Tributyrin enhances growth and intestinal health in green mud crab (Scylla paramamosain) through butyrate-driven metabolic regulation.

BackgroundThe green mud crab (Scylla paramamosain) is the most prevalent crustacean on the southeast coast of China. The molecular regulatory mechanism of sex determination and gonadal differentiation in this species has received considerable attention in recent years because of the huge differences—both biological and economic—between male and female crabs. In this study, next-generation sequencing technology was used to develop deep-coverage transcriptomic sequencing data for the testis and ovary of S. paramamosain.ResultsA total of 365,116 reads (testis 171,962, ovary 193,154) with an average sequence length of 285 bp were produced from testis and ovary cDNA libraries. After filtering out contaminating reads, the clean reads were assembled, producing a total of 21,791 isotigs and leaving 22,814 reads as singlets. Using the BLASTX program, 3,471 unique sequences (2,275 isotigs and 1,196 singletons) were annotated with known protein sequences from the NCBI non-redundant (Nr) protein sequence database. The Gene Ontology and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses allowed the 224 unique sequences that were annotated with enzyme code (EC) numbers to be mapped into 174 KEGG pathways. After comparing the ovary and testis libraries, 4,021 gonad-differentially, 10,522 ovary-specifically, and 19,013 testis-specifically expressed genes were identified. Moreover, 33 ovary-specific, 14 testis-specific, and 34 gonad-differential transcripts were confirmed by semi-quantitative PCR and quantitative real-time PCR. In addition, 8,610 putative simple sequence repeats (SSRs) and 23,879 potential single nucleotide polymorphisms (SNPs) were identified.ConclusionThis is the first large-scale RNA sequencing of S. paramamosain to be reported. We have identified many important functional genes and made a preliminary attempt to construct the regulatory network involved in the gonadal development of crustaceans. The annotated transcriptome data will provide fundamental support for future research into the reproduction biology of S. paramamosain. A large number of candidate SSRs and SNPs were detected, which could be used as genetic markers for population genetics and functional genomics in this species.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-585) contains supplementary material, which is available to authorized users.

The present study for the first time tested the effect of repeated mild air exposure stress (RMS, 150 min) every four days on the growth, survival rate after acute air exposure, and relative pathways in female and male green mud crab ( Scylla paramamosain ) after 63 days. Further, to test the tolerance of these groups to the acute air exposure, crabs were exposed to the air until death and sampled after 24 h for omics analysis. The results indicated that RMS did not significantly decline growth, molting rate, and survival after 63 days. However, after acute air exposure (AAE) treatments, animals exposed to RMS, regardless of gender, survived longer than controls. Females and males showed different profiles of transcriptomics, so energy production relative pathways were enriched in all male tissues. Protein processing in the endoplasmic reticulum (ER) and apoptosis enriched with RMS are other evidence that the RMS group shifted to using available energy resources in the body during the farming period. After 24 h AAE, RMS groups showed upregulation of protein processing in the ER, plus DNA replication. Suppression of the biosynthesis of amino acids and energy production was observed as well. Females suppressed the biosynthesis of amino acids and energy production pathways, as well as other pathways related to amino acid metabolism. Female RMS did not show completely the same results, and ribosome was the main pathway that was downregulated in gill and muscle, as well as the biosynthesis of amino acids in hepatopancreas. Male and male RMS showed a similar response, and downregulation of protein synthesis and energy production pathways was observed. In conclusion, amino acid metabolism, energy production, and DNA replication were the key to air exposure response, and RMS could improve crab tolerance to stress. • Mild air stress did not change growth performance, molting, and survival rate. • RMS had a higher survival rate than the control after acute air stress. • RMS could decrease aggressiveness and improve crab tolerance to stress. • The energy production and DNA replication were highly changed.

