Abstract:There are huge growth differences in Chinese mitten crab (Eriocheir sinensis) resulting from different culture environments. In order to study the influence of environmental conditions on growth of larval crab, and to understand the temporal and spatial changes of gene expression and their interaction with environments, the growth and gene expression characteristics were investigated for megalopas and larval crab employing full-sib individuals from one family reared in outdoor ponds and indoor closet. Expression profiles of five molting-related genes using quantitative real-time PCR (qRT-PCR) technology were investigated, including crustacean hyperglycemic hormone (CHH); molt-inhibiting hormone (MIH); ecdysteroid receptor (EcR); retinoid X receptor (RXR) and gonad-inhibiting hormone (GIH). The results indicated that the average weight of larval crabs reared in outdoor pond was significantly higher than that of crab reared in indoor closet (P<0.05) . The environmental conditions had no significant influence on the expression of MIH and RXR genes, but gave rise to significant influence on CHH, EcR and GIH genes (P<0.01) . There was significant expression difference between all the five genes (RXR, CHH, EcR, GIH and RXR) among different stages of larval crab. Meanwhile, significant interaction effects (P<0.01) between rearing environments and development stages were found in the four genes (RXR, CHH, EcR and GIH) with the exception of the MIH gene (P>0.05). Furthermore, the positive co-expression was detected for the MIH, GIH, CHH genes, but negative expression was found between the RXR and GIH genes, which regulate molting and growth in crab.

Abstract:The effects of the different dietary carbohydrates and different carbohydrate levels on GH /IGF-Ⅰ gene expression, body composition and amino acid composition were studied in juvenile mirror carp (Cyprinus carpio). 420 Songpu mirror carp (mean weight=8.30±0.15g) were randomly divided into 4 dietary treatments triplicate groups and 35 fish per triplicate. The fish in 4 groups were fed two carbohydrates (starch and glucose) diets with two levels (250 g/kg and 500 g/kg) (LS/HS/LG/HG) and were reared for 60 days. Results showed that the GH mRNA expression levels of HS and LS groups were significantly lower than that of LG group (P<0.05). The IGF-Ⅰ mRNA expression level of HG group was significantly lower than that of LS and LG groups (P<0.05). The crude protein was not significantly different among groups (P>0.05). The moisture of HS group was significantly lower than that of the other groups (P>0.05). The crude fat of HS group was significantly higher than that of the other groups (P>0.05). The body amino acid composition results showed that Leu and Cys contents of HS group were significantly lower than those of LG group (P<0.05). Ala content of HS group was significantly lower than that of LS and LG groups (P<0.05). The other amino acids contents were not significantly different among groups (P>0.05). The total essential amino acids, semi-essential amino acid, total non-essential amino acids and total amino acids had no significant difference mong groups (P>0.05). In conclusion, high dietary starch could inhibit the expression of GH and IGF-Ⅰ genes, increase body crude fat content and decrease some amino acids contents.

Abstract:The triangle pearl mussel, Hyriopsis cumingii, has uninominal special life cycle, and the glochidia need to undergo a short parasitic life and intake of adequate nutrition from the host fish to ensure that they could complete juvenile metamorphosis. The hydrostatic breathing room method was applied to study effects of infection stress by glochidia of triangle pearl mussel on oxygen consumption rate and ammonia excretion rate in yellow catfish Pelteobagrus fulvidraco, then the survival rate and the appropriate number of glochidia parasitized were analyzed. The results showed survival rate in experimental groups of Pelteobagrus fulvidraco were 100%, 93.3% and 50.0% after the glochidia falling completely; and there was no significant difference in the oxygen consumption rate of the host fish infected by glochidia (P>0.05); the ammonia excretion rate was significantly increased and O/N ratio decreased (P<0.05),and, there was a positive correlation between the quantity of glochidia and ammonia excretion rate, and positive with the mortality of host fish. So it could be concluded that: after being parasitized by the glochidia, a large number of cysts were induced to affect the respiratory system of host fish, thus hindering its use of oxygen.

