Dietary tryptophan decreases the impacts of seawater temperature changes on behavior and gut health of the sea cucumber Apostichopus japonicus.

Seawater temperature change is an important concern for seed production and pond culture of sea cucumbers. The present study found that tentacle activity frequency was significantly lower in sea cucumbers exposed to continuous and rapid temperature increases than that of those at ambient temperature. Feeding behavior directly determines food intake, and further affects physiology and growth efficiency of sea cucumbers. This means that the decline in feeding caused by continuous and rapid temperature increases needs to be addressed in sea cucumber aquaculture. However, a sudden temperature change of 5 °C had no significant effect on behaviors of sea cucumbers. This indicates that continuous temperature increases, rather than a sudden increase, result in behavioral impacts on sea cucumbers. Therefore, we recommend aqua-farmers reduce the feeding amount for sea cucumbers during continuous and rapid temperature increases. In the present study, feeding behavior was significantly higher in sea cucumbers fed with 3% dietary tryptophan than that of those fed with 0% and 5% dietary tryptophan. This indicates that 3% dietary tryptophan increases the food intake of sea cucumbers, and mitigates the feeding decline caused by continuous and rapid temperature increase. This indicates that tryptophan has the potential to promote the feeding of sea cucumbers in seed production and pond culture. Adhesion capacity of sea cucumbers fed with 5% dietary tryptophan was significantly higher than that of individuals fed with 0% and 3% dietary tryptophan. This suggests that dietary tryptophan increases the feeding of sea cucumbers exposed to continuous and rapid temperature increases in pond culture and seed production. In addition, this study found that sea cucumbers fed with 3% dietary tryptophan had higher intestinal colony richness under the continuously rapid temperature change. The present study provides an effective method to improve adhesion behavior and to alleviate the impacts on feeding behavior for seed production and pond culture of sea cucumbers exposed to continuous and rapid temperature increases.

Effects of Dietary Zinc on Growth Performance, Digestive Enzyme Activities, Antioxidant Status, and Immune Responses of Sea Cucumber Apostichopus japonicus.

Zinc is an essential micronutrient for organisms involved in regulating various biological processes. This study evaluated the effects of dietary zinc on growth performance, digestive enzyme activities, antioxidant status, and immune responses of sea cucumber Apostichopus japonicus. Five experimental diets were formulated with graded levels of zinc (0, 20, 40, 60, and 80 mg/kg, respectively), and the actual dietary zinc values were 31.4, 51.0, 68.2, 91.9, and 110.8 mg/kg diet, respectively. Sea cucumbers were fed with diets for 2 months. The results showed the growth performance, amylase, and trypsin activities of sea cucumber increased significantly with zinc supplementation, and the best growth performance and enzyme activities were observed at 40 mg/kg zinc diet. Zinc supplementation significantly increased activities of superoxide dismutase, catalase, anti-superoxide anion, and inhibiting hydroxyl radical, while significantly reduced the malondialdehyde content. Furthermore, the higher zinc supplementation levels resulted in significantly upregulated immune-related genes of hsp90, p105, rel, and lsz, suggesting that excessive zinc caused oxidative stress. The broken-line regression analysis of specific growth rate indicated dietary zinc requirement in juvenile sea cucumber was ~ 66.3 mg/kg diet. Overall, dietary zinc contributes to the growth and immune resistance of juvenile sea cucumber, and our study will provide insights into the rational use of dietary zinc in aquaculture.

Sea cucumber sulfated polysaccharides and Lactobacillus gasseri synergistically ameliorate the overweight induced by altered gut microbiota in mice.

Sulfated polysaccharides from sea cucumber Stichopus japonicus (SCSPsj) have been found to modulate the gut microbiota by promoting the growth of probiotics. However, the effects of the combination of SCSPsj and probiotics are still less known. Thus, the present study aimed to investigate the effects of SCSPsj and Lactobacillus gasseri on gut microbiota-altered mice through gut microbiota and metabolomics analysis. In the present study, supplementation with SCSPsj, L. gasseri or the combination of SCSPsj and L. gasseri could effectively ameliorate the body weight gain and fat accumulation in gut microbiota-altered mice treated with low-dose penicillin. The better effect of the combination of SCSPsj and L. gasseri is attributed to the synergistic effect of SCSPsj and L. gasseri. 16S rRNA sequencing revealed that the combination of SCSPsj and L. gasseri can synergistically improve gut microbiota dysbiosis by increasing Lactobacillus and reducing Coriobacteriaceae_UCG-002. Furthermore, metabolomics results revealed that the combination of SCSPsj and L. gasseri can alleviate metabolic disorders by reducing the levels of lipid and lipid-like molecules in the serum samples, such as trans-vaccenic acid and 3ß-hydroxy-5-cholestene. Our findings have proved that the combination of SCSPsj and L. gasseri can benefit host health attributed to the synergistic effect, which is conducive to further application in functional food.

