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This mini-review evaluates the use of marine sponges in integrated culture systems, two decades after the idea was first proposed. It was predicted that the concept would provide a double benefit: sponges would grow faster under higher organic loadings, and filtration by sponges would improve water quality. It is promising that the growth of some commercially interesting sponges is indeed faster in organically enriched areas. The applicability of sponges as filters for undesired microorganisms has been confirmed in laboratory studies. However, upscaled farming studies need to be done to demonstrate the value of sponges for in situ bioremediation of sewage discharge or waste produced by fish cages. In addition, a new idea is presented – the use of sponges as an engine to convert dissolved organic matter (DOM) into particulate organic matter (POM) that can be consumed by deposit feeders through a chain of processes termed the sponge loop. A theoretical design of an integrated culture with seaweeds (Gracilaria sp.), sponges (Halisarca caerulea) and sea cucumbers (Apostichopus japonica) shows that 37% of the part of the primary production that is excreted by the seaweeds as DOM can be directly recovered in sponge biomass and a subsequent 12% in sea cucumber biomass after mediation (conversion of DOM to POM) by sponges. Hence, the total recovery of DOM into (sponge and sea cucumber) biomass within this IMTA is 49%.

A water flow simulation device capable of adjusting flow velocity was designed in flow velocity range of 0–30 cm/s, with which an indoor experiment was conducted to simulate the movement and adhesive behaviors of different-sized Apostichopus japonicus under different flow velocities. Observation showed that, in slow flow (~5 cm/s), A. japonicus moved more distance than in still water, and hardly moved in the riptide (~30 cm/s); and the adhesive capacity of A. japonicus was related to the flow velocity and attachment time. A. japonicus were able to attach to the bottom after any attachment time in the slow flow, after 10 s in the medium flow (~15 cm/s), and after 60 s in the riptide (~30 cm/s). In addition, larger A. japonicus were stronger with adhesive ability than smaller ones. The transcriptome data showed that the expression of transient receptor potential cation channel subfamily A, member 1 (TRPA1) in the tube feet was increased significantly in a flowing water, but those in the tentacles and tube feet were not significantly changed. Fluorescence in-situ hybridization results showed that TRPA1 was expressed around the watervascular of tentacles, tube feet, body wall, and spines. Therefore, tube feet were important for sea cucumbers to keep themselves stable in relatively swift flow with adhesion ability.

Cost-effective reefs improve the yield of sea cucumber Apostichopus japonicas cultured in ponds. The reaction to reef models was studied in laboratory experiments regarding selectivity and fitness-related behaviors (crawling, feeding and defecation) in different roughness (rough and smooth), angles (30°, 60° and 90°) and heights (3.5, 7, 10.5 and 14 cm). The present study found that significantly more sea cucumbers selected the rough model, with significantly better crawling frequency, tentacles activity frequency and defecation behavior compared with those on the smooth model. This indicates that rough materials in artificial reefs are appropriate for the fitness-related behaviors of sea cucumbers. Regarding the angles, the 30° model attracted significantly more sea cucumbers than those of 60° and 90°. Among the three angles, sea cucumbers in the 30° model showed significantly better defecation behavior, while showed higher frequencies of crawling and tentacles activity in comparison with the 90° model. In other words, the models of 30° and 60° serve as the "toilet" and the "kitchen" of sea cucumbers better in defecation and food intake. No significant difference was found in the number of sea cucumbers selecting any model of three heights. The 7-cm model sees significantly higher frequencies of crawling and tentacles activity than the ones of 3.5 and 14 cm. These results indicate that the higher reef may not necessarily be valuable in the pond culture and a shorter one may help boost the feeding efficiency of sea cucumbers.

The gut microbiota composition of sea cucumber (Apostichopus japonicas) was investigated using high-throughput sequencing techniques. The mRNA expression of complement component 3 and lysozyme genes was evaluated using quantitative fluorescence PCR. Sea cucumbers were fed with a basal diet (control group) and an experimental diet supplemented with Codonopsis pilosula (experimental group) for 30 days. The results showed that the alpha diversity of the gut microbiota was changed in different indices, including Chao1, the abundance-based coverage estimator, the Shannon index, and Good’s coverage. Dietary C. pilosula promoted the proliferation of the Flavobacteriaceae family of the Proteobacteria phylum and reduced the relative abundance of the Verrucomicrobiaceae family of the Verrucomicrobia phylum. We concluded that dietary C. pilosula supplementation could alter the network interactions among different microbial functional groups by changing the ecological network’s microbial community composition and biological evolution. A positive effect on A. japonicus immune responses in the gut was seen via increasing the mRNA expression of the complement component 3 and lysozyme genes. It seems to happen via modulating the balance in gut microbiota.

The viability of placing abalones (Haliotis discus hannai), sea cucumbers (Apostichopus japonicas) and rockfish (Sebastes schlegeli) in a polyculture system, the effect of this mixed species group on the system's nitrogen (N) and phosphorous (P) budgets, and the growth and food intake of the organisms in the system were examined using a recirculating aquaculture system. Four replicates were set up for each of three treatment groups (abalone only (C), abalone-sea cucumber (AS) and abalone-sea cucumber-rockfish (ASF)) with an experimental period of 60 d. Compared with the C group, in the AS group the abalone survival rate and specific growth rate (SGR) of body weight increased and the harvested abalones from the polyculture system became the main source of N and P output of the polyculture system. However, the N and P output in the water layer did not differ significantly from that in the C group (p > 0.05), and the N utilization rate was significantly higher than that in the C and ASF groups (p < 0.05). Compared with the AS group, in the ASF treatment the SGR of body weight as well as the protease and amylase activities of sea cucumbers were significantly higher (p < 0.05), the water layer and faeces became the main sources of N and P output in the system. These results showed that the AS polyculture mode significantly improved the N and P utilization rates in the system and led to increased aquaculture production.

The effect of commercial processing methods on the nutritional value of ready‐to‐eat (RTE) sea cucumber Apostichopus japonicas was examined in this study. RTE sea cucumber products named RTE‐T and RTE‐V were prepared by two commercial methods, traditional processing, and vacuum cooking, respectively. Proximate, polysaccharide and mineral element composition, amino acid profiles, and true retention values of RTE sea cucumber products were evaluated and compared. Both commercial processing methods significantly changed the nutrient composition in RTE products, except that of Zn and Cu. Comparison of true retention values among RTE products showed that novel commercial method of vacuum cooking resulted in lower nutrient loss and had a shorter processing time than traditional processing. However, soaking after vacuum cooking significantly increased the nutrient loss of RTE sea cucumber. Therefore, vacuum cooking without soaking may be a promising alternative for producing RTE sea cucumber products with high nutritional quality.

Cross-species transmission of emerging viruses happens occasionally due to epidemiological, biological, and ecological factors, and it has caused more concern recently. Covert mortality nodavirus (CMNV) was revealed to be a unique shrimp virus that could cross species barrier to infect vertebrate fish. In the present study, CMNV reverse transcription-nested PCR (RT-nPCR)-positive samples were identified from farmed sea cucumber (Apostichopus japonicas) in the CMNV host range investigation. The amplicons of RT-nPCR from sea cucumber were sequenced, and its sequences showed 100% identity with the RNA-dependent RNA polymerase gene of the original CMNV isolate. Histopathological analysis revealed pathologic changes, including karyopyknosis and vacuolation of the epithelial cells, in the sea cucumber intestinal tissue. The extensive positive hybridization signals with CMNV probe were shown in the damaged epithelial cells in the in situ hybridization assay. Meanwhile, transmission electron microscopy analysis revealed CMNV-like virus particles in the intestine epithelium. All the results indicated that the sea cucumber, an Echinodermata, is a new host of CMNV. This study supplied further evidence of the wide host range of CMNV and also reminded us to pay close attention to its potential risk to threaten different aquaculture animal species.

