Purification and characterization of a cysteine-like protease from the body wall of the sea cucumber <Emphasis Type="Italic">Stichopus japonicus</Emphasis>

The sea cucumber (Stichopus japonicus) is able to undergo autolysis in response to a variety of environmental and mechanical cues. Within the framework of a long-term study of this phenomenon we have purified a protease from the body wall of the sea cucumber by means of ion-exchange chromatography with DE-52 cellulose and gel filtration chromatography with Sephadex G-100. The final enzyme preparation was nearly homogeneous on polyacrylamide gel electrophoresis, and its molecular weight was estimated to be approximately 35.5 kDa. The purified enzyme exhibited a maximum activity for the hydrolysis of casein at pH 7.0 and 50°C and a remarkable stability at pH 4.0–7.0 and 40–60°C. Based on the inhibition and activation profiles obtained with numerous specific protease inhibitors and an activator, the protease purified from the body wall of the sea cucumber was defined to be a cysteine-like protease.     

Effect of dietary carbohydrate levels on growth performance,non‐specific immune enzymes and acute response to low salinity and high temperature of juvenile sea cucumber Apostichopus japonicus

This study was performed to determine the optimum dietary carbohydrate (CHO) levels of sea cucumber, based on the parameters of growth, digestive enzymes, digestibility, non‐specific immune enzymes and acute low‐salinity (20 g/L) stress and high‐temperature (30°C) stress tolerance. Diets with eight different CHO (dextrin) levels (32.9, 107.6, 192.5, 257.2, 316.8, 428.0, 482.4 and 572.8 g/kg) were fed to sea cucumber juveniles (0.49 ± 0.01 g) for 60 days. Significant higher amylase activity was observed in sea cucumbers fed diet with CHO ranging between 32.9 and 192.5 g/kg than that of other treatments (p < .05). The sea cucumbers fed with 192.5 g/kg CHO showed significantly higher acid phosphatase activity than the treatments of 482.4 and 572.8 g/kg CHO (p < .05), and significantly higher alkaline phosphatase activity than other treatments (p < .05, except 257.2 g/kg). The treatments of 428.0–572.8 g/kg were found significantly lower values than other treatments in apparent digestibility coefficients for dry matter and crude protein (p < .05). The sea cucumbers fed with 192.5, 257.2 and 316.8 g/kg CHO showed better tolerance to high‐temperature (30°C) and low‐salinity (20 g/L) stress than other treatments. In brief, the optimal dietary CHO level for the growth of juvenile sea cucumber is 177.96 g/kg. However, excessive CHO will inhibit amylase enzyme activity and decrease digestibility, resulting in low growth of sea cucumber.     

Effect of temperature on growth,digestion and immunity of green,white and purple sea cucumbers,Apostichopus japonicus (Selenka)

Three color morphs (white, green and purple strains) of Apostichopus japonicus (Selenka) were cultured in artificial seawater, for approximately 90 days, in three temperature ranges: 27–22°C (high), 22–17°C (mid) and 17–12°C (low). All strains grew in all temperature ranges. Temperature significantly affected growth rate, digestibility, digestive enzymes and immune‐related enzymes. Highest specific growth rates were exhibited in 4‐month‐old sea cucumbers at mid and high temperatures, and in 16‐month‐old sea cucumbers at mid and low temperatures. Specific growth rates of green and purple strains were not significantly different, but were significantly higher than that of the white strain at mid temperatures. The digestibility of each strain was significantly higher at 27°C, 22°C and 17°C than at 12°C. Green‐strain digestibility was higher than that of purple and white strains at specific temperatures. Protease and amylase activities of all strains followed bell‐shaped temperature curves with maximum digestive enzyme activity at 17°C. The activities of alkaline and acid phosphatases were higher in the guts of the green strain than in the white or purple strains at the same temperature. Superoxide dismutase activity was higher in the purple strain than in white and green strains.     

