Sea Cucumber Research Articles

Characterization and comparative effect of drying process on antioxidant activity over Chilean sea cucumber (Athyonidiun chilensis)

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.

Aquaculture of emerging species in North-Eastern Atlantic and Mediterranean Sea: a systematic review on sea cucumber farming and potential development

Sea cucumbers are considered a traditional food delicacy in Asian countries. In last decades high market demand, uncontrolled exploitation and inadequate management have led to stock overexploitation, driving commercial interest in new target species and new areas. In recent years, Mediterranean and North-East Atlantic sea cucumbers have become fishing targets, and, due to overfishing, a significant decline of wild populations have been observed, with detrimental effects on benthic communities and ecosystems. Indeed, in addition to being an important economic resource, sea cucumbers play a key ecological role in benthic dynamics where they are involved as ecosystem engineers in the processing of organic matter in the detrital food web pathway. In this context, aquaculture can play a crucial role in supporting the conservation of natural stocks by reducing harvesting pressure on wild populations and enabling restoration programmes for depleted stocks. Commercial sea cucumber farming is already an established reality in the Indo-Pacific region, where it has become one of the most profitable sectors of aquaculture production. In Europe, on the other hand, sea cucumber aquaculture is still an emerging sector, whose development is hampered by poor and fragmented information on the farming requirements of native species. In this context, this systematic review was carried out with the aim of providing a comprehensive summary of the state of the art of farming practices of the European sea cucumbers considered as a target of commercial fisheries. A total of 34 original articles were included in this review, after title, abstract and full-text screening. The results highlighted a sharp increase in the number of studies over the last six years. Portugal, Turkey and Italy are the countries where most research has been carried out. Among the selected species, Holothuria tubulosa was the most studied, while only one article was found on Parastichopus regalis. The main aims of this review were i) to gather all available literature on the farming practices of North-East Atlantic and Mediterranean sea cucumber species, ii) to outline the most common farming practices, iii) to identify gaps and future directions in this emerging aquaculture sector.

Effectiveness of Sea Cucumber Viscera Waste to Improve Reproductive Performance of Male Tiger Shrimp (Penaeus monodon)

Tiger shrimp has received attention because of the high prices. However, sustainable cultivation of tiger shrimp is still hampered by the low quality of spermatozoa in male broodstock. Sea cucumbers are a type of invertebrate that is very useful because they have many viscera with almost the same nutritional content as fresh food. However, it has other advantages compared to other fresh feeds, namely it has a very high testosterone content so that it can be used to improve the quality and quantity of spermatozoa of male tiger prawns. The study aims to compare the influence between sea cucumber viscera and fresh squid as well as the combination of sea cucumber and squid viscera against the density of tiger shrimp spermatozoa (Penaeus monodon). Test animals used were 18 male tiger shrimp with an average weight of 80.93 g. Shrimp are kept in tanks with a volume of 1 ton, with a density of 3 broodstock/tank and 3 replications. Feeding was carried out with a frequency of 3 times a day and at a dose of 20% of biomass for 30 days. The test feed used consisted of 100% fresh squid feed as a control, a combination of 50% squid and 50% of sea cucumber viscera, and 100% of sea cucumber viscera. The administration of sea cucumber visceral waste in tiger shrimp tend to increase the quantity of spermatozoa tiger shrimp.

Sea Cucumber Polysaccharide from Stichopus japonicu and Its Photocatalytic Degradation Product Alleviate Acute Alcoholic Liver Injury in Mice.

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.

