses. After evisceration, they also show a high regenerative capacity, in which all the eviscerated organs regenerate. Especially in anterior evisceration species, the oral complex structure consisting of multiple organs, including the digestive tract and central nervous system, are reconstructed. The detailed developmental mechanisms underlying the process remains unclear, and therefore, in this study, focusing on Eupentacta quinquesemita, gene expression analyses in the regenerating tissues were carried out. For the formation of the gut tube, genes involved in mesenchymal-epithelial transition were upregulated consistently with the histological changes. Upregulation of Hox and Parahox genes along the anterior-posterior axis was observed, implying the involvement of these genes in the spatial differentiation of the digestive tract. In addition, the expression of otx, six and pax, i.e., transcription factors patterning anterior nervous tissues, was upregulated during the regeneration of the central nervous system. Taken together, these results suggest that conserved genes are co-opted to the internal organ regeneration after evisceration in sea cucumbers. [ABSTRACT FROM AUTHOR]

The growing interest in valorizing industrial by-products has led researchers to focus on exploring different sources and optimizing collagen extraction conditions over the past decade. While bovine hide, cattle bones, pork, and pig skins remain the most abundant collagen sources, there is a growing trend in the industrial utilization of collagen from non-mammalian species. This review explores alternative marine collagen sources and summarizes emerging trends in collagen recovery from marine sources, with a particular focus on environmentally friendly methods. Additionally, this review covers the colloidal structure-forming properties of marine collagens, including foam, film, gel, and emulsion formation. It also highlights the potential and important applications of marine collagen in various food products. Based on the currently reported marine sources, collagens extracted from fish, jellyfish, and sea cucumbers were found to have the highest yield and mostly comprised type-I collagen, while crustaceans and mollusks yielded lower percentages of collagen. Traditional extraction techniques isolate collagen based on acetic acid and pepsin treatment, but they come with drawbacks such as being time-consuming, causing sample destruction, and using solvents. Conversely, marine collagen extracted using conventional methods assisted with ultrasonication resulted in higher yields and strengthened the triple-stranded helical structures. Recently, an increasing number of new applications have been found in the food industry for marine collagens, such as biodegradable film-forming materials, colloid stabilizers, foaming agents, and micro-encapsulating agents. Furthermore, collagen is a modern foodstuff and is extensively used in the beverage, dairy, and meat industries to increase the stability, consistency, and elasticity of products. [ABSTRACT FROM AUTHOR]

To prevent alcoholic liver disease, the addition of bioactive substances to the alcoholic drink Baijiu has been considered a feasible option. In the present study, the hepatoprotective effects of a sea cucumber sulfated polysaccharide (SCSP) isolated from Stichopus japonicu were investigated. Moreover, in order to enhance its solubility in an alcohol solution, it was depolymerized using a photocatalytic reaction, and the photocatalytic degradation products (dSCSPs) with an average molecular weight of less than 2 kDa were studied and compared with SCSP. They were characterized by a series of chemical and spectroscopy methods and the oligosaccharide fragments in the dSCSP were further identified by HPLC-MSn analysis. Then, the in vivo experiment showed that the addition of SCSP or dSCSP to Baijiu could alleviate alcoholic liver injury in mice. Further analysis also revealed their protective effect in reducing oxidative stress damage and their regulation of the metabolism of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in the liver. Of note, dSCSP was more effective at reducing the level of malondialdehyde in the liver. These findings indicate that the addition of sea cucumber polysaccharide or its low-molecular-weight derivative in Baijiu has the potential to alleviate alcoholic liver injury. [ABSTRACT FROM AUTHOR]

Deep-sea holothurian specimens were collected during five scientific expeditions (2018–2023) using the submersible vehicle ‘Shenhaiyongshi’. Our examination of specimens of Deimatidae from the South China Sea and the Mariana fore-arc area revealed three new species, which were described as Oneirophanta idsseica sp. nov., Oneirophanta brunneannulata sp. nov., and Oneirophanta lucerna sp. nov. These species were distinguished from each other and from congeners by the arrangement, and number of ventrolateral tube feet and ossicle types. We also reported Oneirophanta mutabilis mutabilis Théel, 1879 for the first time from the Mariana fore-arc area, and we recorded Deima validum validum for the second time from the South China Sea. The taxonomy of these new species and new records is discussed, and a phylogenetic analysis based on a concatenated dataset of 16S and COI genes was conducted. Additionally, the inter- and intraspecific genetic divergences we calculated among deimatid species. The results support the assignment of these new species to the genus Oneirophanta and their separation from congeners. A description of the main morphological characters of Oneirophanta species is also provided. The data were collected from geographically diverse areas and suggest that species of Deimatidae were abundant in the Pacific Ocean and occupied a wide range of depths. [ABSTRACT FROM AUTHOR]

