Mud Crab Research Articles

Dietary starch level regulates the growth and glycolipid metabolism through the insulin-PI3K-AKT signaling pathway of juvenile mud crab (Scylla paramamosain)

A six-week feeding trial was conducted to investigate the effects of dietary starch levels on growth performance, glucose and lipid metabolism and insulin signaling pathway of juvenile Scylla paramamosain. Three isonitrogenous (41.51% ± 0.31%) and isolipidic (8.68% ± 0.53%) experimental diets were formulated to contain 10%, 20% and 30% starch levels, respectively. A total 96 crabs were divided into 3 treatment groups. There were 4 replicates per treatment group and 8 crabs per replicate (initial weight 5.12 ± 0.05 g). The crabs fed the diet with 20% starch showed the best growth performance, with higher weight gain rate (WGR), specific growth rate (SGR), protein efficiency ratio (PER), and feed efficiency (FE) compared to the other diets. Increasing starch levels in the diet resulted in higher levels of glycogen and lipid in the muscles and hepatopancreas. The levels of glucose (GLU), triglyceride (TG), and free fatty acid (FFA) displayed a significant increase in both hemolymph and hepatopancreas with the escalating dietary starch concentrations. In contrast, as the dietary starch levels increased, the concentrations of crustacean hyperglycemic hormone (CHH) and insulin-like peptides (ILPs) in hemolymph and hepatopancreas demonstrated a notable decline. The glycolysis and pentose phosphorylation pathways were significantly promoted, while the gluconeogenic pathway was significantly inhibited, with dietary starch levels increasing from 10% to 30%. Additionally, increasing dietary starch levels led to a significant down-regulation of genes related to the lipid synthesis, lipolysis and insulin signaling pathway. Histological results showed that hepatopancreas fat accumulation increased with the increase of dietary starch level. Overall, the findings of this study suggest that adding 20% starch to the diet can promote growth and improve nutrient utilization. In addition, the level of dietary starch had significant effects on the glucose and lipid metabolism and insulin signaling pathway of mud crabs, thus affecting the deposition of lipid reserves in hepatopancreas.

Patterns in abundance, size and space‐use of Giant Mud Crab (Scylla serrata) in a temperate marine protected area

Abstract Marine Protected Areas limit fishing to protect a broad range of species and enhance biodiversity. Consequently, closures may not benefit species equally and species‐specific assessments are required to determine the impact of closures. Relative abundance and size of Giant Mud Crab (Scylla serrata) was compared across no‐take and fished zones in Port Stephens‐Great Lakes Marine Park, on the temperate east coast of Australia (32.45°S). In addition, passive acoustic telemetry was used to estimate daily space‐use areas. Similar abundances were observed between no‐take and fished zones; however certain no‐take sites had higher abundances than others. In addition, crabs were 9.9 mm larger in no‐take zones on average. Daily crab space‐use varied widely (~4 to 1000 m2), and generally increased with water temperature and conductivity. These patterns indicate that recruitment processes interact with marine park protection to shape crab abundances across estuaries. However no‐take zoning appears to primarily limit fishing mortality on legal size crabs (i.e., carapace length >85 mm) resulting in larger crabs within no‐take zones. This may mean no‐take zones enhance reproductive output of crab populations since larger individuals are likely to be more fecund.

Tidal Study of Hormonal Conditions Related to Puberty Molting in Mating Behavior of Mud Crab Scylla serrata

Tidal Study of Hormonal Conditions Related to Puberty Molting in Mating Behavior of Mud Crab Scylla serrata

Identification and function analysis of steroid hormone synthesis pathway-related gene—Hsd3b in Scylla paramamosain