Abstract:In order to study the effects of biofloc on water quality and metabolic functions of microbial community in zero-water exchange tanks, glucose was used as carbon source, and water quality and carbon metabolic diversity of microbial community were investigated based on Biolog-ECO plates. The results showed that: mature biofloc reduced effectively the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen (P<0.05) and meanwhile significantly improved the content of total suspended solids (TSS). Average well color development (AWCD) reached stationary phase after 108h cultivation in control and floc treatments, and the floc treatment was 18% higher than that in control group. The utilization of polymers and carbohydrates in biofloc tanks were improved. Meanwhile, the diversity indexes (Shannon index, richness index) of the biofloc tanks were higher than those of control group (P<0.05). The principal component analysis of microbial metabolic characteristics in two treatments showed that principal components 1 (PC1) accounted for 66.9%, and principal components 2 (PC2) accounted for 12.4% respectively. Significant differences in carbon metabolic characteristics of microbial community in the culture water were found between floc treatment and control group. Thus, biofloc technology effectively reduces the nitrogen content, and improves the metabolic activity of microbial community, and also influences the function of microbial community in the culture water.

Abstract:The effect of water hyacinth planting on the microbial community in water of a tilapia cultural pond was investigated with the method of high throughput sequencing. The differences of microbial communities' structure, of bacterial communities' diversity, and of bacterial communities 'richness between the water hyacinth planting area and the open water area were analyzed. And the relationships between some of the environmental parameters and community diversity and richness of planktonic bacteria were analyzed to state some possible mechanism of the effect. The results are as follows: (1) The phyla of Cyanobacteria, Actinobacteria and Proteobacteria were the dominant bacteria in pond water. (2) The planting of water hyacinth reduced the abundance of Cyanobacteria, and the diversity and richness of whole bacterial community in the vicinity of the floating beds, at the same time, increased the abundance of the other important phyla except the Cyanobacteria phylum in the same locations. (3) The concentrations of chlorophyll a and nitrite were negatively correlated with the diversity and richness of microbial community. It might mainly be caused by the planting of water hyacinth.

Abstract:To explore the influence of crab ecological farming on ponds metazoan zooplankton community, crab ponds zooplankton and water source (including Rotifera, Cladocera and Copepoda) of Shanghai Songjiang Maogang district were acquired from April to October at 2013. Zooplankton species composition, biological density, biomass and biodiversity was analyzed. Total of 59 kinds of metazoan zooplankton was detected, including 14 dominant species. The dominant species of Rotifera were Brachionus calyciflorus, Keratella cochlearis, Anuraeopsis fissa, Trichocerca pusill, Polyarthra trigla and Filinia major. The Cladocera dominant species were Diaphanosoma leuchtenbergianum, Diaphanosoma brachyurun, Daphnia pulex, Bosmina longirostris and Chydorus sphaericus. The dominant species of Copepoda were Eucyclops serrulatus, Microcyclops varicans and Mesocyclops leuckarti. The average pond Rotifera biological density was 562.78 ind/L, the average biomass was 0.37 mg/L, the range of Shannon-Wiener diversity index was 1.97-2.36. The average Rotifera biomass density of water source was 388.69 ind/L, the average biomass was 0.25 mg/L, the range of Shannon-Wiener diversity index changes from 1.56 to 2.20. Cladocera average biomass density of ponds was 70.59 ind/L, the average biomass was 4.56 mg/L, the range of Shannon-Wiener diversity index was 1.34 to 2.18. Cladocera average biomass density of water source was 37.92 ind/L, the average biomass was 2.37 mg/L, the range of Shannon-Wiener diversity index was 1.11 to 1.97. Copepoda average biomass density of ponds was 275.00 ind/L, the average biomass was 10.48 mg/L, the range of Shannon-Wiener diversity index changes from 1.25 to 2.26. Copepoda average biomass density of water source was 155.07 ind/L, the average biomass was 7.30 mg/L, the range of Shannon-Wiener diversity index changes from 1.25 to 2.11. In summary, the crab pond zooplankton species, biological density, biomass and biodiversity were higher than the source of water, with the stable community.

