Salinity is one of the most important abiotic factors directly affecting the reproduction, molting, growth, immune, physiological and metabolic activities of Chinese mitten crab (Eriocheir sinensis). This species has strong osmoregulatory capacity and can maintain stringent internal homeostasis. However, the mechanisms conferring tolerance to salinity fluctuations are not well understood. To reveal the genes and pathways involved in osmoregulation, adult male crabs (body weight = 110 ± 5 g) were acclimated for 144 h in freshwater (FW, 0 ppt) or seawater (SW, 25 ppt). Changes in the transcriptome of crab gills were then analysed by RNA-Seq, and 174,903 unigenes were obtained. Comparison of genes between FW- SW-acclimated groups identified 932 genes that were significantly differentially expressed in the gill, comprising 433 and 499 up- and downregulated transcripts. Gene Ontology functional enrichment analysis revealed that important biological processes related to salt stress were significantly enriched, including energy metabolism, ion transport, signal transduction and antioxidant activity. Kyoto Encyclopaedia of Genes and Genomes enrichment analysis mapped the differentially expressed genes to 241 specific metabolic pathways, and pathways related to energy metabolism, oxidative phosphorylation and the tricarboxylic acid (TCA)/citrate cycle were significantly enriched. Salinity stress altered the expression of many enzymes involved in energy metabolism, ion transport, signal transduction and antioxidant pathways, including citrate synthase (CS), Na⁺/K⁺-ATPase (NKA), Na⁺-K⁺-2Cl cotransporter-1 (NKCC1), dopamine receptor D1 (DRD1), synaptic binding protein 1 (STXBP1), Cu²⁺/Zn²⁺ superoxide dismutase (SOD1) and glutathione S-transferase (GST). Additionally, the obtained transcriptomic sequencing data provided a useful resource for identification of novel genes, and further physiological analysis of Chinese mitten crab.

Fish oil supplies worldwide have declined sharply over the years. To reduce the use of fish oil in aquaculture, many studies have explored the effects of fish oil substitutions on aquatic animals. To illustrate the effects of dietary lipids on Chinese mitten crab and to improve the use of vegetable oils in the diet of the crabs, 60 male juvenile Chinese mitten crabs were fed one of five diets for 116 days: fish oil (FO), soybean oil (SO), linseed oil (LO), FO + SO (1:1, FSO), and FO + LO (1:1, FLO). Changes in the crab hepatopancreas transcriptome were analyzed using RNA sequencing. There were a total 55,167 unigenes obtained from the transcriptome, of which the expression of 3030 was significantly altered in the FLO vs. FO groups, but the expression of only 412 unigenes was altered in the FSO vs. FO groups. The diets significantly altered the expression of many enzymes involved in lipid metabolism, such as pancreatic lipase, long-chain acyl-CoA synthetases, carnitine palmitoyltransferase I, acetyl-CoA carboxylase, fatty acid synthase, and fatty acyl Δ9-desaturase. The dietary lipids also affected the Toll-like receptor and Janus activated kinase-signal transducers and activators of transcription signaling pathways. Our results indicate that substituting fish oil with vegetable oils in the diet of Chinese mitten crabs might decrease the digestion and absorption of dietary lipids, fatty acids biosynthesis, and immunologic viral defense, and increase β-oxidation by altering the expression of the relevant genes. Our results lay the foundation for further understanding of lipid nutrition in Chinese mitten crab.

Background: Weight management is strongly promoted for overweight or obese patients with type 2 diabetes (T2DM) by current guidelines. However, the prognostic impact of weight loss achieved without behavioural intervention on the mortality and cardiovascular (CV) outcomes in diabetic patients is still contested. Methods: We searched the PubMed, Embase, and Cochrane Library databases for studies that investigated the association of weight loss or weight variability with mortality and CV outcomes. Results of studies that measured weight loss by percentage weight loss from baseline and stratified it as > 10% and 5–10% or studies that computed weight variability were pooled using random effects model. Study quality was evaluated using the Newcastle–Ottawa Scale. Results: Thirty eligible studies were included in the systematic review and 13 of these were included in the meta-analysis. Large weight loss (> 10%) was associated with increased risk of all-cause mortality (pooled hazard ratio (HR) 2.27, 95% CI 1.51–3.42), composite of major CV events (pooled HR 1.71, 95% CI 1.38–2.12) and CV mortality (pooled HR 1.50, 95% CI 1.27–1.76) among T2DM patients. Moderate weight loss showed no significant association with all-cause mortality (pooled HR 1.17, 95% CI 0.97–1.41) or CV outcomes (pooled HR 1.12, 95% CI 0.94–1.33). Weight variability was associated with high hazard of all-cause mortality (pooled HR 1.54, 95% CI 1.52–1.56). Conclusions: Large weight loss and large fluctuations in weight are potential markers of increased risk of mortality and CV events in T2DM patients. Maintaining a stable weight may have positive impact in these patients.