Mud crab (Scylla paramamosain) has become an important mariculture crab along the southeast coast of China due to its strong adaptability, delicious taste, and rich nutrition. Several vertebrate steroid hormones and their synthesis-related genes and receptors have been found in crustaceans, but there are few reports on their synthesis process and mechanism. 3-beta-hydroxysteroid dehydrogenase (HSD3B) is a member of the Short-chain Dehydrogenase/Reductase (SDR) family, and an indispensable protein in vertebrates' steroid hormone synthesis pathway. In this study, the SpHsd3b gene sequence was obtained from the transcriptome data of S. paramamosain, and its full-length open reading frame (ORF) was cloned. The spatial and temporal expression pattern of SpHsd3b was performed by quantitative real-time PCR (qRT-PCR). SpHsd3b dsRNA interference (RNAi) and HSD3B inhibitor (trilostane) were used to analyze the function of SpHSD3B. The results showed that the SpHsd3b gene has an 1113 bp ORF encoding 370 amino acids with a 3β-HSD domain. SpHSD3B has lower homology with HSD3B of vertebrates and higher homology with HSD3B of crustaceans. SpHsd3b was expressed in all examined tissues in mature crabs, and its expression was significantly higher in the testes than in the ovaries. SpHsd3b expression level was highest in the middle stage of testicular development, while its expression was higher in the early and middle stages of ovarian development. RNAi experiment and trilostane injection results showed that SpHSD3B had regulatory effects on several genes related to gonadal development and steroid hormone synthesis. 15-day trilostane suppression could also inhibit ovarian development and progesterone level of hemolymph. According to the above results, crustaceans may have steroid hormone synthesis pathways like vertebrates, and the Hsd3b gene may be involved in the gonadal development of crabs. This study provides further insight into the function of genes involved in steroid hormone synthesis in crustaceans.

Moulting Performances Evaluation of Female Orange Mud Crab, Scylla olivacea (Herbst, 1796) In-Captivity: Effects of Water Salinity and Limb Autotomy.

Female Scylla olivacea has become more popular in Malaysia as emerging species mainly for soft-shell crabs and crab fattening (to increase weight, size and ovary maturation so that they can be sold at a higher price). To harvest crabs in soft-shell conditions and fattening, both conditions depend mostly on moulting events. To accelerate the moulting process, the manipulation of water parameter (salinity) and autotomy of the limb is commonly used. In this study, the evaluation of the moulting performances of full limb autotomy (the removal of all the appendages except for the swimming legs) and non-ablated (control) using immature S. olivacea cultured in three different salinity treatments (10 ppt, 20 ppt and 30 ppt) were performed. Results indicate there were significant differences between mud crab's culture duration, BW increments, growth performances and feeding efficiency with salinity. However, CW increments and survival indicate no significant effect with salinity. Meanwhile, limb autotomy proved to affect the culture duration, BW increments, survival and feeding efficiency of S. olivacea. The study concludes that both salinity and limb autotomy play significant roles in moulting performances of S. olivacea, with 20 ppt being the best salinity to stimulate S. olivacea moulting and development compared with the other two treatments (10 ppt and 30 ppt). Limb autotomy also indicates promising results as this technique proved to accelerate the moulting duration of S. olivacea with a 100% moulting percentage within 30 days. Therefore, the outcome would certainly benefit in the aquaculture production of this species of commercial importance mainly on soft-shell crabs production and also emerge as crabs fattening technique.

The osmoregulatory mechanism in response to hypoosmotic stress and the key role of ABCC1 in osmoregulation in the mud crab, Scylla paramamosain

Scylla paramamosain is an important mariculture animal. In the present study, we examined the physiological and biochemical characteristics of juvenile S. paramamosain under hypoosmotic stress and further verified the function of ABCC1, a key transport protein in gill tissue. The results showed that Na+/K+-ATPase, Ca2+-ATPase, and Na+/K+/2Cl- cotransporter in gill tissues increased first and then decreased. In addition, SOD and CAT activities also began to gradually increase, protecting gill tissues from oxidative damage. The hemolymph osmolarity decreased rapidly from 792 mOsm/kg to 560 mOsm/kg within 6 h, and then rose to 626.25 mOsm/kg at 48 h, and then remained stable. At the same time, Na+, Cl-, K+, and Ca2+ concentrations were decreased to varying degrees. There were significant changes in free amino acids such as aspartic acid, glutamic acid, and asparagine in hemolymph in response to acute salt depletion. By injection of ABCC1 inhibitor/activator, it was found that while ABCC1 transporter activity in the MK-571 group showed a decreasing trend at 9 h, Na+/K+ -ATPase activity began to increase and reached a peak at 48 h. Compared with the control group, the levels of aspartic acid, glutamic acid, asparagine, glycine, arginine, alanine, lysine, and proline in the MK-571 group showed significant differences at 6 h; Significant differences in glutamate, asparagine, arginine, alanine, lysine, and proline appeared at 12 h in the Thiethylperazine group. These results suggested that the dynamic changes of gill ion transport enzymes, antioxidant enzymes, inorganic ions, and free amino acids in hemolymph occurred in S. paramamosain under hypoosmotic stress, and the ABCC1 transporter played an important role in this regulatory process.