Abstract:Phytoplankton abundance and community structure were investigated and analyzed from January, April to December 2011 in Qingcaosha Reservoir, an important water source in Shanghai, China. Total 8 phyla, 99 genera, 223 taxa of phytoplankton were identified. The phytoplankton abundance ranged from 86.37×10⁴-2594.63×10⁴ cell/L. Cyclotella sp., Anabaena circinalis, Chroococcus minutus, Dactylococcopsis rhaphidioides, Chlamydomonas globosa and Cryptomonas erosa dominated throughout the year. Some species in salt and brackish water appeared occasionally. Cyanobacteria abundance dominated throughout the year, and dominant genera succeed from Chroococcus spp. and Dactylococcopsis spp. in spring, Microcystis spp. in summer, to Anabaena circinalis and Lyngbya spp. in autumn. Canonical Correspondence Analysis (CCA) indicated that water temperature, suspended solid and grazing effect of zooplankton could be the main factors shaping the phytoplankton community in the Qingcaosha Reservoir.

Abstract:Chlorophyll a of eight sampling sites from Jiuduansha Wetland was investigated from 2010 to 2011, and spatial and temporal pattern of primary productivity calculated based on chlorophyll a was also analyzed in the present study. Highest concentration of chlorophyll a was detected in spring with the mean of 5.90 mg/m³, and appeared in tidal creek between Shangsha and Zhongsha. Chlorophyll a in autumn 5.03 mg/m³ was lower than that in spring, however, spatial difference was low. Chlorophyll a was very low in other seasons. Primary productivity in Jiuduansha Wetland was in the range of 87.75 -744.79 mgC/(m²·d), and the highest value appeared in the Xiasha and the lowest in Jiangyanansha. Chlorophyll a and primary productivity in Jiuduansha were not high compared with those values in other waters, which might be closely related to the high content of suspended solids in Yangtze River estuary. Moreover, significant correlation between chlorophyll a and primary productivity and TP indicated that Jiuduansha wetland might be phosphorus-limited waters.

Abstract:Based on the samples collected from the four cruises carried out in November 2012, February, May and August 2013, the species composition, abundance and distribution of zooplankton along the coast of Chang Island in the Bohai Sea were studied. The results showed that a total of 38 species (genera) of zooplankton were identified. There were 26 and 23 zooplankton species (genera) in summer and autumn, respectively, which were significantly higher than those in spring and winter. Variations in the dominant zooplankton species composition occurred obviously between different seasons. The dominant species were Centropages mcmurrichi and Calanus sinicus in spring, but replaced completely by Sagitta crassa, Ophiopluteus larva and Mysidaeea larva in summer. Sagitta crassa was the only dominant species in autumn. In addition to Sagitta crassa, Centropages mcmurrichi and Calanus sinicus dominated the zooplankton community in winter. The abundance of zooplankton varied significantly between different seasons. The average abundance of zooplankton was 1 952.74 ind/m³ in spring, which was significantly higher than those in other seasons. And the average abundance of zooplankton was 352.51 ind/m³, 87.38 ind/m³ and 79.95 ind/m³ in summer, autumn and winter, respectively. The Shannon-Wiener index (H) ranged from 0.222 to 2.766 during the sampling period and the average H value was 1.190. Pielou evenness index (J) varied from 0.121 to 0.940 with an average of 0.444 during the study period. The most important environmental factors influencing the changes of zooplankton species composition, abundance and distribution were water temperature, salinity, phytoplankton abundance and hydrological conditions along the Coast of Chang Island in the Bohai Sea.

Abstract:The article explained that inhibitory components from Myriophyllum spicatum with the ultrasonic-cellulase method and water extraction method caused inhibition of M.aeruginosa. Based on one-way and orthogonal test, and regarding growth inhibition rate of extraction on M. aeruginosa as index of evaluation, an optimal extraction process of Myriophyllum spicatum was obtained as follows: enzymatic hydrolysis time was 4 h, pH was 3.0, optimal temperature was 30 ℃, cellulase dosage(mass of cellulase to Myriophyllum spicatum powder) was 21%, ultrasonic power was 120 W and ultrasonic time was 1h. The inhibition rate of extraction obtained with water extraction method and ultrasonic-cellulase method indicated that the latter showed better effect and had obvious difference with the water extraction (P<0.05). With the increasing of reaction time, the growth inhibition rate of the ultrasonic-cellulase extraction on M. aeruginosa continued to decrease, which was 271.74% at concentration of 40 g/L and reaction time for 24 h and the inhibition rate was more than 20% by the reaction time for 13d with the obvious difference with the other concentration groups (P<0.05).

