Effect of Co-Culture of Chinese Shrimp(Fenneropenaeus chinensis) and Sea Cucumber(Apostichopus japonicus Selenka) on Pond Environment

Monoculture of sea cucumber(pond S) and polyculture of shrimp with sea cucumber(pond SS) were established to evaluate the effect of shrimp on the environmental conditions of sea cucumber farming pond. Contributions of sediment organic matter(SOM2) resuspended from benthic sediment and the suspended particulate organic matter(SPOM) deposited from the water column to the precipitated organic matter(SOM1) collected with sediment traps were estimated with carbon stable isotope analysis. The results showed that the levels of SPOM and SOM2 in pond SS significantly decreased in comparison with those in pond S at the end of experiment(P < 0.05), indicating that co-culturing shrimp in sea cucumber farming pond could purify the farming water. Carbon stable isotope analysis showed that the proportion of SOM2 in SOM1 in pond SS(84.97% ± 0.38%) was significantly lower than that in pond S(95.20% ± 0.30%)(P < 0.05), suggesting that the resuspension of organic matter from benthic sediment into overlying water was reduced in polyculture pond. In contrast, the proportion of SPOM in SOM1 in pond SS(15.03% ± 0.38%) was significantly higher than that in pond S(4.80% ± 0.30%)(P < 0.05), indicating that the sedimentation of SPOM from water column was enhanced in pond SS owing to the biodeposition effect of shrimp.

Optimization of Stocking Density for the Sea Cucumber, Apostichopus japonicus Selenka, Under Feed-Supplement and Non-Feed-Supplement Regimes in Pond Culture

Optimal stocking densities were investigated for the sea cucumber Apostichopus japonicus Selenka under feed-supplement and non-feed-supplement regimes in net enclosures for 333 d. Substantial weight loss occurred during the aestivation phase (AE). Decreased growth rates were also observed during the winter phase (WT). In contrast, sea cucumbers showed rapid growth during the spring (SP) and autumn (AU) phases. Feeding regimes considerably influenced the growth performance, i.e., sea cucumbers grew faster under feed-supplement regime than under non-feed-supplement regime (P < 0.05). The average survival rates of sea cucumbers under feed-supplement regime were higher than those under non-feed-supplement regime for both the autumn phase and spring phase, but the differences were only significant for the latter phase (P < 0.05). The fitted B-N curves showed that the optimal stocking densities, in terms of net production, were 22.3 ind. m-2 for feed-supplement regime and 14.1 ind. m-2 for non-feed-supplement regime.

Sea cucumber enzymatic hydrolysates relieve osteoporosis through OPG/RANK/RANKL system in ovariectomized rats

Osteoporosis harms human health and has a variety of causes,among which the imbalance of bone metabolism caused by menopause is an important one.Studies have shown that sea cucumbers have a variety of physiological activities such as anti-inflammation.Sea cucumber enzymatic hydrolysates(SCEH)were prepared and characterized for peptides and polysaccharides,and then the effects on relieving osteoporosis were explored by feeding ovariectomized Sprague-Dawley rats for 90 days.Bone density and microstructure were measured using micro-CT and pathological sectioning.Serum markers for bone metabolism,and inflammation were measured using ELISA kits.Gene transcription and expression of the OPG/RANKL system in bone were measured using qRT-PCR and western blots.Results showed that SCEH could improve the bone density,strength,microstructure and mass,and inhibit the generation of osteoclasts.The abnormally elevated markers for bone resorption,formation and inflammation were reduced with the intake of SCEH.The mRNA and protein expressions of RANKL were also decreased by feeding SCEH,thereby up-regulating the ratio of OPG to RANKL.These results suggested that SCEH could inhibit the bone resorption by inhibiting the NF-κB pathway related to osteoclast generation via the down-regulation of both the RANKL level and inflammatory response,and also improve the balance of bone metabolism,thus obtaining the effects of increasing bone density and relieving osteoporosis.SCEH with a medium-dose(1000 mg/kg body weight)had the best remission effect and could be used as a potential starting material to develop healthy foods that can assist in treating osteoporosis.