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At least 127 records · Page 7Linked to original sources

PubMed2005

Purification and partial characterization of the plasma clotting protein from the pink shrimp Farfantepenaeus paulensis.

A clotting protein (CP) was purified from the plasma of the pink shrimp Farfantepenaeus paulensis by sequential anion-exchange chromatography. The shrimp CP was able to form stable clots in vitro in the presence of hemocyte lysate and Ca2+, suggesting that the clotting reaction is catalyzed by a Ca2+-dependent transglutaminase present in shrimp hemocytes. Dansylcadaverine was incorporated into the shrimp CP in the presence of endogenous transglutaminase (hemocyte lysate), confirming that the shrimp purified CP is the substrate for the transglutaminase enzyme. The molecular mass of the CP was determined by gel filtration to be 341 kDa and 170 kDa by SDS-PAGE under reducing conditions. These results suggest that the shrimp CP consists of two identical subunits, covalently linked by disulphide bonds. The amino acid sequence at the N-terminus was 100% identical to that of the penaeids Litopenaeus vannamei and Penaeus monodon and 66% to 80% identical to the CPs of other decapods. This is the first report of a CP characterization in an Atlantic penaeid species. Further studies, including a molecular cloning approach would enable to detect which tissues express the gene of the clotting protein. It would be also useful to understand the mechanism by which the coagulation time is delayed in shrimps under stress conditions.

Amino Acid Sequence↗

PubMed2005

Differential gene expression profile in hepatopancreas of WSSV-resistant shrimp (Penaeus japonicus) by suppression subtractive hybridization.

In order to find the immune-relevant factors responsible for the virus resistance in the WSSV-resistant shrimp, a suppression subtractive hybridization method was employed to identify differentially expressed genes and their expression profile in the hepatopancreas of the virus-resistant penaeid shrimp. Thirty five genes were identified from more than 400 clones, of which eight are found for the first time in penaeid shrimp. betaGBP is the most abundant gene in our subtractive library except hemocyanin. Lectin, ferritin, oxygenase and chitinase of the virus-resistant shrimp all showed up-regulation in expression compared with those of normal shrimp. In addition, Ranbp, Rho and Rab were found in the subtractive library. This is the first evidence indicating that small GTPases are involved in the signal transduction in shrimp defense response. Furthermore, a number of genes encoding apoptotic-related proteins and antioxidant enzymes were expressed at a higher level in the virus-resistant shrimp. In short, the high expression of immuno-related genes in response to the virus infection and the involvement of small GTPases in the antiviral response provide a new insight for further study in the crustacean innate immunity.

Amino Acid Sequence↗

PubMed2006

Effects of the insecticide permethrin on three life stages of the grass shrimp, Palaemonetes pugio.

Toxicity of the pyrethroid insecticide permethrin was assessed using three life stages of the estuarine grass shrimp, Palaemonetes pugio. Adult and larval shrimp were tested with and without sediment. An aqueous embryo test was also conducted. Cellular stress biomarkers, glutathione, and lipid peroxidation, were assessed. Larval shrimp were the most sensitive life stage with a 96-h lethal concentration (LC(50)) value of 0.05 microg/L, compared to 0.25 microg/L for adults, and 6.4 microg/L for embryos. The presence of sediment significantly decreased toxicity of permethrin to both adult and larval shrimp. Permethrin exposure increased time to hatch in embryos and decreased swimming behavior of larvae. Lipid peroxidation levels were significantly decreased in the adult shrimp, but increased in larval shrimp exposed to permethrin. Low levels of permethrin may negatively affect grass shrimp health and survival. Permethrin use in the coastal zone should be carefully managed to avoid adverse impacts on nontarget estuarine organisms.

Animals↗

PubMed2005

Quantitative and qualitative studies on the bacteriological quality of Indian white shrimp (Penaeus indicus) stored in dry ice.

Indian white shrimp (Penaeus indicus) stored in dry ice at the 1:1 ratio were found to be organoleptically suitable for consumption when they were stored for 24 h without reicing. Shrimp stored in water ice at the 1:1 ratio (as control) were acceptable up to 18 h. Shrimp stored in a combination of dry ice and water ice at the ratio of 1:0.2:0.5 were also found to be acceptable up to 24 h. Total bacterial load ranged from 10(6) to 10(9) cfu g(-1), while total psychrophiles ranged from 10(3) to 10(6) cfu g(-1). Total lactics were found in the levels of 10(2)-10(6) cfu g(-1). H(2)S producers were from 10(3) to 10(5) cfu g(-1). Lowest temperature of -4.8 degrees C was observed in shrimps stored in dry ice at 1:1 ratio. Bacterial flora associated with fresh raw shrimp were Aeromonas, Pseudomonas, Vibrio, Flavobacterium and Serratia. Aeromonas constituted 38% of the flora in raw shrimp. Flavobacterium (43%), Pseudomonas (47%) and Pseudomonas (38%) were the dominant bacterial flora in the shrimp stored in dry ice at 1:1 ratio, in the combination package, and in water ice at 1:1 ratio, respectively.