The feces of sea urchins as food improves survival, growth, and resistance of small sea cucumbers Apostichopus japonicus in summer.

Mass mortality and low growth highly decrease the production efficiency and sustainable aquaculture development of the sea cucumber Apostichopus japonicus in summer. Sea urchin feces was proposed to address the summer problems. A laboratory study was conducted for ~ 5 weeks to investigate survival, food consumption, growth and resistance ability of A. japonicus cultured with the feces of sea urchins fed kelp (KF feces, group KF), the feces of sea urchins fed prepared feed (FF feces, group FF), and the prepared sea cucumber feed (group S) at high temperature (25 °C). The sea cucumbers of group KF had better survival (100%) than those of the group FF (~ 84%), higher CTmax (35.9 °C) than those of the group S (34.5 °C), and the lowest skin ulceration proportion (0%) when  they were exposed to an infectious solution among the three groups. These results suggest that the feces of sea urchins fed kelp is a promising diet for improving the survival and enhancing the resistance in A. japonicus aquaculture in summer. Sea cucumbers fed significantly less FF feces after 24 h of ageing than the fresh FF feces, suggesting this kind of feces became unsuitable for A. japonicus in a short time (within 48 h). However, the 24 h of ageing at 25 °C for the high fiber feces of sea urchins fed kelp had no significant effects on the fecal consumption of sea cucumbers. In the present study, both fecal diets provide better individual growth to sea cucumbers than the prepared feed. Yet, the feces of sea urchins fed kelp provided the highest weight gain rate (WGR) to sea cucumbers. Therefore, the feces of sea urchins fed kelp is a promising food to reduce the mortality, to address the problems of summer, and to achieve higher efficiency in A. japonicus aquaculture in summer.

Dietary fulvic acid supplementation improves the growth performance and immune response of sea cucumber (Apostichopus japonicas).

The present study aims to explore the effects of dietary fulvic acid (FA) supplementation on the growth performance, digestive enzyme activity and immune response of sea cucumber (Apostichopus japonicas). FA was used to replace 0 (control), 0.1, 0.5 and 1 g cellulose in the basic diet of sea cucumber to formulate four experimental feeds with equivalent nitrogen and energy denoted as F0, F0.1, F0.3 and F1, respectively. No significant differences were observed in the survival rate among all groups (P > 0.05). Results show that the body weight gain rate, specific growth rate, intestinal trypsin, amylase and lipase activities, serum superoxide dismutase, catalase, lysozyme, alkaline and acid phosphatase activities and disease resistance ability against the pathogen, Vibrio splendidus of the sea cucumbers fed with FA-containing diets were significantly higher than those of the control group (P < 0.05). The optimum dose of dietary FA supplementation required for the maximum growth of sea cucumber was 0.54 g/kg. Therefore, dietary FA supplementation to the feed of sea cucumber can significantly improve its growth performance immune response.

Characterization and Expression Analysis of Regeneration-Associated Protein (Aj-Orpin) during Intestinal Regeneration in the Sea Cucumber Apostichopus japonicus.

Apostichopus japonicus achieves intestinal regeneration in a short period after evisceration, and multiple genes are involved in this process. The transcriptome of A. japonicus was screened for regeneration-associated protein (Aj-Orpin), a gene that is specifically upregulated during intestinal regeneration. The expression and function of Aj-Orpin were identified and investigated in this study. The 5' and 3' RACE polymerase chain reaction (PCR) was used to clone the full-length cDNA of Aj-Orpin. The open reading frame codes for a 164 amino-acid protein with an EF-hand_7 domain and overlapping signal peptides and transmembrane regions. Moreover, Aj-Orpin mRNA and protein expression during intestinal regeneration was investigated using real-time quantitative PCR and Western blot. The expression pattern of Aj-Orpin in the regenerating intestine was investigated using immunohistochemistry. The results showed that Aj-Orpin is an exocrine protein with two EF-hand-like calcium-binding domains. Expression levels were higher in the regenerating intestine than in the normal intestine, but protein expression changes lagged behind mRNA expression changes. Aj-Orpin was found to play a role in the formation of blastema and lumen. It was primarily expressed in the serosal layer and submucosa, suggesting that it might be involved in proliferation. These observations lay the foundation for understanding the role of Orpin-like in echinoderm intestinal regeneration.