Mud Crab Fishery in Hoat Sorbay, Kei Kecil Island, Eastern Indonesia: Traditional management and adjustment to intervening regulations

Local communities who live along the coast and have used marine resources for their livelihoods for generations certainly have a resource management and utilization system that was formed as a result of their interactions with and understanding of their aquatic environment. This research focuses on mud crab fishing among the Evu people occupying the shores of Hoat Sorbay Bay on Kei Kecil Island, and how they deal with market, state, and NGO intervention in their traditional harvesting system. Field data were obtained through observation of crab fishing activities in mangrove areas, interviews with mud crab fishers, and examination of documents regarding crab regulation. The result shows that even though mud crab fishing activities are still carried out following traditional practices and strategies based on knowledge passed down from their elders, the fishers also adjust to external requirements of changing market demands and conservation issues by incorporating them into their fishery system.

Contribution and Prospect of Marine Fisheries in the Economy of Bangladesh and Sustainable Blue Economy Challenges: A Review

Marine resources of Bangladesh are abundant, both in terms of huge sea area and its biological richness. The marine water area supports a large number of commercially important fin fish, mollusks, crustaceans, and seaweeds, offering significant economic potential due to their diversified use and high demand in the international market. Therefore, the current review comprehensively examines both the contribution and potentials of marine fisheries resources to the economy, as well as the challenges involved in marine fisheries sectors in attaining a sustainable blue economy in Bangladesh. The study revealed that, the marine fisheries plays an important role in national economy and has huge prospect in employment generation and ensuring food security of Bangladesh. The expansion of mariculture and effective utilization of marine resources will open a new window for the economic development of Bangladesh. Marine fisheries production of Bangladesh has increased over the last two decades, but its relative share in total fisheries production has declined. Despite being rich in marine living resources, commercial mariculture has been developed only for shrimp, prawn, and mud crab. Challenges hindering mariculture expansion includes limited research, technological deficiencies, inadequate skilled workforce, underdeveloped domestic seafood markets, and financial constraints. Concerted efforts including exploring new fishing grounds, conducting stock assessments, implementing scientific management strategies, enacting a national marine fisheries policy, enforcing legislation, and establishing robust surveillance and monitoring mechanisms are required to foster a sustainable blue economy in Bangladesh.

The Analysis of Population Structure of Mud Crab (Scylla serrata) in The Mangrove Forest Area of Bagek Kembar, West Lombok

Scylla serrata is one of the species included in the mangrove forest ecosystem which has high economic value for human life. Seeing that mud crabs have high economic potential both domestically and abroad with a fairly high level of demand and abundant availability of catches in nature, concerns arise about the condition of their population. This research aims to determine the population structure of mangrove crabs in the Bagek Kembar Mangrove Forest Area, West Lombok. The method used is purposive sampling. Sampling was carried out at 3 stations representing the entire research location area, namely on the seafront, in the middle and farthest from the arena facing the sea. Each station has its own characteristics. The distance between stations is 50 m. Each station is installed 6 folding trap with a distance between trap 10 m. The length, width, and high size are 50 cm, 30 cm, and 15 cm respectively. This tools are completed by 3 mm mesh size. The results of the research showed that the carapace length of male and female mud crabs that were mostly caught was in the 3 – 4.5 cm and 2.5 – 4.0 cm classes. The carapace width of male and female mud crabs most often caught is in the range of 4.4 – 6.5 cm and 3.5 – 5.5 cm. And the weight of the most commonly caught male and female mud crabs was in the class range of 11.39 – 111.5 grams and 13.77 – 74.5 grams. This research concludes that mangrove crabs that live in the Bagek Kembar Mangrove Forest Area, West Lombok, based on gender, carapace length, carapace width and body weight, are dominated by juveniles. Only a limited number reach catch size.

