Crab Scylla Tranquebarica Research Articles

Behavioral evidence of saccharide mixture as a potent feeding effector for the purple mud crab Scylla tranquebarica

Behavioral evidence of saccharide mixture as a potent feeding effector for the purple mud crab Scylla tranquebarica

Reproductive biology of green crab Scylla tranquebarica (Fabricius, 1897) found in Ratnagiri Coast, Maharashtra, India

Reproductive biology of green crab Scylla tranquebarica (Fabricius, 1897) found in Ratnagiri Coast, Maharashtra, India

The effectivity of probiotic containing Bacillus spp. applicated in the rearing of mud crab Scylla tranquebarica larvae to produce crablet

Probiotic bacteria in larvae rearing is expected to suppress pathogenic bacteria and improve water quality. The research aimed to determine the effectivity of probiotic bacteria containing Bacillus subtilis and B. licheniformis on larval rearing of purple mud crab Scylla tranquebarica to produce crablet. The larvae were stocked in nine units of conical fiber tank, fed Rotifers, Brachionus plicatilis, and nauplii Artemia sp. The probiotics tested, namely, A). RICA-4, containing the bacterium Bacillus subtilis, B). RICA-5 containing B. licheniformis, C). A combination of probiotics RICA-4 and RICA-5. The administration of each probiotic with a density of 108 CFU g−1 (5 mg L−1) was given to the water media for larvae rearing. The lowest nitrite and Total Organic Matter in the zoea stage were found in treatment B. At the megalopa stage, treatment B’s lowest TOM concentration occurred and was significantly different (p<0.05) from treatment C. On the other hand, the highest population of Vibrio spp (5.5x103 CFU mL−1) was obtained in treatment A. In contrast, treatment C had the highest bacteria population (4.8x104 CFU mL-1). On day 19, the megalopa in treatment B was more abundant than in treatments A and C causing crablet production in treatment B (280.5±47.50 ind. tank −1) was significantly higher (p<0.05) than crablet production in treatment C (196.5±29.50 ind. tank −1) and A (161.0±21.00 ind. tank −1). Therefore, improving water quality in treatment B may have an important factor in enhancing crablet production.

Major and minor allergen Ige reactivity of purple mud crab (Scylla tranquebarica) against a cross-reactive allergen in crustacean and molluscs in patients with a seafood allergy

Background: Crabs have been reported as a high exporter of protein and contains great nutritional value. Objective: It is necessary to identify the allergens and the cross-reactivity concerning the mud crab Scylla tranquebarica, shellfish, and mollusks for control of food safety and to facilitate in the identification and treatment of symptoms related to allergy. Methods: IgE extracted of serum from five patients who suffered from anaphylaxis due to crab and five healthy patients. It was taken for analysis via immunoblotting against 11 different crustaceans and molluscs. Results: Based on the analysis, the sera from the patients had responded specifically to a 38-kDa protein in all the crustaceans and molluscs, and it is known as tropomyosin. In certain absorption studies, the 38-kDa protein had exhibited to be the immunodominant epitopes among all crustaceans and molluscs. Sera from all five subjects with Scylla tranquebarica allergy showed IgE reactivates against crabs, prawns, and molluscs, but not to the chicken or murine muscle. Conclusions: Therefore, it can be concluded that the allergic epitopes on tropomyosin are preserved not only in shellfish but also in insects. Thus, a further examination should be done onto the patient with shrimp allergy to determine the potential cross-reactivity inhalant or sensitivity to ingested insects.