The finite marine resources make it difficult for us to obtain enough fish oil (FO) used in aquatic feeds. Another sustainable ingredients should be found to substitute FO. The effects of replacing FO with vegetable oil have been studied in a variety of crustaceans, but most studies have focused on the phenotypic effects. Little is known about the mechanisms of the effects. To understand the molecular responses during the replacement of FO in Eriocheir sinensis, we investigated the effects of feeding FO or linseed oil (LO) on growth performance, digestive enzyme activity, fatty acid composition and protein expression in E. sinensis. Twenty-four juvenile crabs were fed diets containing FO or LO for 112 days. Weight, carapace length and width were recorded. Fatty acid composition of the diets and the hepatopancreas and protein expression in the hepatopancreas were analyzed. Growth performance and molting interval were unchanged by diet. Crabs fed FO and LO had same activity of lipase and amylase, but comparing with crabs fed LO, crabs fed FO had higher trypsin activity and lower pepsin activity. Hepatopancreas fatty acid composition changed to reflect the fatty acid composition of the diets. In total, 194 proteins were differentially expressed in the hepatopancreas between the diets. Expression of heat shock proteins was higher in crabs fed LO. Expression of fatty acid synthase, long-chain fatty acid transport protein 4, acyl-CoA delta-9 desaturase, and fatty acid-binding protein 1, was higher in crabs fed FO. The substitution of FO with LO didn’t have any effects on the growth and molting of mitten crab, but could significantly decrease the ability of mitten crab to cope with stress. The high content of HUFAs in the hepatopancreas of mitten crab fed FO is due to the high abundance of the proteins relative to the transport of the HUFAs. These findings provide a reason of the high content of EPA and DHA in crabs fed with FO, and provide new information for the replacement of FO in diets of mitten crab.

In order to study the muscle quality of different crustaceans, we aim to provide a comprehensive assessment of their muscle quality characteristics as a theoretical reference. In this work, seven major species of farmed and consumer crustaceans were selected, including crayfish (Procambarus clarkii), freshwater prawns (Macrobrachium rosenbergii), pacific white shrimp (Litopenaeus vannamei), black tiger shrimp (Penaeus monodon), kuruma prawns (Penaeus japonicus), river prawns (Macrobranchium nipponense), and Chinese shrimp (Penaeus chinensis). Their morphometric parameters, nutritional composition, textural properties, and physical and chemical indexes were comparatively analyzed. The results showed that the meat content (MC, about 14.78%) of crayfish was significantly lower than that of the other six species. By contrast, pacific white shrimp had the highest MC, although the MCs of black tiger shrimp, kuruma prawns, and Chinese shrimp are greater than 40%. All seven crustacean species were high in protein and low in fat, while pacific white shrimp had the highest crude protein, crude lipid, and crude ash content compared to the other crustaceans. The content of threonine (Thr) was the highest in crayfish. The content of methionine (Met) and lysine (Lys) was the highest in freshwater prawns. The content of isoleucine (Ile), leucine (Leu), and non–essential amino acid (NEAA) was the highest in pacific white shrimp. C18:2n-6 (linoleic acid, LA) was the highest in freshwater prawns and pacific white shrimp; C18:3n-3 (linolenic acid, LNA), C20:4n-6 (arachidonic acid, AA), unsaturated fatty acids (UFA), and monounsaturated fatty acids (MUFA) were all the highest in crayfish; and polyunsaturated fatty acids (PUFA) was the highest in freshwater prawns, but the content was not significantly different from crayfish, pacific white shrimp, black tiger shrimp, and Chinese shrimp. Pacific white shrimp had the highest values for hardness, cohesiveness, gumminess, and chewiness. The redness values of crayfish, black tiger shrimp, and Chinese shrimp were significantly higher than those of the other three species except kuruma prawns. Compared to other crustaceans, river prawns had the highest drip loss and cooking loss. Black tiger shrimp and Chinese shrimp had the lowest cooking loss rates. The research shows that the tail muscle of the seven species of crustaceans is rich in protein, essential amino acids, unsaturated fatty acids and low in fat, representing a high-quality protein. Among these crustaceans, the main essential amino acids and essential fatty acids in the tail muscle of pacific white shrimp, freshwater prawns, and crayfish are higher in content and better in nutritional value.