Tissues Of Crabs Research Articles

Combined effects of polyethylene spiked with the antimicrobial triclosan on the swamp ghost crab (Ucides cordatus; Linnaeus, 1763).

Domestic sewage is an important source of pollutants in aquatic ecosystems and includes both microplastics (MPs) and pharmaceuticals and personal care products (PPCPs). This study sought to assess the biological effects of the interaction between plastic particles and the antibacterial agent triclosan (TCS). The study relied on the swamp ghost crab Ucides cordatus as a model. Herein polyethylene particles were contaminated with triclosan solution. Triclosan concentrations in the particles were then chemically analyzed. Swamp ghost crab specimens were exposed to experimental compounds (a control, microplastics, and microplastics with triclosan) for 7 days. Samplings were performed on days 3 (T3) and 7 (T7). Gill, hepatopancreas, muscle and hemolymph tissue samples were collected from the animals to evaluate the biomarkers ethoxyresorufin O-deethylase (EROD), dibenzylfluorescein dealkylase (DBF), glutathione S-transferase (GST), glutathione peroxidase (GPx), reduced glutathione (GSH), lipid peroxidation (LPO), DNA strands break (DNA damage), cholinesterase (ChE) through protein levels and neutral red retention time (NRRT). Water, organism, and microplastic samples were collected at the end of the assay for post-exposure chemical analyses. Triclosan was detected in the water and crab tissue samples, results which indicate that microplastics serve as triclosan carriers. Effects on the gills of organisms exposed to triclosan-spiked microplastics were observed as altered biomarker results (EROD, GST, GPx, GSH, LPO, DNA damage and NRRT). The effects were more closely associated with microplastic contaminated with triclosan exposure than with microplastic exposure, since animals exposed only to microplastics did not experience significant effects. Our results show that microplastics may be important carriers of substances of emerging interest in marine environments in that they contaminate environmental matrices and have adverse effects on organisms exposed to these stressors.

Virulence and antimicrobial-resistance of shiga toxin-producing E. coli (STEC) Isolated from edible shellfish and its public health significance

Shiga toxin-producing E. coli (STEC) are an important cause of foodborne illness in humans with infections ranging from mild non-bloody diarrhea to bloody diarrhea (BD) and hemolytic uremic syndrome (HUS). This study aimed to investigate the distribution of STEC in shellfish from coastal shores of Lake Timsah in Ismailia Governorate, Egypt and its probable hazard to seafood consumers. Samples from the external surface and tissues of shrimp (n = 45), crabs (n = 45), and oysters (n = 45) batches were examined bacteriologically for the presence of STEC and tested for their antibiotic sensitivity. Moreover, occurrence of virulence genes was determined via detection of stx1, stx2 and eaeA genes using PCR. Overall, E. coli and presumptive STEC isolates (from CHROMagar) were identified from the surface (55.6 and 5.9%) and tissues (42.2 and 8.9%) of the examined shellfish batches, respectively. Five STEC isolates had been confirmed and found belonging to O26:H11, O125:H6, O146:H21, and O159 serogroups, those were 4 isolates from tissues of the three shellfish species and one isolate from the crab surface. The STEC isolates were multi-drug resistant, showing complete resistance to; penicillins, amoxycillin/clavulanic acid, colistin, fosfomycin, ceftriaxone, ciprofloxacin, and tetracycline, however, they were sensitive to gentamycin except O159 serogroup. The current study revealed low level of contamination of shellfish from coastal shores of Lake Timsah with STEC, however, it also highlights the extreme level of antimicrobial resistance exhibited by the presumptive and confirmed STEC isolates which is very hazardous for seafood consumers in the study area.

A New Crustin Gene Homolog SpCrus8 Identified in Scylla paramamosain Exerting In Vivo Protection Through Opsonization and Immunomodulation.

