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The killer shrimp Dikerogammarus villosus was recorded for the first time in Lithuanian waters in 2015. The species was detected in three sites in the Curonian Lagoon (on two buoys in the lagoon strait and the harbour, and one littoral sampling site) and in the mouth of the Šventoji River. The species presence in the buoy fouling suggests the involvement of shipping in species introduction. Most likely D. villosus has arrived to the Curonian Lagoon with commercial ships, while the invasion into the mouth of the Šventoji River may be associated with leisure shipping as the port situated therein is not currently functioning. Further northward expansion of the killer shrimp in the Baltic Sea basin seems very probable. As the species is highly aggressive, alterations of local macroinvertebrate assemblages can also be predicted.
Considering high nutritive value and sensory qualities, the products manufactured of marine invertebrates are a desirable component of human diet. These products enjoy an increasing demand in Poland. However, considerable accumulation of chlorine- organic pollutants in the tissues of marine animals may pose a threat for consumers. The study included determination of the content of PCB congeners (28, 52, 101, 118, 138, 153, and 180 according to IUPAC) in tinned and pickled seafood products purchased in Szczecin’s fishshops. In all examined products the analysed congeners were found, only in “Octopus in vegetable oil” PCB 138 was not detected. The highest content, 13.8 μg-kg_l m.m. (99.237 μg-kg’1 lipids), was recorded for PCB congener 153 in “Squid in American sauce”. The lowest residue levels were found for PCB 101 (0.002 to 0.07 μg-kg'1 m.m.). The highest percentage (from among analysed congeners) in majority of examined products was found for PCB 153 (to 95% in “Octopus in vegetable oil”) and PCB 180 (to 58% in “Pickled mussels”). The lowest percentage was stated for PCB congeners 101 (to 2.2% in “Shrimps natural”) and 52 (to 9.9% in “Greenland shrimps in brine”).
Wild caught shrimp can have a shortened shelf life compared to farm raised shrimp due to handling and on-ship limitations. The loss of freshness in shrimp is partly due to autolytic reactions caused by endogenous enzymes such as polyphenol oxidase. The objective of this study was to determine the effect of sulfi tes combined with Modified atmosphere packaging (MAP) on the shelf life of non-frozen shrimp. Fresh South Atlantic white shrimp were subjected to one of four treatments, no bisulfite rinse-air packaged, 1.25% bisulfite rinse-air packaged, 1.25% bisulfite rinse-MAP (60% CO2, 18% O2, 22% N2) and 1.25% bisulfite rinse-MAP (36% CO2, 64%N2). The quality and freshness of shrimp was measured by determining total aerobic bacterial populations, package gas headspace analysis, shrimp volatiles (GC-MS), meat pH, nucleotide degradation, and visual analysis. Fresh non-frozen shrimp treated with a combination of sulfites and MAP maintained the shelf life of fresh shrimp up to 10 days while shrimp in non-MAP without sulfite and non-MAP with sulfite developed black spots within 2 and 6 days, respectively. Both MAP treatments slowed bacterial growth while the MAP with high CO2 and with O2 was more effective in preventing off odors and nucleotide degeneration.
The high level of cadmium in the abdominal muscle of the brown shrimp Crangon crangon is due to the serious pollution of the water in the Gulf of Gdańsk. The inhibition of malic enzyme (ME) activity by cadmium, and in consequence the reduced formation of NADPH, could interfere with cellular mechanisms for detoxifying the organism and reducing oxidative stress. The reduced glutathione (GSH) concentration in the abdominal muscle of C. crangon was calculated to be 5.8 mM. The objective of this study was to evaluate the part played by GSH in the effect of cadmium on the activity of NADP-dependent malic enzyme from abdominal muscles of brown shrimps. This enzyme is activated by certain divalent cations (Mg, Mn). The results demonstrate that cadmium inhibits ME activity from shrimp muscle, and that GSH and albumin can reduce this cadmium-inhibited NADP-dependent malic enzyme activity.
Background. Luminous vibriosis caused by Vibrio harveyi, is a serious disease problem in shrimp aquaculture. The use of "green water", a technique that involves the stocking of tilapia, Oreochromis in the reservoir for the production of green microalgae, Chlorella is believed to help in the reduction of the incidence of luminous vibriosis. Though most shrimp farmers have been using Mozambique tilapia, Oreochromis mossambicus for the production of "green water", the mechanism involved in the efficiency of using this fish species in reducing luminous vibriosis remains unknown and is largely based on speculations. It was for this reason that the present experiment was conducted. The aim of the study was to determine the antibacterial activity of "green water" obtained from tank culture of Oreochromis mossambicus against Vibrio harveyi under laboratory conditions. Materials and Methods. "Green water" collected from broodstock and juvenile tanks of Oreochromis mossambicus as well as water from a commercial shrimp pond, and filtered boiled seawater were inoculated with Vibrio harveyi. Luminous bacteria were counted in nutrient agar, while presumptive and green colony-forming vibrios were determined on thiosulfate-citrate bile salt (TCBS). The experiment was carried out for one week. Results. Luminous bacteria were not detected, and the presumptive and the green colony-forming vibrios were generally lowest in "green water" obtained from the broodstock tank. Luminous bacteria in "green water" obtained from juvenile tank were not detected starting day 5, indicating delayed inhibition. Conclusion. The present findings show that "green water" from broodstock tank of O. mossambicus has the ability to inhibit luminous vibriosis over a one-week period, and that broodstock are a better source of "green water" than juveniles in controlling luminous vibriosis.
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Epibionts of ornamental freshwater shrimps bred in Taiwan. One of the major problems in breeding Neocaridina davidi in Taiwanese aquaculture ponds are epibionts found on the body of ornamental shrimp. These organisms affect shrimp wellbeing by causing distress which leads directly to shrimp weakness, loss of colour and even casualties. They can also be observed in imported shrimps which put in danger individuals bred in Europe, mostly characterised by high level of inbreeding and sensitivity to pathogens. Microscopic analyses indicated presence of 6 freshwater shrimp epibionts. Some of them showing parasitic lifestyle (Cladogonium ogishimae, Saprolegnia sp., Scutariella japonica), others (phyla Ciliophora and Rotifera) may indicate level of organic matter in water. To allow an effective treatment and control of the spread of parasites, all of their preferred locations on shrimp body observer in this study should be checked and become a vital part of diagnostic methods. Researches on ornamental freshwater shrimps’ epibionts are important to achieve success in shrimp breeding as well as to effectively monitor epibiont populations globally, especially that in some regions they may become potentially invasive organisms to the native crustaceans.
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