Sea cucumbers (Holothuroidea, Echinodermata) are ecologically significant constituents of benthic marine habitats. We surveilled RNA viruses inhabiting eight species (representing four families) of holothurian collected from four geographically distinct locations by viral metagenomics, including a single specimen of Apostichopus californicus affected by a hitherto undocumented wasting disease. The RNA virome comprised genome fragments of both single-stranded positive sense and double stranded RNA viruses, including those assigned to the Picornavirales, Ghabrivirales, and Amarillovirales. We discovered an unconventional flavivirus genome fragment which was most similar to a shark virus. Ghabivirales-like genome fragments were most similar to fungal totiviruses in both genome architecture and homology and had likely infected mycobiome constituents. Picornavirales, which are commonly retrieved in host-associated viral metagenomes, were similar to invertebrate transcriptome-derived picorna-like viruses. The greatest number of viral genome fragments was recovered from the wasting A. californicus library compared to the asymptomatic A. californicus library. However, reads from the asymptomatic library recruited to nearly all recovered wasting genome fragments, suggesting that they were present but not well represented in the grossly normal specimen. These results expand the known host range of flaviviruses and suggest that fungi and their viruses may play a role in holothurian ecology.

Fas-associated death domain (FADD) is an adaptor protein that functions in transferring the apoptotic signals regulated by the death receptors. In this study, a full-length cDNA of FADD homologue in sea cucumber Apostichopus japonicas (AjFADD) was cloned and characterized, and its functional roles in apoptosis investigated. In healthy sea cucumbers, AjFADD was expressed in all detected tissues, with higher levels in coelomocytes and intestine. AjFADD mRNA and protein levels were significantly expressed in coelomocytes after exposed with LPS or poly (I:C) in vitro, and challenged with Vibrio splendidus in vivo. Moreover, siRNA-mediated AjFADD knockdown in coelomocyte much decreased AjFADD mRNA and protein levels as well as the coelomocytes apoptosis levels. Furthermore, over-expression of the expression plasmid pcDNA3.1 encoding AjFADD (pcAjFADD) significantly increased the apoptosis levels in HEK293 cells. Taken together, our results support that AjFADD is a novel pro-apoptotic protein that might play key roles in defensing the bacterial and virus invasion in sea cucumber.

Correlation, multiple regression, and path analyses were used to investigate the relationships between body weight and three other morphological traits in juvenile Japanese sea cucumbers Apostichopus japonicus. We measured live body weight (BW), body length (BL), numbers of papillae (NP), and numbers of tube feet (NF) at 60, 80, 100, and 130 days post-hatching (dph). We calculated path correlation coefficients, correlation indices (R2), and coefficients of determination with BW as the dependent variable and the other morphological traits as independent variables. The coefficient of variation for BW was high across all age groups, and all measured morphological traits were significantly correlated (P < 0.01). BL had the greatest direct effect on BW across all age groups (60 dph, 0.526; 80 dph, 0.404; 100 dph, 0.620; and 130 dph, 0.681), while NF had the greatest indirect effect on BW across all age groups (60 dph, 0.528; 80 dph, 0.452; 100 dph, 0.666; and 130 dph, 0.603). Regression analyses between morphological traits and BW indicated that R2 was greater than 0.85 only in the 100-dph specimens. The indirect effects of the other measured morphological traits on BW were age-dependent. The optimal regression equations, as determined with stepwise regression, were, for 60-dph specimens: BW60 =10 (-3.04+0.092BL+0.014NP+0.014NF) (R2 =0.632); for 80-dph specimens: BW80 =10 (- 3.035+0.056BL+0.017NP+0.02NF) (R2 =0.686); for 100-dph specimens: BW100 =10 (- 3.742+0.069BL+0. 633 × lg (NP)+0. 464 × lg (NF)) (R2 =0.893); and for 130-dph specimens: BW130 =10 (- 2.472+0.065BL+0.012NP) (R2 =0.774). Our work clarified the correlation between various morphological traits and body weight of a commercially-important sea cucumber species (A. japonicus). Our predictive models for body weight might be useful for the aquaculture and selective breeding of A. japonicus. These models might also provide theoretical support for the indirect selection of traits that are difficult to select directly.

The sea cucumber, Apostichopus japonicas, is an important economic species with high nutritive value. In recent years, driven by significant market demand, the sea cucumber breeding industry has developed rapidly. Body color and number of papillae are important factors that determine the value and price of sea cucumbers. In this study, metabolite profiling of four sea cucumber varieties (green, white, purple and spiny) was performed using ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-QTOF-MS) combined with multivariate analysis. Orthogonal partial least-squares discriminant analysis (OPLS-DA) clearly discriminated the body wall metabolites of four sea cucumber varieties. Differential metabolites included fatty acids, phospholipids, and sugars. KEGG metabolic pathway analysis revealed that carbohydrate, protein, and phospholipid metabolism were highly conserved among the varieties. These results provide a comprehensive insight into differences in the metabolite profile of four A. japonicus varieties and a deeper understanding of sea cucumber varieties breeding.

Sea cucumber Apostichopus japonicas is distinguished by high diversity of biologically active substances. Their extraction by honey is one of traditional ways of the sea cucumber using as a therapeutic and prophylactic agent. Mixture of xanthan gum and locust bean gum with apple pectin in different concentrations is used as the honey solvent. Organoleptic properties and viscosity of the compound of sea cucumber mixed with this honey solvent in different proportions are evaluated and their ratio providing uniform and stable consistency with viscosity 3.0-4.5 Pa . s during long-term storage is chosen as the optimal one. The product heating to 70 о C causes a significant increase in viscosity that can be explained by loss of water from muscular tissue of the sea cucumber and its binding with the structure-forming agent. The heating of the compound with 1 % of xanthan gum causes the viscosity increasing in 4 times as compared with the control sample. The sequence of technological methods for producing the biologically active supplement «Trepang on honey» with stable structure and composition is proposed. The supplement contains 0.3 % of glucosamine and 0.1 % of glycosides. Daily dosage of this supplement is determined.

Thirty-five new microsatellite loci from the sea cucumbers Holothurian scabra (Jaeger, 1833) and Apostichopus japonicas (Selenka, 1867) were screened and characterized using the method of magnetic bead enrichment. Of the twenty-four polymorphic loci tested, eighteen were consistent with Hardy-Weinberg equilibrium after a modified false discovery rate (B-Y FDR) correction, whereas six showed statistically significant deviations (CHS2 and CHS11: P

The sea cucumber (Apostichopus japonicus) is an economically important mariculture species in Asia. However, the genetic breeding of sea cucumbers is difficult because the sexes cannot be identified by appearance. Therefore, studies on sex-related genes are helpful in revealing the mechanisms of sex determination and differentiation in sea cucumbers. P-element induced wimpy testis (piwi) is a germ cell marker involved in gametogenesis in vertebrates; however, the expression pattern and function during gametogenesis remain unclear in sea cucumbers. In this study, we identified a piwi homolog gene in A. japonicus (Ajpiwi1) and investigated its expression pattern, and function. Ajpiwi1 is a maternal factor and is ubiquitously expressed in adult tissues, including the ovary and testis. Ajpiwi1 expression is strong in early oocytes, spermatocytes, and spermatogonia; weak in mature oocytes; and undetected in spermatids and intra-gonadal somatic cells. The knockdown of Ajpiwi1 by RNA interference (RNAi) led to the downregulation of other conserved sex-related genes such as dmrt1, foxl2, and germ cell-less. Therefore, Ajpiwi1 might play a critical role during gametogenesis in A. japonicus. This study creates new possibilities for studying sex-related gene functions in the sea cucumber and builds a gene function research platform based on RNAi for the first time.