A challenge for evolutionary developmental (evo-devo) biology is to expand the breadth of research organisms used to investigate how animal diversity has evolved through changes in embryonic development. New experimental systems should couple a relevant phylogenetic position with available molecular tools and genomic resources. As a phylum of the sister group to chordates, echinoderms extensively contributed to our knowledge of embryonic patterning, organ development and cell-type evolution. Echinoderms display a variety of larval forms with diverse shapes, making them a suitable group to compare the evolution of embryonic developmental strategies. However, because of the laboratory accessibility and the already available techniques, most studies focus on sea urchins and sea stars mainly. As a comparative approach, the field would benefit from including information on other members of this group, like the sea cucumbers (holothuroids), for which little is known on the molecular basis of their development. Here, we review the spawning and culture methods, the available morphological and molecular information, and the current state of genomic and transcriptomic resources on sea cucumbers. With the goal of making this system accessible to the broader community, we discuss how sea cucumber embryos and larvae can be a powerful system to address the open questions in evo-devo, including understanding the origins of bilaterian structures. [ABSTRACT FROM AUTHOR]

Holothuria scabra is widely used in traditional medicine or consumed as a healthy or exotic food, causing wild stocks to decrease. Therefore, aquaculture is the best solution to address this issue and support the growing market demand. However, up to now, H. scabra production is facing problems related to the nursery phase, survival rate of larvae and juveniles, production cost, and broodstock for mass production. In this study, the juveniles of H. scabra were divided into three different stocking densities and fed with 1 g of dissolved Spirulina powder once on alternate days. Their length was recorded every two weeks. After six weeks, the juveniles reared with 100 individual densities showed the highest survival rate at 80% compared to 200 and 400 stocking densities. Meanwhile, every tank showed a positive growth rate, indicating that Spirulina powder could potentially promote the growth of juvenile H. scabra. The specific growth rate for stocking density at 100, 200, and 400 were 1.2, 0.86, and 1.37%/day, respectively. In conclusion, the optimum initial stocking density is between 100 and 200 individuals for a 1-ton fibreglass tank with a 500 L water capacity. The Spirulina can be used as the main protein source as compared to other diets for juvenile H. scabra. [ABSTRACT FROM AUTHOR]

Black teatfish (Holothuria whitmaei) is a high value sea cucumber that has been listed under the Convention on International Trade of Endangered Species (CITES) Appendix II. The Black teatfish fishery in Torres Strait, Australia, is fished solely by Indigenous Torres Strait Islanders. Black teatfish were closed to fishing in 2003, based on the results of stock surveys and concerns of overexploitation. A stock survey in 2009 found the Black teatfish population had recovered substantially but the fishery was again closed after trial openings exceeded catch limits. In line with a new harvest strategy adopted for the fishery in 2019, we conducted a stock survey in 2019–2020 that suggested the stock had recovered sufficiently to support a sustainable catch limit of 20 t. Empowering Indigenous Torres Strait Islanders to use Island custom alongside western management strategies, contributed to the success of a trial opening in 2021. The combination of a harvest strategy developed in consultation with traditional owners, a rigorous scientific survey and trial opening protocols informed by Island custom, supported the CITES positive Non‐Detriment Finding for the Torres Strait Bêche‐de‐mer Fishery. This is a significant example of the successful recovery and ongoing sustainable management of a depleted sea cucumber population. [ABSTRACT FROM AUTHOR]