Animals↗

PubMed2006

Administration of hot-water extract of brown seaweed Sargassum duplicatum via immersion and injection enhances the immune resistance of white shrimp Litopenaeus vannamei.

The total haemocyte count (THC), phenoloxidase activity, and respiratory burst were examined when the white shrimp Litopenaeus vannamei (10.42+/-1.39 g) were immersed in seawater (34 per thousand) containing hot-water extract of brown alga Sargassum duplicatum at 100, 300 and 500 mg l(-1), or injected with hot-water extract of S. duplicatum at 2, 6, 10 and 20 microg g(-1). These parameters increased significantly when the shrimp were immersed in seawater containing hot-water extract at 300 and 500 mg l(-1) after 1 h, or when the shrimp were injected with hot-water extract at 10 and 20 microg g(-1) after 1 day. L. vannamei that were injected with hot-water extract at 6, 10 and 20 microg g(-1) had increased phagocytic activity and clearance efficiency to V. alginolyticus after 1-6 days. In another experiment, L. vannamei which had been immersed in seawater containing hot-water extract at 100, 300 and 500 mg l(-1), or injected with hot-water extract at 2, 6, 10 or 20 microg g(-1) were challenged with V. alginolyticus at 1 x 10(6), or 1.4 x 10(6) colony-forming units (cfu) shrimp(-1), and then placed in seawater. The survival of shrimp that received hot-water extract at either dose was significantly higher than that of control shrimp after 2 days, as well as at the termination of the experiment (6 days after the challenge). It is therefore concluded that L. vannamei that were immersed in hot-water extract of S. duplicatum at 300 mg l(-1), or the shrimp that were injected with hot-water extract at 10 microg g(-1) or less had increased immune ability as well as resistance to V. alginolyticus infection.

Animals↗

PubMed2005

Effect of salinity on the immune response of tiger shrimp Penaeus monodon and its susceptibility to Photobacterium damselae subsp. damselae.

Addition of NaCl at 2.5% to tryptic soy broth (TSB) significantly increased the growth of Photobacterium damselae subsp. damselae. Tiger shrimp Penaeus monodon held in 25 per thousand seawater were injected with P. damsela subsp. damselae grown in TSB containing NaCl at 0.5%, 1.5%, 2.5% and 3.5% at a dose of 8.48 x 10(4)colony-forming units (cfu)shrimp(-1). Over 24-96 h, the cumulative mortality was significantly higher for the shrimp challenged with P. damselae subsp. damselae grown in 2.5% NaCl than those grown in 0.5%, 1.5% and 3.5% NaCl. In another experiment, P. monodon held in 25 per thousand were injected with TSB-grown P. damselae subsp. damselae (8.48 x 10(4)cfushrimp(-1)), and then transferred to 5 per thousand, 15 per thousand, 25 per thousand (control) and 35 per thousand. After 96 h, the mortality was highest for the P. damselae subsp. damselae-injected shrimp held in 5 per thousand, and the lowest for the P. damselae subsp. damselae-injected shrimp held in 25 per thousand. In a separate experiment, P. monodon held in 25 per thousand and then transferred to 5 per thousand, 15 per thousand, 25 per thousand (control) and 35 per thousand were examined for immune parameters, and phagocytic activity and clearance efficiency of P. damselae subsp. damselae after 12-96 h. The THC, hyaline cell, phenoloxidase activity, respiratory burst, superoxide dismutase (SOD) activity, phagocytic activity and clearance efficiency decreased significantly for the shrimp held in 5 per thousand, 15 per thousand and 35 per thousand after 12h. It is concluded that tiger shrimp P. monodon transferred from 25 per thousand to low salinity levels (5 per thousand and 15 per thousand) and high salinity (35 per thousand) had reduced immune ability and decreased resistance against P. damselae subsp. damselae infection.