两株芽孢杆菌的生长特性及其对仿刺参的益生作用

本实验室前期从大连湾地区健康的仿刺参养殖池塘沉积物中分离出两株芽孢杆菌即B6和B7。首先,通过分析二者的生长特性发现,B6和B7的最适生长温度为15~35℃;最适pH范围为6~8;最适盐度为3%~5%。菌株产酶特性检测结果表明,B6和B7均可产生淀粉酶和蛋白酶,B7产脂肪酶。将两种菌悬液投喂仿刺参后发现,B6和B7可有效提高仿刺参肠道内的消化酶活性以及体腔液中多种非特异性免疫酶活性。本研究结果表明:B6和B7可作为益生菌剂的基础菌株添加至仿刺参生长环境中,并且对仿刺参的消化及免疫功能具有正向刺激作用。     

Ontogeny of protease, amylase and lipase in the alimentary tract of hybrid Juvenile tilapia (Oreochromis niloticus × Oreochromis aureus)

Juvenile tilapias (Oreochromis niloticus × O. aureus), with average body weights of groups I, II and III of 55.14, 122.82, and 225.68 g respectively were used to study changes in the activity of protease, amylase, and lipase in different organs and sections of the alimentary tract. Additionally, tract containing digesta, which is closer to physiological conditions, may help reveal the mechanisms of whole chemical digestion process. Another group of tilapias (mean body weight of 111.81 ± 0.14 g) was used to analyze changes in activity of protease, lipase, and amylase in response to varying pH and temperatures. The activity of enzymes in all digestive organs increased when body weight increased from 55 to 122 g, and the activity further increased when the weights increased from 122 to 225 g. The rates of increase in digestive enzyme activity were significantly greater than the rates of growth of the fish. When the activity was compared in different sections of the tract, a similar regularity was found for the three enzymes in all fish. The highest amounts of activity were seen in the foregut and the lowest in the rectum, with the middle amount of activity in the hindgut. The pH ranges for the maximum activity of tilapia protease in the stomach and intestine were 1.6–3.3 and 9.5–10.5 respectively and the optimal temperature in these organs was 55°C. The pH ranges for the maximum amylase activity in the intestine and hepatopancreas were 6–7 and 7.5 respectively, and high amylase activity in these organs was found at 25–35°C. The activity of lipase in the intestine remained unchanged at pH 6.0–9.0 and with temperatures between 25 and 35°C. These results suggest that the ability of tilapia to utilize feed varies at different growth stages and remains relatively stable with changes in environmental pH and temperature, which should be taken into account when designing feed formulas for tilapia.     

Effects of Dietary Lysine Levels on Growth,Intestinal Digestive Enzymes,and Coelomic Fluid Nonspecific Immune Enzymes of Sea Cucumber,Apostichopus japonicus,Juveniles

A 56‐d feeding trial was conducted to evaluate the effects of dietary lysine levels on growth performance, intestinal digestive enzymes, and nonspecific immune response of Apostichopus japonicus juveniles. Five semipurified diets were formulated to contain graded levels of lysine (from 0.28 to 2.32% of dry matter). Although no significant differences (P > 0.05) were observed in survival rate, final weight (FW), and body weight gain (BWG), the FW and BWG increased from 0.28 to 1.19% with increasing dietary lysine levels, then showed a declining tendency. Broken‐line regression analysis of BWG indicated sea cucumber requires lysine at 0.76% of dry diet. Proximate composition, lysine content of the body wall, and total amino acid profiles were not affected by dietary treatments. Intestinal protease level increased with increasing dietary lysine level from 0.28 to 1.19%, then decreased. Acid phosphatase and superoxide dismutase activities of the sea cucumbers were not affected by various dietary lysine levels; however, significantly (P < 0.05) higher alkaline phosphatase activity was observed in sea cucumbers fed 2.32% lysine diet than those fed diets having 0.28 and 1.89% lysine. Overall, sea cucumber juveniles fed with diets containing between 0.76 and 1.19% lysine showed better growth performance, digestive enzymes, and nonspecific immune enzyme activities.     

Effects of dietary heat‐killed Lactobacillus plantarum L‐137 (HK L‐137) on the growth performance,digestive enzymes and selected non‐specific immune responses in sea cucumber,Apostichopus japonicus Selenka