To understand the physiological response of sea cucumber, Apostichopus japonicas, were exposed to different concentration of benzo[a]pyrene (B[a]P), and the growth, survival, antioxidant enzyme (SOD and T-AOC) activities were tested. Meanwhile, the quantitative real-time PCR technology was utilized to quantize the expression of immune related genes (i.e. innate immune genes, HSP genes and anti-oxidative genes). In our result, the SOD activity and T-AOC activity were induced at lower level of B[a]P (0.03 μg/L), however, a reduction of SOD activity and T-AOC activity were observed at relatively high B[a]P concentration (3 and 9 μg/L) for A. japonicas. Furthermore, the distinct expression patterns of selected immune-related genes were detected among different concentrations, and a general trend of down-regulation was observed at higher concentration. Especially, lysozyme almost showed the highest down-regulation at all concentrations, followed by NOS. Collectively, the growth, survival and expression signatures of immune related genes reflected an overall suppression of innate immunity in sea cucumber following exposure. Future functional studies should be carried out to characterize the detailed roles of immune genes and their related responses under B[a]P toxicity. Additionally, better understanding of the molecular indicators governing the healthy status under environmental toxicity would facilitate a healthy and sustainable culture program.

This study aimed at investigating the chain conformation and physicochemical properties of fucosylated chondroitin sulfate extracted from sea cucumber Apostichopus japonicas (Aj-fCS). By using HPSEC-MALLS-Visc-RI, Mw,s(2)z(1/2), Rh and [η] for Aj-fCS were determined as 58.0±4.4kDa, 21.8±1.3nm, 12.5±1.3nm and 27.8±0.5mL/g respectively. Conformation parameter αs derived from the relationship of Mw-s(2)z(1/2) (0.39) and structure-sensitive parameter ρ (1.74) consistently indicated that Aj-fCS adopted a random coil conformation in solution, which was also supported by atomic force microscopy. Stiffness parameters of Aj-fCS chains including q (2.72nm), d (1.03nm) and C∞ (5.28) were furthermore deduced from the worm-like cylinder model. Aj-fCS demonstrated a shear-thinning rheological behavior, relatively low apparent viscosity, negative charge in wide pH and ionic strength ranges, and favorable thermostability. These results have important implications for designing and fabricating functional foods or drugs based on Aj-fCS.

Shewanella marisflavi is considered responsible for infection in juvenile sea cucumber, Apostichopus japonicas. A bacteriophage specific to S. marisflavi was isolated from seafood wholesale market sewage and designated as vB_SmaM_PSM (PSM‐1). The phage was classified as a member of the Myoviridae family by negative staining transmission electronic microscopy. The stability of phage PSM‐1 was observed after treatment with different temperature gradients and pH values. The results showed that the lytic activity of phage PSM‐1 was optimum at 28 C with a pH of 7.0 and ceased at temperatures higher than 60 C. A one‐step growth curve analysis of the phage revealed eclipse and latent periods of 20 and 40 min, respectively, with a burst size of 219 plaque forming units per infected cell. The ability of phage PSM‐1 to inhibit the growth of S. marisflavi AP629 was tested in vitro using the phage with three multiplicity of infection (MOI) values of 0.1, 1, and 10. All treated cultures that produced an inhibition of the growth of S. marisflavi AP629 were compared with the untreated culture, and the treatment group with a MOI value of 10 showed the highest inhibition effect among the three doses. In an in vivo performance experiment, the sea cucumbers (15–20 g) were randomly assigned to five groups (one negative control, one antibiotic treatment group, and three phage treatment groups) in a phage injection trial as well as a phage immersion trial. All groups were infected with S. marisflavi strain AP629 (3.3 × 10⁶ colony forming units/g, LD₅₀ [lethal dose 50%] level) by intraperitoneal injection. After 8 d of observation, the survival rates ranged from 40 to 80% in all phage treatment groups, while 10% in the negative control group. The optimal therapeutic time points of the two trials were also determined. The results showed that using phage prior to infection could be a good choice to protect sea cucumbers. The overall results of this experiment indicate that using phage may be a feasible biological control agent to prevent S. marisflavi infection in sea cucumbers.

An 8-week feeding trial was conducted to investigate the effects of dietary chitosan oligosaccharide complex with cerium (Ce IV) (COS-Ce) on growth performance, nonspecific immunity and disease resistance of sea cucumber, Apostichopus japonicas. Five isonitrogenous (18.6%) and isolipidic (1.1%) practical diets were formulated with graded level of COS-Ce (0, 150, 300, 600 and 1200 mg kg−1 dry feed), which were named as COS-Ce/0, COS-Ce/150, COS-Ce/300, COS-Ce/600, COS-Ce/1200 respectively. Each diet was allocated to four replicates of sea cucumbers (Initial weight: 6.72 ± 0.02 g). Sea cucumbers were fed to apparent satiation once daily (19:00 hours) for 56 days. During the experiment, water temperature was kept at 16 ± 0.5°C, pH 7.8–8.2, dissolved oxygen beyond 5 mg L−1, ammonia nitrogen below 0.5 mg L−1 and salinity from 30‰ to 31‰. Results showed that the specific growth rate of sea cucumbers was significantly higher in COS-Ce/600 than that in other four treatments. Activities of phagocytosis, respiratory burst, acid phosphatase and alkaline phosphatase in COS-Ce/600 were significantly higher than that in COS-Ce/0 (P

With the constant quest for new sources of superfoods to supplement the largely nutrient deficient diet of the modern society, sea cucumbers are gaining increasing popularity. Three species of sea cucumbers, Cucumaria frondosa, Apostichopus californicus and Apostichopus japonicus were collected from three geographical regions, Atlantic and Pacific coast of Canada and Yellow sea/ East China sea in China, respectively. These organisms were sectioned into parts (body wall, tentacles, internal organ, skin and muscle) and analysed for total arsenic (As) by inductively coupled plasma mass spectrometry (ICP-MS) and As species by high-performance liquid chromatography (HPLC) coupled to ICP-MS. Normal and reversed sequential extractions were optimised to address As distribution between lipids (polar and non-polar) and water-extractable fractions. Two extraction methods for water-extractable As were compared in terms of the number and the amount of extracted species. The results revealed that total As concentration and As species distribution varies significantly between sea cucumbers species. Total As in studied body parts ranged between 2.8 ± 0.52 and 7.9 ± 1.2 mg kg−1, with an exception of the muscle tissue of A. californicus, where it reached to 36 ± 3.5 mg kg−1. Arsenobetaine (AsB) was the most abundant As species in A. californicus and A. japonicus, however, inorganic As represented over 70% of total recovered As in the body parts of C. frondosa. Arsenosugars-328 and 482 were found in all studied body parts whereas arsenosugar-408 was only found in the skin of A. californicus. This is the first time that such a variation in As species distribution between sea cucumber species has been shown.