Study purpose. This study aims to analyze and highlight the potential of Sea Cucumber in reducing oxidative stress and inflammation caused by exercise. Materials and methods. The study is a type of systematic review research using searches from various journal databases such as Science Direct, Pubmed and Web of Science. The inclusion criteria in this study were journals published in the last 5 years which discussed sea cucumber, oxidative stress, inflammation and exercise. Furthermore, the exclusion criteria in this research are journals that are not reputable or are not indexed by Scopus and Web of Science. A total of 1038 articles from the Science Direct, Pubmed and Web of Science databases were identified. A total of 8 articles that met the inclusion criteria were selected and analyzed for this systematic review. For standard operations, this study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) assessment. Results. The results of this systematic review research report that the strong phenolic content found in Sea Cucumber has anti-oxidant properties which may reduce oxidative stress. Furthermore, the anti-inflammatory properties of sea cucumbers have the potential to reduce uncontrolled inflammation caused by intense exercise. Conclusions. The phenolic content in sea cucumbers has strong anti-oxidant properties in reducing oxidative stress. In addition, the anti-inflammatory properties of sea cucumbers may reduce uncontrolled inflammation caused by exercise. In this case, sea cucumbers have an anti-inflammatory effect by suppressing the secretion of pro-inflammatory cytokines. Through this systematic review, we recommend that future studies should perform clinical trials on the potential effects of sea cucumber on oxidative stress biomarkers and inflammatory biomarkers after exercise. [ABSTRACT FROM AUTHOR]

Chilean sea cucumber, Athyonidium chilensis, has both a high nutritional value and a high economic potential to increase the trade of other marine products. Currently there is a minimal commercialization of sea cucumber within Chile, and it is sold exclusively to China in dry or frozen forms where it is then used nutraceutical, cosmetic and nutricosmetic products marketed mostly in Asia. The objective of this study was to determine the nutritional, heavy metals, mineral and amino acids contents of Chilean sea cucumber (eviscerated and ground form) and compare its antioxidant capacity following three different drying processes. The results showed that A. chilensis had very high level of protein contain (68.17%), ash (17.41%), fiber (13.22%), and very low fat and carbohydrate contents. The antioxidant activity measured by ORAC (oxygen radical absorbance capacity) was between 6676.34 and 10,321.30 μmol TE(Trolox equivalents)/100 g, depending on the drying process used. Amino acid profile analysis showed that total amino acids in Chilean sea cucumber was 60.3 g/100 g protein. The information obtained illuminates the antioxidant capacity and amino acid profile that has not previously been reported for Athyonidium chilensis, which indicates that this species has a competitive commercial value for use in food or nutraceutical products, when compared to similar sea cucumbers found on the international market.

The surging market demand for sea cucumbers (Apostichopus japonicus) has fueled a thriving growth in the sea cucumber breeding industry. Pheromones are molecules that evolve signals in defined proportions in the case of multicomponent pheromones, emitted by one individual and received by a second individual of the same species to cause a specific response. It remains an enigma as to how the species of sea cucumber, devoid of visual, auditory, and olfactory senses, aggregate and communicate within their groups, as well as coordinate gamete release during the breeding period. We hypothesize that pheromones may serve as the medium for facilitating these behaviors and propose conducting experiments centered around pheromonal investigation. In this study, we aimed to analyze common metabolites of male A. japonicus using LC-MS/MS technology and bioinformatics. Coelomic fluid and ejaculate fluid were analyzed, with aquaculture water serving as the control. Eight target pheromones were analyzed, and eight of metabolite analogs were tested for aggregation and spawning behaviors. Results showed that β-sitosterol at a concentration of 10 μg·L−1 significantly promoted aggregation (21.25 % average rate) and induced a significant increase in spawning rate (58 %) of A. japonicus. The significance of this study lies in the fact that by collecting and utilizing pheromones of A. japonicus, farmers can accurately determine the reproductive cycle and optimal breeding season for A. japonicus. This enables fish farmers to implement effective breeding management strategies at the appropriate time, thereby increasing the success rate of reproduction and providing valuable technical support for the cultivation of A. japonicus seedlings.