Regio-specific lipid fingerprinting of edible sea cucumbers using LC/MS

Sea cucumbers are a rich source of bioactive compounds and are gaining popularity as nutrient-rich seafood. They are consumed as a whole organism in Pacific regions. However, limited data are available on the comparison of their lipid composition and nutritional value. In this study, untargeted liquid chromatography/mass spectrometry was applied to comprehensively profile lipids in the skin, meat, and intestinal contents of three color-distinct edible sea cucumbers. Multivariate principal component analysis revealed that the lipid composition of the intestinal contents of red, black, and blue sea cucumbers differs from that of skin, and meats. Polyunsaturated fatty acids (PUFAs) are abundant in the intestinal contents, followed by meats of sea cucumber. Lipid nutritional quality assessments based on fatty acid composition revealed a high P:S ratio, low index of atherogenicity, and high health promotion indices for the intestinal contents of red sea cucumber, suggesting its potential health benefits. In addition, hierarchical cluster analysis revealed that the intestinal contents of sea cucumbers were relatively high in PUFA-enriched phospholipids and lysophospholipids. Ceramides are abundant in black skin, blue meat, and red intestinal content samples. Overall, this study provides the first insights into a comprehensive regio-specific profile of the lipid content of sea cucumbers and their potential use as a source of lipid nutrients in food and nutraceuticals.

Molecular Cloning and Functional Analysis of Secretory Phospholipase A2 from Apostichopus japonicus.

Secretory phospholipase A2 (sPLA2) plays important roles in phospholipid metabolism, skin barrier maintenance, immune response and other processes in organisms. sPLA2 of sea cucumber A. japonicus (AjPLA2) has not yet been reported. This study successfully amplified the AjPLA2 sequence. The total cDNA of AjPLA2 is 931bp, including a 480bp ORF that encodes 159 amino acids. The AjPLA2 protein includes a 16-aa signal peptide, a 5-aa precursor peptide and a 138-aa mature peptide. Homologous alignment showed that AjPLA2 and the sPLA2s from starfish have the typical domains of the Group IB sPLA2. And additional amino acid sequences were found around the β-Wing, which is different from the Group IB sPLA2. These results showed that AjPLA2 and sPLA2s from starfish all belong to a new group in the Group I sPLA2 family. AjPLA2 is widely distributed in sea cucumber tissues. The functional analysis also showed that AjPLA2 was upregulated in the intestine by feeding. Whenthe body wall was damaged, it was significantly upregulated around the wound. And the expression levels of AjPLA2 were significantly increased in V. splendens-infected sea cucumbers. The results indicated that AjPLA2 plays roles in the sea cucumber immunologicprocess. Combined with the upregulation of unsaturated fatty acids (PUFAs) content in A. japonicus, it demonstrated that AjPLA2 could participate in the immune of A. japonicus by hydrolyzing phospholipid and releasing PUFAs. This study had a solid foundation for the further research of AjPLA2 gene function in vivo, development and application of AjPLA2 protein.

A2M possesses anti-bacterial functions by recruiting and enhancing phagocytosis through GRP78 in an echinoderm

Alpha-2-macroglobulin (A2M) is an extracellular macromolecule mainly known for its role as a broad-spectrum protease inhibitor in mammals. However, the immune recognition and regulation mechanisms of A2M in invertebrates are still not well investigated. In the current study, the role of sea cucumber Apostichopus japonicus A2M in the regulation of innate immune responses was explored. We found that AjA2M promotes phagocytosis of Vibrio splendidus in coelomocytes of sea cucumber. Then two major functional structural domains of AjA2M, the thioester domain (TED) and the receptor-binding structural domain (RBD) were cloned. It was found that the AjA2M-TED binds to pathogens while causing Vibrio splendidus aggregation; the AjA2M-RBD interacts with the Glucose Regulated Protein 78 (AjGRP78), subsequently AjGRP78 accelerates the degradation of Vibrio splendidus in lysosomes by facilitating polymerisation and rearrangement of the cytoskeleton. Collectively, the findings together suggest that A2M-GRP78 axis mediates immune signaling pathway of phagocytosis and AjA2M has been characterized to play an essential crucial role in antibacterial immune responses of invertebrates.

First Evidence of the Bioaccumulation and Trophic Transfer of Tire Additives and Their Transformation Products in an Estuarine Food Web.