Shelter colour preference in the purple mud crab Scylla tranquebarica (Fabricius)

Cannibalism a serious problem in the grow-out of mud crabs in ponds. Studies have proven that presence of shelters decreases aggressive behaviour of Scylla spp. in ponds and tanks. In this study, the shelter colour preference was determined in the wild captured purple mud crab Scylla tranquebarica (Fabricius) in an outdoor round black tank. Eight out of 48 PVC pipes were painted either blue, green, red, black or white. Other eight were not painted and were provided as grey shelters. The shelters were presented in different two-colour pairs to a group of 35 crabs; eight shelters of one colour and eight of other colour were arranged alternately on the tank bottom, and the number of occupants was recorded. After emptying the shelters, the shelters rearranged for the next observation. Each colour combination was repeated five times, and total of 15 combinations were tested. The number of occupants against each colour of the different pairs were analyzed by the χ2-test and Thurstone’s law of comparative judgment. The data were converted into mean z-scores and significant biases from zero were noted. Underwater visibility of each colour shelter was visually measured through a waterproof digital CCD camera. The crabs showed a strong bias for blue shelter and white shelter chosen the least under the holding condition. The underwater visibility was highest in blue and white colour shelters among the six colour shelters. The observed colour preference was probably due to colour per se and may be an innate ability, rather than due to relative underwater visibility. During the observations, the shelter occupants were tolerant of intruders; there was no aggressive competition for shelter and two to four crabs shared one shelter. It was hypothesized that the touch stimulus of shelter suppresses the aggressiveness and results in low cannibalism of S. tranquebarica.

Behavioural evidence for colour vision determined by conditioning in the purple mud crab Scylla tranquebarica

Crabs and shrimps (order Decapoda) use colours in various tasks such as foraging and mate choice. Colour vision requires at least two types of photoreceptors with different spectral sensitivities. Previous physiological studies revealed that most crabs including Scylla mud crabs have a single visual receptor system, i.e. they are colour blind. We determined colour vision by means of a behavioural experiment on hatchery-produced and wild-captured purple mud crab Scylla tranquebarica in a roofed hatchery. Adult crabs (8-10 cm carapace width) were subjected to classical conditioning to associate a food reward with a blue or a green stimulus placed among seven shades of grey. The hatchery-produced crabs learnt this task after 14 days of reward training, and thereafter distinguished blue in 27 non-reward trials, and green in 39 non-reward trials. The wild-captured crabs did so after 25 days of reward training, and distinguished green in 49 non-reward trials. These results indicated colour vision in S. tranquebarica. However, the crabs were unable to distinguish blue or green in dim light of 4.4 cd/m2 (which is slightly brighter than full moon light). The high colour vision threshold was attributed to the small optic parameters of the apposition compound eyes of S. tranquebarica.

THE EFFECTS OF AN ARTIFICIAL COMMERCIAL FEED SUPPLEMENTATION ON LARVAL REARING AND CRABLET PRODUCTION OF MUD CRAB Scylla tranquebarica

The effects of an artificial commercial feed supplementation on larval rearing and crablet production of mud crab Scylla tranquebarica. In mass production of mud crab seeds, only rotifer and Artemia nauplii are usually fed to mud crab larvae rearing until the larvae develop to crablet stage. The supplementation of artificial commercial feed from zoea-3 stage is expected to supply an essential nutrient required for an optimum larval development. The research was aimed to determine the optimum dosage of commercial feed supplementation for a successful larval rearing to produce crablet in hatchery. Newly hatched larvae of mud crab were stocked at a density of 100 ind./L. The larvae were fed with rotifer and Artemia nauplii. Microbound artificial commercial feed sized &lt;100 microns (protein 52%, fat 14,5%, fiber 3% and water content 10%) was supplemented to the larvae from zoea-3 to megalopa stage at different dosages namely: a). 0.5 mg/L/2 days; b). 0.75 mg/L/2 days; c). 1.0 mg/L/2 days; d). 1.25 mg/L/2 days. Larval population, larval development indices (LDI), megalopa occurrence index (MOI) and crablet production were observed and measured. Water quality (ammonium, nitrite, Total Organic Matter (TOM), and total Vibrio sp. count were also monitored. The LDI, MOI, and crablet production from each treatment were compared and tested using one way-ANOVA. The results showed that the survival rate of larvae at zoea-5 ranged between 29-33%. The LDI was not significantly different (P&gt;0.05) among treatments. However, the MOI of treatment A and B at day 21 ph was significantly higher (P&lt;0.05) compared with treatment C and D. In addition, the crablet production in treatment B, C and D were significantly higher (P&lt;0.05) compared with treatment A. It was concluded that the supplementation of artificial commercial feed in larval rearing of S. tranquebarica could be applied at the dosage range of 0.75-1.25 mg/L/2-days from zoea-3 until crablet (C-7) stage.