Sea cucumbers (Holothuroidea; Echinodermata) are ecologically significant constituents of benthic marine habitats. We surveilled RNA viruses inhabiting 8 species (representing 4 families) of holothurian collected from four geographically distinct locations by viral metagenomics, including a single specimen of Apostichopus californicus affected by a hitherto undocumented wasting disease. The RNA virome comprised genome fragments of both single-stranded positive sense and double stranded RNA viruses, including those assigned to the Picornavirales, Ghabrivirales, and Amarillovirales. We discovered an unconventional flavivirus genome fragment which was most similar to a shark virus. Ghabivirales-like genome fragments were most similar to fungal totiviruses in both genome architecture and homology, and likely infected mycobiome constituents. Picornavirales, which are commonly retrieved in host-associated viral metagenomes, were similar to invertebrate transcriptome-derived picorna-like viruses. Sequence reads recruited from the grossly normal A. californicus metavirome to nearly all viral genome fragments recovered from the wasting-affected A. californicus. The greatest number of viral genome fragments was recovered from wasting A. californicus compared to any other surveyed holothurian, including the grossly normal A. californicus, which reflects a pattern observed in viral metagenomics study of sea star wasting. These results expand the known host range of flaviviruses, and suggest that fungi and their viruses may play roles in holothurian ecology.

Catalase is an important oxidoreductase enzyme that catalyzes the conversion of hydrogen peroxide molecules into water and oxygen and regulates the homeostasis of ROS in animals and humans. Catalase functions in host immune defense, cellular apoptosis, aging, inflammation, and tumor formation. The intestine is not only an important site of nutrient digestion and absorption but also an important site of innate immunity against microbial infection in invertebrates. Catalase can participate in intestinal immune responses. However, the role of catalase in intestinal immunity in the sea cucumber (Aj-catalase) has not been elucidated. In this study, we showed that Aj-catalase plays a key role in intestinal immunity and microbiota homeostasis. The expression level of Aj-catalase was upregulated, and its enzymatic activity was increased in the Apostichopus japonicus intestine after challenge with Vibrio splendidus via oral infection. When Aj-catalase was knocked down by RNA interference (RNAi), the survival rate of sea cucumbers declined; microbiota homeostasis was disturbed in the intestine compared with that in the control group, and the intestinal villi protruding from the epithelial lining of the intestinal wall were damaged. Further study results demonstrated that the ROS level was increased for a long period in Aj-catalase-knockdown sea cucumbers, which is likely the main mechanism by which catalase is involved in regulating intestinal immunity. These results suggest that Aj-catalase participates in intestinal immunity and microbiota homeostasis by regulating ROS levels.

The sea cucumber is an economically important aquaculture species in China, where it encounter hypo-saline conditions caused by freshwater outflow from rivers and rainfall. MicroRNAs (miRNA) are small noncoding RNAs of about 22 nucleotides, which are crucial regulators of gene expression at the post-transcriptional level and are involved in a variety of physiological and pathophysiological processes. miR-10 is differentially expressed in salinity acclimation, and has a seed-region match with TBC1D5. The expression profiles of miR-10 and TBC1D5 indicate that miR-10 negatively regulates the expression of TBC1D5 in coelomocytes and sea cucumbers with a miR-10 agomir or antagomir. During salinity acclimation, up-regulation of miR-10 was induced after transfection in coelomocytes with a miR-10 inhibitor, while down-regulation of TBC1D5 was induced. The miR-10 expression maximum in coelomocytes appeared at 48 h post-transfection with a miR-10 inhibitor, was later than that of in sea cucumbers, which appeared 24 h after miR-10 antagomir injection. There was no longer a negative relationship between miR-10 and TBC1D5 expression in coelomocytes and sea cucumbers with miR-10 mimics or agomir during salinity acclimation. The miR-10 antagomir or agomir only affected sodium and NKA enzyme activities, and has little effect on other chloride and potassium ions. Our results demonstrate miR-10 directly regulates TBC1D5 by targeting its 3’-UTR, and that miR-10 suppression substantially increases TBC1D5 mRNA levels in vivo and in vitro. Furthermore, miR-10 and TBC1D5 fluctuating expression patterns after treatment with a miR-10 inhibitor or mimics during salinity acclimation may indicate that they are required for adaptation to salinity stress caused by environmental change. Especially, the miR-10 up-regulation in coelomocytes with miR-10 inhibitor during salinity acclimation indicated that they are required for adaptation to salinity stress caused by environmental change. We propose that miR-10 participates in a regulatory circuit that allows for rapid gene program transitions in response to osmotic stress.

The sea cucumber Apostichopus japonicus—an endangered species on the IUCN Red List—is economically and ecologically important echinoderm species. Here we describe a set of 21 amplified microsatellites for A. japonicus isolated through biotinylated probes for hybridization and a library screening method, which were used to genotype an artificially propagated stock of sea cucumber offspring from Lianyungang City of China. The observed and expected heterozygosity at the population level ranged from 0.2083 to 0.1000 and 0.6260 to 0.9304, respectively. The number of alleles varied between 6 and 19, and none of the loci deviated significantly from the Hardy–Weinberg equilibrium (P

A feeding trial was conducted to estimate the optimum level of dietary n-3 highly unsaturated fatty acids (HUFAs) for juvenile sea cucumber, Apostichopus japonicas, based on growth performance and fatty acid compositions. Diets with five n-3 HUFAs levels (0.15, 0.22, 0.33, 0.38, and 0.46%) were fed to sea cucumber juveniles (1.97 ± 0.01 g) once a day for 60 d. The sea cucumbers fed diets containing 0.22% n-3 HUFAs showed significantly (P 0.05) from those of sea cucumbers fed diets containing 0.33, 0.38, and 0.46% n-3 HUFAs. The sea cucumbers fed diets containing 0.46% n-3 HUFAs showed significantly (P 0.05) from those of sea cucumbers fed diets containing 0.22, 0.33, and 0.38% n-3 HUFAs. The results of growth performance and n-3 HUFA compositions of body wall indicated that the optimum level of dietary n-3 HUFAs for juvenile sea cucumber is between 0.22 and 0.46%.

Usually, the chemical structures of cerebrosides in sea creatures are more complicated than those from terrestrial plants and animals. Very little is known about the method for high-throughput molecular profiling of cerebrosides in sea cucumbers. In this study, cerebrosides from four species of edible sea cucumbers, specifically, Apostichopus japonicas, Thelenota ananas, Acaudina molpadioides and Bohadschia marmorata, were rapidly identified using reversed-phase liquid chromatography-quadrupole-time-of-flight mass spectrometry (RPLC-QToF-MS). [M + H](+) in positive electrospray ionization (ESI) mode were used to obtain the product ion spectra. The cerebroside molecules were selected according to the neutral loss fragments of 180 Da and then identified according to pairs of specific products of long-chain bases (LCB) and their precursor ions. A typical predominant LCB was 2-amino-1,3-dihydroxy-4-heptadecene (d17:1), which was acylated to form saturated and monounsaturated non-hydroxy and monohydroxy fatty acids with 17-25 carbon atoms. Simultaneously, the occurrence of 2-hydroxy-tricosenoic acid (C23:1h) was characteristic of sea cucumber cerebrosides, whereas this molecule was rarely discovered in plants, mammals, or fungi. The profiles of LCB and fatty acids (FA) distribution might be related to the genera of sea cucumber. These data will be useful for identification of cerebrosides using RPLC-QToF-MS.