Molecular cloning and characterization of three carnitine palmitoyltransferase (cpt) isoforms from mud crab (Scylla paramamosain) and their roles in respond to fasting and ambient salinity stress

As rate-limiting enzymes of β-oxidation of fatty acids in mitochondria, the carnitine palmitoyltransferase (CPT) played an important role in regulating energy homeostasis of aquatic animals. However, there was very little research on β-oxidation of fatty acids in crustaceans. In the present study, the full-length cDNA sequences of cpt-1a, cpt-1b and cpt-2 were isolated from the hepatopancreas of Scylla paramamosain, and contained 4206, 5303 and 3486 bp respectively. Sequence analysis showed that the CPT-1A, CPT-1B and CPT-2 encoded proteins with 777, 775 and 672 amino acids respectively, and only the CPT-1A possessed a transmembrane region. In addition, both the CPT-1B and CPT-2 contained conservative functional domains like N-terminal domain and acyltransferases choActase 2, while the CPT-1A lacked. The results of phylogenetic tree indicated that the CPT-1A, CPT-1B and CPT-2 of S. paramamosain gathered together with their corresponding orthologues from crustaceans. The tissue distribution exhibited that the cpt-1a was highly expressed in hepatopancreas, followed by muscle, eyestalk and cranial ganglia, and the muscle, eyestalk and heart were main expressed tissues of cpt-1b. Furthermore, the high expression levels of cpt-2 were mainly detected in hepatopancreas, muscle and heart. The transcriptional levels of cpt-1a, cpt-1b and cpt-2 were significantly up-regulated under chronic low salinity stress. Besides, at the acute low salinity stress condition, the expression levels of cpt-1a, cpt-1b and cpt-2 in hepatopancreas were dramatically increased in 14‰ and 4‰ salinity groups at the 6h and 48h, while the transcriptional levels of cpt-1a, cpt-1b and cpt-2 in muscle were signally up-regulated in 14‰ and 4‰ salinity groups at the 12h and 24h, showing an alternate response pattern. Similarly, the present study found that fasting could markedly increase the expression levels of cpt-1a, cpt-1b and cpt-2 in hepatopancreas and muscle, especially cpt-1a in hepatopancreas as well as cpt-1a and cpt-1b in muscle. The results above indicated that the cpt-1a, cpt-1b and cpt-2 played a crucial part in providing energy for coping with fasting and salinity stress. These results would contribute to enhancing the knowledge of cpt phylogenetic evolution and their roles in energy metabolism of crustaceans.

Comparative transcriptomic characterization of the ovary in the spawning process of the mud crab Scylla paramamosain.

Oviposition is induced upon mating in most insects. Spawning is a physiological process that is fundamental for the reproduction of Scylla paramamosain. However, the molecular mechanisms underlying the spawning process in this species are poorly understood. Herein, comprehensive ovary transcriptomic analysis was conducted at the germinal vesicle breakdown stage (GVBD), spawning stage, 0.5 h post-spawning stage, and 24 h post-spawning stage of S. paramamosain for gene discovery. A total of 67,230 unigenes were generated, and 27,975 (41.61%) unigenes were annotated. Meanwhile, the differentially expressed genes (DEGs) between the different groups were identified, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was subsequently conducted. These results suggested that octopamine (OA) and tyramine (TA) could induce oviposition, while dopamine (DA) and serotonin (5-hydroxytryptamine [5-HT]) inhibit oviposition. The 20-hydroxyecdysone (20E) and methyl farnesoate (MF) signal pathways might be positively associated with oviposition. Furthermore, numerous transcripts that encode neuropeptides and their G-protein-coupled receptors (GPCRs), such as CNMamide, RYamide, ecdysis-triggering hormone (ETH), GPA2/GPB5 receptor, and Moody receptor, appear to be differentially expressed during the spawning process. Eleven unigenes were selected for qRT-PCR and the pattern was found to be consistent with the transcriptome expression pattern. Our work is the first spawning-related investigation of S. paramamosain focusing on the ovary at the whole transcriptome level. These findings assist in improving our understanding of spawning regulation in S. paramamosain and provide information for oviposition studies in other crustaceans.

Incidence of mud crab reovirus (MCRV) outbreak in polyculture ponds of Andhra Pradesh, south east coast of India