The accumulation of heavy metals in the edible tissue of the white spot sea cucumber, Holothuria poli, revealed the transfer of metal contaminants to sea cucumbers when produced below fish cages in a Mediterranean port area. Sea cucumbers were cultured on the seafloor directly below a fish cage at 0 m, then at 10 m and at 25 m away from the cage, as part of an open-water integrated multi-trophic aquaculture (IMTA) system, and then at a reference site over 1 km from the fish farm, over a one-year period. At the end of the study, sea cucumbers and seafloor sediments were sampled from the IMTA sites near the fish cages, except at 0 m due to mass sea cucumber mortalities within the first month of the study, and again at the reference site. The concentrations of cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), and zinc (Zn) were significantly higher in sediments near fish cages than the reference site. Localised enrichment from marine aquaculture could explain the significant concentration of metals in sediments below fish cages that are typically ascribed to their use in aquaculture. Arsenic (As), lead (Pb) and mercury (Hg), which are not associated with commercial fish diets, did not vary between sites. Concentrations of iron (Fe), which is available in commercial diets, were similar near fish cages and at the reference site. The body wall/muscle tissue of the sea cucumber. H. poli revealed high concentrations of the essential metals Fe and Zn near fish cages and in natural sediments at the reference site. H. poli can regulate these essential metals that characterised the edible tissue of the sea cucumbers. Non-essential metals like Hg and Cd had the lowest concentrations of all analysed metals in the sea cucumber tissue. However, the bioaccumulation of toxic metals, Hg and As, reveal the bioavailability of these contaminants in sediments and the propensity of bottom-dwelling sea cucumbers to bioconcentrate these metals, when cultured under a commercial fish cage in IMTA and elsewhere in natural sediments in this industrial environment. Holothuria poli did not exhibit bioaccumulation of Cu, Cr, Fe, Ni, Pb and Zn in its body wall/muscle tissue. The bioaccumulation of Hg and As reveal the need to account for the potential effects of farm-level variability throughout longer production cycles and bay-wide dynamics on sediment contamination and bioaccumulation in sea cucumbers until harvest. Site-specific dynamics in ports, whether natural or anthropogenic, can be expected to influence bioaccumulation of metal contaminants and therefore require long-term and fine resolution monitoring for better representation in open-water IMTA production.

The sandfish Holothuria (Metriatyla) scabra, is a high-value tropical sea cucumber harvested from wild stocks for over four centuries in multi-species fisheries across its Indo-Pacific distribution, for the global bêche-de-mer (BDM) trade. Within Southeast Asia, the Philippines is an important centre of the BDM trade, however overharvesting and largely open fishery management have resulted in declining catch volumes. Sandfish mariculture has been developed to supplement BDM supply and assist restocking efforts; however, it is heavily reliant on wild populations for broodstock supply. Consequently, to inform fishery, mariculture, germplasm and translocation management policies for both wild and captive resources, a high-resolution genomic audit of 16 wild sandfish populations was conducted, employing a proven genotyping-by-sequencing approach for this species (DArTseq). Genomic data (8,266 selectively-neutral and 117 putatively-adaptive SNPs) were used to assess fine-scale genetic structure, diversity, relatedness, population connectivity and local adaptation at both broad (biogeographic region) and local (within-biogeographic region) scales. An independent hydrodynamic particle dispersal model was also used to assess population connectivity. The overall pattern of population differentiation at the country level for H. scabra in the Philippines is complex, with nine genetic stocks and respective management units delineated across 5 biogeographic regions: (1) Celebes Sea, (2) North and (3) South Philippine Seas, (4) South China and Internal Seas and (5) Sulu Sea. Genetic connectivity is highest within proximate marine biogeographic regions (mean Fst=0.016), with greater separation evident between geographically distant sites (Fst range=0.041–0.045). Signatures of local adaptation were detected among six biogeographic regions, with genetic bottlenecks at 5 sites, particularly within historically heavily-exploited locations in the western and central Philippines. Genetic structure is influenced by geographic distance, larval dispersal capacity, species-specific larval development and settlement attributes, variable ocean current-mediated gene flow, source and sink location geography and habitat heterogeneity across the archipelago. Data reported here will inform accurate and sustainable fishery regulation, conservation of genetic diversity, direct broodstock sourcing for mariculture and guide restocking interventions across the Philippines.