Animals↗

PubMed2006

Hepatopancreatic nuclease of black tiger shrimp Penaeus monodon unlikely to be involved in viral triggered apoptosis.

Nucleases are phosphodiesterases that hydrolyze DNA and/or RNA. In a search for shrimp nucleases involved in apoptosis, we discovered a nuclease from hepatopancreatic cDNA of the black tiger shrimp Penaeus monodon. The full-length nuclease gene was amplified and revealed to contain 1668bp corresponding to 381 deduced amino acid residues in the mature enzyme. Sequence analysis indicated 83% nucleic acid identity and 89% amino acid identity to a nuclease from the Kuruma shrimp Penaeus japonicus (also called Marsupenaeus japonicus). Comparative analysis of sequences, conserved motifs and phylogenetic trees indicated that P. monodon nuclease (PMN) belonged to the family of DNA/RNA non-specific endonucleases (DRNSN). RT-PCR analysis using primers specific for PMN mRNA with seven different shrimp tissues revealed that expression in normal shrimp was restricted to the hepatopancreas. Semiquantitative RT-PCR analysis of PMN using hepatopancreatic mRNA from normal shrimp and from shrimp challenged with white spot syndrome virus (WSSV) indicated significant up-regulation of PMN in the hepatopancreas (P<0.05) at the early stage of viral infection but a return to baseline levels as gross signs of disease developed. At the same time, expression was always confined to the hepatopancreas and never seen in other tissues, including those reported to be prime targets for WSSV and subject to increased levels of apoptosis after infection. The results suggested that PMN is probably a digestive enzyme that is unlikely to be involved in hallmark DNA digestion associated with apoptosis.

Amino Acid Sequence↗

PubMed2004

Molecular cloning and expression of a mammalian homologue of a translationally controlled tumor protein (TCTP) gene from Penaeus monodon shrimp.

White spot syndrome, caused by white spot syndrome virus (WSSV), is a deadly disease of shrimps, causing a catastrophic loss in shrimp industries worldwide. In order to investigate molecular response of shrimp haemocyte to WSSV infection, we performed subtraction hybridization of mRNAs from healthy and WSSV-infected haemocyte. One of the genes that were severely down-regulated in moribund WSSV-infected-haemocyte was translationally controlled tumor protein (TCTP) (or fortilin). Strikingly, while there was a slight difference in the amount of TCTP message between normal and early WSSV-infected shrimps, shrimps that exhibited severe symptoms uniformly had very little TCTP in their haemocyte. Taken together with the fact that TCTP functions as an anti-apoptotic protein in mammals, our data suggest that TCTP in shrimp protects WSSV-infected shrimps from death.

Amino Acid Sequence↗

PubMed2006

Quantification of Vibrio penaeicida, the etiological agent of Syndrome 93 in New Caledonian shrimp, by real-time PCR using SYBR Green I chemistry.

Shrimp farming is a small but growing industry in New Caledonia. Since 1993, "Syndrome 93" has been affecting New Caledonian shrimp farming industry every cold season, causing severe epizootic mortalities in grow-out ponds and significant losses. Highly pathogenic strains of Vibrio penaeicida are considered the etiological agent of the disease in Litopenaeus stylirostris. On one hand, studies demonstrated that healthy shrimp may carry V. penaeicida for weeks with a high overall prevalence, regardless of any seasonal pattern or temperature conditions. On the other hand, larvae are free of V. penaeicida and are also resistant to experimental infection. V. penaeicida is frequently detected in incoming water pumped from the bays, which was shown, by a molecular typing study, to be the infectious source. This particular epidemiological pattern highlights the major role of the factors that trigger and aggravate the disease in grow-out ponds, where shrimp populations carry the pathogen all year round. In order to gain a better understanding of "Syndrome 93" epidemiology, quantification of V. penaeicida both in shrimp and the shrimp farm ecosystem is necessary. This article describes the steps in the successful development of a real-time PCR quantification assay of V. penaeicida in shrimp haemolymph, seawater (from ponds or bays) and sediment pore water, including the choice of an accurate extraction technique. The entire detection method; including sample processing, DNA extraction and real-time PCR amplification, can be completed within 4 h.

Animals↗

PubMed2003

PmAV, a novel gene involved in virus resistance of shrimp Penaeus monodon.