Reovirus designated as Mud crab reovirus (MCRV) is associated with the mass mortalities of mud crabs resulting in significant economic loss to crab and shrimp-mud crab polyculture farmers in the Nagayalanka, Krishna district, Andhra Pradesh. The 100 % chronic mass mortalities have been attributed to the outbreak of Mud crab reovirus (MCRV) in the polyculture farms. The moribund crabs showed autotomy, discoloration of carapace, loss of appetite, slow movement and loose gills. Histopathological observations of the infected mud crabs showed an atrophied hepatopancreas, complete degeneration of tissues along with viral inclusions in hepatopancreas, gills and muscles. Further analysis using Transmission electron microscopy (TEM), showed that the viral particles had a diameter of 70 nm and exhibited a non-enveloped, icosahedral shape arranged in a crystalline manner. The virus mainly infects the connective tissue of hepatopancreas, gills, muscle and develops in the cytoplasm. RT-PCR reconfirmed the presence of reovirus in the hepatopancreas of spontaneously infected mud crab Scylla serrata. The current study shows the importance of monitoring the MCRV prevalence in polyculture farms to minimize its spread and precautionary measures can be taken by screening the brooders from the crab hatchery and stocking of wild crabs without screening should be avoided in order to prevent MCRV outbreak.

Pengaruh jenis substrat berbeda dalam proses penggemukan kepiting bakau (Scylla serrata) di CV. Elitism NTT, Kelurahan Oesapa Barat, Kecamatan Kelapa Lima, Kota Kupang

This research aims to determine how different types of substrate affect the duration of growth during the fattening phase of mud crabs (Scylla serrata). Carried out for one month at CV.Elitsm NTT, in West Oesapa Village, Kelapa Lima District, Kupang City. Randomized Block Design (RAK) was used in this research which consisted of four treatments and replications. The treatments given include: Muddy substrate with mangrove leaves (A), Muddy substrate (B), Mangrove leaf substrate (C), and Without substrate (D). The findings show that the use of muddy substrates with mangrove leaves provides the most beneficial results in accelerating the growth period during the mud crab fattening process. In 14 days after cultivation, the mud crabs were already developing well.
 
 Keywords: Mangrove crab (Scylla serrata), fattening and substrate.

Protein and lipid nutrition in crabs

AbstractUnderstanding the nutrition of crabs has a key role in ensuring the success and sustainability of their culture, as providing a well‐balanced, cost‐effective and sustainable diet that ensures the survival, growth and health of crabs is crucial. The present review is the first to focus primarily on the current state of knowledge of the nutrient requirements and related nutritional aspects in farmed crab species. The most common farmed and studied crabs are the Chinese mitten crab (Eriocheir sinensis Milne‐Edwards, 1853), giant mud crab (Scylla serrata Forsskal, 1775), green mud crab (Scylla paramamosain Estampador, 1949) and swimming crab (Portunus trituberculatus Miers, 1876). The article reviews how levels of dietary protein and lipid, the two most important and expensive macronutrient ingredients for most marine animals, directly affect reproduction, growth performance and survival of crabs, and the important impacts they have on immune response and antioxidant capacity. Furthermore, essential amino acids, and essential fatty acids, especially the long‐chain polyunsaturated fatty acids, as well as key lipid classes such as cholesterol and phospholipid will be discussed in terms of dietary requirements. Nutrient digestibility is a crucial method to determine protein quality, and studies on this topic in crabs were covered. The replacement of fishmeal and fish oil, as the predominant ingredients traditionally used in aquafeeds for marine animals, with more sustainable alternatives in diet formulations for crabs are also discussed. Modern ‘omics’ studies and high‐throughput technologies as fast‐growing approaches in protein and lipid research are also covered. Crabs generally require approximately 35%–50% protein, 5%–10% lipid, ~2.5% arginine, ~2.5% lysine, 1.5%–2.5% phenylalanine, 2.2% leucine, 0.7% tryptophan, 0.7% taurine, 1%–2% each of eicosapentaenoic acid, docosahexaenoic acid and arachidonic acid, 1% cholesterol and ~2% phospholipid in their diets.

Effects of terrestrial animal fats replacing dietary fish oil on the growth performance, antioxidant capacity and lipid metabolism in juvenile Scylla paramamosain