The sea cucumber (H. glaberrima) is a species found in the shallow waters near coral reefs and seagrass beds in Puerto Rico. To characterize the microbial taxonomic composition and functional profiles present in the sea cucumber, total DNA was obtained from their intestinal system, fosmid libraries constructed, and subsequent sequencing was performed. The diversity profile displayed that the most predominant domain was Bacteria (76.56 %), followed by Viruses (23.24 %) and Archaea (0.04 %). Within the 11 phyla identified, the most abundant was Proteobacteria (73.16 %), followed by Terrabacteria group (3.20 %) and Fibrobacterota, Chlorobiota, Bacteroidota (FCB) superphylum (1.02 %). The most abundant species were Porvidencia rettgeri (21.77 %), Pseudomonas stutzeri (14.78 %), and Alcaligenes faecalis (5.00 %). The functional profile revealed that the most abundant functions are related to transporters, MISC (miscellaneous information systems), organic nitrogen, energy, and carbon utilization. The data collected in this project on the diversity and functional profiles of the intestinal system of the H. glaberrima provided a detailed view of its microbial ecology. These findings may motivate comparative studies aimed at understanding the role of the microbiome in intestinal regeneration.

Antimicrobial peptides (AMPs) from natural sources represent promising candidates for novel antimicrobial agents instead of antibiotics in aquaculture. Moricin, a family of AMPs from Lepidoptera, has shown bactericidal activity against both gram-positive and gram-negative bacteria. However, it remains uncertain whether these peptides possess antimicrobial activity against Vibrio pathogens affecting various aquatic animals, including sea cucumbers. In this study, we investigated five moricin-like peptides (MLPs) from Antheraea pernyi (Anpe) and identified Anpe-MLP1 as a new member of the moricin family through bioinformatics analysis. Anpe-MLP1 was heterologously expressed using the AnpeNPV bacmid system and purified from A. pernyi pupae. Our findings revealed that recombinant Anpe-MLP1 (rAnpe-MLP1) exhibited antimicrobial activity against gram-positive Staphylococcus aureus (S. aureus ATCC 6538 P), gram-negative Escherichia coli (E. coli ATCC 25922) and three Vibrio species. Moreover, both in vitro and in vivo assays showed that rAnpe-MLP1 effectively inhibited wild-type Vibrio fluvialis infections in the sea cucumber (Apostichopus japonicus). These results suggest that Anpe-MLP1 holds great potential as a novel anti-infective agent and provide valuable insights for its future application in aquaculture.

This study assessed potential improvement of sandfish (Holothuria scabra) culture using supplemental feeding with seaweed to explore its potential to support short-cropping. Three phased experiments evaluated juvenile growth and survival performance by: offering two types of seaweed-based supplemental feeds (Sargassum sp. and Gracilaria verrucosa) both processed by fermentation and pulverisation (Experiment 1); evaluating three stocking densities (25, 35 and 45 individuals per m2) using the best-performing diet from Experiment 1 (Experiment 2); and upscaling to commercial-level culture in three 400 m2 earthen ponds (Experiment 3). Fermented diets were prepared using a probiotic mixture (Saccharomyces boulardii, Lactobacillus acidophilus and Bacillus subtilis) added to ground, dried seaweed; while the pulverised diets were offered as a ground powder (350–450 µm particle sizes). Sandfish offered fermented Sargassum and Gracilaria reached 35.0% and 29.7% heavier mean final weights (18.18 ± 0.19 g and 16.81 ± 0.08 g, respectively), compared to their pulverised equivalents (11.82 ± 1.09 g across both seaweed species, p 0.05). Valuable new information has been generated for further development of supplemental feeding of sandfish, and results here demonstrate high technical feasibility to support short cropping, with optimisation of this culture model required.