Diseases caused by viruses especially by white spot syndrome virus (WSSV) are the greatest challenge to worldwide shrimp aquaculture. The innate immunity of shrimp has attracted extensive attention, but no factor involved in the virus resistance has been reported. Here we report for the first time the identification of an antiviral gene from shrimp Penaeus monodon. A differential cDNA (designated as PmAV) cloned from virus-resistant shrimp P. monodon by differential display (DD) was found to have an open reading frame (ORF) encoding a 170 amino acid peptide with a C-type lectin-like domain (CTLD). The PmAV gene was expressed in Escherichia coli and the protein was purified. Recombinant PmAV protein displayed a strong antiviral activity in inhibiting virus-induced cytopathic effect in fish cell in vitro. Moreover, native PmAV protein was isolated from shrimp hemolymph by immuno-affinity chromatography and confirmed by Western blot. No agglutination activity was observed both in recombinant and native PmAV protein. Immunohistological study showed that PmAV protein was located mainly in the cytoplasm, and not bound to the shrimp WSSV. It implies that the antiviral mechanism of PmAV protein is not by inhibiting the attachment of virus to target host cell. The discovery of PmAV gene might provide a clue to elucidate the innate immunity of marine invertebrates and would be helpful to shrimp viral disease control.

Amino Acid Sequence↗

PubMed2003

Relative importance of dissolved and food pathways for lead contamination in shrimp.

The relative importance of dissolved and food pathways and the influence of food type in the bioaccumulation and retention of lead in the shrimp Palaemonetes varians were examined using a radiotracer method. Shrimp were exposed to 210Pb-labelled seawater or fed two types of 210Pb-labelled food, viz. mussels or worms. The amount of radiotracer accumulated by shrimp was examined over a 7-day period, followed by a 1-month and a 7-day depuration period for the dissolved and food source, respectively. Steady state in the uptake was reached after 2 days exposure to dissolved lead, with a resultant estimated concentration factor of 98+/-3. Transfer factors following ingestion of contaminated mussels and worms were lower than unity for both food types, with lead transfer from worms being significantly higher than that from mussels. Accumulation of dissolved Pb by shrimp was found to occur mainly through adsorption on the exoskeleton with a minor accumulation in the internal tissues probably resulting from the intake of seawater for osmoregulation. In contrast, lead taken up from contaminated food was readily absorbed and bound in the internal tissues of P. varians. Although the transfer of lead to P. varians through the ingestion of contaminated food was low (TF<1%), it still represented 4 to 8% of the lead content in the prey which is a significant additional contribution of lead to the shrimp body burden. Independent of food type, following ingestion of contaminated food, approximately 23-27% of total lead accumulated in shrimp was located in the edible parts (e.g. muscle). Therefore, the food pathway is suggested to be a significant contributor to the lead transfer to humans through ingestion of contaminated shrimp. After exposure to contaminated food, lead loss kinetics were described by a two-component model, whereas Pb loss following direct uptake from seawater was best described by a three-component model. The additional compartment representing 64% of total Pb retained and characterized by a turnover<10 min, corresponded to lead weakly adsorbed on the exoskeleton and incorporated in the hepatopancreas. Nevertheless, a significant fraction of lead accumulated from the dissolved (2%) and food (52-57%) pathways remained irreversibly retained in the tissues, suggesting that this organism could also serve as an effective long-term bioindicator of lead contamination in marine waters.

Adsorption↗

PubMed2003

Organization of the shrimp vitellogenin gene: evidence of multiple genes and tissue specific expression by the ovary and hepatopancreas.