Apostichopus armatus (Selenka, 1867) Figs 1–5 Holothuria armata Selenka, 1867: 330, pl. XVIII, fig. 66; Lampert, 1885: 91. Stichopus armatus (Holothuria): Théel, 1886: 196 Stichopus (Holothuria) armatus: Mitsukuri, 1896: 408; Mitsukuri, 1912: 164 Stichopus japonicus var. typicus Théel, 1886: 161, pl. VIII, fig. 2. Apostichopus japonicus: Liao, 1980: 116, fig. 1; Sun et al., 2010: 280 –285. Apostichopus armata [sic]: Kuramochi & Naganuma, 2010: 50, figs 1[2a, 2b]–3 [the ossicles in figs 2 and 3 were erroneously given under the name ‘ A. japonicus ’ on the figures]. Type material examined. Syntype MCZ HOL –741, Hakodate, Japan. Additional materials examined. NSMT –E7045A, Tateyama Bay, Chiba, 21 April 2011; NSMT –E7047A, Aburatsubo Bay, Kanagawa, 10 July 2011, Y. Tamura; NSMT –E7047F, Aburatsubo Bay, Kanagawa, 10 July 2011, Y. Tamura; NSMT –E7047C, Aburatsubo Bay, Kanagawa, 10 July 2011, Y. Tamura; NSMT –E7047E, Aburatsubo Bay, Kanagawa, 10 July 2011. Type locality. Hakodate [misspelled as Hakodadi by Selenka (1867)], Japan. Description. Twenty peltate tentacles. Two rows of dorsal papillae, each arranged alternately in zig-zag pattern along dorso-lateral radius. Single row of conical papillae along each ventro-lateral radius. Numerous, loosely arranged, small papillae scattered on dorsal and lateral body. Ventral side flattened. Tube feet arranged in 5–6 rows in central ambulacral area, 4–5 rows in both lateral ambulacral areas. Interambulacra narrow. Oral opening subventral, surrounded by ring of small papillae. Dorsal and ventral body surfaces uniformly light green to yellowish in alcohol. Gonads in two tufts; one on each side of dorsal mesentery. Free-hanging tentacular ampullae 20 in number. Polian vesicle single, in various shapes and forms. Intestine connected to dorsal mesentery with rete mirabile. Dorsal body wall with tables. Disk of tables rounded to oval in shape with 2–16 irregular perforations; rim of disk spinous or smooth (Fig. 2A–E). Pillar of reduced tables entirely absent or forming only a knob (Fig. 2C). Tables usually having four pillars; tip of each pillar often branched into multiple spines (Fig. 2A). Papillae containing multiperforated plates, tables, rods and elongated buttons. Multiperforated plates in papillae with numerous irregular perforations; rim uneven (Fig. 3E–F). Tables in papillae similar to those in dorsal body; pillars absent or forming knobs; rim spinous (Fig. 3A); mostly four pillars present, each having single spine on tip (Fig. 3B–C). Elongated buttons in papillae having two parallel longitudinal rows, each with 7–13 perforations (Fig. 3D). Rods in papillae variable in shape from straight to curved; surface of curved rods smooth (Fig. 3G), surface of straight rods spinous (Fig. 3H). Tentacles containing rods; curved (Fig. 4A–B); surface covered with spinelets. Tube feet containing multiperforated plates (Fig. 5A–B). Cloacal wall containing oval to rounded complex plates; surface very spinous surface. Distribution. Shallow temperate waters in the coasts of China, Japan, Korea and Russia. Northern distribution limit at Sakhalin Island, Russia and Southern limit in the Kagoshima prefecture in Japan (see Zhao 2015). Remarks. Reduced tables are the dominant spicules in the dorsal body wall of A. armatus. They are similar to the spicules found in the type material of H. armata in which Selenka (1867) described as “Spärlich durchlöcherte plättchen” [sic] or sparsely perforated plates which he compared to the spicules found in Holothuria (Halodeima) floridana (Pourtalès, 1851) (Selenka 1867: fig. 49). However, Selenka (1867) did not include the details of both the rims in the platelet spicules, and figures for the spicules from the type material. It is unfortunate that we are also unable to determine the spicules from the type material in this study because they appeared to be absent or completely dissolved. Incidentally, Selenka’s (1867) H. armata is “schwarz” (black) coloured, which is clearly still visible upon examining the specimen (Fig. 1), which now forms part of the diagnosis for A. armatus. Apostichopus armatus can be differentiated from A. japonicus by the absence of reduced table spicules with spinous rim in A. japonicus. Similar spinous reduced table spicules are also clearly illustrated in S. j. var. typicus by Théel (1886: pl. 8, fig. 2), S. japonicus in Liao (1980: fig. 1), and A. armata in Kuramochi and Naganuma (2010: fig. 2), which all represents A. armatus. Although some reduced tables with smooth rim (similar to those found in the dorsal body of A. japonicus) are also present in A. armatus, they are only present in small amount compared to the dominant number of spinous ones. Spicules from the papillae, tentacles and tube feet are similar to those of A. japonicus., Published as part of Woo, Sau Pinn, Ogawa, Akito, Tan, Shau Hwai, Yasin, Zulfigar, Kajihara, Hiroshi & Fujita, Toshihiko, 2017, A taxonomic revision of the genus Apostichopus (Holothuroidea: Stichopodidae) from Japan, pp. 121-135 in Zootaxa 4350 (1) on pages 123-127, DOI: 10.11646/zootaxa.4350.1.7, http://zenodo.org/record/1050945, {"references":["Selenka, E. (1867) Beitrage zur Anatomie und Systematik der Holothurien. Zeitschrift fur wissenschaftliche Zoologie, 17, 291 - 372. [in German]","Lampert, K. (1885) Die Seewalzen, Holothurioidea, eine systematische Monographie mit Bestimmungs- und Verbreitungstabellen. In: Semper, C. (Ed.), Reisen im Archipel der Philippinen, Zweiter Theil, Wissenschaftliche Resultate 4 (3). CW Kreidel, Wiesbaden, pp. 151 - 312. [in German]","Theel, H. (1886) Reports on the Holothurioidea dredged by H. M. S. Challenver during the years 1873 - 76. Part 2. Report of the Scientific Results of the Voyages of H. M. S. Challenger during the years 1873 - 76, Zoology, 39, 160 - 162.","Mitsukuri, K. (1896) A list of holothurians known to occur in Japan. Zoological Magazine, 8, 405 - 413. [in Japanese]","Mitsukuri, K. (1912) Studies on actinopodous Holothurioidea. Journal College Science, Tokyo Imperial University, 29 (2), 163. https: // doi. org / 10.5962 / bhl. title. 37880","Liao, Y. (1980) The aspidochirote holothurians of China with erection of a new genus. In: Jangoux, M. (Ed.), Echinoderms - Present and Past. Proceedings of the European Colloquium on Echinoderms. Balkema Press, Rotterdam, pp. 115 - 117.","Sun, X., Li, Q. & Kong, L. (2010) Comparative mitochondrial genomics within sea cucumber (Apostichopus japonicus): provide new insights into relationships among color variants. Aquaculture, 309, 280 - 285. https: // doi. org / 10.1016 / j. aquaculture. 2010.08.001","Kuramochi, T. & Naganuma, T. (2010) Reclassification of the Apostichopus holothurians from Sagami Bay, central Japan. Biosphere Science, 49, 49 - 54. [in Japanese]","Zhao, H. (2015) Taxonomy and identification: distribution. In: Yang, H., Hamel, F. & Mercier, A. (Eds.), The Sea Cucumber Apostichopus japonicus: History, Biology and Aquaculture. Developments in Aquaculture and Fisheries Science, 39, pp. 46 - 49.","Pourtales, L. F. (1851) On the Holothuriae of the Atlantic Coast of the United States. Proceedings of the American Association for the Advancement of Science, Fifth Meeting, Washington, 1858, 8 - 16."]}

Complete redescriptions of sea cucumbers in the genus Apostichopus Liao, 1980 are provided using the type specimens and specimens deposited in the National Museum of Nature and Science, Tsukuba, Japan. The genus consists of A. armatus (Selenka, 1867) and A. japonicus (Selenka, 1867), which can be distinguished by some spicules in the dorsal body wall; the rim of reduced table spicules in A. armatus is spinous, while that in A. japonicus is smooth. Spicules from the tentacles, papillae, tube feet, and cloaca are similar for both species.

