A Comparative Analysis of the Growth Performance, Morphological Indicators, and Transcriptome Between Two Coastal Regions of China in the Mud Crab (Scylla paramamosain)

Transcriptome analysis of mud crab (Scylla paramamosain) gills in response to Mud crab reovirus (MCRV)

Hypoxia-induced oxidative stress and transcriptome changes in the mud crab (Scylla paramamosain)

Transcriptome analysis and histopathology of the mud crab (Scylla paramamosain) after air exposure

Ammonia toxicity in the mud crab (Scylla paramamosain): The mechanistic insight from physiology to transcriptome analysis

Whole transcriptome RNA sequencing provides novel insights into the molecular dynamics of ovarian development in mud crab, Scylla paramamosain after mating

Mud crab (Scylla paramamosain) is one of the important species for aquaculture. The experiment was conducted at Ca Mau Community College to develop a mud crab fattening process in a recirculating tank system and to diversify aquaculture models in the Mekong Delta. In this experiment, mud crabs were reared at different salinities of 5, 15, 25, and 35‰ with three replicates for each treatment. Early gravid female crabs were stocked at 20 individuals/m2 in 200 L tanks linked with biofilters. Mud crabs were fed with trash fish at 3% of body weight daily. After 33 days of rearing, the results showed that the survival rates of full-gravid crabs in the treatments with salinities of 5‰, 15‰, 25‰, and 35‰ were 54.3%, 64.8%, 95.8%, and 91.5%, respectively. The daily weight gain, specific growth rate & gonadosomatic index of crabs in treatments ranged from 0.51 - 0.60 g/day, 0.17 - 0.20%/day, and 7.67 - 8.87%, respectively. However, there were no significant differences in these parameters among treatments (P > 0.05). The ovary weight (from 19.33 to 28.67 g) and the ratio of weight of ovary to hepatopancreas (from 147.22 to 220.24%) of crabs among treatments increased significantly with culture time, but were not significantly different (P > 0.05). Generally, the present study revealed that mud crab fattening at the salinity of 25‰ gave the best profit. These findings significantly contribute to improving technical processes for fattening of mud crabs reared in recirculating systems.

Nitrite in the aquatic environment is highly toxic to aquatic animals. However, the mechanism by which the mud crab responds to nitrite-induced stress remains unclear. In this study, we investigated the physiological response and molecular mechanism in the mud crab (Scylla paramamosain) exposed to the acute nitrite exposure (20 mg/L) for 24h. The results showed that nitrite exposure induced significant changes in antioxidant enzyme activity and MDA content. Severe cytological damage was observed in the hepatopancreas. After 24h exposure to nitrite, 11,638 differentially expressed genes (DEGs) were identified by transcriptome analysis. These DEGs were involved in many pathways related to oxidative stress and immune responses. Our results also found that FoxO signaling pathway, p53 signaling pathway, and NF-kB signaling pathway participated in the anti-stress defense against nitrite stress. The study provides new insight into the understanding of nitrite-induced toxicity in the mud crab.

Roles of eyestalk in salinity acclimatization of mud crab (Scylla paramamosain) by transcriptomic analysis

Comparative transcriptome analysis combining SMRT and NGS sequencing provides novel insights into sex differentiation and development in mud crab (Scylla paramamosain)

Identification of key genes and molecular pathways associated with claw regeneration in mud crab (Scylla paramamosain)

Effects of Vibrio parahaemolyticus infection on physiological response, histopathology and transcriptome changes in the mud crab (Scylla paramamosain)

An eight-week feeding trail was carried out to investigate the impacts of different dietary arachidonic acid (ARA) supplementations on growth performance, antioxidant capacity, tissue fatty acid profiles, and lipid metabolism of mud crab (Scylla paramamosain) juvenile. Six isonitrogenous (480 g kg-1 crude protein) and isolipidic (80 g kg-1 crude lipid) diets were formulated to contain 0.40, 2.50, 4.60, 8.90, 12.50, and 15.70 g ARA kg-1 (dry matter), respectively. Each experimental treatment included 24 mud crab juveniles (initial weight 11.29 ± 0.09 g) and was assigned to triplicate groups (n = 3). Crabs fed diets with 2.50, 4.60, and 8.90 g kg-1 ARA presented significantly higher percent weight gain (PWG) and specific growth rate (SGR) than those fed the other diets. Based on two-slope broken-line and quadratic curve regression analysis of PWG against dietary ARA levels, optimal dietary ARA levels were determined to be 5.20 g kg-1 and 6.20 g kg-1, respectively. Crabs fed with 4.60 g kg-1 ARA diet showed the lowest activities of alanine aminotransferase (ALT) as well as aspartate aminotransferase (AST) in hemolymph among all treatments. In hemolymph and hepatopancreas, total antioxidant capacity (T-AOC), the activities of total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px) as well as the contents of reduced glutathione (GSH) rose first and then dropped with the increase of dietary ARA levels, while the concentration of malondialdehyde (MDA) showed an opposite trend. Tissue fatty acid profiles reflected diets fatty acid compositions. The ARA contents in hepatopancreas and muscle significantly increased with the increase of dietary ARA levels. Furthermore, the areas of blasenzellen (B) cells and restzellen (R) cells were significantly downregulated with the increase of dietary ARA levels. Crabs fed with 0.40 g kg-1 ARA diet showed significantly higher gene expression levels of fatty acid synthase (fas) as well as acetyl-CoA carboxylase (acc) among all treatments. Relative gene expression levels of 6-phosphogluconate dehydrogenase (6pgd) as well as glucose-6-phosphate dehydrogenase (g6pd) have been significantly upregulated in 0.40 and 2.50 g kg-1 ARA groups. Relative gene expression level of fatty acid binding protein 1 (fabp1) significantly increased in 4.60, 8.90, 12.50, and 15.70 g kg-1 ARA groups. However, the gene expression levels of fatty acid binding protein 4 (fabp4) as well as scavenger receptor class 2 (srb2) have not been influenced by dietary ARA levels. What is more, crabs fed diets with 4.60, 8.90, 12.50, and 15.70 g kg-1 ARA had a significantly higher expression level of carnitine palmitoyltransferase 1 (cpt1) than those fed diets with 0.40 and 2.50 g kg-1 ARA. In summary, optimum dietary ARA can promote growth, enhance antioxidant capacity, and improve health of mud crab juveniles. It also demonstrated that lipogenesis has been restrained with the increasing dietary ARA levels. These findings could provide theoretical guidance and reference for the lipid nutrition research as well as the development of the commercial diet in mud crab.