Crustins are the most abundant class of antimicrobial peptides in crustaceans and are essential for protecting animals from infection. Among them, type II crustins usually exhibit potent antimicrobial activity. Interestingly, in this study, a newly identified type II crustin gene homolog (named SpCrus8) from mud crab Scylla paramamosain, the recombinant proteins of which (rSpCrus8 and rTrx-SpCrus8) showed no obvious antibacterial effects, but could significantly reduce the bacterial load in crab hemolymph and improve the survival rate of crabs infected with Vibrio alginolyticus. The immune-related function of SpCrus8 and the underlying mechanism deserve further investigation. It was found that the SpCrus8 gene was widely distributed in various tissues of adult crabs. In the hepatopancreas of crabs infected with V. alginolyticus or Staphylococcus aureus, transcripts of the SpCrus8 gene were remarkably induced, indicating that the SpCrus8 gene was involved in the immune response to bacterial infection in vivo. In addition, rSpCrus8 and rTrx-SpCrus8 had strong binding activity not only to microbial surface components (lipopolysaccharide, lipoteichoic acid, peptidoglycan, and glucan), but also to the tested bacteria (S. aureus, Pseudomonas aeruginosa and V. alginolyticus). Notably, rSpCrus8 and rTrx-SpCrus8 could significantly promote hemocyte phagocytosis. After rSpCrus8 and rTrx-SpCrus8 treatment, a large number of fluorescent microspheres were observed to aggregate into clusters and be phagocytosed by multiple hemocytes, while hemocytes in the control group phagocytosed only individual microspheres, indicating that SpCrus8 played an important role in opsonization. When the SpCrus8 gene was knocked down, the expression levels of the key phagocytosis-related genes SpRab5 and SpRab7 were significantly downregulated, as well as the IMD signaling pathway genes SpIKKβ and SpRelish, and another crustin gene SpCrus5. Correspondingly, all the SpIKKβ, SpRelish and SpCrus5 genes were significantly upregulated after rSpCrus8 treatment, suggesting that SpCrus8 might be involved in the immunomodulation of S. paramamosain. Taken together, this study revealed the immune-related functions of the SpCrus8 gene in opsonization and regulation, which will help us further understand the role of the crustin gene family in the immune system of mud crabs and provide new insights into the function of type II crutins.

Heavy Metals and their Effects on Macroinvertebrates Present in the Ojo River, Lagos, Nigeria

Aim: To provide information regarding the presence of heavy metals in the tissues of crab (Potamon fluviatile), prawn (Macrobrachium rosenbergii), and crayfish (Metanephrops australiensis) obtained from the Ojo river of Lagos State, Nigeria.
 Study Design: Commercially sold marine crustacean samples (crab, prawn, and crayfish) obtained from the Ojo river of Lagos, Nigeria, were assessed for the presence of heavy metals, and also the potential health risks for local consumers.
 Place and Duration of Study: Ojo river, located close to Ojo local government secretariat, Ojo, Lagos State, Nigeria.
 Methodology: Live samples of macroinvertebrates such as Metanephrops australiensis, Potamon fluviatile, and Macrobrachium rosenbergii were purchased from the fishermen at the riverside in Ojo and immediately transferred to the laboratory. The samples were oven-dried and ground into a fine powder, then subjected to sample digestion and finally atomic absorption spectrophotometer (AAS), to obtain the various heavy metal concentrations present in each sample.
 Results: The result indicated variations in the metal body load among species. All the metals were below the FAO/WHO permissible limit for food consumption except for Cd in crayfish which was slightly beyond the set limit. The highest concentration examined were found in crayfish, followed by crab and prawn. Zinc and iron were of higher concentrations in the tissues of the macroinvertebrates while lead was the least concentrated metal present only in the tissues of crayfish and absent in the tissues of both crab and prawn.
 Conclusion: The human health risk evaluation for the marine organisms indicated that both the crab and the prawn samples examined were safe for consumption, while crayfish may not be considered safe for consumption. Also, the potential health risk from consuming seafood exposed to these metals should not be ignored.

Metabolic Response in the Gill of Portunus trituberculatus Under Short-Term Low Salinity Stress Based on GC-MS Technique

Salinity is an important factor affecting the survival, growth, and metabolism of marine crustaceans. Low-salt stress will result in the death of swimming crabs. This paper investigates the metabolic response in the gills of Portunus trituberculatus under short-term low-salt stress by comparing the metabolic molecules in the four salinity treatment groups (24‰, 16‰, 12‰, and 8‰) by GC-MS technique. In this study, nine common differential metabolites such as pyruvate, malic acid, and phosphoethanolamine were found in the gill tissues of crabs. KEGG enrichment analysis revealed that six metabolic pathways, including the citric acid cycle, pyruvate metabolism, and the HIF-1 signaling system, were significantly impacted by low salt stimulation. According to the findings, salinity 12‰ is a critical node in crab adaptation to low salinity. In the process of adaptation to short-term low-salinity environment, amino acids participated in osmotic regulation, and organic acids such as pyruvate and malic acid were involved in energy metabolism to ensure their energy supply. This research further enriched the theory of osmotic regulation and metabolic mechanism of adaptation to low salt in crustaceans, with the goal of providing guidance for the improvement of culture technique in Portunus trituberculatus.