Oral administration of sea cucumber (Stichopus japonicus) protein exerts wound healing effects via the PI3K/AKT/mTOR signaling pathway.

This study aimed to investigate the effect of the oral administration of sea cucumber protein (SCP) on wound healing. SCP was isolated and purified from the body wall of Stichopus japonicus. A mouse skin incision model was operated on to evaluate the wound repair effect of SCP. The histological changes in the skin at the wound sites of BALB/c mice were observed by staining with haematoxylin and eosin (H&E) and Masson's trichrome. The enzyme-linked immunosorbent assay (ELISA) was used to analyze the expression of inflammatory cytokines in BALB/c mice. The boost cell migration ability was detected by a scratch assay after HaCaT cells were cultured with digested SCP (dSCP). Western blotting and RT-PCR assays were performed to determine the mechanism of SCP promoting wound healing. As a result, the wound healing rate in the SCP high dose group was 1.3-fold, compared to that in the blank group on day 14. Also, increased epidermal thickness and 1.79-fold collagen deposition contrasted with the blank group. Additionally, SCP could up-regulate the levels of pro-inflammatory factors (IL-1ß, IL-6, TNF-α) from day 3 to 7 firstly and decreased from day 7 to 14. IL-8 expression continuously decreased while the level of anti-inflammatory factor (IL-10) increased during the healing stage. Furthermore, the cell closure area reached 67% after being treated with 50 µg mL-1 of dSCP for 48 h. Cell proliferation was associated with the dSCP-activated PI3K/AKT/mTOR pathway. Taken together, SCP can be orally used as an effective agent for wound repair.

Structure and hypoglycemic effect of a neutral polysaccharide isolated from sea cucumber Stichopus japonicus.

In addition to its high nutritious value, sea cucumber has been recognized by folk medicine for a long time. This study investigated the structure and hyperglycemic activity of a neutral polysaccharide (NPsj) from sea cucumber Stichopus japonicus, whose molecular weight was determined as 301.75 kDa by HPGPC method. Monosaccharide composition analysis indicated that NPsj is a glucan. The structure of NPsj was obtained by combining the analysis of methylation analysis, FTIR, NMR, periodate oxidation, Smith degradation and ESI-MS, which is mainly composed of (1 â†’ 4)-α-d-glucoses with ß-d-glucose(1→) branches substituted at O-6 every 7-9 of 1,4 linked glucoses. An in vitro insulin resistance Hep G2 cells model and a 3 T3-L1 cells model were established, and the NPsj has significant effect to increase glucose consumption with no toxicity at 10-100 µg/mL. Furthermore, NPsj upregulates the phosphorylation of Akt1 and down-regulated GSK3ß, and then reduces the phosphorylation of GS, indicating its mechanism of ameliorating insulin resistance via Akt/GSK3ß/GS signaling pathway.

Characterizations and the Mechanism Underlying Osteogenic Activity of Peptides from Enzymatic Hydrolysates of Stichopus japonicus.

Sea cucumber (Stichopus japonicus) is a kind of fishery product with high nutritional value. It exhibits a wide range of biological activity and has potential application in the food, pharmaceutical, and biomedical industries. However, there are no reports available on the effects of S. japonicus peptides (SJP) on bone mineral density regulations. The purpose of this work was to analyze the composition and osteogenic activity of SJP and explore its underlying mechanism. The results showed that SJP stimulated cell proliferation, differentiation, and mineralization in a dose-dependent manner. In addition, SJP could promote the proliferation of MC3T3-E1 cells by altering the cell cycle progression and regulating the expression of Cyclins. Besides, SJP activated the WNT/ß-catenin pathway and increased the nuclear level of the active form ß-catenin. Furthermore, SJP also induced the expression of bone morphogenetic protein (BMP-2) and increase the phosphorylation levels of p38, JNK, and ERK, suggesting that the osteogenic activity of SJP may be achieved through the activation of WNT/ß-catenin and BMP/MAPK signal pathways. In vivo, SJP significantly inhibited the serum levels of RANKL, ALP, and TRAP, whereas it increased the levels of osteocalcin and osteoprotegerin in OVX-mice. These results indicate that SJP may have the potential to stimulate bone formation and regeneration, and may be used as a functional food or nutritional supplement to prevent osteoporosis.