Abstract Numerous spatiotemporal species distribution modeling frameworks are now available to the ecological practitioner. This study compared three such frameworks accessible in the R programming language: generalized additive models with spatiotemporal smooths as implemented by mgcv, spatiotemporal generalized linear mixed models based on nearest neighbor Gaussian processes as implemented by starve, and spatiotemporal generalized linear mixed models based on the stochastic partial differential equations approach as implemented by sdmTMB. The primary focus was to compare the inferences obtained from applying these frameworks to the case study of the orange‐footed sea cucumber, Cucumaria frondosa, on the Scotian Shelf off Nova Scotia, Canada. Each model was fit to catch data (2000–2019) from Fisheries and Oceans Canada's annual Research Vessel and Snow Crab surveys. Environmental covariates were sourced from high‐resolution data layers, including physical oceanographic, bathymetric, and seafloor morphometric datasets. The three models captured variability in sea cucumber distribution that would have been overlooked without a spatiotemporal approach. Although their predictions were similar, including within C. frondosa spatial reserves, the models provided different inferences regarding covariate effects. This suggests that while practitioners primarily interested in mapping species distributions need only apply the most familiar framework, those most concerned with identifying predictive environmental covariates may benefit from comparing the output from multiple approaches. Employing multiple approaches can also serve as a validation technique.

Sea cucumbers are the second most diverse class among echinoderms. They are characterized by an elongated body and dermal ossicles in the body wall. Among the included groups in that class, the order Holothuriida encompasses many species of commercial interest. Faced with the threats of biodiversity loss resulting from the climate crisis and the advancement of cities, this study provides an overview of recent research involving the Holothuriida of the Brazilian Coast. Searches were carried out in the main periodical databases, using appropriate keywords, targeting publications on the subject in the period between 2000 and 2023. In total, 69 publications were found, most of them corresponding to scientific articles in international journals. Most of the studies come from the Northeast region in Brazil (56.52%). Regarding lines of research, those involving taxonomy and molecular analysis were the most prevalent. Over these 20 years, seven species constituted new occurrences. Of note are the studies focused on Holothuria (Halodeima) grisea, which makes up 39.13% of papers. Despite progress, little is known about morphological variations, genetic distance between populations, population densities, and on reproductive biology of species. Brazil has a vast, heterogeneous coastal area, with unique characteristics to which the species are adapted. The findings reinforce the importance to expand studies aiming on knowing the biodiversity, reproductive biology, and population densities of species. Such data are essential for the creation of public policies aimed at the conservation of species of Holothuriida and their habitats.

Abstract Background Sea cucumbers exhibit a remarkable ability to regenerate damaged or lost tissues and organs, making them an outstanding model system for investigating processes and mechanisms of regeneration. They can also reproduce asexually by transverse fission, whereby the anterior and posterior bodies can regenerate independently. Despite the recent focus on intestinal regeneration, the molecular mechanisms underlying body wall regeneration in sea cucumbers still remain unclear. Results In this study, transverse fission was induced in the tropical sea cucumber, Holothuria leucospilota, through constrainment using rubber bands. Histological examination revealed the degradation and loosening of collagen fibers on day-3, followed by increased density but disorganization of the connective tissue on day-7 of regeneration. An Illumina transcriptome analysis was performed on the H. leucospilota at 0-, 3- and 7-days after artificially induced fission. The differential expression genes were classified and enriched by GO terms and KEGG database, respectively. An upregulation of genes associated with extracellular matrix remodeling was observed, while a downregulation of pluripotency factors Myc, Klf2 and Oct1 was detected, although Sox2 showed an upregulation in expression. In addition, this study also identified progressively declining expression of transcription factors in the Wnt, Hippo, TGF-β, and MAPK signaling pathways. Moreover, changes in genes related to development, stress response, apoptosis, and cytoskeleton formation were observed. The localization of the related genes was further confirmed through in situ hybridization. Conclusion The early regeneration of H. leucospilota body wall is associated with the degradation and subsequent reconstruction of the extracellular matrix. Pluripotency factors participate in the regenerative process. Multiple transcription factors involved in regulating cell proliferation were found to be gradually downregulated, indicating reduced cell proliferation. Moreover, genes related to development, stress response, apoptosis, and cell cytoskeleton formation were also involved in this process. Overall, this study provides new insights into the mechanisms of whole-body regeneration and uncover potential cross-species regenerative-related genes.