Abstract:Through fitting the Acoustic Doppler Current Profiler (ADCP) backscatter intensity data obtained by field survey and suspended sediment concentration in Jiangsu Yellow Sea in August and December 2012,we learned that the correlation coefficient was 0.8 or more, the inversion results were ideal. Combined with the simultaneous observation of the hydrological data such as temperature, salinity, we studied vertical distribution of suspended sediment transport characteristics, formative causes of two seasons of summer and winter in the region. The results show that Jiangsu typical seasonal variation of suspended sediment distribution in nearshore waters was obvious, and suspended sediment concentration was generally higher in winter than in summer. The distribution and transportation of suspended sediment were affected by Subei coastal water, western Yellow Sea coastal currents, Yangtze diluted water, Yellow Sea warm current, Yellow Sea cold water mass and other factors, in which seasonal variation of western Yellow Sea coastal currents were its main influence factors. Subei coastal water carrying the resuspended sediment in Yellow River estuary and nearshore suspended sediment spread to the south-east coast, and the transportation amount and diffusion range is larger in winter than in summer. Warm currents of Yellow Sea prevented suspended sediment from outward diffusion, which was captured in nearshore. Northeasterly direction deflection of Yangtze diluted water caused the distribution stratification phenomenon of suspended sediment in southern Subei in summer.

Abstract:An infectious disease outbreak in Penaeus vannamei Boone(Litopenaeus vannamei) occurred in Guangdong Province in 2012. For the diagnosis, and effective prevention and control of this disease, the pathogen was isolated and characterized via molecular biology. One isolate of Aeromonas caviae (ZHBX12016) was isolated. This strain could induce symptoms of natural disease in Penaeus vannamei and resulted in 95% mortality in 5 days by immersion infection, and with LD₅₀ of 6.43×103 cfu/mL via muscle injection. The isolate was Gram-nagative straight rod. Biochemical characterization of Galactose, Sucrose, Mannitol, Glucose, Arginine dihydrolase, Lysine decarboxylase and gluconate showed that the isolate was similar to Aeromonas caviae isolated from other aquatic animals. The 16S rDNA gene was amplified by polymerase chain reaction (PCR) and sequencing. Analysis of 16S rRNA gene showed that the isolate shared 97.7%-100% identity with A. caviae. The phylogenitic tree derived from 16S rDNA gene of Aeromonas showed that the isolate and A. caviae clustered into the same branch. Based on morphological, biochemical and physiological responses, pathogenicity and 16S rRNA gene analysis, the isolate was identified as A. caviae. The antibiotic sensitivity test showed that the strain ZHBX12016 was hypersensitive to chloramphenicol, terramycin, amikacin and furazolidone.

Abstract:In this study, the pharmacodynamics (PK) of thiamphenicol on pathogenic Aeromonas hydrophila strain (AH10) and the pharmacokinetic (PD) parameters of thiamphenicol in crucian carp(Carassius auratus)were investigated by high-performance liquid chromatography (HPLC) system, which were used to draw reasonable medication regimen to control disease and prevent drug resistant bacteria. The in vitro pharmacodynamic results showed that the minimal inhibitory concentrations(MIC) of thiamphenicol on AH10 was 1.0 μg/mL, and the minimal bactericidal concentrations (MBC) was 2.0 μg/mL; the mutant prevention concentration (MPC) was 8.0 μg/mL (8MIC); the mutant selection window (MSW) of thiamphenicol on the pathogenic bacterial strains was 1.0-8.0 μg/mL. The time of thiamphenicol concentration in serum of crucian carp above MPC was 3h at the dosage of 20 mg/kg; 8h at the dosage of 30 mg/kg, 22 h at the dosage of 40 mg/kg, respectively;AUC₂₄(Area under the drug concentration-time curve)/MIC and C_max(Maximum concentration in the interval)/MIC of thiamphenicol in serum were 89.539 and 14.92 at the dosage of 20 mg/kg, respectively; 174.560 and 17.69 at the dosage of 30 mg/kg, respectively; 251.682 and 24.22 at the dosage of 40 mg/kg, respectively. Considering the drug remained in the plasma with a concentration above MPC for 24 h and AUC₂₄/MIC>125 or C_max/MIC>10, it is suggested that hemorrhagic septicemia can be controlled using a dosing regimen of 40 mg/kg thiamphenicol, at intervals of 24 h. The proposed withdrawal time in crucian carp should not be less than 15 d at the water temperature of (22±1)℃.