Cloning and characterization of the SpLRR cDNA from green mud crab, Scylla paramamosain

Molecular characterization and expression profiles of cdc2 and cyclin B during oogenesis and spermatogenesis in green mud crab (Scylla paramamosain)

Mud crab is a group of commercially important species that are found throughout the Indo-Pacific region. In this study, the full-length cDNA of molt-inhibiting hormone (Scp-MIH) was cloned from the green mud crab, Scylla paramamosain. The conceptually translated peptide precursor consists of a 78-residue mature peptide, preceded by a 35-residue signal peptide. The mature peptide shares a high identity with the other known MIHs, and contains six conserved cysteine residues that have been proposed to be functionally critical for MIH activity. Analysis of genomic sequence revealed that Scp-MIH gene was organized in a 3 exons/2 introns manner. Quantitative real-time PCR showed that Scp-MIH transcripts were detected mainly in the eyestalk ganglion and brain. During the molting cycle, Scp-MIH mRNA increased significantly from postmolt stage to intermolt stage, then decreased sharply at premolt stage. It implies that MIH is closely related to ecdysteroid production in S. paramamosain. In the ovarian cycle, Scp-MIH transcripts in some neural tissues (eyestalk ganglion and brain) increased from stage I to stage II, and reached the peak value at stage III, then declined at later stage. It suggests that MIH might be involved in the ovarian maturation in S. paramamosain.

用蛋白质水平分别为31.45%，36.37%，41.55%，46.13%，51.72%和56.86%的6种等能饲料，对初始体重为（11.86±0.11） mg的拟穴青蟹（）幼蟹进行为期3周的养殖实验，考察饲料蛋白质水平对拟穴青蟹幼蟹生长性能、体成分以及消化酶活性的影响，以期获得拟穴青蟹幼蟹饲料蛋白质的适宜添加量。结果表明，饲料蛋白质水平对拟穴青蟹幼蟹的成活率影响不显著（0.05）后稍有下降，最大值出现在蛋白质水平为51.72%的实验组；随着饲料蛋白质水平的提高，幼蟹粗蛋白质含量显著升高（<0.05）后显著降低（<0.05），淀粉酶活性显著降低（<0.05），但没有明显的变化规律。本研究条件下，饲料蛋白质水平在41.55%~56.86%，拟穴青蟹幼蟹均表现出较好的生长率，增重率和蛋白质水平的回归分析表明，幼蟹饲料蛋白质适宜水平为49.03%。

Growth performance, antioxidant capacity, tissue fatty acid composition and lipid metabolism of juvenile green mud crab Scylla paramamosain in response to different dietary n-3 PUFA lipid sources

Aims: The problem addressed in this research is the lack of empirical data on the optimal immersing duration and bait type to maximize the efficiency of dragon trap fishing for banana prawns (Penaeus merguiensis) in the coastal waters of Semarang. To analyze the effect of immersing duration and bait type on the catch of Banana Prawn (Penaeus merguiensis) in the waters of Semarang Study Design: Experimental fishing. Place and Duration of Study: This research was conducted in November 2024 at Tambak Lorok, Semarang City, Central Java, Indonesia. Methodology: The method used in this study was experimental fishing, involving two variables: immersing duration and bait type, with seven repetitions. The immersing durations were set at 12 hours and 24 hours, and the bait type used were discarded catch, chicken intestines, and green mussel shells. Results: The catch composition of the dragon trap includes banana prawn (Penaeus merguiensis), tiger shrimp (Penaeus monodon), dory snapper (Lutjanus fulviflamma), green mud crab (Scylla paramamosain), mangrove stone crab (Myomenippe hardwickii), barracuda (Sphyraena barracuda), and orange-spotted grouper (Epinephelus coioides). The highest average catch was obtained with a soaking time of 6 hours using discarded catch as bait, yielding a mean catch of 2.8 kg per trap. This was followed by the 8-hour soaking duration with discarded catch, which resulted in a slightly lower average catch of 2.5 kg. The 4-hour soaking time consistently produced the lowest yields across all bait types, with an average of 1.2 kg per trap. The Mann-Whitney test results showed an Asymp. Sig value of 0,018 (&lt;0,05) for immersing duration, indicating a significant difference. Meanwhile, the Kruskal-Wallis test fir bait type resulted in a Asymp. Sig value of 0,173 (&gt;0,05), indicating No. significant effect. The interaction between immersing duration and bait type using the Friedman test showed a significant effect with a value of ,0,000 (&lt;0,05). Conclusion: The study demonstrates that a 12-hour immersion period using discarded catch as bait is the most effective combination for maximizing banana prawn catch in dragon trap fishing operations, with immersion duration having a significant impact on catch efficiency.