Apostichopus japonicus Oligopeptide Induced Heterogeneity in the Gastrointestinal Tract Microbiota and Alleviated Hyperuricemia in a Microbiota-Dependent Manner.

SCOPE: This study aims to investigate the protective effect of Apostichopus japonicus oligopeptide (AJOP) on hyperuricemia, demonstrate the modulation of the gastrointestinal tract (GIT) microbiota, and clarify the underlying microbiota-dependent mechanism. METHODS AND RESULTS: Hyperuricemic mice treated with AJOP and subjected to corresponding fecal microbiota transplantation (FMT) are used to observe the beneficial effects of AJOP and microbiota. Gene transcriptions are measured using quantitative real-time PCR. The GIT (stomach, colon, cecum, and feces) microbiota is analyzed by 16S rDNA sequencing and the short-chain fatty acids are detected using GC-MS. Dietary administration of AJOP significantly alleviates hyperuricemia, regulates uric acid metabolism, inhibites the activation of the NLRP3 inflammasome and NF-κB-related signaling pathway, and restores m6A methylation levels. In addition, substantial heterogeneity is observed in GIT microbiota. Furthermore, FMT effectively alleviates hyperuricemia in mice by selectively regulating the corresponding pathways associated with AJOP treatment, indicating that the mechanism underlying the protective effects of AJOP is partly microbiota-dependent. CONCLUSION: This study demonstrates that AJOP exerts a protective effect on hyperuricemic mice by regulating uric acid metabolism, resulting in substantial heterogeneity among the GIT microbiota, thus mediating the beneficial effects in a microbiota-dependent manner.

Structural elucidation and antidiabetic activity of fucosylated chondroitin sulfate from sea cucumber Stichopus japonicas.

A fucosylated chondroitin sulfate was isolated from the body wall of sea cucumber Stichopus japonicus (FCSsj), whose structure was characterized by NMR spectroscopy and HILIC-FTMS. At the ratio of 1.00:0.26:0.65, three fucosyl residues were found: 2,4-disulfated-fucose (Fuc2,4S), 4-sulfated-fucose (Fuc4S) and 3,4-disulfated-fucose (Fuc3,4S), which were only linked to the O-3 of glucuronic acid residues (GlcA). Besides mono-fucosyl moieties, di-fucosyl branches, namely Fuc2,4Sα(1→3)Fuc4S, were also found to be attached to the O-3 of GlcA. The antidiabetic activity of FCSsj was evaluated using glucosamine induced insulin resistant (IR) Hep G2 cells in vitro. It was found that FCSsj significantly promoted the glucose uptake and glucose consumption of IR-Hep G2 cells in a dose-dependent manner, and could alleviate the cell damage. Furthermore, FCSsj could promote the glycogen synthesis in the glucosamine-induced IR-Hep G2 cells. These results provided a supplement for studying the antidiabetic activity of FCSsj.

Effects of Supplementary Selenium and Vitamin E on the Growth Performance, Antioxidant Enzyme Activity, and Gene Expression of Sea Cucumber Apostichopus japonicus.

