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Shrimp Culture (shrimp + culture)
Selected AbstractsAcute and Chronic Effects of Nitrite on White Shrimp, Litopenaeus vannamei, Cultured in Low-Salinity Brackish WaterJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2004Amit Gross The marine white shrimp Litopenaeus vannamei is widely cultured. Recently, farmers have begun to culture this shrimp in low-salinity brackish water (< 6 g/L). The intensification of shrimp culture often results in occurrences of elevated nitrite concentration during the growing season. Nitrite is toxic to shrimp and exposure to high concentrations may cause retarded growth and mortalities. The current study was aimed at investigating the acute and chronic toxicity of nitrite to L. vannamei grown in low-salinity (2 g/L) brackish water. Studies of the 96-h EC50 and LC50 values of nitrite were performed to determine the acute toxicity, and an aquarium growth study (2 d post exposure to elevated nitrite concentrations) was conducted to evaluate the chronic effects of nitrite on shrimp production. The 96-h EC50 and LC50 values for juvenile L. vannamei grown in water of 2 g/L salinity was about 9 mg/L NO2 -N, suggesting a safe concentration for shrimp production in ponds to be less than 0.45 mgIL NO2 -N. Exposing shrimp to nitrite concentration of 4 mg/L for 2 d reduced their growth but did not affect their survival. [source] Effect of practical diets with different protein levels on the performance of Farfantepenaeus paulensis juveniles nursed in a zero exchange suspended microbial flocs intensive systemAQUACULTURE NUTRITION, Issue 2 2010E.L.C. BALLESTER Abstract Farfantepenaeus paulensis juveniles (72 ± 24 mg), were reared in a suspended microbial flocs system and fed practical diets containing increasing amounts of crude protein (250, 300, 350, 400 and 450 g kg,1 CP). Development of microbial flocs was promoted by high aeration rates and fertilization with wheat bran and molasses. Flocs were composed of detritus in the form of flocculated matter colonized by heterotrophic bacteria, cocoid and filamentous cyanobacteria, flagellate and ciliate protozoa and rotifers. Proximate composition analysis of the suspended microbial floc showed CP levels of 304 g kg,1. After 45 days, mean shrimp survival were above 89%, with no significant differences between treatments. Shrimp fed diets with 350 g kg,1 or higher CP content achieved significant higher (P < 0.05) final weight (0.66,0.68 g), weight gain (0.58,0.61 g) and instantaneous growth rate (0.049,0.050), with feed conversion rates (2.17,2.30) significantly lower (P < 0.05). Results show that, when rearing is carried out in a suspended microbial flocs system, dietary CP levels can be kept at 350 g kg,1. Furthermore, results confirm that microbial-based systems allow shrimp culture without compromising the surrounding environment and shows the possible reduction of production costs and fish meal dependence. [source] Dietary protein level and natural food management in the culture of blue (Litopenaeus stylirostris) and white shrimp (Litopenaeus vannamei) in microcosmsAQUACULTURE NUTRITION, Issue 3 2003L.R. Martinez-Cordova Abstract The effect of dietary protein level and natural food management on the production parameters of blue and white shrimp, as well as on water quality, was evaluated in a microcosms system (plastic pools simulating aquaculture ponds). Two experimental trials were carried out in the facilities of DICTUS, University of Sonora, Northwest México. Treatment with low protein diet (LP) consisted of a low protein input (diet with 250 g kg,1 crude protein) through the culture period; treatment with high protein diet (HP) consisted of a high protein input (diet with 400 g kg,1 crude protein) through the trial, and finally treatment VP consisted of an adjustment of protein input (diets with 250, 350 or 400 g kg,1 crude protein), depending on the abundance of biota (zooplankton and benthos) in the system. Each species responded differently to the treatments. For blue shrimp, low protein input resulted in the lowest final body weight (12.9 ± 0.6 g) and biomass (696.0 g pool,1). Survival and feed conversion ratio were similar in the three treatments. For white shrimp, the best growth, biomass and food conversion ratio were obtained in the low protein input treatment. Water quality parameters such as nitrate, ammonia and organic matter during the two trials, were better for LP and VP treatments. White shrimp seems to have lower protein requirements than blue shrimp. For the blue shrimp culture, adjusting protein input according to natural food abundance (zooplankton and benthos) in the system, seems to be advantageous because of the