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Shan H.W.,Ocean University of China | Bao W.Y.,Yangzhou University | Ma S.,Ocean University of China | Wei D.P.,Ocean University of China | Gao L.,Liaoning Ocean and Fishery Science Institute
Aquaculture International | Year: 2015

The toxicity of nitrogen in the shrimp culture water has been well established. In this study, SA beads composed of Vibrio alginolyticus VZ5, sodium alginate (SA) and sugarcane bagasse were used for ammonia nitrogen (NH4-N) and nitrite nitrogen (NO2-N) removal. A 50-day cultivation experiment was carried out in aquaria to evaluate the activity of the SA beads in shrimp culture. The results indicate that SA beads have a maximum capacity of 1.06 × 108 colony-forming units (cfu)/bead. However, the optimal initial density of the bacteria embedded in the SA beads is 104–105 cfu/bead. The maximum NO2-N degradation rate achieved for the SA beads was 8.44 mg/L/day, and the average NO2-N degradation per bead was 0.06 mg. The addition of a carbon source accelerated the degradation of NH4-N and NO2-N by the SA beads. The NH4-N and NO2-N concentrations after treatment with SA beads were below 1.55 and 1.62 mg/L, respectively, at later time points, and these concentrations were significantly lower than in the group without any treatment (P < 0.05, df = 17). There were no significant differences in the NH4-N and NO2-N concentrations following treatments with SA beads and water exchange (P > 0.05, df = 29), and the yield resulting from water treatment with SA beads reached approximately 70 % of the yield with water exchange treatment. Moreover, the particulate organic carbon and dissolved organic carbon concentrations in the water were enhanced by the addition of SA beads. At later time points, some of the SA beads had broken down, and the sugarcane bagasse from the SA beads may have served as a carbon source for forming bioflocs. The new approach proved effective for NH4-N and NO2-N removal in shrimp culture. © 2015 Springer International Publishing Switzerland Source


Ma Z.,Dalian Fisheries Research Institute | Ma Z.,Ocean University of China | Song X.,Ocean University of China | Wan R.,Ocean University of China | And 2 more authors.
Aquaculture | Year: 2014

We used a backpropagation neural network (BP-NN) model to predict the water quality in intensive (300PLs/m2) Litopenaeus vannamei shrimp tanks. The model has a tan-sigmoid transfer function for the hidden layer and a linear transfer function for the output layer. It was developed using measured water quality data that were generated over 120days (from 1 July to 28 October 2008) with weekly monitoring in four different shrimp tanks. Nine parameters were selected as input variables: water temperature, pH, total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, dissolved inorganic phosphorus, chlorophyll-a, chemical oxygen demand, and five-day biochemical oxygen demand. The Levenberg-Marquardt algorithm was used to overcome the shortcomings of the traditional BP algorithm; that is, low computational power and getting stuck in local minima. The number of hidden layer nodes was optimized by a trial and error approach, and five optimal neuron nodes were identified. The computed results for water quality show good agreement with the experimental values. The correlation coefficients of the training, testing, and training+testing sets between computed results and experimental values are 0.990, 0.979, and 0.992 respectively. The simulation results reveal that the BP-NN model efficiently predicts the water quality in intensive shrimp tanks. © 2014. Source


Ma Z.,Ocean University of China | Song X.,Ocean University of China | Wan R.,Ocean University of China | Gao L.,Ocean University of China | Gao L.,Liaoning Ocean and Fishery Science Institute
Ecological Indicators | Year: 2013

A modified water quality index (WQI) was used to evaluate the water quality of intensive culture ponds of Litopenaeus vannamei. Multivariate statistical technique, principal component analysis (PCA), was applied to interpret the large complex water quality data set generated over a span of 120 days (from 1st July to 28th October, 2008) with weekly monitoring of 11 variables in four different shrimp ponds. The PCA revealed three, four, three, and three latent factors that accounted for 82.843%, 81.6%, 81.629%, and 84.801% of the total variance in the water quality data sets from each of the four shrimp ponds, respectively. The varifactors indicated that the variables responsible for water quality deterioration were mainly related to organic matter group (COD and BOD 5), natural condition group (pH and T), and nutrient group (TAN, Chl-a and DIP) in intensive shrimp ponds. A modified WQI based on the varifactors was applied to evaluate the water quality in shrimp culture ponds. The result revealed that the overall water quality in the shrimp ponds were mainly excellent during the early period and deteriorated in the mid to late period. The WQI evaluates water quality synthetically; furthermore, it reveals the outcome when some of the other variables deteriorate significantly. Thus, this study illustrates the necessity and usefulness of multivariate statistical techniques for interpreting large and complex data sets regarding water quality in shrimp culture pond. Furthermore, the evaluation results revealed that the modified WQI can be used as a tool for determining water quality. © 2012 Elsevier Ltd. All rights reserved. Source