Suppressed COP9 signalosome 5 promotes hemocyte proliferation through Cyclin E in the early G1 phase to defend against bacterial infection in crab.

Hemocytes are invertebrate immune cells that are similar to blood cells in vertebrates and play a crucial role in innate immunity. Previous work has found that mature circulating hemocytes lack the ability to proliferate. However, recent single-cell RNA sequencing and functional studies in invertebrate have challenged this view. Here, we report that bacteria induced hemocytes proliferation in the Chinese mitten crab, Eriocheir sinensis. Flow cytometry was used to collect non-proliferating and proliferating hemocytes populations, while the expression of EsCyclin E was highly expressed in proliferating hemocytes, but the expression of EsCsn5 was significantly suppressed in proliferating hemocytes. Subsequent studies have found EsCsn5 distributed in two fractions include holo-complex and monomeric form, whereas knockdown of EsCsn5has little impact on the amount of the holo-complex. EsCsn5 was widely expressed in different crab tissues, while its expression was significantly reduced upon bacterial infection. Crab hemocytes showed significantly enhanced proliferation when EsCsn5 was genetically knocked down, suggesting a critical role for CSN5 in the negative regulation of crab hemocyte proliferation. Moreover, EsCSN5 but not the EsCSN8 was demonstrated to negatively regulate the early G1 phase of the cell cycle by controlling the degradation of EsCyclin E through ubiquitination steps, rather than affecting its transcription. Furthermore, in the EsCyclin E-suppressed crab there was a significantly reduced survival rate and an up-regulated hemolymph bacterial concentration. Taken together, this study provides evidence demonstrating that invertebrate hemocytes down-regulate the expression of EsCsn5 upon bacterial challenge, thus promoting proliferation in an EsCyclin E-dependent manner in order to protect the crab from infection.

Effect of biological and anthropogenic habitat sounds on oxidative stress biomarkers and behavior in a key crab species

Soundscapes are characterized by a combination of natural and anthropogenic sounds. This study evaluated the stress effect of biological and anthropogenic sounds characterizing a Man and Biosphere UNESCO wetland, by assessing the protein content, oxidative biomarkers, and behavior of a key crab species (Neohelice granulata), through a tank-laboratory experiment. Biological sounds corresponded to predators of N. granulata (fish and crustacean stimuli), while anthropogenic ones belonged to motorboat passages (boat stimulus). Biochemical results showed differences depending on the sound stimuli used and the crab tissue analyzed. Protein content was higher in hemolymph when crabs were exposed to fish and boat stimuli, and in gills when exposed to boat stimulus. The enzymatic activity in hemolymph showed a decreased GST (fish stimulus) and CAT (fish and boat stimuli) activity, in hepatopancreas a higher GST (crustacean stimulus) and CAT (crustacean and boat stimuli) activity was found, and in gills a higher CAT activity was also observed (crustacean and boat stimuli). Lipid peroxidation was higher only in hemolymph (fish and crustacean stimuli). Protein oxidation was higher in gills (fish stimulus) and hepatopancreas (crustacean stimulus). Behavioral analysis demonstrated that the crab locomotion activity diminished when exposed to diverse sound stimuli. Thus, both sound sources caused physiological and behavioral stress in this species. The results contribute important data to be used in the development of management plans considering the habitat importance in terms of biodiversity, the ecosystem services provided and the role of the studied species.