The discovery of the significant lethal impacts of the tire additive transformation product N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q) on coho salmon has garnered global attention. However, the bioaccumulation and trophic transfer of tire additives and their transformation products (TATPs) within food webs remain obscure. This study first characterized the levels and compositions of 15 TATPs in the Pearl River Estuary, estimated their bioaccumulation and trophic transfer potential in 21 estuarine species, and identified priority contaminants. Our observations indicated that TATPs were prevalent in the estuarine environment. Eight, six, seven, and 10 TATPs were first quantified in the shrimp, sea cucumber, snail, and fish samples, with total mean levels of 45, 56, 64, and 67 ng/g (wet weight), respectively. N,N'-Diphenyl-p-phenylenediamine (DPPD) and N,N'-bis(2-methylphenyl)-1,4-benzenediamine (DTPD) exhibited high bioaccumulation. Significant biodilution was only identified for benzothiazole, while DPPD and DTPD displayed biomagnification trends based on Monte Carlo simulations. The mechanisms of bioaccumulation and trophodynamics of TATPs could be explained by their chemical hydrophobicity, molecular mass, and metabolic rates. Based on a multicriteria scoring technique, DPPD, DTPD, and 6PPD-Q were characterized as priority contaminants. This work emphasizes the importance of biomonitoring, particularly for specific hydrophobic tire additives.

Wicked problem of improving fishery livelihoods through capacity building

Development programs can train fishers in value-adding but factors influencing who is likely to benefit are not well understood. Small-scale fishers worldwide often fall short increasing the value of their catch and wellbeing benefits from their harvests. Here, we sought to improve technical capacity of sea cucumber fishers in postharvest processing and examine intrinsic and extrinsic factors that shape long-term livelihood impacts. Manuals, videos and village-based workshops were used to train hundreds of fishers in 29 villages across seven island regions in Fiji. Our linear mixed models found that trained fishers spent more time processing their catch and were more likely to report increased sale prices. However, the fishery was in decline and so fishers’ weekly incomes did not improve overall. The capacity building led to gender-transformative outcomes by motivating women to increase catch rates and it improved their weekly fishery income. Perceived changes in trading prices and economic dependence on the fishery varied regionally, implying inconsistent trader behaviour. Our study reveals that improving fishery livelihoods can be a “wicked problem” involving a complexity of external factors that hinder livelihood impacts. Capacity-building of fishers was insufficient on its own to markedly improve wellbeing. Income also depended on the fishery stocks, equitable behaviour of traders and access of fishers to raw materials for postharvest processing. Development programs should consider a holistic approach through partnerships with institutions to improve the management of natural resources, value chains and technical capacity of fishers.

Apoptosis-inducing factor 1 mediates Vibrio splendidus-induced coelomocyte apoptosis via importin β dependent nuclear translocation in Apostichopus japonicus

As is well known, apoptosis is an important form of immune response and immune regulation, particularly playing a crucial role in combating microbial infections. Apoptosis-inducing factor 1 (AIF-1) is essential for apoptosis to induce chromatin condensation and DNA fragmentation via a caspase-independent pathway. The nuclear translocation of AIF-1 is a key step in apoptosis but the molecular mechanism is still unclear. In this study, the homologous gene of AIF-1, named AjAIF-1, was cloned and identified in Apostichopus japonicus. The mRNA expression of AjAIF-1 was significantly increased by 46.63-fold after Vibrio splendidus challenge. Silencing of AjAIF-1 was found to significantly inhibit coelomocyte apoptosis because the apoptosis rate of coelomocyte decreased by 0.62-fold lower compared with the control group. AjAIF-1 was able to promote coelomocyte apoptosis through nuclear translocation under the V. splendidus challenge. Moreover, AjAIF-1 and Ajimportin β were mainly co-localized around the nucleus in vivo and silencing Ajimportin β significantly inhibited the nuclear translocation of AjAIF-1 and suppressed coelomocyte apoptosis by 0.64-fold compared with control. In summary, nuclear translocation of AjAIF-1 will likely mediate coelomocyte apoptosis through an importin β-dependent pathway in sea cucumber.