possibility of getting a production similar to that obtained with a high protein input through the farming period, but at lower feed cost, and with a lower environmental impact. It is concluded that a high protein input through the whole farming period is not the best feeding strategy for any of the two species. [source] Feasibility of pacific white shrimp Litopenaeus vannamei culture in southern Brazil: effects of stocking density and a single or a double CROP management strategy in earthen pondsAQUACULTURE RESEARCH, Issue 2 2010Dariano Krummenauer Abstract Marine shrimp culture at southern Brazil is restricted to the warmer season (November to April). Therefore, farmers must consider culture strategies and competition with shrimp landings from artisanal fishery. The fishing season starts every 1 February; in order to obtain higher prices, farmers may consider shrimp culture in two crops, with a first harvest before the start of the fishing season, and a second harvest after the end of the landings. The present study evaluated the performance and feasibility of Litopenaeus vannamei reared at 10, 25 and 40 shrimp m,2 either in two short consecutive culture cycles or one longer cycle (LC). The experimental design consisted of two sets of nine pens installed in a 3.8 ha earthen pond. In one set of pens, shrimp were harvested after 75 days and pens were restocked for another 75-day-long rearing period. In the second set of pens, shrimp were cultured for 150 days. Shrimp survival and final weight ranged from 79% to 91% and 6.67 to 14.53 g respectively. Feasibility analysis pointed towards culture at higher densities (25 and 40 shrimp m,2) in a LC as productivity (2274,4227 kg ha,1) and shrimp final weight (13.05,13.21 g) resulted in higher profitability (US$7761,12 379). [source] Growth performance, survival and maturation of Litopenaeus vannamei (Boone) in an inland CRS with no water repositionAQUACULTURE RESEARCH, Issue 12 2009Abundio González-González Abstract Closed recirculation systems (CRS) present an alternative for providing organisms to the aquaculture. A CRS with zero water exchange was used in the present study; the CRS consisted of a culture and maturation facility, biofilter system and reservoirs tanks. During two consecutive trials, the CRS efficiency was evaluated by assessing the growth, survival and maturation of juveniles into adults Litopenaeus vannamei (Boone). Throughout the study, water quality parameters (temperature, pH, salinity, NH3, NO2 and NO3) and ion concentration were monitored. Most parameters showed fluctuations without significant differences. However, a decrease in pH was observed during the maturation phase, and an increase in phosphorus was detected, in both the trials, compared with that in initial seawater. Growth and survival for juvenile and pre-adult shrimps presented similar variations without significant differences. Female gonadal maturation and spawning rate were not significantly different between trials. Unfortunately, shrimp eggs underwent lysis 6 h after spawning. These results show that the growth, survival and maturation obtained under CRS conditions are reproducible, and suggest the possibility of using these systems for biosecure shrimp culture, protected against eventual diseases outbreaks. The results of this study also suggest the importance of future studies addressing ion concentration changes in a CRS with zero water exchange. [source] Histological alterations in the hepatopancreas of Penaeus monodon Fabricius (1798) given aflatoxin B1 -incorporated dietsAQUACULTURE RESEARCH, Issue 11 2009Radhika Gopinath Abstract Aflatoxin is a toxic contaminant produced by toxigenic fungi of the genus Aspergillus during the processing and storage of feeds and feed ingredients. Aflatoxins can cause abnormalities such as poor growth, physiological imbalances and histological changes that result in a reduction in the yield and profitability of shrimp culture. Histological changes in Penaeus monodon sub-adults fed different doses of aflatoxin B1 were studied. The doses of aflatoxin B1 administered in the diets were 50, 100, 150, 500, 1000 and 2000 ppb. At the end of the fourth and the eighth weeks of the experiment, the shrimps were sampled and the cephalothorax was observed for histological changes. Significant changes were observed in the different treatment groups at the fourth and eighth weeks. The severity of pathological changes was proportional to the increase in the concentration of aflatoxin fed to the shrimps. Histological changes in the hepatopancreas were loss of structure of the cells and tubules, nodule formation, cell elongation, desquamation, rounding of cells, fibrosis, necrosis, haemocytic infiltration and