Effects of two natural diets on the biochemical compositions of post‐mating female mud crab ( Scylla paramamosain )

Understanding the effects of different natural diets on the growth performance and nutritional quality of mud crab Scylla paramamosain is important for both aquaculture and human nutrition perspectives. In the present study, female S. paramamosain were fed with two different natural diets, a marine bivalve species Potamocorbula rubromuscula (initial weight of the experimental crabs: 192.1 ± 29.2 g) and lizardfish Harpadon nehereus (initial weight of the experimental crabs: 188.1 ± 42.9 g) during the post-mating period. Furthermore, the weight gain ratio (WGR), specific growth rate (SGR), gonado-somatic index (GSI), hepatosomatic index (HSI), proximate compositions, total carotenoid content, amino and fatty acid profiles were investigated. Different diets affected HSI, carotenoid, lipid, amino acid and fatty acid contents in the claw muscle, hepatopancreas and ovary of female S. paramamosain. However, different diets did not affect the growth parameters including WGR, SGR and GSI. Crabs fed with P. rubromuscula had significantly higher amino acid content in the claw muscle, hepatopancreas and ovary, but lower HSI value and lipid content in the hepatopancreas and ovary compared with the crabs fed with H. nehereus. The carotenoid content was significantly higher in the hepatopancreas and ovary tissues of crabs fed with P. rubromuscula, whereas crab fed with H. nehereus displayed higher carotenoid content in the claw muscle. These results indicated that feeding S. paramamosain with P. rubromuscula could enhance amino acid contents (in claw muscle, hepatopancreas and ovary) and carotenoid contents in the hepatopancreas and ovary. Moreover, this study showed that the post-mating period is a critical period for nutritional deposition and a short feeding strategy during this period dramatically alters the body biochemical compositions.

A A Trend of Zinc Uptake into Tachypleus Gigas Tissues After a Month of Exposure

Tachypleus gigas is one of the species of horseshoe crabs found in Peninsular Malaysia. Metals in the surrounding water can accumulate into horseshoe crab tissues. This study was conducted to determine zinc (Zn) uptake into horseshoe crab tissues after continuous exposure to the metals. T. gigas that were sampled from Gelang Patah, Johor and Cherating, Pahang were reared in the control tank and Zn treatment tank (20 mg/L) with aeration supply for a month. Twelve horseshoe crabs from Zn treatment tank and 6 horseshoe crabs from control tank were dissected for tissues namely operculum, gills, chelicerae, leg, digestive tract, hepatopancreas and carapace in different intervals (Day 0, Day 10, Day 20 and Day 30). These tissues were freeze dried and digested with 65% nitric acid on a hotplate at 200oC. Zn were measured using Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). Different concentrations of Zn were measured in different tissues. The tissues of T. gigas showed increased concentrations of Zn by following exposure in 30 days. The increasing pattern of Zn uptake into the tissues from day 0- 30 are clear. The gills showed highest concentrations of metals accumulation with the value of 6398.60 ± 909.51 µg/g (dw). Thus, uptake of Zn into T. gigas was confirmed, therefore it has the potential to become the suitable bio-indicator (especially their gills) to detect the metal pollution in the surrounding water.

Seasonal heavy metal concentrations in blue crab (Callinectes sapidus) tissues from the Mediterranean coast of Egypt, Port Said.

Seasonal heavy metal concentrations in blue crab (Callinectes sapidus) tissues from the Mediterranean coast of Egypt, Port Said.

ATP catabolism and bacterial succession in postmortem tissues of mud crab (Scylla paramamosain) and their roles in freshness

The seafood microbiome is highly diverse and plays an essential role in the spoilage of seafood. Nevertheless, how such a diverse microbiome influences freshness of mud crab (Scylla paramamosain) remains unclear. Here we investigated the postmortem ATP catabolism and succession of the bacterial community in the hepatopancreas and muscle of S. paramamosain using a high-performance liquid chromatography method and 16S rRNA gene amplicon sequencing. Our results showed a tissue-dependent change in ATP catabolism determinized the differences in the changes of nucleotide freshness indices of hepatopancreas and muscle over postmortem time of mud crab. The muscle K value could be used as an optimal nucleotide freshness indicator for the freshness of mud crab, with a proposed threshold of 20%. From a microbiota perspective, a more significant bacterial community change was observed in the muscle than in the hepatopancreas. These changes could result in a close relationship between ATP and its catabolites and microbial taxa in the muscle. Moreover, Photobacterium, Peptostreptococcaceae, average path distance, OTU richness, and Shannon index of muscle bacterial community markedly contributed to K value. These findings suggest that the mud crab of 4 h postmortem at room temperature is still edible. Notably, the importance of microbial community composition and interaction for the spoilage of mud crab should be carefully considered.