A 60-day feeding experiment was conducted to evaluate the effects of single selenomethionine (Se) and its mixture with vitamin E (VE) on the growth, antioxidant enzyme activities, and gene expression of juvenile sea cucumber Apostichopus japonicus. The design of the experiment contained two factors and 5 × 2 levels by means of adding various levels of Se and VE in the feed, i.e., combination of 0, 0.3, 0.6, 0.9, or 1.2 mg Se kg-1 and 0 or 200 mg VE kg-1. The results revealed that the specific growth rate and weight gain rate were the highest in the group with 0.3 mg Se kg-1 and 200 mg VE kg-1, followed by the group with 0.6 mg Se kg-1 without VE. Se significantly improved the activities of amylase and protease with VE also imposed positive effect on the amylase activity. Glutathione peroxidase (GPX) activity was highest in the group with 1.2 mg Se kg-1 and lowest with the basal diet. The activity of catalase (CAT) was increased while glutathione reductase (GR) activity was decreased in response to the addition of Se. No significant interactive effects of Se and VE on the enzyme activities were found except superoxide dismutase (SOD) activity. While relative expressions of GPX, CAT, and SOD genes were significantly responsive to the addition of dietary Se, VE significantly promoted the gene expression of SOD. The results suggested that Se and VE might have beneficial effects on the growth and antioxidant responses of A. japonicus.

Combined Effects of Elevated Temperature and Crude Oil Pollution on Oxidative Stress and Apoptosis in Sea Cucumber (Apostichopus japonicus, Selenka).

Currently, global climate change and oil pollution are two main environmental concerns for sea cucumber (Apostichopus japonicus) aquaculture. However, no study has been conducted on the combined effects of elevated temperature and oil pollution on sea cucumber. Therefore, in the present study, we treated sea cucumber with elevated temperature (26 °C) alone, water-accommodated fractions (WAF) of Oman crude oil at an optimal temperature of 16 °C, and Oman crude oil WAF at an elevated temperature of 26 °C for 24 h. Results showed that reactive oxygen species (ROS) level and total antioxidant capacity in WAF at 26 °C treatment were higher than that in WAF at 16 °C treatment, as evidenced by 6.03- and 1.31-fold-higher values, respectively. Oxidative damage assessments manifested that WAF at 26 °C treatment caused much severer oxidative damage of the biomacromolecules (including DNA, proteins, and lipids) than 26 °C or WAF at 16 °C treatments did. Moreover, compared to 26 °C or WAF at 16 °C treatments, WAF at 26 °C treatment induced a significant increase in cellular apoptosis by detecting the caspase-3 activity. Our results revealed that co-exposure to elevated temperature and crude oil could simulate higher ROS levels and subsequently cause much severer oxidative damage and cellular apoptosis than crude oil alone on sea cucumber.

Immunomodulatory effects of fucosylated chondroitin sulfate from Stichopus chloronotus on RAW 264.7 cells.

Sea cucumbers were nutritional food and traditional Chinese medicine. In this study, fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus (fCS-Sc), a potential anticoagulant agent and immunological adjuvant, was investigated for its immune activation effects on RAW 264.7 macrophage for the first time. The results indicated that fCS-Sc could significantly promote the proliferation, the pinocytic activity of RAW 264.7 cells, and the production of NO, TNF-α, IL-1ß, and IL-6. The fluorescence labeling assay indicated that fCS-Sc could bind to the macrophage. Moreover, the specific pattern recognition receptor inhibition assays showed that toll-like receptor 4 (TLR4) and TLR2 were involved in the recognition of fCS-Sc. Western blot assays indicated that fCS-Sc could induce degradation of cytoplasm IκB-α, and promotion of NF-κB p65 subunit translocation to nucleus, leading to a functional improvement of macrophage through NF-κB pathway. The results suggested that fCS-Sc might served as a promising candidate of immunomodulator.

Effects of Dietary Supplementation with κ-Selenocarrageenan on the Selenium Accumulation and Intestinal Microbiota of the Sea Cucumbers Apostichopus japonicus.

A 30-day feeding trial was conducted to investigate the effect of κ-selenocarrageenan on the growth performance, selenium accumulation, antioxidant capacity, and intestinal microbiota of sea cucumbers Apostichopus japonicus, with different sizes (70 g ± 10 g and 100 g ± 10 g). Sea cucumbers of each size were randomly assigned into two groups; a diet without supplemented κ-selenocarrageenan was referred to as a control diet, or supplemented with κ-selenocarrageenan at selenium (Se) levels of 2.0 µg/g. Selenium accumulation in the body wall and intestine was determined on days 0, 10, 20, and 30. The survival rate (SR) was significantly higher in the κ-selenocarrageenan-treated group (Se group) than in the control group. After 30 days of feeding, κ-selenocarrageenan supplementation increased the activities of glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC), and decreased malondialdehyde (MDA) levels in A. japonicus. Furthermore, the intestinal microbiota diversity of sea cucumbers was increased by dietary supplementation with κ-selenocarrageenan and the relative abundances of some probiotics (such as Sulfitobacter and Rhodobacteraceae) were also increased. It is suggested that κ-selenocarrageenan could increase the antioxidant capacity and modulate the intestinal microbiota of sea cucumbers A. japonicus. Further researches will be conducted for its optimal administration concentrations in vivo.