cellular inflammation. [source] Experimental evaluation of co-culture of juvenile sea cucumbers, Holothuria scabra (Jaeger), with juvenile blue shrimp, Litopenaeus stylirostris (Stimpson)AQUACULTURE RESEARCH, Issue 5 2006Steven W Purcell Abstract The co-culture of juvenile sea cucumber Holothuria scabra (Jaeger), or ,sandfish', with juvenile blue shrimp Litopenaeus stylirostris (Stimpson) was tested by growing groups in co-culture and monoculture for 3 weeks in tanks with enriched sand substratum. Feed was supplied on trays, accessible only to shrimp. Survival of shrimp and sandfish was high in all treatments (73,100%). Growth of shrimp did not differ between monoculture and co-culture, but sandfish grew significantly slower in co-culture (P=0.03), although their sand burying and surface foraging were apparently unaffected by shrimp (P=0.76). However, shrimp increased the levels of total ammonia-N in tanks, which related inversely with sandfish growth (P=0.04). Conversely, sandfish did not appear to lower the water quality for shrimp culture. While sandfish bioturbate sediments and eat organic deposits, the juveniles did not significantly reduce the organic content of sand in tanks. Co-culturing juveniles of the two species in earthen ponds appears feasible, with no detriment to shrimp production, presenting a cost-effective method for growing sandfish to larger sizes for restocking. These findings underpin further studies to test the viability of commercial co-culture of sandfish with blue shrimp at later stages in the production cycle of shrimp. [source] Carbon and nitrogen dynamics in zero-water exchange shrimp culture as indicated by stable isotope tracersAQUACULTURE RESEARCH, Issue 11 2002M A Epp Abstract The uptake and assimilation of nitrogen and carbon by shrimp were measured in 1200 L mesocosms using stable isotope enrichments. Labels were added via 15N-, 13C-glycine and amino acid mixtures in feeds or as 15NH4+ to pond water. Label was incorporated into shrimp via algal growth indicating that up to 31% of nitrogen requirements were derived from pond ecosystem dynamics. This value is low in comparison with other shrimp aquaculture isotopic tracer studies but is probably due to differences in shrimp-rearing conditions. Direct incorporation of the enriched feed label was low in shrimp muscle tissue (3.3% for 13C-glycine, 5.9% for 15N-glycine and 7.8% for 15N-amino acid mixture). Mass balance calculations indicate the remaining shrimp biomass was derived from feed, but loss of label into solution during feeding led to underestimation based on tracers. Incorporation of isotopic labels into feed as large molecular weight proteinaceous or microencapsulated/fat-coated compounds is recommended to prevent dissolution and loss. [source] A dual infection by infectious cuticular epithelial necrosis virus and a Chlamydia -like organism in cultured Litopenaeus vannamei (Boone) in EcuadorAQUACULTURE RESEARCH, Issue 11 2001R Jimenez During 1996, microscopic examinations of post larvae and juveniles of moribund Litopenaeus vannamei showed multifocal necrosis in the cuticular epithelial tissues. In addition to these severe degenerative alterations in the epithelial cells typical of infectious cuticular epithelial necrosis virus (ICENV), columnar cells of the epithelium displayed small round intracytoplasmic inclusions in the necrotic tissue. Examination by electron microscopy of affected tissues demonstrated prokaryotic organisms in the cytoplasm of epithelial cells delineated by a distinct cytoplasmic vesicle; the prokaryotic organisms were morphologically similar to the genus Chlamydia. The necrotic tissue also showed the presence of particles of ICENV; the double infection by two different organisms in cuticular epithelial cells has not been reported previously. Two distinct stages in the intracellular development of a Chlamydia -like organism were recognized: (1) pleomorphic elementary bodies (EBs) that were spherical to oval were often observed in the process of division or in forming a common chain of three cells, the cells were surrounded by a rigid cell envelope and the presence of a cap or plaque hexagonally arrayed; (2) the reticular bodies (RBs) were forms often in the process of division. These cells had an electron-dense cytoplasm and contained a loose network of nuclear fibrils and a more fragile cell envelope. Regardless of the development stages of the Chlamydia -like organism within the cytoplasmic vesicles, ICENV particles were observed, either dispersed or in clusters, surrounded or inside the vesicles. The potential adverse impact of this dual infection on shrimp culture should be considered, especially in high-density operations. [source] | ||||||||||