Genus Apostichopus Liao, 1980 Type species. Stichopus japonicus Selenka, 1867 (but see Remarks below). Type locality. Japan Diagnosis. Mouth ventral, surrounded by twenty peltate-shaped tentacles. Body stout and cylindrical. Conical papillae conspicuous or less conspicuous, protruding at dorsal and lateral sides of body; similar conical papillae arranged in one line at ventro-lateral sides; smaller papillae scattered on dorsal and lateral surfaces. Background body colour highly variable from red to brown and green to black. Gonads in two tufts. Spicules taking form of tables, buttons, multiperforated plates, rods, and complex plates. Dorsal body-wall spicules composed of tables; often reduced with pillars absent, but simple and not spinous if present; rims smooth or spinous. Dorsal body wall of juvenile contains tables with four spires, each having multiple spines on its end, with two to three crossbeams. Rosette and C-shaped spicules absent in dorsal body wall of both adult and juveniles. Papillae containing elongated buttons, rods, tables, and multiperforated plates. Rods in tentacles. Ventral tube feet containing multiperforated plates and tables, the latter without pillars. Spinous complex plates present in cloacal walls both in adult and juvenile. Species composition. Apostichopus armatus (Selenka, 1867); Apostichopus japonicus (Selenka, 1867) (see Remarks). Remarks. Liao (1980) erected this genus based on material from the northern East China Sea that was identified as Apostichopus japonicus. Judging from the drawings of the spicules, Liao’s (1980) material was most likely to represent Apostichopus armatus (Liao 1980: fig. 1), to which Article 70.3 (Misidentified type species) of the Code (International Commission on Zoological Nomenclature 1999) applies. In order to serve stability and universality of the name, we take the option stipulated under Article 70.3.1, in which the nominal species previously cited as the type species is to be retained, because alteration of the type species will not affect the genus name usage. The diagnosis for Apostichopus given by Liao (1980) sufficiently illustrated clear separation of Apostichopus from other genera based on reduced table spicules without pillars in the body wall (Liao 1980: fig. 1). The absence of C-shaped spicules and the presence of reduced table spicules in the dorsal body of Apostichopus differentiate it from the genera Stichopus and Isostichopus Deichmann, 1958, which have abundant C-shaped spicules and no reduced table in the dorsal body (Clark 1922; Deichmann 1958). The genus Apostichopus also can be easily distinguished from the genera Thelenota Brandt, 1835 and Astichopus Clark, 1922 by the presence of table spicules that are absent in the dorsal body of the two genera (Clark 1922). Complex plates in the cloacal walls and elongated buttons in the papillae are observed in Apostichopus (Théel 1886; Liao 1980) and Parastichopus Clark, 1922 (Clark 1922; Lambert 1986). The well-developed table spicules with complete spires in the dorsal body of Parastichopus are absent in adult Apostichopus (body length greater than 70 mm) (Mitsukuri 1897). Furthermore, Apostichopus can be found from the intertidal zone to the depth of about 20‒40 m (Zhao 2015), while Parastichopus is distributed only in deeper waters from 30 m down to the depth of 600 m (Deichmann 1937; Lambert 1986; Imaoka et al. 1990). We only included two species in the species list of Apostichopus. This is contrary to the inclusion of Parastichopus californicus (Stimpson, 1857), Stichopus johnsoni Théel 1886, Parastichopus leukhothele Lambert, 1986, Parastichopus multidentis Imaoka, 1991, Stichopus nigripunctatus Augustin, 1908, Parastichopus nipponensis Imaoka, 1990 (synonym of P. nigripunctatus) and Stichopus parvimensis Clark, 1913 by Paulay (2013) as part of the species list in Apostichopus. The inclusion is deemed invalid because the nomenclatural act of transferring these species to the genus Apostichopus did not fulfil the requirements of Article 8 (What constitutes published work) of the Code (International Commission on Zoological Nomenclature 1999)., Published as part of Woo, Sau Pinn, Ogawa, Akito, Tan, Shau Hwai, Yasin, Zulfigar, Kajihara, Hiroshi & Fujita, Toshihiko, 2017, A taxonomic revision of the genus Apostichopus (Holothuroidea: Stichopodidae) from Japan, pp. 121-135 in Zootaxa 4350 (1) on pages 122-123, DOI: 10.11646/zootaxa.4350.1.7, http://zenodo.org/record/1050945, {"references":["Liao, Y. (1980) The aspidochirote holothurians of China with erection of a new genus. In: Jangoux, M. (Ed.), Echinoderms - Present and Past. Proceedings of the European Colloquium on Echinoderms. Balkema Press, Rotterdam, pp. 115 - 117.","Selenka, E. (1867) Beitrage zur Anatomie und Systematik der Holothurien. Zeitschrift fur wissenschaftliche Zoologie, 17, 291 - 372. [in German]","International Commission of Zoological Nomenclature (1999) International Code of Zoological Nomenclature Fourth Edition. International Trust for Zoological Nomenclature, London, 306 pp.","Deichmann, E. (1958) The Holothurioidea collected by the Velero III and IV during the years 1932 to 1954 part II. Aspidochirota. Allan Hancock Pacific Expeditions, 11 (2), 253 - 349.","Clark, H. L. (1922) The holothurian of the genus Stichopus. Bulletin of the Museum of Comparative Zoology, 65 (3), 39 - 74.","Theel, H. (1886) Reports on the Holothurioidea dredged by H. M. S. Challenver during the years 1873 - 76. Part 2. Report of the Scientific Results of the Voyages of H. M. S. Challenger during the years 1873 - 76, Zoology, 39, 160 - 162.","Lambert, P. (1986) Northeast Pacific holothurians of the genus Parastichopus with a description of a new species, Parastichopus leukothele (Echinodermata). Canadian Journal Zoology, 64, 2266 - 2272. https: // doi. org / 10.1139 / z 86 - 340","Mitsukuri, K. (1897) On changes which are found with advancing age in the calcareous deposits of Stichopus japonicus, Selenka. Annotationes Zoologicae Japonenses, 1, 31 - 42.","Zhao, H. (2015) Taxonomy and identification: distribution. In: Yang, H., Hamel, F. & Mercier, A. (Eds.), The Sea Cucumber Apostichopus japonicus: History, Biology and Aquaculture. Developments in Aquaculture and Fisheries Science, 39, pp. 46 - 49.","Deichmann, E. (1937) The Templeton Crocker Expedition. IX. Holothurians from the Gulf of California, the West Coast of Lower California and Clarion Island. Zoologica: Scientific Contributions of the New York Zoological Society, 22 (10), 161 - 176.","Imaoka, T., Irimura, S., Okutani, T., Oguro, C., Oji, T., Shigei, M. & Horikawa, H. (1990) Echinoderms from Continental Shelf and Slope around Japan Vol. I. Japan Fisheries Resource Conservation Association, Tokyo, pp. 135 - 140.","Stimpson, W. (1857) The Crustacea and Echinodermata of the Pacific shores of North America. H. O. Houghton and Company, Riverside, Cambridge, pp. 92.","Imaoka, T., Irimura, S., Okutani, T., Oguro, C., Oji, T. & Kanazawa, K. (1991) Echinoderms from Continental Shelf and Slope around Japan. Vol. II. Japan Fisheries Resource Conservation Association, Tokyo, pp. 190 - 195.","Augustin, E. (1908) Uber japanische Seewalzen. In: Doflein, F. (Ed.), Beitrage zur Naturgeschichte Ostasiens. Abhandlungen der Mathematisch - Physikalischen Klasse der Koniglich Bayerischen Akademie der Wissenschaften. Supplement 2 (1). Lindauer'schen Hofbuchdruckerei, Munchen, pp. 1 - 45. [in German]","Clark, H. L. (1913) Scientific results of the expedition to the Gulf of California in charge of C. H. Townsend, by the U. S. Fisheries steamship ' Albatross' in 1911. No. 5. Echinoderms from lower California, with descriptions of new species. Bulletin of the American Museum of Natural History, 32 (8), 185 - 236. https: // doi. org / 10.5962 / bhl. title. 16360","Paulay, G. (2013) Apostichopus. World Register of Marine Species. Available from: http: // www. marinespecies. org / aphia. php? p = taxdetails & id = 241373 / (accessed 13 June 2017)"]}