Synergistic Effects of Dietary Selenomethionine and Vitamin C on the Immunity, Antioxidant Status, and Intestinal Microbiota in Sea Cucumber (Apostichopus japonicus).

A 30-day feeding trial was carried out to investigate the interactive effects of dietary selenium (selenomethionine) and vitamin C (Vc) in Apostichopus japonicus. Two selenium (0 and 5 mg/kg) and three vitamin C (0, 5000, and 10,000 mg/kg) combined groups of feed were formulated (Designated as LSeLVc, LSeMVc, LSeHVc, HSeLVc, HSeMVc and HSeHVc, respectively) and fed the sea cucumbers. Our results showed no significant effects on the growth-related parameters in sea cucumber (P > 0.05). Furthermore, the reciprocal action between Se and Vc had significant (P < 0.05) effects on Se accumulation in the respiratory tree and intestines. Also, the lysozyme, glutathione peroxidase activity, and the relative expression levels such as LZM, GPX, Hsp70, and Hsp90 in different tissues were significantly increased in the group of sea cucumber fed diet with 5 mg Se in combination with 5000 mg Vc compared with the control group (P < 0.05). However, MDA and H2O2 contents in the body wall were significantly reduced in the HSeHVc group (P < 0.05). In addition, analysis of intestinal flora revealed that Haloferula abundance was highest in the LSeMVc group than other treatment groups, and Vibrio abundance was decreased with combined Se and Vc supplement. Finally, the species diversity of the gut microbial community of sea cucumber in HSeMVc group was lower than those in other treatment groups. The results showed that the interaction of selenium and vitamin C had positive effects on improving the immune status, antioxidant capacity, and digestive ability of A. japonicus.

Regulation of dietary astragalus polysaccharide (APS) supplementation on the non-specific immune response and intestinal microbiota of sea cucumber Apostichopus japonicus.

Astragalus polysaccharide (APS) plays important roles in antibacterial, antiviral and antiparasitic activities in mammals, birds and aquatic animals. However, the relationship between non-specific immune responses and intestinal microbiota in sea cucumber (Apostichopus japonicus) after dietary APS supplementation has not been reported to date. Here, the effect of dietary APS supplementation on the non-specific immune response and intestinal microbial composition and species distribution of sea cucumber was explored. We found that although there was no significant effect on sea cucumber growth, the enzymatic activity and expression level of immune- and antioxidant-related genes changed after dietary APS supplementation. Furthermore, the intestinal microbial composition and species distribution of sea cucumber were different at the phylum and genus levels after dietary APS supplementation. The phyla Proteobacteria and Bacteroidetes were significantly different between the APS2 group and CK group. The results of PCA and PCoA analysis also showed that the APS2 group was significantly different compared to the other groups. Finally, analysis of the relationship between non-specific immune responses and the intestinal microbiota showed that the expression level of NF-κB was significantly correlated with intestinal microbiota at the genus level. This finding suggests that dietary APS supplementation might affect the non-specific immune response and intestinal microbiota of sea cucumber through the NF-κB signalling pathway; the appropriate added level was 800 mg/kg. Taken together, our results lay a foundation for further understanding the relationship between non-specific immune responses and intestinal microbial of sea cucumber.

Isolation and identification of zinc-chelating peptides from sea cucumber (Stichopus japonicus) protein hydrolysate.