Four experimental diets containing 45% crude protein and 11% crude lipid were formulated by replacing total fish oil (FO) with poultry oil (PO), beef tallow (BT) and lard oil (LO) to evaluate the effects of terrestrial animal fats (TAFs) replacing dietary FO in juvenile green mud crabs (Scylla paramamosain). A total of 120 female juveniles (initial body weight 43.23 ± 0.21 g) was randomly assigned to four diet (three replicates per diet) and stocked into single crab cells (0.23 m × 0.15 m × 0.33 m, width × height × length) with circulating seawater (25–29 °C) for 8 weeks. Compared to FO, crabs fed BT and LO group had about 20% lower weight gain, and significantly lower specific growth rate, feed efficiency and molting ratio, hepatopancreas and muscle lipid, hemolymph total triglyceride contents, and lipase activity, but had approximately 400% higher hepatopancreas aspartate aminotransferase and 100% higher alanine aminotransferase activities. There was no difference in growth performance and feed utilization between PO and other groups. The contents of linoleic acids (18:2n-6) in hepatopancreas and muscle were higher in PO group. TAFs groups had significantly lower docosahexaenoic acids (22:6n-3) and total n-3 polyunsaturated fatty acids contents, as well as lower elongase of very long-chain fatty acids 4, acyl-CoA oxidase 3 and fatty acid transport protein 4 mRNA levels. BT and LO groups had lower mRNA levels of delta-6 fatty acyl desaturase, sterol regulatory element binding protein-1, fatty acid synthase, 6-phosphogluconate dehydrogenase and acetyl-CoA carboxylase. Therefore, dietary BT and LO could reduce the health status and lipid content via decreasing lipase activity, upregulating fatty acid β-oxidation, downregulating lipogenesis and inhibiting the transporting and metabolizing of long chain polyunsaturated fatty acids, thus decrease the growth performance of mud crab. Moreover, PO could be a potential FO substitute for juvenile S. paramamosain.

Variations in lipid composition of ovaries and hepatopancreas during vitellogenesis in the mud crab Scylla paramamosain: Implications of lipid transfer from hepatopancreas to ovaries

Lipid accumulation in ovaries is essential for reproductive success in decapods. Understanding of the mechanism of ovarian lipid accumulation is still in its infancy. In this study, we investigated lipid compositions of ovaries and hepatopancreas throughout vitellogenesis and hemolymph in the late-vitellogenic stage in the mud crab Scylla paramamosain. Total lipid content in ovaries consecutively increased from the early to late stage, and the main accumulated lipids were phosphatidylcholine (PC), alkenylglycerophosphoethanolamine (alkenyl-PE), triacylglycerol (TG), cholesteryl ester, and cholesterol. The lipid composition of hemolymph indicated that PC, alkenyl-PE, diacylglycerol (DG), ether DG, monoacylglycerol, and cholesterol were the main lipids transferred to ovaries from hepatopancreas. In hepatopancreas, the total lipid content appeared to increase during vitellogenesis and the late stage was significantly different from early and mid-stages. TG was the predominant lipid class that slightly decreased from the early to mid-stage, but dramatically increased in the late stage. In contrast, PC and alkenyl-PE significantly increased from the early to mid-stage and remained constantly in relatively low proportion until the late stage. These findings suggested PC and alkenyl-PE in the hepatopancreas likely play critical roles in regulating lipid transfer. Esterified fatty acids in ovaries and hepatopancreas were mainly C16:0, C18:0, 16:1, C18:1, C18:2, C20:4, C20:5, and C22:6, of which highly unsaturated fatty acids (HUFA) primarily occurred in alkenyl-PE and phosphatidylserine (PS) but not PC. In hemolymph, PC was abundant in HUFA besides of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA), while PS was predominantly composed of SFA and MUFA, implying a transformation of HUFA between phospholipids prior to transfer. These findings highlight the importance of phospholipid metabolism in the hepatopancreas to ovarian lipid accumulation. Our study provides novel insights into the mechanism of ovarian lipid accumulation in decapods.

Giant mud crab shell biochar: A promising adsorbent for methyl violet removal in wastewater treatment

Giant mud crab (Scylla serrata sp.) shell prepared through pyrolysis at various temperatures without any modification were characterized for physicochemical properties and methyl violet (MV) removal potential. Hence, this paper investigated the performance and mechanism of biochar derived from giant mud crab shell as adsorbent in the removal of methyl violet as well as the potential for regenerating adsorbents via hot water regeneration. The results show that CSB500 (produced through pyrolysis at 500 °C) exhibits a surface area of 59.73 m2/g and mesopore size of 31.3 nm, favorable for methyl violet removal at 3139 mg/g. The equilibrium adsorption data agreed well with Langmuir and Redlich-Peterson isotherm models, indicating a monolayer adsorption of MV. The kinetics data fitted better with both pseudo-first-order and pseudo-second-order models. The intraparticle diffusion and Boyd's models revealed that both film and pore diffusion may be involved in the adsorption process. In hot water regeneration studies, CSB500 shown superior regeneration performance when using water with temperature of 70 °C rather than 30 °C for 9th regeneration cycles, with retained to achieve >90 % MV removal for 6th regeneration cycles. Biochar derived from giant mud crab shell has shown significant promise as a low-cost, effective, and ecologically friendly with reasonably good adsorption capacity and reusability for dye removal, and it can be considered as an environmental sustainability strategy in wastewater treatment.