The Heavy Metal Characteristics (Pb and Cu) in Wideng Crab Tissue from the Gonjol River, Demak

Objective and Background: The Gonjol river serves as a lifeline for the communities surrounding Demak's brackish water ponds. Currently, factory waste is poisoning rivers. The purpose of this research was to investigate the levels of heavy metals Pb and Cu in Wideng crab tissue, water, and sediment in the Gonjol river's upper course and estuary.
 Methods: This study was place from January to March 2020. Heavy metal concentration was determined using atomic absorption spectroscopy. The linear regression method was used to analyze the data. 
 Results: Except for Cu in upstream and estuary sediments, the concentration of Pb and Cu in the waters, sediments, and Wideng crab tissue remained below the acceptable limits. Heavy metals Pb and Cu in both sediment and tissue did not reveal a significant association in the upstream and estuary, although there was a correlation between water and tissue. There is no association between silt and water in the upstream and estuary. The river's quality is based on the Decree of the Minister of the Environment of the Republic of Indonesia No.115 of 2003, which places it in category C, which means it has moderate levels of Pb and Cu pollution. While tissue and sediment levels are below the tolerance limit. 
 Conclusion: The state of the Gonjol River is a source of concern, particularly the circumstances of Cu and Pb, which allow bioaccumulation in the future, posing a threat to the ecosystem and the communities surrounding it.

Geographical discrimination of swimming crabs (Portunus trituberculatus) using stable isotope and multi-element analyses

Reliable identification of the origin of economically important animal species is essential to preventing fraud. We investigated the efficacy of stable isotope and multi-element analyses in claw meat, abdominal meat, gills, and the hepatopancreas of swimming crabs (Portunus trituberculatus) using specimens from three discrete production areas in China and developed an origin discrimination model using stepwise discriminant analysis. Stable isotope ratios (δ13C, δ15N) and the contents of 14 elements (Na, Mg, Al, K, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Ag, and Ba) varied significantly by tissue and by sampling location (P < 0.01). Obvious isotopic fractionation effect was observed among different tissues, the muscle tissue and gills isotope ratios were more effective geographical origin indicators than hepatopancreas. Although the accumulation effects of the elements differed between tissues, the discriminatory correctness was generally consistent across tissues. By combining stable isotopes and elemental contents., stepwise discriminant analysis of these indicators was continued at the 0.01 level of significance, and the correct extent of discrimination was improved for all tissues. The correct extent of discrimination of claw meat, abdominal meat, gills, and hepatopancreas were 100%100 %, 100 %, 100 % and 94.7 %, respectively, indicating that all crab tissues can distinguish the origin of P. trituberculatus to some extent. This method supports the geographical traceability and origin identification of P. trituberculatus.

Determination of the proximate composition of most sought-after crab species from Devi estuary, Odisha, India

Two species of Portunid crabs, Portunus pelagicus (Linnaeus, 1758) and P. sanguinolentus (Herbst, 1783) abundant in Devi estuary, Astaranga, Odisha were analyzed for key nutrients (carbohydrates, proteins, and lipids) through standard protocols. Findings revealed high protein content in the females than in the male species. Furthermore, the body muscles were richer in protein than the chelate tissues of the species examined. The crab P. sanguinolentus was nutritionally productive with significantly (p < 0.05) higher protein (173.58 mg/g) and other nutrients (carbohydrates 5.23 mg/g; and lipids 22.95 mg/g) than P. pelagicus (protein 59.58 mg/g; carbohydrate 4.2 mg/g; and lipid 19.93 mg/g). Notably, muscle tissues of female crabs were higher in nutrients than that of males. Further, nutrient content in body muscles was greater than in the chelate appendages. Given the near absence of data on the nutrient composition of palatable crabs from the Devi estuary, Astaranga, it is contended that the information obtained could be decisive in addressing the nutritional needs of the coastal populace and aid judicious utilization and marketing of the species.