Development of broodstock of the green mud crab (Scylla paramamosain) was assessed under three different captive growout protocols viz. in the open fibre glass tanks (T1), in plastic boxes (T2) floating on fibre glass tanks and in plastic drawer/compartment (T3) for a period of 5 months under the Centre for Marine and Coastal Studies (CEMACS), Universitiy Sains Malaysia (USM). The male (M) and female (F) mud crab were cultured separately to maintain virginity. Suitability of both the sexes were evaluated considering the weight gain (size), survival and intactness of limbs during harvesting. Result of the present study revealed that, irrespectives of growout protocols, growth of mud crab happened following the sigmoid pattern. A noticeable intersexual weight attainment was observed with significantlyhigher (p&lt;0.05) weight gain for the males. Meanwhile, growth was influenced by the culture protocols for both the sexes with significant (p&lt;0.05) weight gain in outdoor tanks (M= 319.75 g, F= 246.17 g) followed by outdoor floating boxes (M= 250.50 g, F= 198.70 g) and indoor compartment (M= 246.40 g, F= 178.50 g). Survival and the proportion of intact crabs under indoor compartment and outdoor floating boxeswere significantly higher (p&lt;0.05) than out door tank culture system. The result of the present study suggested that, outdoor growout protocol could be followed for faster broodstock development purposes to reduce the dependence on natural broodstock for hatchery operations.SAARC J. Agri., 16(1): 169-180 (2018)

Cloning and characterisation of the SpToll gene from green mud crab, Scylla paramamosain

Dietary tributyrin supplementation promotes the growth by improving intestinal digestive and antioxidant capacity and the abundance of intestinal beneficial bacteria for swimming crab (Portunus trituberculatus)

Understanding 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.

Effect of dietary egg yolk lecithin levels on survival, growth, lipid metabolism, and antioxidant capacity of early juvenile green mud crab Scylla paramamosain

Four iso-nitrogenous and iso-lipidic diets were designed to investigate the effects of dietary phospholipids (PL) levels (with 0%, 1%, 2%, and 4% PL supplementation) on growth performance, lipid metabolism, and antioxidant capacity in early juvenile green mud crab (Scylla paramamosain). There were three replicates of 28 crabs (initial body weight from 42.02 to 42.44 mg) for each diet treatment, and growth trial lasted for 8 weeks. At the end of the growth trial, there was no significant difference in survival among all treatments. Crabs fed diet with 2% PL obtained highest weight gain (WG) and specific growth rate than other crabs. The molting frequency was not affected by different dietary PL addition. Besides, the contents of whole body lipid and long chain highly unsaturated fatty acids significantly increased with elevating dietary PL levels. In the hepatopancreas, crabs fed diet with 0% PL had significantly higher malondialdehyde concentration than other crabs. And crabs fed diet with 2% PL obtained significantly higher superoxide dismutase activity than crabs fed diets with 0% and 4% PL. Moreover, the mRNA expression of Na+/K+-ATPase was significantly down-regulated with dietary PL supplementation over 2%. Based on the second order polynomial regression analysis of WG, 2.37% dietary PL level was the optimal demand for early juvenile S. paramamosain. Moreover, we found crabs fed diet with 2% PL obtained better antioxidant capacity than other crabs.

Effect of essential fatty acids (EFA) on growth and survival of the green mud crab (Scylla paramamosain) larvae was assessed by feeding with natural to commercial diets. The feeding schemes were: larvae reared with Artemia (T1); larvae initially fed with rotifers (up to Z2) and ended (Z3 to megalopa) with Artemia (T2); and larvae fed with rotifers up to Z2 and ended (Z3 to megalopa) with commercial diet (T3). The commercial diet had significantly (p&lt;0.05) higher levels of docosahexaenoic acid (11.23%), ?n-3’s (15.90%) and ?n-6’s (4.21%); and lacked in eicosapentaenoic acid (2.25%) than rotifer and Artemia. The earliest commencement of megalopa stage within 15 days with significantly (p&lt;0.05) higher larval stage index (LSI) of 5.90±0.17 was achieved from the feeding scheme of T2 than other two feeding schemes. This feeding scheme deposited 17.32±0.19% eicosapentaenoic acid (EPA) and 3.82±0.11% docosahexaenoic acid (DHA); the ?n-3 to ?n-6 ratio of 0.20 and EPA to DHA ratio of 0.22 in megalopa, that stimulated significantly higher (p&lt;0.05) megalopa survival (20.00±6.96%) indicating the superiority over rest feeding schemes. Meanwhile, some deformities and mortalities in Z5 and megalopa stages suggested further studies for optimization of specific fatty acid requirements for late larval stages (Z5 and megalopa).