&lt;i&gt;Haliphthoros sabahensis&lt;/i&gt; sp. nov. Isolated from Mud Crab &lt;i&gt;Scylla tranquebarica&lt;/i&gt; Eggs and Larvae in Malaysia

&lt;i&gt;Haliphthoros sabahensis&lt;/i&gt; sp. nov. Isolated from Mud Crab &lt;i&gt;Scylla tranquebarica&lt;/i&gt; Eggs and Larvae in Malaysia

Molecular identification and characterization of Type I crustin isoforms from the hemocytes of portunid crabs, Scylla tranquebarica and Portunus pelagicus

Crustins are cationic antimicrobial peptides of ca. 7–14kDa with a characteristic four-disulphide core containing WAP domain, present in the hemocytes of crustaceans. The present study reports the first crustin sequences from two portunid crabs, viz. the mud crab Scylla tranquebarica (St-Crustin, JQ965930) and the blue swimmer crab Portunus pelagicus (Pp-Crustin, JQ753312). St-Crustin and Pp-Crustin represented the complete cDNA sequence of Type I crustin, with an ORF of 336bp encoding 111aa with a predicted molecular weight of 10kDa and a pI of 8. The signal sequence contained 21aa residues, which was followed by a mature peptide with a WAP domain at the C-terminus. Peptide model of St-Crustin and Pp-Crustin indicated a randomly coiled structure enclosing two β-sheets but no helices. St-Crustin and Pp-Crustin shared significant similarities with crustins of portunid crabs (68–95%) and other crabs (60–73%). Phylogenetic analysis showed that St-Crustin and Pp-Crustin possess the same ancestral origin and have a similar evolutionary status like other crustins, which has subsequently diverged at different phases of evolution. St-Crustin and Pp-Crustin were closely related to crab crustins rather than to the crustins of other crustacean groups. The wide distribution of crustins in crustaceans indicates the importance of these AMPs in the innate immunity. Discovery of novel crustins might pave way to the discovery of promising therapeutic/prophylactic agents in health management and disease control in crustacean aquaculture.

Two isoforms of anti-lipopolysaccharide factors identified and characterized from the hemocytes of portunid crabs, Portunus pelagicus and Scylla tranquebarica

Anti-lipopolysaccharide factors (ALFs), a type of cationic antimicrobial peptides (AMPs), and their derivatives are becoming predominant candidates for potential drugs in viral and bacterial diseases. This study reports the first ALF from the mud crab Scylla tranquebarica (StALF, JQ899453) and the second ALF isoform from the blue swimmer crab Portunus pelagicus (PpALF2, JQ899452). Both sequences encoded for precursor molecules, starting with a signal peptide containing 26 amino acid residues, followed by a highly cationic mature peptide, containing two conserved cysteine residues flanking a putative lipopolysaccharide (LPS)-binding domain. BLAST analysis revealed that both PpALF2 and StALF exhibited significant similarity with crustacean ALF sequences. The predicted molecular mass of the mature ALFs was 11.2kDa with an estimated pI of 10.0. PpALF2 and StALF also showed the typical pattern of alternating hydrophobic and hydrophilic residues in their putative disulphide loop, suggesting that they comprise the same functional domain. Phylogenetic analysis showed that PpALF2 and StALF have similar evolutionary status and they were phylogenetically ancient immune effector molecules which may play an essential role in the host defense mechanism. The spatial structures of PpALF2 and StALF possessed four beta-strands and two alpha-helices. The results indicated that there were more than one ALF involved in crab immunity against various pathogens. ALFs would provide candidate promising therapeutic or prophylactic agents in health management and diseases control in crustacean aquaculture.