Apostichopus japonicus (Selenka, 1867) Figs 6–13 Stichopus japonicus Selenka, 1867: 318, pl. 18, figs 33–36; Semper, 1868: 74; von Marenzeller, 1882: 136 –137, taf V, fig 11; Théel, 1886: 160, pl. VII, fig. 3; Mitsukuri 1896: 408; Augustin, 1908: 6 –7, fig. 4; Mitsukuri, 1912: 163, pl. 4, figs 32–44; Ohshima, 1915: 247 –248; Clark, 1922: 61; Choe & Ohshima, 1961: 97 –105; Levin, 1983:1 –45, figs 1–12. Stichopus japonicus typicus Théel, 1886: 196. Stichopus (Apostichopus) japonicus – Kanno et al., 2006: 672 –685. Apostichopus japonicus – Kuramochi & Naganuma, 2010: 49 –54, fig. 1a, 1b, 2. Stichopus roseus Augustin, 1908: 13 –14, fig. 10. Type material examined. Syntype MCZ HOL –763, Northwest Pacific Ocean, Japan. Additional materials examined. NSMT –E3673, Fukue Island, Nagasaki, 14 March 1998, T. Fujita; NSMT – 7045A, Tateyama Bay, Chiba, 21 April 2011, Y. Tamura; NSMT –E7046A, Futtsu, Chiba,4 29 June 2011, Y. Tamura; NSMT –E7046C, Futtsu, Chiba, 29 June 2011, Y. Tamura; NSMT –E7047B, Aburatsubo Bay, Kanagawa, 10 July 2011, Y. Tamura; NSMT –E7047D, Aburatsubo Bay, Kanagawa, 10 July 2011, Y. Tamura; NSMT –E7048, Uchiura Bay, Kanagawa, K. Yakiguchi, 28 September 2011; NSMT –10122A-E, 5 specimens, Takeoka, Futtsu, Chiba, K. Kawata & A. Ogawa, 24 December 2014. Type locality. Japan. Descriptions. Twenty peltate tentacles. Two rows of dorsal papillae, each arranged alternately in zig-zag pattern along the dorso-lateral radii. Single row of conical papillae along each ventor-lateral radius. Similar conical papillae, but larger, arranged single row at both ventro-lateral radii. Numerous, loosely arranged, small papillae scattered on dorsal and lateral body. Ventral side flattened. Tube feet arranged in 5–6 rows in central ambulacral area; 4–5 rows in both lateral ambulacra areas. Interambulcra narrow. Mouth subventral, surrounded by a ring of small papillae. Background body colour in alcohol dark reddish brown on dorsal, lighter brown on both lateral and ventral body. Gonads in two tufts; one each side of dorsal mesentery. Twenty free-hanging tentacular ampullae. Polian vesicle single, in various shapes and forms. Intestine connected to dorsal mesentery with rete mirabile. Dorsal body wall containing tables. Tables in dorsal body wall of adult reduced, pillars absent (Figs. 7, 8). Disk of table oval to round in shape with smooth rims; 2–14 irregular perforations on disk. Tables in dorsal body of juvenile with four pillars; single spine at tip of each pillar. Papillae containing multiperforated plates, reduced tables, rods, and elongated buttons. Multiperforated plates in papillae with four central perforation and numerous peripheral perforations; rim of uneven (Fig. 9A–D). Reduced tables in papillae similar to those in dorsal body (Fig. 9E), size larger and more perforations (2–14 perforations); rims smooth to uneven, but not spinous. Elongated buttons in papillae having two longitudinal rows of 5–11 perforations (Fig. 10A). Rods in papillae straight to curved; surface spinous (Fig. 10B). Rods in tentacles curved; surface covered with multiple spinelets (Fig. 11A–C). Tube feet with multiperforated plates (Fig. 12). Cloacal wall containing oval to rounded complex plates; surface very spinous and knobby (Fig. 13). Distribution. Shallow temperate waters in the coasts of China, Japan, Korea and Russia. Northern distribution limit at Sakhalin Island, Russia and Southern limit in the Kagoshima prefecture in Japan (see Zhao 2015) Remarks. The reduced table spicules of other materials examined in the dorsal body are similar to the spicules named “hemmungsbildungen” meaning table spicules reduced to the ring in Selenka (1876: pl. 18, fig. 36). The most contrasting difference between A. japonicus and A. armatus can be seen in the rims of reduced tables found on the dorsal body. The reduced tables have only smooth and non-spinous rims in A. japonicus compared to spinous disk rim tables in A. armatus. Observations on the reduced table spicules of type material using SEM (Fig. 7) confirms that the rims of reduced table spicules in the dorsal body are smooth and non-spinous. Kuramochi & Naganuma (2010) also observed similar characters at rim of tables in materials they examined. Although the figures of reduced tables of A. japonicus observed under compound microscope in Kuramochi & Naganuma (2010: fig. 2) showed that the rim of disks in tables appear to be spinous, greater resolution observation using scanning electron microscope in this study revealed that the rim on the disks of the reduced tables are merely undulating on the rims but do not form spines., Published as part of Woo, Sau Pinn, Ogawa, Akito, Tan, Shau Hwai, Yasin, Zulfigar, Kajihara, Hiroshi & Fujita, Toshihiko, 2017, A taxonomic revision of the genus Apostichopus (Holothuroidea: Stichopodidae) from Japan, pp. 121-135 in Zootaxa 4350 (1) on pages 127-130, DOI: 10.11646/zootaxa.4350.1.7, http://zenodo.org/record/1050945, {"references":["Selenka, E. (1867) Beitrage zur Anatomie und Systematik der Holothurien. Zeitschrift fur wissenschaftliche Zoologie, 17, 291 - 372. [in German]","Semper, C. (1868) Reisen im Archipel der Philippinen, zweiter Theil, wissenschaftliche Resultate, erster Band, Holothurien. W. Engelmann, Leipzig, pp. 288. [in German]","Marenzeller, E. V. (1882) Neue Holothurien von Japan und China. Verhandlungen der Zoologisch-Botanischen Gesellschaft in Wien, 31, 121 - 140. [in German] https: // doi. org / 10.5962 / bhl. part. 20315","Theel, H. (1886) Reports on the Holothurioidea dredged by H. M. S. Challenver during the years 1873 - 76. Part 2. Report of the Scientific Results of the Voyages of H. M. S. Challenger during the years 1873 - 76, Zoology, 39, 160 - 162.","Mitsukuri, K. (1896) A list of holothurians known to occur in Japan. Zoological Magazine, 8, 405 - 413. [in Japanese]","Augustin, E. (1908) Uber japanische Seewalzen. In: Doflein, F. (Ed.), Beitrage zur Naturgeschichte Ostasiens. Abhandlungen der Mathematisch - Physikalischen Klasse der Koniglich Bayerischen Akademie der Wissenschaften. Supplement 2 (1). Lindauer'schen Hofbuchdruckerei, Munchen, pp. 1 - 45. [in German]","Mitsukuri, K. (1912) Studies on actinopodous Holothurioidea. Journal College Science, Tokyo Imperial University, 29 (2), 163. https: // doi. org / 10.5962 / bhl. title. 37880","Ohshima, H. (1915) Report of the holothurians collected by the United States Fisheries Steamer Albatross in the Northwestern Pacific during the summer of 1906. Proceedings of the United States National Museum, 48, 213 - 291. https: // doi. org / 10.5479 / si. 00963801.48 - 2073.213","Clark, H. L. (1922) The holothurian of the genus Stichopus. Bulletin of the Museum of Comparative Zoology, 65 (3), 39 - 74.","Choe, S. & Ohshima, Y. (1961) On the morphological and ecological differences between two commercial forms, \" green \" and \" red \", of the Japanese common sea cucumber, Stichopus japonicus Selenka. Bulletin of the Japanese Society of Scientific Fisheries, 27 (2), 97 - 106. [in Japanese] https: // doi. org / 10.2331 / suisan. 27.97","Levin, V. S. (1983) Japanese Sea Cucumber. USSR Academy of Science, Vladivostok, pp. 7 - 30. [in Russian]","Kanno, M., Suyama, Y., Li, Q. & Kijima, A. (2006) Microsatellite analysis of Japanese sea cucumber, Stichopus (Apostichopus) japonicus, supports reproductive isolation in color variants. Marine Biotechnology, 8, 672 - 685. https: // doi. org / 10.1007 / s 10126 - 006 - 6014 - 8","Kuramochi, T. & Naganuma, T. (2010) Reclassification of the Apostichopus holothurians from Sagami Bay, central Japan. Biosphere Science, 49, 49 - 54. [in Japanese]","Zhao, H. (2015) Taxonomy and identification: distribution. In: Yang, H., Hamel, F. & Mercier, A. (Eds.), The Sea Cucumber Apostichopus japonicus: History, Biology and Aquaculture. Developments in Aquaculture and Fisheries Science, 39, pp. 46 - 49."]}