Composition and nutritional qualities of edible tissues of Chinese mitten crab (Eriocheir sinensis) from Ya Lake over different months

The edible tissue yield, proximate, fatty acid, and free amino acid composition were examined and compared among Chinese mitten crabs (Eriocheir sinensis) samples from Ya Lake over different months. Regardless of gender, the gonadosomatic index (GSI) was higher in May and June than that in August and September (P < 0.05), whereas the hepatopancreas index (HSI), meat yield (MY), and total edible yield (TEY) were higher in August and September. For proximate composition, regardless of gender, the total lipid content in the hepatopancreas was significantly higher in September than in other months, and the total lipid and protein content in the gonads was the highest. Furthermore, the content of EPA in female hepatopancreas was the highest in August. Regardless of sex, C16:1n7 in muscle was higher in September than in other months (P < 0.05), and the ratio of n-3/n-6 PUFA was the highest. Moreover, females had the highest glutamate and arginine content in their ovaries in August (P < 0.05). Among the muscles, both sexes contained higher levels of alanine and glutamate in September. Thus, the edible tissue yield, nutritional quality, and taste of Ya Lake E. sinensis in September were the best.

Metschnikowia bicuspidata isolated from milky diseased Eriocheir sinensis: Phenotypic and genetic characterization, antifungal susceptibility and challenge models.

A severe disease occurred in farmed Eriocheir sinensis characterized by milky liquid accumulation in the pectoral cavity, in the province of Liaoning, China, during October 2018-April 2019. Diseased crabs moved sluggishly, exhibited appetite loss and readily lost legs. Under the microscopic analysis, it was observed that the milky liquid contained a large number of yeastlike microorganisms (0.8-1.2μm × 1.5-1.9μm), which were also present in the muscle, hepatopancreas and gills. A dominant strain was isolated from the milky liquid and other tissues of diseased crabs. It grew on nutrient agar and formed 1- to 3-mm white opaque colonies, each with a protuberance in the centre. Besides, the results of TEM and SEM also demonstrate a typical multilateral budding model of the yeast clearly. We identified the strain, which we named 2EJM001, as Metschnikowia bicuspidata based on 18S rDNA, ITS and 26S rDNA sequence analyses and on its morphological, physiological and biochemical characteristics. Phylogenetic analysis revealed that 26S rDNA of 2EJM001 was clustered with M. bicuspidata (LNES0119) as reported by Bao et al. In addition, unlike Bao et al., two challenge experiments (injection and immersion) were used in this study. The results of challenge experiments show that 2EJM001 was pathogenic to E. sinensis and caused signs similar to those found in the naturally infected crabs. At the same time, the minimum inhibitory concentrations (MIC80 and MIC90 ) were determined. This study further confirms that M. bicuspidata 2EJM001 was the pathogen responsible for 'milky disease' in E. sinensis from Liaoning Province.

Target hazard quotient evaluation of selected trace elements in highly consumed crustacean species in Lagos, Nigeria

Crustaceans are known for their trace element bioaccumulation abilities. Muscle tissues of lagoon crab, marine crab, pink shrimp and mantis shrimp marketed for consumption in Nigeria were analyzed for Mn, Fe, Cu, Zn, Hg and Cr levels using standard methods. Muscle levels in mg kg-1 of Mn (0.03±0.00 in lagoon crab), Fe (0.072±0.01 in mantis shrimp), Cu (0.344±0.01 in lagoon crab) and Zn (0.073±0.00 in mantis shrimp) were significantly different (p&lt;0.05) from their corresponding values in other examined crustaceans. The mean values of Cr and Hg were not significantly different across samples. The estimated daily intake of trace element (mg person-1day-1) revealed that Hg (0.000001) in marine crab contributed the lowest daily intake while Zn (0.000226) in lagoon crab contributed the highest daily intake. Total hazard quotient (THQ) values for the trace elements followed descending order of Hg &gt; Cu &gt; Zn &gt; Fe &gt; Mn &gt; Cr. Lagoon crab showed the highest total hazard index among the organisms with 44.80 %, while the least was observed in mantis shrimp with 13.30 %. It is concluded that, as far as human health is concerned, the mean elemental levels in the muscle tissues of the organisms examined pose no danger (THQ &lt; 1).