Integrated metabolome–metagenome analysis provides new insights into the impacts of sea cucumber (Apostichopus japonicus) aestivation on marine sediment composition

To explore the impacts of sea cucumber aestivation on sediment composition, sediments were sampled from aestivation sites and non-aestivation sites of a commercial Apostichopus japonicus culture pond, and metabolome–metagenome integrated analysis was performed. The results showed that 1) there was no significant difference in the microbial composition of sediments between aestivation and non-aestivation sites, but the relative abundances of some bacterial species changed slightly (especially pathogenic and spoilage species); 2) altered average relative abundances of potential host bacteria of antibiotic resistance genes (ARGs) were observed; 3) compared with non-aestivation site sediments, decreased average absolute abundances of two ARGs (tetW and floR) and increased average absolute abundance of one ARG (tetM) were observed in aestivation site sediments; and 4) a total of 74 significantly differentially expressed metabolites (SDMs) were identified in aestivation sites compared with non-aestivation sites. Four SDMs were closely correlated with antibacterial activity and bacterial physiology. All data observed in this study indicate that sea cucumber aestivation does not affect sediment microbial composition but does influence the relative abundances of some bacteria species; in addition, tetM might be considered a key indicator for monitoring and indicating ARG transfer or the sediment status of sea cucumber culture ponds during aestivation. In conclusion, the observations of this study enrich our knowledge of the impacts of the physiological behavior of marine ecosystem inhabitants on their ecosystem and provide novel insights for the management of aquaculture activities.

Gene-expression patterns during regeneration of the multi-organ complex after evisceration in the sea cucumber Eupentacta quinquesemita

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.

Biochemical and ecological components of Holothuria (Halodeima) grisea, Selenka 1867 (Echinodermata:Holothuroidea)

Sea cucumber is a marine invertebrate that is of great interest in Asian cuisine because of its nutritional characteristics and in scientific research due to its medicinal properties, including antioxidant, anti-inflammatory, antiviral and other actions. Knowledge of biochemical composition is an essential pillar to explain, confirm and/or instigate ecological and reproductive studies. This work aimed to determine the biochemical composition in relation to lipids, proteins and total carbohydrates and fatty acids of the gonad, digestive tract and/or body wall of Holothuria (Halodeima) grisea and relate the biochemical information with environmental conditions (temperature, pH, salinity, food sources) in the winter and summer. Biometric measurements were obtained by weighing of the entire body and the tissues. Quantifications and characterizations of biomolecules were obtained by combining gravimetric and analytical techniques. Sexes were identified using classical histology techniques. Atherogenic (AI), thrombogenic (TI) indices and the hypocholesterolemic/hypercholesterolemic ratio were used to assess the quality of fatty acids. The organisms showed significant differences between seasons and/or between sexes among biometric and biochemical parameters. In general, females have greater amounts of biomolecules than males and these fluctuations are related to water temperature and reproductive stage. The fatty acids coincided with the literature for sea cucumbers and the nutritional quality indices were better than other species, in addition to indicating summer as the ideal season for consumption. Therefore, Holothuria (Halodeima) grisea presented a variable biochemical composition between seasons and sexes, being influenced by water temperature and diet, and has the potential to be used in an aquaculture system and in the management of natural stocks.

Analysis of environmental selection pressure of superoxide dismutase in deep-sea sea cucumber

Analysis of environmental selection pressure of superoxide dismutase in deep-sea sea cucumber

Sea Cucumber Viscera Contains Novel Non-Holostane-Type Glycoside Toxins that Possess a Putative Chemical Defense Function.