A feeding trial was conducted to evaluate the efficacy of dietary heat‐killed Lactobacillus plantarum L‐137 (HK L‐137) on growth performance, digestive, non‐specific immune and phagocytosis of sea cucumber, Apostichopus japonicus. Sea cucumbers (initial body weight 1.35 ± 0.04 g) were fed diets supplemented with five levels of HK L‐137 (0, 0.005, 0.025, 0.05 and 0.25 g HK L‐137 kg^?1 diets) for 60 days. Results indicated sea cucumbers fed with diets containing 0.05 and 0.25 g HK L‐137 kg^?1 diets showed significantly (P < 0.05) higher body weight gain and specific growth rate than other groups. Sea cucumbers fed with diets containing 0.05 and 0.25 g HK L‐137 kg^?1 diets showed significantly (P < 0.05) higher protease activity than control group. Higher amylase, lysozyme and phagocytic activities were found in 0.25 g HK L‐137 kg^?1 diet group. Higher superoxide dismutase enzyme and alkaline phosphatase activity was found in 0.05 g HK L‐137 kg^?1. While no significant differences (P > 0.05) were found in acid phosphatase activity. These results suggested that dietary supplementation of 0.05 g HK L‐137 kg^?1 diets would have benefit on growth, digestive enzymes and several non‐specific immune parameters of sea cucumber.     

Partial characterization of digestive proteases of the three‐spot cichlid Cichlasoma trimaculatum (Günter 1867)

Partial characterization of digestive proteases in the three‐spot cichlid Cichlasoma trimaculatum juveniles was conducted. It was determined that there is higher alkaline proteases activity (3.95 ± 0.32 IU mg^?1 protein) compared to acidic proteases (2.01 ± 0.57 IU mg^?1 protein). Optimal temperature for alkaline proteases is 60 °C which resulted in more thermostability to temperature changes. On the other hand, optimal temperature for acidic proteases is 50 °C. Optimal pH for acidic proteases was pH 2, while for alkaline proteases, it was pH 10, which resulted in more stability in relation to pH changes than acidic protease. The use of specific inhibitors and the SDS‐PAGE electrophoresis analysis revealed seven types of bands for alkaline proteases, which make evident the main presence of serine proteases. In acidic proteases, more than 98 g kg^?1 of the activity was inhibited with pepstatin A inhibitor. Therefore, it is evident that C. trimaculatum digestion is composed by acidic and alkaline proteases; thus, it should be considered an omnivorous fish.     

Combined influence of water temperature, salinity and body size on energy budget in the sea cucumber Apostichopus japonicus Selenka

The worldwide demand for sea cucumber is outpacing the sustainable harvest capabilities of fisheries. Sea cucumber ranches and farms are striving to supplement wild harvest, but variable temperature and salinity conditions in pond culture systems make sea cucumber production challenging. In this study, we evaluated how water temperature, salinity and body size affected the energy budget of pond-cultured sea cucumber Apostichopus japonicus Selenka. An orthogonal design was used to identify the most suitable conditions for energy consumption and scope for growth (SFG). After the 42-day experimental period, we found that water temperature, salinity and body size significantly influenced energy consumption, while salinity and body size were the main influencing factors on SFG. Based on these results, we suggest that a water temperature of 16 °C and a salinity of 30 g L^?1 are optimal conditions for stocking sea cucumber A. japonicus with a body size of 37.34 ± 4.63 g. As such, the optimum stocking seasons for sea cucumber A. japonicus may be April in the spring and October in the autumn.     

Requirement of vitamin E of growing sea cucumber Apostichopus japonicus Selenka

This feeding trial was conducted to determine the vitamin E requirement of growing sea cucumber Apostichopus japonicus Selenka. Six isonitrogenous and isoenergetic experimental diets were formulated to contain graded levels of vitamin E (6.7, 81.2, 159.3, 237.8, 314.6, 395.9 mg/kg diet). Each diet was assigned randomly to 30 growing sea cucumber with initial body weight 15.43 g in triplicates for 8 weeks. Survival rate was not affected by dietary vitamin E; meanwhile, both the weight gain (WG) and specific growth rate were presented the trend of increasing first and then kept stable. With the increasing of dietary vitamin E, crude lipid content of body wall was evaluated firstly and dropped afterwards. When dietary vitamin E contents were lower than 159.3 mg/kg, vitamin E contents of body wall were increased by dietary vitamin E levels, but there were no more differences when dietary vitamin E higher than 159.3 mg/kg. There were minor effects on digestive enzymes of intestine by dietary vitamin E. Contents of malondialdehyde were decreased, while the total superoxide dismutase activity was increased first and then decreased with the increasing of dietary vitamin E. Activities of intestinal alkaline phosphatase were increased, and glutamic oxaloacetic transaminase were decreased first and then increased with the increasing of dietary vitamin E. In conclusion, analysis by a linear regression equation of WG or vitamin E contents in body wall indicated that the optimum requirement of vitamin E for growing sea cucumber (initial body weight 15.43 g) was 165.2–187.2 mg/kg diet.     