Yang Q.,National Marine Environmental Monitoring Center | Yang Z.,National Marine Environmental Monitoring Center | Li H.,National Marine Environmental Monitoring Center | Li H.,Liaoning Ocean and Fishery Science Institute
Fish and Shellfish Immunology | Year: 2011

Inhibitor of NF-κB (IκB) is an important member of Rel/NF-κB signaling pathway, which is an important mediator of immune responses in innate immune system. In this study, the IκB cDNA of hard clam Meretrix meretrix (designated as Mm-IκB) was cloned and characterized. The full-length cDNA of Mm-IκB was of 2098 bp, containing a 5′ untranslated region (UTR) of 123 bp, a 3′ UTR of 810 bp with a poly (A) tail, and an open reading frame (ORF) of 1164 bp encoding a polypeptide of 387 amino acids. The high similarity of Mm-IκB with other IκBs from invertebrates indicated that Mm-IκB should be a member of IκB family. Similar to most IκBs, Mm-IκB possessed all conserved features critical for the fundamental structure and function of IκBs, such as five ankyrin repeats and a conserved degradation motif (DS 44RYSS 48). Two PEST domains and a phosphorylation site motif (S 367EEE 370) at the C-terminus of Mm-IκB were identified. By quantitative real-time RT-PCR analysis, mRNA level of Mm-IκB was found to be most abundantly expressed in the tissues of mantle, gill and hepatopancreas, weakly expressed in muscle, foot and haemocyte. The Mm-IκB gene expression was significantly up-regulated at 24 h in haemocyte and at 12 h in gill after Vibrio anguillarum challenge, respectively. The results suggested the involvement of Mm-IκB in response against bacterial infection and further highlighted its functional importance in the immune system of M. meretrix. © 2011 Elsevier Ltd. Source


Li H.-J.,Liaoning Ocean and Fishery Science Institute | Yang Q.,National Marine Environmental Monitoring Center | Gao X.-G.,Liaoning Ocean and Fishery Science Institute | Su H.,Liaoning Ocean and Fishery Science Institute | And 2 more authors.
Molecular Biology Reports | Year: 2012

LPS-induced TNF-α (LITAF) is a novel tran-scriptional factor that mediates the expression of inflammatory cytokines in LPS-induced processes. In the present study, the full-length cDNA encoding LITAF (designated as Mm-LITAF) was identified from Asiatic hard clam, Meretrix meretrix, by expressed sequence tag and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of Mm-LITAF was 1653 bp, consisting of a 5′ untranslated region (UTR) of 91 bp, a 3′UTR of 1166 bp with one cytokine RNA instability motif (ATTTA) and one polyadenylation signal (AATAAA), and an open reading frame (ORF) of 396 bp encoding a polypeptide of 131 amino acids with a theoretical isoelectric point of 7.49, and predicted molecular weight of 14.47 kDa. The deduced amino acid of Mm-LITAF shared 29-63% similarity with the LITAFs from other species, indicating that Mm-LITAF should be a member of the LITAF family. Two highly conserved CXXC motifs forming a compact Zn 2+-binding structure were also identified in Mm-LITAF. A quantitative reverse transcriptase real-time PCR (qRT-PCR) assay was developed to assess the expression of Mm-LITAF mRNA in different tissues, and the temporal expression of Mm-LITAF in clams challenged with Vibrio anguillarum. The mRNA transcript of Mm-LITAF could be detected in all the examined tissues with the highest expression level in the gill. Mm-LITAF expression was up-regulated significantly at 16 h in the gill and at 8 h in haemocytes after bacterial challenge, respectively. These results suggest that the Mm-LITAF is a constitutive and inducible acute-phase protein that perhaps involved in the innate immune response of hard clam. © 2011 Springer Science+Business Media B.V. Source

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