Vitellogenin is the major egg yolk protein synthesized in female shrimp during gonad maturation. Although there are several reports for the cloning of vitellogenin complementary DNA (cDNA) in different crustaceans, little is known of the gene organization of this protein. This study reports the first cloning and characterization of a full-length gene encoding the vitellogenin precursor from the shrimp Metapenaeus ensis. By genomic DNA library screening, six different lambda clones were isolated using shrimp partial gene sequence as probe. Initial DNA sequence determination revealed that these clones are derived from different genes with coding sequence similar to other crustacean vitellogenins. Two of these clones were used for further analysis. One of the lambda clones (lambda 3.3) carries most of the coding sequence that correspond to the M. ensis vitellogenin gene (MeVg1) and the other clone (lambda 8.3) carries a smaller portion of the coding sequence of a different vitellogenin gene (MeVg2). The lambda 3.3 clone was chosen for further characterization. To clone the remaining 5' end upstream promoter region, 5' untranslated region and the remaining coding sequence of MeVg1, a polymerase chain reaction (PCR)-based gene walking approach was used. Subsequently, a PCR clone with overlapping sequence identical to the genomic clone was obtained and the organization of MeVg1 gene was constructed. The MeVg1 gene consists of 15 exons and 14 introns spanning approximately 10 kb. Several potential cleavage sites were identified from the deduced vitellogenin precursor. Cleaving of the precursor in these sites would result in the production of several vitellogenin subunits. To clone the cDNA for the vitellogenin, 5' and 3' rapid amplification of cDNA ends was performed using ovary cDNA of the shrimp. A 4.4 kb 5' cDNA clone and a 4 kb 3' end cDNA clone were isolated. The size of the reconstructed cDNA for M. ensis Vg is 7.97 kb and consists of the longest open reading frame of 7776 bp. Unlike the vitellogenin precursor of most insects and vertebrates, the deduced vitellogenin precursor lacks the polyserine domain important for receptor-mediated endocytosis. Phylogenetic analysis revealed a closer relationship of the MeVg1 with other crustacean vitellogenins but distantly related to other invertebrate and vertebrate vitellogenins. By reverse transcription-PCR, we have demonstrated that the shrimp MeVg1 gene is expressed only in the ovary and hepatopancreas while the MeVg2 gene is expressed exclusively in the hepatopancreas. In conclusion, the shrimp ovary also contribute significantly in the production of vitellogenin at transcription level and the gene organization of the shrimp protein may provide an insight in the evolution of this group of important proteins.

Amino Acid Sequence↗

PubMed2004

A synthetic antibacterial peptide from Mytilus galloprovincialis reduces mortality due to white spot syndrome virus in palaemonid shrimp.

White spot syndrome virus (WSSV) isolated from Penaeus monodon was found to be highly infective for the western Mediterranean shrimp, Palaemon sp. Using polymerase chain reaction (PCR), it was demonstrated that such shrimp are not naturally carriers of WSSV. Following challenge with virus, mortality reached 100% 3.5-4 days after injection at 22 degrees C. Incubation of infected shrimp at 10 degrees C totally suppressed the mortality which rapidly developed when shrimp were returned to 18 or 22 degrees C. Preincubation of WSSV with mature synthetic mytilin significantly reduced shrimp mortality with a 50% efficient dose of about 5 microM. Survival of shrimp was not due to the development of an active mechanism of defence as re-injection of WSSV produced the same mortality pattern. Mortality was probably due to WSSV replication as dot blot failed to detect viral DNA in the injection sample but was positive 1 day post-injection. Protection by mytilin was by interaction at the virus level, preventing replication as no WSSV nucleic acid was detected by PCR even after 7 days in shrimp injected with WSSV preincubated with 10 or 50 microM mytilin.

Amino Acid Sequence↗

PubMed2006

The pink shrimp Farfantepenaeus duorarum, its symbionts and helminths as bioindicators of chemical pollution in Campeche Sound, Mexico.

The pink shrimp Farfantepenaeus duorarum may acquire pollutants, helminths and symbionts from their environment. Statistical associations were studied between the symbionts and helminths of F. duorarum and pollutants in sediments, water and shrimps in Campeche Sound, Mexico. The study area spatially overlapped between offshore oil platforms and natural shrimp mating grounds. Spatial autocorrelation of data was controlled with spatial analysis using distance indices (SADIE) which identifies parasite or pollutant patches (high levels) and gaps (low levels), expressing them as clustering indices compared at each point to produce a measure of spatial association. Symbionts included the peritrich ciliates Epistylis sp. and Zoothamnium penaei and all symbionts were pooled. Helminths included Hysterothylacium sp., Opecoeloides fimbriatus, Prochristianella penaei and an unidentified cestode. Thirty-five pollutants were identified, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides and heavy metals. The PAHs (2-3 ring) in water, unresolved complex mixture (UCM), Ni and V in sediments, and Zn, Cr and heptachlor in shrimps were significantly clustered. The remaining pollutants were randomly distributed in the study area. Juvenile shrimps acquired pesticides, PAHs (2-3 rings) and Zn, while adults acquired PAHs (4-5 rings), Cu and V. Results suggest natural PAH spillovers, and continental runoff of dichlorodiphenyltrichloroethane (DDT), PCBs and PAHs (2-3 ring). There were no significant associations between pollutants and helminths. However, there were significant negative associations of pesticides, UCM and PCBs with symbiont numbers after controlling shrimp size and spatial autocorrelation. Shrimps and their symbionts appear to be promising bioindicators of organic chemical pollution in Campeche Sound.

Animals↗

PubMed2005

Coordinated group response to nest intruders in social shrimp.