饲料中添加浒苔对仿刺参幼参生长、消化酶活性和免疫力的影响

在水温17~18℃和盐度30条件下,将初始体质量为(4.09±0.26)g的仿刺参饲养在15个循环水玻璃缸(容积100L)中,投喂在基础饲料中添加0%、3%、6%、9%和12%浒苔的饲料,于投喂后第7、14、28d和42d分别检测仿刺参的生长指标、消化酶(蛋白酶、淀粉酶、纤维素酶和褐藻酸酶)和体腔液免疫酶(溶菌酶、酸性磷酸酶、碱性磷酸酶和超氧化物歧化酶)的活性。试验结果表明,投喂试验饲料后第14、28d和42d:(1)饲料中添加6%和9%浒苔组仿刺参的特定生长率显著增加(P0.05),在不同取样时间其他添加组仿刺参的的特定生长率与对照组差异不显著(P0.05);(2)饲料中浒苔添加量为6%和9%试验组仿刺参的4种消化酶比活力显著高于对照组(P0.05),其中6%组仿刺参的消化酶比活力最高;(3)饲料中浒苔添加量为6%时,仿刺参溶菌酶活力显著高于对照组及其他试验组(P0.05);饲料中浒苔添加量为6%和9%时,仿刺参碱性磷酸酶活力和超氧化物歧化酶活力显著高于对照组及其他试验组(P0.05);添加浒苔可以显著提高酸性磷酸酶活力,至第42d,试验组酸性磷酸酶活力高于对照组(P0.05),且浒苔添加量为6%时活力最高。在本试验条件下,饲料中添加浒苔可以提高仿刺参的特定生长率、消化酶活力及免疫力,浒苔的最适添加量为6%~9%。     

Effects of kelp residues fermented with probiotics on the culture of sea cucumber,Apostichopus japonicus

The kelp aquaculture production in China is the largest in the world, and a large amount of kelp residue is produced by kelp processing. Kelp residues contain substantial quantities of crude fibre, protein, and residual alginic acid, and may be used as feedstuff for aquaculture animals. In this study, we used probiotics to ferment kelp residues to improve kelp nutrient content and then fed the fermented kelp to the sea cucumber, Apostichopus japonicus. To study the effect of fermented feed on sea cucumber, its growth performance, digestive enzyme activity, diversity of intestinal microbiota and water quality of the sea cucumber culture water were determined. Growth performance of sea cucumber fed with fermented feed significantly (p < .01) increased when compared with sea cucumber fed with formulated feed. Amylase, cellulose and alginase activities were significantly (p < .01) higher in the fermented feed group when compared with the formulated feed group. The total number and diversity of intestinal microbiota showed a significant increase in sea cucumbers fed with the fermented feed. The water quality of the fermented feed group showed much lower ammonia and nitrite (<0.050 mg/L) levels when compared with the formulated feed group. These results suggest that kelp residues fermented with probiotics enhance the growth, digestive enzyme activities and intestinal microbiota of sea cucumbers and improve the culture water quality. Fermented kelp residues are a new supplementary nutrient source for sea cucumbers and may be applicable to other animal aquacultures.     

枯草芽孢杆菌B2的生长及其对仿刺参的益生特性

从大连湾地区健康的仿刺参养殖池塘沉积物中分离得到一株芽孢杆菌菌株B2,经16SrDNA鉴定以及形态学分析确定其为枯草芽孢杆菌。该菌株生长适宜温度为15~35℃,适宜pH为6~8,适宜盐度为30~50。电镜观察发现,枯草芽孢杆菌B2周围有明显可见的芽孢。枯草芽孢杆菌B2可产淀粉酶和蛋白酶,但不具有产脂肪酶的能力。将枯草芽孢杆菌B2按照仿刺参体质量的0.1%、0.2%和0.3%配成不同密度的菌液,添加至饲料中,投喂7d后发现,该菌株可有效提高仿刺参肠道内的消化酶以及体腔液中多种非特异性免疫酶的活性。结果表明,枯草芽孢杆菌B2可作为益生菌剂的基础菌株添加至仿刺参饲料中。     

Effect of replacing dietary fish meal with silkworm (Bombyx mori L) caterpillar meal on growth and non‐specific immunity of sea cucumber Apostichopus japonicus (Selenka)