Evaluation of the dietary taurine requirement for early juvenile mud crab Scylla paramamosain

As a conditionally essential amino acid (CEAA), taurine plays an important role in the growth, development, and physiological metabolism of aquatic animals; however, its demand level in the mud crab Scylla paramamosain is still poorly understood. A 60-day growth trial was conducted to investigate the effects of different taurine levels (0% (T0.0), 0.2% (T0.2), 0.4% (T0.4), 0.8% (T0.8), and 1.6% (T1.6)) added to diet on the survival, growth, body composition, immunity, antioxidant and osmoregulatory capacity of early juvenile S. paramamosain (initial body weight 8.69 ± 0.19 mg). The results showed that dietary taurine levels >0.4% (inclusive) significantly increased the survival of early juvenile mud crabs. The growth performance (final body weight (FBW), weight gain (WG), specific growth rate (SGR)) of early juvenile mud crabs increased significantly with increasing dietary taurine levels, reaching a maximum in the T0.8 group, and the target of rapamycin (tor) gene transcription levels also peaked in the T0.8 group. The body composition of mud crabs was not affected by dietary treatments. Further, dietary taurine significantly increased digestive enzyme (trypsin, lipase, and amylase) activities and transcript levels of appetite-related genes (neuropeptide F1 (npf1) and neuropeptide F2 (npf2)) in early juvenile mud crabs. In addition, dietary taurine increased the expression levels of immune-related genes (prophenoloxidase (proPO), prophenoloxidase activating factor 1 (ppaf1), prophenoloxidase activating factor 2 (ppaf2), crustin antimicrobial peptide (crustin), lysozyme (lzm)) and antioxidant capacity (total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and catalase (CAT) activities) in early juvenile mud crabs. Finally, the results of the acute salinity challenge showed that the early juvenile mud crabs' survival in the T0.8 group was significantly higher than that of the other groups, while significantly higher Na+/K+-ATPase (NKA) activity and Na+/K+-ATPase α-subunit (nka-α) and Na+/K+/2Cl−-cotransporter (nkcc) gene expression levels were also detected in the T0.8 group. Together with growth performance, immunity, antioxidant capacity and osmoregulatory capacity, the present study concluded that the appropriate dietary taurine level for early juvenile mud crabs was 1.08%–1.33%.

THE CRUSTACEAN'S EXPORT-IMPORT MAPPING OF FISH QUARANTINE AND INSPECTION AGENCY (FQIA) JAKARTA I ON 2021-2022 PERIOD

Indonesia's crustacean has great potential fisheries business. The depletion of fisheries natural resources needs to be solved to avoid overfishing, especially for crustaceans. The study aim was to analyze crustacean diversity and mapping its products on export and import markets, as well as to analyze the sustainability of crustacean export-import across Indonesia. The study was conducted at FQIA Jakarta I on January until February 2023. The descriptive analysis method was used. The results of the study showed that Indonesia's fisheries export were higher than import activities. On crustacean exports, the highest destination country for lobster (Panulirus sp.) is Cina, the highest destination country for crab (Portunus pelagicus) is the USA, the highest destination country for mud crab (Scylla serrata) is Cina, and the highest destination countries for mantis shrimp (Squilla mantis) are Hongkong and Cina. Meanwhile, for imported crustaceans, snow crab (Chionoecetes opilio) came from Japan, and American lobster (Homarus americanus) came from Canada and USA. The overfishing has not occurred as illustrated for fishing grounds in Indonesia. It indicated by the average of annual catch value which has not higher than MSY catch. Keywords: Crustacea, fish market, fishing ground, annual catch, sustainable.

Impact of Iso-Protein Feed with Different Carbohydrate and Lipid Ratios on Growth and Feed Efficiency of the Mud Crab, Scylla serrata

Impact of Iso-Protein Feed with Different Carbohydrate and Lipid Ratios on Growth and Feed Efficiency of the Mud Crab, Scylla serrata