A key characteristic of highly social animals is collective group response to important stimuli such as invasion by enemies. The marine societies of social snapping shrimp share many convergences with terrestrial eusocial animals, including aggressive reaction to strangers, but no group actions have yet been observed in shrimp. Here we describe 'coordinated snapping', during which a sentinel shrimp reacts to danger by recruiting other colony members to snap in concert for several to tens of seconds. This distinctive behaviour is a specific response to intrusion by strange shrimp into the colony's sponge and is highly successful at repelling these intruders. Although coordinated snapping apparently functions analogously to alarm responses in other social animals, colony members in social shrimp do not rush to the site of the attack. Coordinated snapping appears instead to be a warning signal to would-be intruders that the sponge is occupied by a cooperative colony ready to defend it. This is the first evidence for coordinated communication in social shrimp and represents yet another remarkable convergence between social shrimp, insects and vertebrates.

Animal Communication↗

PubMed2006

Occurrence and recent long-distance dispersal of deep-sea hydrothermal vent shrimps.

Deep-sea hydrothermal vents and methane seeps are extreme environments that have a high concentration of hydrogen sulphide. However, abundant unique invertebrates including shrimps of the family Bresiliidae have been found in such environments. The bresiliid shrimps are believed to have radiated in the Miocene (less than 20 Myr); however, the period when and the mechanisms by which they dispersed across the hydrothermal vents and cold seeps in oceans worldwide have not been clarified. In the present study, we collected the deep-sea blind shrimp Alvinocaris longirostris from the hydrothermal vent site in the Okinawa Trough and carried out the first investigation of the 18S rRNA gene of a bresiliid shrimp. The phylogenetic analysis revealed that the bresiliid shrimp is situated at an intermediate lineage within the infraorder Caridea and shows monophyly with palaemonid shrimps, which live in shallow sea and freshwater. Furthermore, the mitochondrial cytochrome oxidase I (COI) gene sequences were analysed to determine the phylogenetic relationship with known bresiliid shrimps. A. longirostris of the Okinawa Trough had two haplotypes of the COI gene, one of which was identical to the Alvinocaris sp. of the cold seeps in Sagami Bay. These results indicate that a long-distance dispersal of A. longirostris occurred possibly within the last 100,000 years.

Animals↗

PubMed2000

Vision in hydrothermal vent shrimp.

Bresiliid shrimp from hydrothermal vents on the Mid-Atlantic Ridge have non-imaging eyes adapted for photodetection in light environments of very low intensity. Comparison of retinal structures between both vent shrimp and surface-dwelling shrimp with imaging eyes, and between juvenile and adult vent shrimp, suggests that vent shrimp have evolved from ancestors that lived in a light environment with bright cyclic lighting. Whether the vent shrimp live in swarms and have large dorsal eyes or live in sparse groupings and have large anterior eyes, the basic retinal adaptations are the same across species. Retinal adaptations in adult vent shrimp include the loss of dioptrics, enlargement of both the rhabdomeral segment of the photoreceptors and the light-sensitive rhabdomere therein, attenuation of the arhabdomeral segment of the photoreceptors, reduction of black screening pigment, development of a white diffusing layer behind the photoreceptors, and the loss of rhabdom turnover.

Adaptation, Physiological↗

PubMed1971

Microbial Flora of Pond-Reared Brown Shrimp (Penaeus aztecus).

Agar plate counts and microbial types are reported for brown shrimp reared in 2-acre natural marshland and in 0.5-acre artificial ponds during June to October 1970. Bacterial counts of pond-reared shrimp ranged from 5 x 10 to 5.5 x 10 per g. At final harvest in October, bacterial counts ranged from 2 x 10 to 5.5 x 10 per g. In marsh ponds, bacterial counts of shrimp and pond water were lowest in August when both water temperature and salinity were high. Coryneform bacteria and to a lesser extent Vibrio were the predominant isolates from fresh pond shrimp. Shrimp stored at 3 to 5 C for 7 days were acceptable as judged by appearance and odor. Between 7 and 14 days of refrigerated storage, bacterial counts increased sharply and about 50% of the samples became unacceptable. Refrigerated storage of pond shrimp caused increases in coryneform bacteria and micrococci and decreases in Vibrio, Flavobacterium, Moraxella, and Bacillus species. Pseudomonas species were not significant in fresh or stored pond shrimp. The microbial flora of pond water usually was dominated by coryneform bacteria, Flavobacterium, Moraxella, and Bacillus species.

Journal Article↗