The effect of dietary substitution of silkworm (Bombyx mori L) meal (SM) for fishmeal (FM) on the growth performance and non‐specific immunity of sea cucumber (Apostichopus japonicus) (initial weight: 12.8 ± 0.16 g) was determined. Four isonitrogenous and isocaloric diets were formulated: Diet 1, which served as the control diet, contained 5% FM; Diet 2 contained 3.75% FM and 1.25% SM; Diet 3 contained 2.5% FM and 2.5% SM; and Diet 4 contained 5% SM. Other ingredients in each of the four diets were kept in the same proportion. After 8 weeks of feeding, the results showed that sea cucumbers fed Diet 2 had 18.7% increases in weight over those fed the control diet, but no significant difference was observed. No obvious difference in body wall composition was detected among the sea cucumbers fed the four different diets. Immunity analysis indicated that phagocytosis and serum alkaline phosphatase activity were not significantly (P > 0.05) affected when FM was partially or completely replaced with SM. Serum lysozyme activity of sea cucumbers fed Diet 4 showed a significant (P < 0.05) growth increase compared with those fed control diet. The results revealed that SM could be an effective substitute for FM in sea cucumber diet.     

Temperature and dietary starch level affected protein but not starch digestibility in gilthead sea bream juveniles

A study was carried out with gilthead sea bream juveniles to assess the effect of water temperature (18 and 25°C) and dietary pregelatinized starch level (10, 20 and 30%) on digestibility of protein and starch and on the activity of proteolytic and amylolytic enzymes. ADC of pregelatinized starch was very high (>99%) irrespectively of dietary inclusion level, and it was not affected by water temperature. ADC of protein was also high (>90%) but improved at the higher water temperature. Dietary starch interacted with protein digestibility, which decreased as dietary starch level increased. Temperature affected both acid and basic protease activities, with acid protease activity being higher at 25°C and basic protease activity being higher at 18°C. However, total proteolytic activity and amylase activities were not affected by water temperature. Dietary carbohydrate exerted no effect on proteolytic or amylolitic activities. It is concluded that gilthead sea bream juveniles digest pregelatinized starch very efficiently irrespective of water temperature, due to adjustments of amylase activity to cope with temperature differences. Pregelatinized starch interacts negatively with protein digestibility, with the ADC of protein decreasing as dietary starch levels increase.     

The effects of seasonal,sex and size on the digestive enzyme activities in freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823)

The effects of seasonal, sex and size on digestive enzyme activities of Astacus leptodactylus in natural habitat were investigated in the present study. The freshwater crayfish were sampled 584 individual as seasonally from Egirdir Lake. Ten male and 10 female individuals were sampled randomly from caught crayfish in each two different size ranges (4.5–7.0, 7.1–9.9 cm) and each season. The gastrointestinal tract, gastric, intestine and midgut gland were individually dissected on ice for enzyme analysis and stomach contents. At the end of the study, amylase activities were affected by interaction of season × sex × size in intestinal, season × sex in midgut gland. However, any interaction was not determined in amylase activities of the gastric. Lipase activities were affected by interaction of season × sex × size in intestinal and gastric, season × sex in midgut gland. The protease activities in each organ were affected by interaction of season, sex and size (p ? .05). In all organs, amylase and lipase activities were similar. However, the highest protease activity was in stomach while the lowest protease activity was the intestine. The protease activities were higher than amylase and lipase activities. There is a positive correlation between protease enzyme activities in gastric with gonad maturation and active feeding period. It can be said based on data of digestive system and high protease activity that A. leptodactylus is an omnivore species in need high protein. In addition, the reason for the low levels of lipase activity may be A. leptodactylus not prefer high fat foods or not fed high fat foods.     

The responses of digestive enzymes in juvenile and adult Rapana venosa (Valenciennes, 1846) to different temperatures

The veined rapa whelk, Rapana venosa (Valenciennes, 1846), is an important and valuable fishery species; however, it has not been routinely artificially cultured on a large scale. Here, we studied the effect of temperature (6, 16, 22 and 28°C) on the digestive enzymes in R. venosa of different sizes (Juvenile (small, S: 1.2–1.8 cm) and adult (medium, M: 4.1–5.2 cm; large, L: 7.6–8.9 cm)) by detected the enzyme activity in different digestive glands (the salivary gland, Leiblein's gland (oesophageal gland) and liver) using spectrophotometric method, to determine the optimal temperature for artificial cultivation and to explore the feeding habits of this whelk. The optimal temperature was determined to be approximately 22°C. The food intake was significantly higher at 22°C than at other temperatures, and the activity of the digestive enzyme, trypsin, was at the highest in the main digestive gland of R. venosa, the liver, at 22°C. In addition, the observed presence of cellulase and α‐amylase may suggest that carbohydrates are necessary during R. venosa development. The results of this study will help in the formulation of technical procedures for R. venosa aquaculture and in preventing its overexploitation, and explained its invasion mechanism to some extent.     