BACKGROUND: Zinc is known to play an essential role in the biological activities in the human body. In this study, a zinc-chelating peptide (ZCP) produced by Alcalase-assisted hydrolysis of the body wall of sea cucumber was isolated and identified. The ZCP was purified stepwise by ultrafiltration, anion-exchange chromatography, and gel filtration chromatography, in conjunction with ultraviolet-visual (UV-visual) spectrophotometry, which was used to analyze each purified fraction. RESULTS: Analysis of the purified ZCP revealed that its zinc-chelating ability was 33.31%. Analysis of isothermal titration calorimetry suggested that the binding of ZCP and zinc (N ≈ 2) was endothermic, with weak binding affinity. Fourier transform infrared spectroscopy spectra (FTIR) indicated that carboxylic and amide groups in ZCP were the primary binding sites of Zn. Sequencing the result by ultra-performance liquid chromatography-quadrupole/time of flight mass spectrometry (UPLC-Q-TOF-MS/MS) showed that a representative ZCP had the sequence WLTPTYPE with a molecular weight of 1005.5 Da. CONCLUSION: These results provide a promising foundation for the production of zinc supplements from sea-cucumber-derived ZCPs. © 2019 Society of Chemical Industry.

The influence of three antibiotics on the growth, intestinal enzyme activities, and immune response of the juvenile sea cucumber Apostichopus japonicus selenka.

The global abuse and misuse of antibiotics in the treatment and prevention of bacterial infections has resulted in the ubiquitous existence of these drugs in aquatic environments, which causes frequent antimicrobial resistance and pollution in ecosystems. However, the chronic effects of antimicrobial agents on aquatic animal growth and health have not been fully evaluated. In the present study, three typical antibiotics (tetracycline, erythromycin, and norfloxacin) were administered orally to juvenile sea cucumbers Apostichopus japonicus for 45 days, to mimic the long-term use of antibiotics. As a result, tetracycline and erythromycin promoted the growth and digestive activity of lipase, pepsin, and trypsin, but norfloxacin did not show significant prompting effect on digestive activity and even retarded the weight gain of the sea cucumbers. The mortality was higher in antibiotic treated groups between the 2nd and 4th days after challenge with Vibrio splendidus. At the same time, lower immune-related parameters were found in antibiotic feeding juveniles, suggesting that the use of antibiotics might weaken the immune defense system of sea cucumbers. This study revealed that antibiotic administration could facilitate the growth of sea cucumbers to varying degrees yet coupled with high risks of impaired immune function and compromised disease resistance.

Effects on skin of Stichopus japonicus viscera extracts detected with saponin including Holothurin A: Down-regulation of melanin synthesis and up-regulation of neocollagenesis mediated by ERK signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Stichopus japonicus (sea cucumber), edible traditional food in Asia, and its extracts are renowned for their wound healing, pain relieving, and cosmetic effects in traditional medicine. Holothurins, toxins isolated from sea cucumber, are thought to be active components for their beneficial effects. However, researchers have yet to outline specific mechanisms thereof. AIM OF THE STUDY: The present study was designed to evaluate the anti-melanogenic and anti-wrinkle properties of S. japonicus viscera extracts (VF) on the skin via in vitro and ex vivo experiments and to assess the anti-aging effects of S. japonicus viscera extracts in relation to known wound healing and cosmetic processes. MATERIALS AND METHODS: The viscera of live S. japonicus specimens were freeze dried and ground into a powder. Aqueous extracts were subsequently prepared from the concentrated powder using a water extraction method. To investigate the inhibitory effects of VF on melanogenesis, mushroom tyrosinase activity assay and melanin assay were performed on Melan-A cells. To further delineate the anti-melanogenic properties of VF, western blot analysis for tyrosinase, TRP-1, TRP-2, MITF, and ERK was conducted. Changes in collagen synthesis in human dermal fibroblast (HDF) were evaluated via CCK-8 assay and immunocytochemistry to determine the anti-wrinkle effects of VF. Finally, anti-aging properties were examined in a human skin equivalent ex vivo model. RESULTS: In Melan-A cells, VF treatment reduced melanin contents in a concentration-dependent manner. The anti-melanogenic effects of VF appeared to be due to enzymatic inhibition of tyrosinase. In CCK-8 assay, VF also significantly increased the viability of HDFs in a concentration-dependent manner. Immunoblot analysis revealed phosphorylation of ERK in HDFs treated with VF. In a human skin equivalent ex vivo model (Neoderm®-ED), VF treatment at a concentration of 50 µg/ml enhanced collagen type IV and Ki-67 expression and downregulated MMP-9 expression. CONCLUSION: This study demonstrated that aqueous extracts from S. japonicus viscera are effective whitening and anti-aging agents that stimulate ERK signaling to inhibit melanin synthesis and promote collagen synthesis.