Sea cucumbers frequently expel their guts in response to predators and an aversive environment, a behavior perceived as releasing repellents involved in chemical defense mechanisms. To investigate the chemical nature of the repellent, the viscera of stressed sea cucumbers (Apostichopus japonicus) in the Yellow Sea of China were collected and chemically analyzed. Two novel non-holostane triterpene glycosides were isolated, and the chemical structures were elucidated as 3ꞵ-O-[ꞵ-D-glucopyranosyl-(1→2)-ꞵ-D-xylopyranosyl]-(20S)-hydroxylanosta-7,25-diene-18(16)-lactone (1) and 3ꞵ-O-[ꞵ-D-quinovopyranosyl-(1→2)-ꞵ-D-xylopyranosyl]-(20S)-hydroxylanosta-7,25-diene-18(16)-lactone (2) by spectroscopic and mass-spectrometric analyses, exemplifying a triterpene glycoside constituent of an oligosaccharide containing two sugar-units and a non-holostane aglycone. Zebrafish embryos were exposed to various doses of 1 and 2 from 4 to 96 hpf. Compound 1 exposure showed 96h-LC50 41.5 µM and an increased zebrafish mortality rates in roughly in a dose- and time-dependent manner. Compound 2, with different sugar substitution, exhibited no mortality and moderate teratogenic toxicity with a 96h-EC50 of 173.5 µM. Zebrafish embryos exhibited teratogenic effects, such as reduced hatchability and total body length. The study found that triterpene saponin from A. japonicus viscera had acute toxicity in zebrafish embryos, indicating a potential chemical defense role in the marine ecosystem.

Population survey of Holothuria (Halodeima) grisea (Aspidochirotida: Holothuriidae) at its limit of geographic distribution in the Western South Atlantic

Introduction: The sea cucumber Holothuria (Halodeima) grisea Selenka, 1867 is a common echinoderm in intertidal regions along the Brazilian coast, which recently became the focus of unreported and unregulated fisheries. This study was carried out in sandy-rocky substrates at Armação do Itapocoroy, Penha, Santa Catarina (26o47’ S; 48o36’ W), near its southern limit of geographic distribution.
 Objective: To determine the densities (individuals*m-2) of Holothuria (H.) grisea within a spatial-temporal perspective as well as to determine biometric and growth characteristics of the population.
 Methods: Two-meter wide transects perpendicular to the coastline were carried out in winter and spring 2019 and in summer and spring 2020, in periods of spring low-tides. In each sampling occasion the total number of specimens of H. grisea were determined, and a group of 90 organisms was submitted to in situ biometrics (weight, length and width), and immediately returned alive to their habitat.
 Results: The densities of H. (H.) grisea were significantly higher in the subtidal sector and lower in the upper intertidal sector with no indication of significant differences among sampling campaigns. Depth was the primary factor explaining the observed density patterns and rugosity of the substrate was secondary but also important. The body length ranged from 5.2 to 22.5 cm, whereas the weight varied from 6.0 to 230 g. The mean and modal lengths were 12.54 and 13 cm, respectively. Approximately 75 % of the population sampled was between 10 and 14 cm and the average weight was 60 g. Estimates from von Bertalanffy growth function indicate that the youngest sea cucumber was one year-old, and the oldest had approximately two and a half years.
 Conclusions: This is the first study to determine biometric parameters for H. (H.) grisea in southern Brazil and the first one to estimate growth and age estimates for a wild population of this species. The densities recorded in the present study were lower than those previously reported for this region, suggesting anthropic influence.

YTHDC1/CRM1 Facilitates m6A-Modified circRNA388 Nuclear Export to Induce Coelomocyte Autophagy via the miR-2008/ULK Axis in Apostichopus japonicus.