Effects of dietary lipid level on growth performance,body composition and digestive enzymes activity of juvenile sea cucumber,Apostichopus japonicus

A feeding trial aimed to determine the effects of dietary lipid level on growth performance, body composition and digestive enzymes activity of juvenile sea cucumber, Apostichopus japonicus. Diets with six crude lipid levels (1.9, 13.8, 29.1, 43.6, 59.6 and 71.6 g kg^?1) were fed to sea cucumbers (initial weights 0.65 ± 0.01 g) at a density of 30 juveniles, once a day. After 60 days, body weight gain (BWG), specific growth rate (SGR), feed intake (FI) and protein efficiency ratio (PER) decreased with increasing dietary lipid levels. The sea cucumbers fed 1.9 g kg^?1 crude lipid showed significantly higher (P < 0.05) BWG than those of the sea cucumbers fed 59.6 and 71.6 g kg^?1 crude lipid. Intestinal protease and lipase activities generally increased with increasing dietary lipid levels. Eicosapentaenoic acid (EPA) content of body walls generally increased with increasing dietary lipid levels. Docosahexaenoic acid (DHA) content of body walls reached the maximum value at a dietary lipid level of 13.8 g kg^?1. N‐3 highly unsaturated fatty acid content followed the same pattern of DHA. According to the growth performance and body composition of sea cucumbers, it can be indicated that the optimum dietary lipid level for juvenile sea cucumbers is between 1.9 and 13.8 g kg^?1.     

Immune responses of the sea cucumber Apostichopus japonicus to stress in two different transport systems

We report the effect of transport stress on the immune responses of the sea cucumber Apostichopus japonicus. The total coelomocytes counts, phagocytosis activity, reactive oxygen species production, acid phosphatase activity, phenoloxidase activity and catecholamine levels were measured in A. japonicus following both damp and water transportation methods. With both transport methods, stress resulted in significant elevation of catecholamine levels. Total coelomocytes counts increased following transportation, whereas phagocytic activity and reactive oxygen species production decreased. Damp transport significantly depressed acid phosphatase and phenoloxidase activity in A. japonicus. However, there were no significant differences in acid phosphatase and phenoloxidase activity after water transportation. These results show that transport stress induces modifications in the immune system of A. japonicus and that damp transport elicited more severe stress than water transport. This study increased understanding of the mechanism of transport stress inducing neuroendocrine responses and immune modification in A. japonicus. The information obtained should be helpful to optimize transport process in sea cucumber culture.     

Growth performance and digestion improvement of juvenile sea cucumber Apostichopus japonicus fed by solid‐state fermentation diet

In this study, the compound probiotics including Pseudoalteromonas. Sp D11, Bacillus subtilis A142, Saccharomyces cerevisiae Y23 and Lactobacillus plantarum L54 were applied for solid‐state fermenting the artificial diet of juvenile sea cucumber Apostichopus japonicus. The quality of solid‐state fermented (SSF) feed and its potential effects on growth performance and digestive enzyme activities were investigated. The results showed that, compared to unfermented diet, SSF feed had a better palatability quality; meanwhile, a higher ratio of crude protein, free amino acids and reducing sugars and a lower ratio of crude fibre, crude ash and alginic acid were found in SSF feed. The results of the feeding trial showed that feeding SSF feed could improve growth performance of sea cucumbers more than those fed with the unfermented diet. The results of digestive enzyme assays showed that feeding SSF feed to animals could significantly improve activities of amylase, cellulase, alginic acid enzyme and protease, which implied that fermented feed could improve digestibility of A. japonicus. In summary, the SSF feed fermented by compound probiotics had better palatability and nutrition value than unfermented feed. And feeding SSF feed could significantly improve the growth performance and digestion ability for sea cucumbers in the phases of nursery and grow‐out.