From field to plate: Agricultural pesticide presence in the guayas estuary (Ecuador) and commercial mangrove crabs

Mangroves are unique coastal ecosystems, located in tropical and subtropical regions. Yet, the functioning of these essential ecosystems is threatened by the presence of pollutants, including pesticides originating from agricultural activities. We investigated pesticide residues in the Guayas estuarine environment, since agricultural activities rapidly increased in the Guayas river basin over the past decades. A multi-residue analysis involving a selection of 88 pesticides was performed on the white meat and the hepatopancreas of the red mangrove crab (Ucides Occidentalis) at 15 sampling sites within the Guayas estuary along with water, sediment, and leaves samples. We found that 35 active compounds were present in the Guayas estuary, of which pyrimethanil was most commonly detected and had the highest concentrations in almost all compartments. Also, cadusafos was present in all studied compartments of the Guayas mangrove system and several prohibited pesticides (including carbendazim, carbofuran, and parathion) were detected. An ecotoxicological and probabilistic consumer risk assessment pointed out that current butachlor, carbendazim, and fludioxonil concentrations can cause adverse effects in aquatic organisms in the long term. Moreover, high potential acute and chronic risks of cadusafos residues on aquatic invertebrates and of diuron on algae in the Guayas wetlands were observed. Still, the exposure results indicated that the health risk for the consumers of the commercial red mangrove crab is low concerning cadusafos, chlorpyrifos, diuron, linuron, and pyrimethanil residues in crab tissues. The findings presented in this research can provide a useful basis for local water managers and environmental conservation groups to act and reduce the usage of pesticides, to avoid threatening aquatic and human health.

Farming practices affect the amino acid profiles of the aquaculture Chinese mitten crab.

Farming operation and amino acid profiles of pond-reared Chinese mitten crabs, Eriocheir sinensis (Milne Edwards, 1853), collected from different areas in Jiangsu Province, China were investigated and compared with the aim to elucidate how farming practices affected the nutritional values of three edible tissues (muscle, hepatopancreas and gonad) of crab. The crab pond aquaculture practices including snail input, macrophytes coverage, total commercial feed, the ratio of trash fish to total feed, were much higher in Gaochun and Jintan than that in other sites (having larger pond size), which leads to higher average individual body weight and commercial yields. Further, the mean body weight, muscle weight, carapace length and width, and the ratio of gonad to hepatopancreas were significantly higher in Jintan, Suzhou and Gaochun areas than in other regions. Amino acid assessment showed that all crabs collected delivered high-quality protein (Amino acid score >1 except Valine), the main amino acids being glutamic acid, aspartic acid, and alanine. Significant differences in amino acid profiles were observed between sites, tissues and sexes. Muscles were rich in total amino acids, essential amino acids, and delicious amino acids, followed by gonads and hepatopancreas. The contents of essential amino acids in crab muscles from Gaochun, Jintan, Suzhou and Guannan were significantly higher than those from Suqian, Sihong and Xinghua. All the amino acids except Serine and Glycine were significantly higher in gonads from males than from females. The redundancy analysis revealed that the snail input, trash fish ratio to the total feed, macrophytes coverage and total trash fish supply explained 84.3% of the variation in the amino acid content and structure in crabs from Gaochun, Jintan and Suzhou. Overall, our results show that mitten crabs collected in Jiangsu province had good nutritional quality suitable for human dietary needs, and that farming practices, especially degree of fish-source protein feeding, influence the amino acids composition of crabs.

An analysis of the heavy element distribution in edible tissues of the swimming crab (Portunus trituberculatus) from Shandong Province, China and its human consumption risk

This study evaluated the food safety of the swimming crab (Portunus trituberculatus) found in Shandong Province, China and obtained information on possible edible parts and gender differences. White and brown muscle samples from 108 swimming crabs were collected from seven cities along the eastern coastline of Shandong Province and analyzed for levels of Cu, Zn, Ni, As, Fe, Mn, Cr, Se, Cd, and Pb. There were significant differences in the metal concentrations among different edible muscles. High concentrations of Zn, Mn, and Cr were found in leg and claw meat while Fe, Cu, Ni, As, Cd, Pb, and Se were predominantly found in the hepatopancreas and gonads. Gender differences were found only for Fe and Zn. Based on the estimated daily intake (EDI), target hazard quotient (THQ), total target hazard quotient (TTHQ), and the permissible safety limits prescribed by various agencies, consumption of the swimming crab is considered safe.