Abstract:Yellowfin tuna (Thunnus albacares) is the main target species for Chinese tuna fisheries fleets in Indian Ocean. According to a total of 1233 yellowfin tuna samples collected by Chinese national observers in the central-western Indian Ocean during two stages (Oct. 2012-Jan. 2013 and Oct. 2013-Feb. 2014),we conducted the study on the reproductive biology of this tuna. The main reproductive biological parameters were estimated in this study. The results indicated: (1)The relationship between fork length and dressed weight for female and male were W=7×10^-6L^3.244 and W=6×10^-6L^3.197, respectively. (2) From these samples, the total sex ratio of female to male was 0.74:1, and the sex ratio was 0.69:1 in such mature samples. (3) The gonadsomatic index for female and male were calculated from 0.39 to 5.92, and from 0.44 to 3.37, respectively.(4) The logistic regression was described the relationships between fork length and maturity for both female and male which were P=1/[1+e^{0.08276×(122.991-FLm)}] and P=1/[1+e^{0.03767×(118.618-FLm)}], respectively. (5)The maturity analysis showed that the percentages of female and male samples which reached mature were highest in January and December, respectively. And the lowest percentages of both female and male were in February. (6) The cut-off point for larger and smaller groups was 115 cm,and the percentage of larger female and male were 63.13% and 75.40%,respectively, which was significantly different between male and female. This study will contribute to the evaluation for this fish resources.

Abstract:Pacific saury Cololabis saira is one of main fishing targets in the temperate waters of the northern Northwest Pacific Ocean, and fishing lamp lighting configuration is an important content of efficient fishing technology for saury fishery. Through the imitating experiment of the optical properties of lamp boxes, the paper established the illuminate distribution models of saury aggregation lights using Matlab7.0 software and analyzed the light illumination effects of fish aggregation lamp boxes under different inclination scenarios. The results show that, when the angle of fish aggregation lamp boxes was 30°, 45°, and 60°, the ground illumination of saury aggregation lamp boxes decreases with the increasing of ground distance, and there were significant differences between ground illumination distribution at different inclinations, and the attenuation degree of illumination distribution also decreased with the increasing of light box angle. Significant difference on fluctuation of light field can be found between the illuminations at different inclinations. The fluctuation of light field for the illumination at 30° inclination was remarkable compared with those at 45° and 60° inclinations. The density of illumination isoline decreases as the increasing of inclination angles. When the angle of fish aggregation lamp box was 60°, the distribution of illumination and the fluctuation of light fields were relatively stable, and the larger area conducive to aggregating saury can be found.

Abstract:To verify catch performance of LED fish-attracting lamp in actual scene,contrast test was made. We equipped LED lamps(300W rated power each) on squid jigging vessel of Ningtai 61 and also sent another squid jigging vessel of Ningtai 62 equipped with Metal Halide Lamps(MHL) as contrast. Both vessels fished in southeast pacific ocean off the coast of Peru at same time.We recorded the yield and fuel every day, meanwhile we tested illumination and spectrum around ship. After comprehensiveness analysis, we reached the conclusion:the equal illumination curve of 0.1 Lx of LED lamps could reach 35 m in vertical direction, 10 m distance less compared with MHL;In vertical direction, illumination distribution of LED is analogous to MHL.LED spectrum distribution power attenuation rate underwater was less than MHL.LED fish lamp becomes really adequate, not just reducing fuel consumption but also having same catch performance compared with MHL light in the process of fishing. LED fish-attacting lamp can be a new light source for replacing traditional fish lamp.