The effects of a diet containing Hanseniaspora opuntiae C21 on growth and digestive enzyme activity were estimated in juvenile Apostichopus japonicus. Groups of sea cucumbers were fed diets containing H. opuntiae C21 at 0 (control), 104, 105, and 106 CFU (colony-forming units)/g feed. Results showed that after 45 d the specific growth rate (SGR) of sea cucumbers fed a C21-supplemented diet at 10 4 CFU/g feed was significantly higher than that of the control (P < 0.05). Intestinal trypsin and lipase activities were significantly enhanced by C21 administration at 104 and 105 CFU/g feed compared with the control (P < 0.05). After feeding for 23–42 d, C21 was demonstrated by denaturing gradient gel electrophoresis to be present in the intestine of sea cucumbers. In addition, after feeding the C21-supplemented diets for 15 d, the sea cucumbers were switched to an unsupplemented diet and C21 was confirmed to be capable of colonizing the intestine for at least 31 d after cessation of feeding. In conclusion, C21 was shown to successfully colonize the intestine of juvenile A. japonicus via dietary supplementation, and improve growth and digestive enzyme activity.

UNLABELLED This study was aimed to evaluate the antimicrobial resistance and molecular resistance mechanisms of 87 Vibrio parahaemolyticus isolates from cultured sea cucumbers (Apostichopus japonicus). The results showed that all isolates were resistant to ampicillin and cephazolin, fewer of them were resistant to streptomycin (43·7%), cefuroxime sodium (18·4%), tetracycline (4·6%), sulphamethoxazole/trimethoprim (2·3%) and four quinolones (2·3%). More than half (56·2%) of the isolates displayed multiple resistance to at least three antimicrobials. The resistance genes were detected in all antimicrobial-resistant isolates except two tetracycline-resistant isolates. Among all these tested resistance genes, blaTEM , sul2, strA and strB were predominant, and none of blaSHV , blaCTX-M , blaOXA , sul1, sul3, tetA, tetM and tetQ genes was detected. Point mutations were found in quinolone resistance-determining regions of gyrA and parC genes in quinolone-resistant isolates. All isolates harboured class 1 integrons but only one carried gene cassette without any resistance genes, and none of them was positive to class 2, 3 integrons and SXT constins. These results indicate that the antimicrobial-resistant V. parahaemolyticus isolates from sea cucumbers and resistance genes could be potential risks to public health or other environments. SIGNIFICANCE AND IMPACT OF THE STUDY This study is the first report on characterization of antimicrobial resistance of Vibrio parahaemolyticus from sea cucumbers (Apostichopus japonicus). Our findings reveal a high level of resistance to some antimicrobials and prevalence of the resistance genes in V. parahaemolyticus isolates from sea cucumbers and underline the need for prudent use of antimicrobials in aquaculture to minimize the spread of antimicrobial-resistant V. parahaemolyticus.

Around the world, abalone species are a highly valuable marine resource. In recent years, abalone fisheries in the Northeast Pacific have suffered massive mortalities because of environmental factors. Aquaculture has been proposed as a solution to stop the collapse of this multimillion-dollar resource. Moreover, it has been shown widely that coculturing two or more species can increase the productivity of the resources cultured. The aim of this study was to test whether the growth rates of the green abalone Haliotis fulgens would increase when cocultured with the warty sea cucumber Apostichopus parvimensis. Growth rates of juvenile abalone increased by 29% in the presence of medium densities of A. parvimensis; however, coculture settings are not common in the Northeast Pacific. To our knowledge, this is the first coculture reported of these two species. Thus, these findings provide relevant information to promote innovative strategies for sustainable production of food.

We evaluated the effect of light intensity on the specific growth rate(SGR),food intake(FI),food conversion efficiency(FCE),and the energy budget of red and green variants of the sea cucumber Apostichopus japonicus.We reared 96 green(6.28 g ± 0.02 g) and 96 red(6.34 g ± 0.04 g) individuals under six light intensities(0,50,300,1 000,2 000,or 3 500 lx) for 60 d at 16°C.Light intensity had a significant effect on specific growth rate(SGR)(P0.05) in both variants.Within the range of 50–3 500 lx,there was a negative relationship between the SGR of sea cucumber and illumination intensity.Both red and green variants grew fastest(P0.05) at levels 50 lx.The maximum SGR,FI,and FCE(P0.05) were observed in individuals reared under 50 lx.Stronger light intensity inhibits FI and reduces the efficiency of food conversion.The lower FCE under stronger intensity lighting may be function of the oxygen consumption rate(OCR).Our results suggest that OCR is significantly affected by light intensity(P0.05).The minimum OCR was observed in animals reared under 50 lx,suggesting that little energy was expended on respiration,with most being invested in growth.Energy metabolism was significantly affected by light intensity(P0.05).At light levels under 50 lx,A.japonicus allocate 7% for growth and 90% for respiration and production of feces.As light intensity increases,the energy allocated to growth decreases and is instead diverted to respiration and production of feces.