Mud crab (Scylla paramamosain) fed five different diets with varying concentrations of guava leaf aqueous extract (0 mg·kg–1, 80 mg·kg–1, 160 mg·kg–1, 320 mg·kg–1, and 640 mg·kg–1) for 30 days. Mud crabs in the 320 mg·kg–1 guava-leaf extract groups outperformed the control group in terms of survival rates (SR), weight gain rates (WGR), and specific growth rates (SGR). When compared to the control group, mud crabs in the 320 mg·kg–1 guava-leaf extract groups had significantly higher levels of lipase (LPS), pepsin, lysozyme (LZM), superoxide dismutase (SOD), acid phosphatase (ACP), and glutathione (GSH) (P < 0.05). The amylase (AMS) activity was significantly decreased in all experimental groups (P < 0.05). Malondialdehyde (MDA) content in the hepatopancreas of mud crabs in the 160 mg·kg–1, 320 mg·kg–1, and 640 mg·kg–1 guava-leaf extract groups were significantly reduced compared to the control group (P < 0.05). Additionally, real-time PCR results illustrated that the expression levels of GPx3, CAT, and JNK were all considerably increased in the 80 mg·kg–1 guava-leaf extract groups compared to the control group (P < 0.05). In the 160 mg·kg–1, 320 mg·kg–1, and 320 mg·kg–1 guava-leaf extract groups, the expression levels of SOD genes were considerably greater than the control (P < 0.05), which was consistent with the level of SOD activity. GST and P53 gene expression levels were significantly up-regulated in the 80 mg·kg–1, 160 mg·kg–1, 320 mg·kg–1, and 640 mg·kg–1 guava-leaf extract groups compared to the control group (P < 0.05). Overall, the addition of 160 mg·kg–1-320 mg·kg–1 guava-leaf extract to the feed of Scylla paramamosain promoted growth, enhanced the activities of digestive and antioxidant enzymes, and strengthened immunity.

The mud crab, Scylla paramamosain, holds great commercial significance as a marine crustacean widely cultivated in the Indo-Pacific region. Understanding the core gut microbiota of aquatic animals is crucial for their overall health and growth, yet the core gut microbiota of mud crab remains poorly characterized. In this study, we gathered gut samples from mud crabs across five locations within Sanmen Bay, China. Through the utilization of high-throughput sequencing, we delved into the composition of the gut microbial community and identified the core gut microbiome of mud crab. Our results demonstrate that the gut microbial diversity of mud crab did not exhibit significant variation among the five sampling sites, although there were some differences in community richness. At the phylum level, we identified 35 representative phyla, with Firmicutes, Proteobacteria, Bacteroidota, and Campilobacterota as the dominant phyla. Among the 815 representative genera, we discovered 19 core genera, which accounted for 65.45% of the total sequences. These core genera were distributed across 6 phyla, and among them, Photobacterium exhibited the highest average relative abundance. Photobacterium has probiotic activity and may play a crucial role in enhancing the immune response of the host and maintaining the diversity of the gut microbiota. Moreover, we observed a positive correlation between the relative abundance of core genera and the stability of the gut microbial community. Furthermore, our findings revealed distinct differences in gut microbial composition and specific taxa between the sexes of mud crab. These differences subsequently influenced the functionality of the gut microbial community. Overall, our investigation sheds light on the core gut microbiota of mud crab, emphasizing the importance of core gut microbial communities in maintaining the health and growth of these commercially significant marine crustaceans.

The role of Mu-type glutathione S-transferase in the mud crab (Scylla paramamosain) during ammonia stress