N 6-methyladenosine (m6A), the most prevalent internal modification in eukaryotic RNA, was able to mediate circular RNA (circRNA) function in many immune processes. Nevertheless, the functional role of m6A-modified circRNAs in innate immunity of invertebrates remained unclear. In this study, we identified m6A-modified circRNA388 from cultured sea cucumber (Apostichopus japonicus) coelomocytes, which was mainly detected in cytoplasm after Vibrio splendidus infection. A knockdown assay indicated that cytoplasm circRNA388 promoted coelomocyte autophagy and decreased the number of intracellular V. splendidus. Mechanistically, the circRNA388 in the cytoplasm directly sponged miR-2008 to block its interaction with Unc-51-like kinase 1 from A. japonicus (AjULK) and further promoted autophagy to resist V. splendidus infection. More importantly, we found that m6A modification was vital to circRNA388 nuclear export with YTH domain-containing protein 1 from A. japonicus (AjYTHDC1) as the reader. AjYTHDC1 facilitated the nuclear export of m6A-modified circRNA388 via interaction with exportin-1 (chromosomal maintenance 1) from A. japonicus (AjCRM1). Knockdown of AjCRM1 could significantly decrease the content of cytoplasm circRNA388. Overall, our results provide the first evidence that nuclear export of m6A-modified circRNA388 is dependent on the novel AjCRM1 to our knowledge, which was further promoted coelomocyte autophagy by miR-2008/AjULK axis to clear intracellular V. splendidus.

Fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus alleviate the intestinal barrier injury and oxidative stress damage in vitro and in vivo

This study aimed to investigate the alleviative effects of fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus (fCSSc) on the intestinal barrier injury and oxidative stress damage in vitro and in vivo. The results showed that fCS-Sc protected the intestinal barrier and improved the antioxidant function in H2O2 damaged Caco-2 cells via up-regulating the tight junction proteins and activating Keap1-Nrf2-ARE antioxidant pathway. Furthermore, administration fCS-Sc could ameliorate the weight loss and spleen index decrease in Cyclophosphamide (Cy) treated mice, improve the expressions of ZO-1, Claudin-1, Nrf2, SOD, and NQO-1 in Cy damaged colon tissue, showing significant protective effects against intestinal barrier damage and oxidative stress in vivo. fCS-Sc intervention also alleviated the gut microbiota disorder though increasing the richness and diversity of intestinal bacteria, regulating the structural composition of gut microbiota. fCS-Sc promoted the relative abundance of beneficial microbiota and inhibited the growth of harmful bacteria. This study provided a theoretical basis for the application of fCS-Sc as a prebiotic in chemotherapy.

Phytochemical Compounds in Sea Cucumber Have the Potential to Reduce Oxidative Stress and Inflammation Due to Exercise: Systematic Review

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.

Pseudocryptic diversity and species boundaries in the sea cucumber Stichopus cf. horrens (Echinodermata: Stichopodidae) revealed by mitochondrial and microsatellite markers

Morphologically cryptic and pseudo-cryptic species pose a challenge to taxonomic identification and assessments of species diversity and distributions. Such is the case for the sea cucumber Stichopus horrens, commonly confused with Stichopus monotuberculatus. Here, we used mitochondrial cytochrome oxidase subunit I (COI) and microsatellite markers to examine genetic diversity in Stichopus cf. horrens throughout the Philippine archipelago, to aid species identification and clarify species boundaries. Phylogenetic analysis reveals two recently diverged COI lineages (Clade A and Clade B; c. 1.35–2.54 Mya) corresponding to sequence records for specimens identified as S. monotuberculatus and S. horrens, respectively. Microsatellite markers reveal two significantly differentiated genotype clusters broadly concordant with COI lineages (Cluster 1, Cluster 2). A small proportion of individuals were identified as later-generation hybrids indicating limited contemporary gene flow between genotype clusters, thus confirming species boundaries. Morphological differences in papillae distribution and form are observed for the two species, however tack-like spicules from the dorsal papillae are not a reliable diagnostic character. An additional putative cryptic species was detected within Clade B-Cluster 2 specimens warranting further examination. We propose that these lineages revealed by COI and genotype data be referred to as Stichopus cf. horrens species complex.