Abstract:Microcapsules of tilapia oil was prepared by using spray-drying method in this study. The microencapsulation rate was chosen as the evaluation index, six variables, such as the proportion of two kinds of starch, oil content, homogeneous times, homogeneous pressure, inlet-air temperature, and inlet feed rate were optimized. The differences of oxidation stabilities between fish oil microcapsules and refined fish oil (added vitamin E, sesamol and TBHQ, respectively) were studied. The results showed that the optimal technological conditions of microencapsulation of tilapia oil were obtained as follows: 2:3 (w/w) for the rate of octenyl succinic acid modified starch Mira CAP to the octenyl succinic acid modified starch Mira mist SE; 30% for the oil content; 3 times for the homogenization under 25 MPa of the homogenization pressure; 170 ℃ for the temperature of inlet-air and 10mL/min for the inlet feed rate, the microencapsulation efficiency of tilapia oil microcapsules reached up to 95.9%±0.73%. The sensory evaluation and physicochemical indexes (Moisture content: 1.93%, Surface oil content: 0.59%, POV: 2.10 mmol/kg) of microencapsulation products met the requirements of fish oil microcapsule standard of the aquatic product industry of China SC/T 3505-2006. By scanning electron microscope, the micro-structure observation of the microcapsules of Tilapia oil showed that they had smooth surface, no cracks. The results of the oxidative stability showed that the microcapsules of fish oil had the best oxidative stability. After storage at (65±1) ℃ for 12 days, the peroxide value of microcapsules of fish oil was only 5.22 mmol/kg, which was lower than the industrial standard (6 mmol/kg), and TBA was also significantly lower than the refined fish oil. It was estimated that this kind of product could keep good quality for more than 1 year at ambient temperature. Among the fish oils added different antioxidants, the fish oil with TBHQ showed the best oxidation stability, it can keep good quality for 8 months.

Abstract:In order to understand whether the total number of bacteria and yeasts in Tibetan kefir grains was subjected to change by using qPCR method, their genomic DNAs were prepared successfully by adding lysozyme and lyticase simultaneously. Subsequently, qPCR was performed. It revealed that the gene copy number of bacteria (16S rRNA gene) and yeasts (26S rRNA gene) was 10⁷ copies/μL and 10⁵ copies/μL respectively after 1, 4, 8 and 12 week(s) of cultivation, which indicates that the communities of bacteria and yeasts are relatively stable in Tibetan kefir grains. These results give an insight into exploration of symbiosis mechanism between bacteria and yeasts in Tibetan kefir grains.

Abstract:Isolation and identification of an efficient aerobic denitrifying bacteria strain by using the selective medium to isolate and screen aerobic denitrifying bacteria through the quantitative increase of nitrite content, after a preliminary screening, and then second screening through denitrification performance testing for bacterial isolation. Physiological and biochemical tests and 16S rRNA gene amplification and blasting in GenBank ,and phylogenetic tree construction were used to identify the selected strain. Only the DB-6 with effective denitrification .During 5 days, NO₂^- -N was decreased from 3 570 mg/L to 22 mg/L, the removal efficiency was 99.4%, NO₃^- -N was decreased from 2 464 mg/L to 27 mg/L, the removal efficiency was 98.9% and without nitrite accumulation. The strain was identified as Enterobacter cloacae DB-6 according to its morphological, physiological and biochemical characters. In order to further confirm the result, 1 445 bp sequence of DB-6 16S rRNA was amplified and blasted in GenBank. Homology analysis study showed that DB-6 has the highest similarity to Enterobacter cloacae with 99% identity. And phylogenetic tree was constructed together with the discovered nitrifying bacteria, denitrifying bacteria and Enterobacter cloacae. It was suggested that Enterobacter cloacae DB-6 be a novel strain of aerobic denitrifying bacteria,which will be helpful in nitrogen removal of mariculture water.