This study investigated the physicochemical properties, functionalities, and antioxidant capacities of protein extracts from wild sea cucumber Australostichopus mollis collected from four distinct locations in New Zealand. Protein was extracted from sea cucumber body walls using trypsin enzymatic extraction, followed by cold acetone precipitation. The amino acid analysis revealed high glycine (189.08 mg/g), glutamic acid (119.45 mg/g), and aspartic acid (91.91 mg/g) concentrations in all samples. The essential amino acid indexes of the protein extracts (62.96, average) were higher than the WHO/FAO standard references, indicating the excellent protein quality of A. mollis. Furthermore, protein extracts from A. mollis demonstrated superior emulsifying activity (202.3–349.5 m2/g average) compared to commercial soy and whey protein isolates under all tested pH conditions, and enhanced foaming capacity (109.9–126.4%) and stability (52.7–72%) in neutral and acidic conditions. The extracts also exhibited good solubility, exceeding 70% across pH 3–11. Antioxidant capacities (ABTS and DPPH free radical scavenging activity and ferric reducing antioxidant power) were identified in A. mollis protein extracts for the first time, with clear variations observed among different locations. These findings elucidate the advantageous functional properties of protein extracts from wild New Zealand A. mollis and highlight their potential application as high-quality antioxidant food ingredients.

Sea cucumbers are well demarcated for their valuable role in the food, pharmaceutical, nutraceutical, and cosmeceutical sectors. The demand for well-processed dried sea cucumber retaining quality is prioritized by local markets and industries. There are several techniques for the pre-processing of fresh sea cucumbers, including traditional and modern methods, such as salting, boiling, high-pressure processing, high-pressure steaming, and vacuum cooking, among others, in order to inactivate enzymes and microbial attacks. Further, pre-treated sea cucumbers require post-processing before human consumption, transportation, or industry uses such as hot air, freeze, cabinet, sun, or smoke drying. However, despite the ease, traditional processing is associated with several challenges hampering the quality of processed products. For instance, due to high temperatures in boiling and drying, there is a higher chance of disrupting valuable nutrients, resulting in low-quality products. Therefore, the integration of traditional and modern methods is a crucial approach to optimizing sea cucumber processing to obtain valuable products with high nutritional values and retain bioactive compounds. The value of dried sea cucumbers relies not only on species and nutritional value but also on the processing methods in terms of retaining sensory attributes, including colour, appearance, texture, taste, and odour. Therefore, this review, for the first time, provides insight into different pre- and post-treatments, their perspective, challenges, and how these methods can be optimized for industry use to obtain better-quality products and achieve economic gains from sea cucumber.

Simple Summary: Marine organisms are facing multifaceted changes in their environment due to near-future ocean warming and acidification. We aimed to analyze the impacts of concurrent climate change stressors (seawater warming and acidification) on the embryo/larval development and gene expression patterns of the sea cucumber Apostichopus japonicus. Elevated temperatures have been found to expedite the embryo–larval development of A. japonicus, while decreased pH inhibited these processes, but the effect of combining the former two seemed to be slight. At the transcriptomic level, acidification induced attenuated biomineralization and skeletogenesis, and triggered the risk of extracellular acid–base imbalance and oxidative injury; warming introduced a noticeable stress response; while dual stresses strengthened these stress responses, resulting in reduced immune resistance and heightened system instability. This study provides new insights into the potential adaptive mechanisms employed by sea cucumbers and projects the potential effects of climate change on marine organisms and ecosystems. Ocean acidification (OA) and ocean warming (OW) are potential obstacles to the survival and growth of marine organisms, particularly those that rely on calcification. This study investigated the single and joint effects of OA and OW on sea cucumber Apostichopus japonicus larvae raised under combinations of two temperatures (19 °C or 22 °C) and two pCO2 levels (400 or 1000 μatm) that reflect the current and end-of-21st-century projected ocean scenarios. The investigation focused on assessing larval development and identifying differences in gene expression patterns at four crucial embryo–larval stages (blastula, gastrula, auricularia, and doliolaria) of sea cucumbers, using RNA-seq. Results showed the detrimental effect of OA on the early development and body growth of A. japonicus larvae and a reduction in the expression of genes associated with biomineralization, skeletogenesis, and ion homeostasis. This effect was particularly pronounced during the doliolaria stage, indicating the presence of bottlenecks in larval development at this transition phase between the larval and megalopa stages in response to OA. OW accelerated the larval development across four stages of A. japonicus, especially at the blastula and doliolaria stages, but resulted in a widespread upregulation of genes related to heat shock proteins, antioxidant defense, and immune response. Significantly, the negative effects of elevated pCO2 on the developmental process of larvae appeared to be mitigated when accompanied by increased temperatures at the expense of reduced immune resilience and increased system fragility. These findings suggest that alterations in gene expression within the larvae of A. japonicus provide a mechanism to adapt to stressors arising from a rapidly changing oceanic environment. [ABSTRACT FROM AUTHOR]