Extraction Of Chitin And Chitosan From Mud Crab Scylla Tranquebarica (Fabricius, 1798)

Chitin is a polysaccharide of animal origin, is obtained from waste material of seafood industries. It occurs in the skeletal material of crustaceans such as crabs, shrimps, lobsters, prawns and crayfish. The extraction of the chitin and chitosan of various body parts of mud crab Scylla tranquebarica showed that the legs shell yield more than carapace shell and claw shell. The quality parameters of chitin & chitosan was analysed by Fourier Transform Infrared (FT-IR) Spectrometry and compared with standards. Chitin, chitosan, mud crab, Scylla tranquebarica, FT-IR. I. INTRODUCTION Chitin is a poly - B - (1-4) - N - acetyl -D-glucosamine. It is a nitrogen containing polysaccharide, related chemically to the cellulose. Chitin is the second most abundant natural polymer, after cellulose. Like cellulose, it is a polysaccharide – a compound formed of many identical simple sugar molecules. Chitin was first found in mushrooms in 1811 by Professor Henri Braconnot, Director of the Botanical Gardens at the Academy of Sciences in Nancy, France. The crustacean processing industries over the world turn out more than 60,000 tonnes of waste every year. The head and shell of crustaceans such as prawn, lobster, crab, squilla, krill etc. form the waste. The crustacean wastes contain about 10% of chitin on dry weight basis. The proper utilization of these shell wastes not only solves the problem of their disposal but also forms the basis for many potential products used in the fields such as textiles, photography, medicine, agriculture, food processing etc. The global attention on the importance of chitin and chitosan has been demonstrated in three International conferences on chitin and chitosan held in the years 1977, 1982 and 1985 (Udgata et al., 1994). Ministry of Health and Welfare, Japan has approved chitin, chitosan and their derivatives as food additives. In India, chitin has been found to promote growth in broiler chicks. Incorporation of chitin in poultry feed at a level of 0.5 percent decreases the food consumption ratio and increases the body weight by 12 percent in comparison with chicks fed on a chitin-free diet (Brzerki, 1987). The Central Institute of Fisheries Technology (CIFT), Cochin conducted experiment on chicken that was fed with chitin-incorporated diet. The results showed 10 - 12% increase in the chicken than fed with the normal feed(Patel and Sadam, 2002).

Assessment of biochemical components and enzyme activities in the estuarine crab Scylla tranquebarica from naphthalene contaminated habitants

To document the impact of naphthalene, a comparative toxicological research was performed in the estuarine crab Scylla tranquebarica habitant of Ennore creek (polluted site) and Kovalam creek (pristine site) for a period of 6 months. The biochemical constituents, such as protein, carbohydrate, lipid and enzyme activities like acid and alkaline phosphatase, aspartate and alanine transaminase were analysed in hepatopancreas, heamolymph and ovary of the female crabs collected from the two creeks. The results revealed that there was a significant measurable difference in these parameters in the tissues of crabs sampled from the polyaromatic hydrocarbon (PAH) polluted site (Ennore creek) when compared with the reference site (Kovalam creek). In addition naphthalene was detected in gill, hepatopancrease, heamolymph and ovary of the crabs sampled from the polluted creek. The results indicate that the indicators selected for toxic impact in S. tranquebarica may be related to the uptake of naphthalene in the tissues examined and support the feasibility of employing these types of analyses as biochemical biomarkers for PAH contaminant-exposed organisms.

Bleeding stress and metabolic changes in the crab Scylla tranquebarica (Fabricius).

In the crab scylla tranquebarica, bleeding stress is characterized by changes in proteins, lactic acid and water content of muscles, hepatopancreas and haemolymph. Proteins seemed to be involved in energy expenditure and internal osmotic balance. Lactate levels increased, suggesting a shift in aerobic metabolism. Water content fell.