Four new mono- and trisulfated triterpene penta- and tetraosides, djakonoviosides C1 (1), D1 (2), E1 (3), and F1 (4) were isolated from the Far Eastern sea cucumber Cucumaria djakonovi (Cucumariidae, Dendrochirotida), along with six known glycosides found earlier in other Cucumaria species. The structures of unreported compounds were established on the basis of extensive analysis of 1D and 2D NMR spectra as well as by HR-ESI-MS data. The set of compounds contains six different types of carbohydrate chains including two new ones. Thus, djakonovioside C1 (1) is characterized by xylose as the second residue, that was a branchpoint in the pentasaccharide chain. Meanwhile, only quinovose and rarely glucose have been found earlier in pentasaccharide chains branched at C-2 of the second sugar unit. Djakonovioside E1 (3) is characterized by a tetrasaccharide trisulfated chain, with glucose as the second residue. So, in the series of isolated glycosides, three types of sugars in the second position were presented: the most common, quinovose—in six compounds; glucose—in three substances; and the rare xylose—in one glycoside. The set of aglycones was composed of holostane- and non-holostane-type polycyclic systems; the latter comprised normal and reduced side chains. Noticeably, isokoreoside A (9), isolated from C. djakonovi, was a single glycoside having a 9(11)-double bond, indicating two oxidosqualenecyclases are operating in the process of the biosynthesis of aglycones. Some of the glycosides from C. djakonovi, which were characterized by pentasaccharide branched chains containing one to three sulfate groups, are chemotaxonomic features of the representatives of the genus Cucumaria. The assortment of sugar parts of Cucumaria's glycosides was broadened with previously undescribed penta- and tetrasaccharide moieties. The metabolic network of sugar parts and aglycones is constructed based on biogenetic relationships. The cytotoxic action of compounds 1–10, isolated from C. djakonovi, against human breast cancer cell lines was investigated along with the hemolytic activity. Erythrocytes were, as usual, more sensitive to the membranolytic action of the glycosides than cancer cells. The triple-negative breast cancer MDA-MB-231 cell line was more vulnerable to the action of glycosides in comparison with the other tested cancer cells, while the MCF-7 cell line was less susceptible to cytotoxic action. Djakonovioside E1 (3) demonstrated selective action against ER-positive MCF-7 and triple-negative MDA-MB-231 cell lines, while the toxic effect in relation to normal mammary epithelial cells (MCF-10A) was absent. Cucumarioside A2-5 (6) inhibited the formation and growth of colonies of cancer cells to 44% and tumor cell migration to 85% of the control. Quantitative structure–activity relationships (QSAR) were calculated on the basis of the correlational analysis of the physicochemical properties and structural features of the glycosidic molecules and their membranolytic activity. QSAR revealed the extremely complex nature of such relationships, but these calculations correlated well with the observed SAR. [ABSTRACT FROM AUTHOR]

Echinoderms, such as sea cucumbers, have the remarkable property of changing the stiffness of their dermis according to the surrounding chemical environments. When sea cucumber dermal specimens are constantly strained, stress decays exponentially with time. Such stress relaxation is a hallmark of visco-elastic mechanical behavior. In this paper, in contrast, we attempted to interpret stress relaxation from the chemoelasticity viewpoint. We used a finite element model for the microstructure of the sea cucumber dermis. We varied stiffness over time and framed such changes against the first-order reactions of the interfibrillar matrix. Within this hypothetical scenario, we found that stress relaxation would then occur primarily due to fast crosslink splitting between the chains and a much slower macro-chain scission, with characteristic reaction times compatible with relaxation times measured experimentally. A byproduct of the model is that the concentration of undamaged macro-chains in the softened state is low, less than 10 % , which tallies with physical intuition. Although this study is far from being conclusive, we believe it opens an alternative route worthy of further investigation. [ABSTRACT FROM AUTHOR]