Abstract:Diversity index (Shannon-Weaver index) of nanophytoplankton (H′) is influenced by many factors. Based on four surveys during 2006-2007,this study focused on the relationship between the structure of nutrients and H′ in six bays along Weihai coast, China. It was found that H′ was closely related to nitrate/ammonia ratio (NO₃^--N/NH₄⁺-N) at temperatures of 5-27℃, showing significant correlations. At 16-27℃, significant and negative correlation was found between H′ and NO₃^--N/NH₄ -N, with correlation coefficient of -0.526 (n=14) and -0.575 (n=19) in July 2006 and October 2007, respectively. However, when the water temperature was in the range of 5 -12℃, there was a highly positive correlation between H′ and NO₃^--N/NH₄ -N with correlation coefficient of 0.665 (n=15) and 0.415 (n=25) in December 2006 and April 2007, respectively. The results indicated that the nitrogen source preferred by nanophytoplankton was probably different at different temperature. Nanophytoplankton preferentially absorbed NO₃^--N at temperatures below 12℃ in winter and spring, while they preferentially utilized NH₄ -N at temperatures above 16℃ in summer and autumn.

Abstract:The method of grey relationship analysis was used to study the relationships between Noctiluca scintillans density and eight environmental factors in Qinhuangdao coastal area，with the Noctiluca scintillans density（ind/L）of different investigation stations as reference sequence ( X0=｛x0(k)︱k=1,2，…,24｝), with inorganic nitrogen（mg/L）,labile phosphate（mg/L）,silicate（mg/L）,COD（mg/L）,BOD5,temperature（℃）,salinity,pH,the phytoplankton ect as collating sequence ( Xi=｛xi(k)︱k=1,2…,24,i=1,2, …,16｝). The results showed that from May to July, the phytoplankton,COD,and temperature had more influence on the density of N. scintillans than any other factors.

Abstract:In this research, an acute toxicity experiment was carried out to study the effects of different concentrations of suspended solids on the growth of phytoplankton and zooplankton. Phytoplankton, Skeletonema costatum and Nitzschia closterium, and zooplankton captured by plankton trawl in Jiaozhou Bay with the dominant species of Barnacle nauplii,Calanus sinicus，Oithona similis, and Paracalanus parvus, were used as the experimental organisms. The results showed that the effects of different concentrations of suspended solids on the growth of S. costatum and N. closterium were highly significant (P<0.01). Linear relationship was found between the concentration of suspended solids and the inhibition rate on the growth of S. costatum and N. closterium, with the half inhibition concentration 48 h-EC50 as 1.58 g/L (R=0.977) and 96 h-EC50 as 2.82 g/L (R=0.993) for S. costatum; 48 h-EC50 as 4.27 g/L (R=0.933) and 96 h-EC50 as 4.47 g/L (R=0.939) for N. closterium. Experiments on zooplankton showed that the suspended solids also had a significant impact on the growth of zooplankton with the lethal concentration of 96 h-LC50 as 60.172 mg/L.

Abstract:Collecting acoustic data from fishing vessels is an important trend in fishery resources study, yet the quality of the data may be seriously compromised by inter-instrument acoustic interferences due to the lack of signal synchronization apparatus for onboard acoustic instruments. In order to fully use the contaminated acoustic data, a method of extracting swarm signals from echogram with strong interference was established based on the relevant modules in the Echoview,an acoustic data post-processing software. The methods were then applied to the acoustic data on Antarctic krill collected onboard a fishing vessel operated around South Orkney Islands during February 2011, and the interference was effectively removed from the echogram. Distinct diel vertical migration was observed in the krill swarms. The geometrical center of the krill swarms was distributed in layers with a mean depth of 77.4 m and a mean thickness of 41.2 m in daytime, while the swarms tended to migrate upward nocturnally at a mean depth of 34.9 m and a mean thickness of 8.8 m.

Abstract:The effects of temperature and salinity on the respiration and excretion of dragon-tiger grouper (hybrid of Epinephelus fuscoguttatus♀× E. lanceolatus♂) at body weight of (98.8±4.3)g were studied using methods in experimental ecology. The results showed that temperature and salinity had significant effects on both oxygen consumption and ammonia excretion (P<0.05) of the grouper. The oxygen consumption rate increased as the temperature increased from 15℃ to 35℃, with the highest value of (0.228±0.011)mg/（g • h） at 35℃; while the ammonia excretion rate showed an increase-decrease trend with the highest value of (3.985±0.094)μg/（g • h） at 30℃. As salinity increased from 5 to 35, the ammonia excretion rate decreased and the relationship was expressed as RN=3.689e-0.067S (R2=0.963). At salinity ranges of 5-15 and 25-35, the oxygen consumption rate decreased as salinity increased, while within salinity of 15-25 it increased with the increasing salinity. The O/N ratio ranged from 44.416 to 73.667 at temperature of 15-35℃ and salinity of 28, and from 59.577 to 275.034 at salinity of 5-45 and temperature of 28℃.

Abstract:Four groups of inbreed F1 of Cyprinus carpio haematopteru(HH), inbreed F1 of C. carpio var. Jian(JJ), F1 of C. carpio haematopteru♀×C. carpio var. Jian ♂(HJ), F1of C. carpio haematopteru ♂×C. carpio var. Jian ♀(JH) were established and cultured in the same pond after passive integrated transponder(PIT) marking. Four growth parameters (body weight, body length, body height and body width) were determined at 198 d and 588 d culturing and the growth traits, growth rate, fullness and growth index were analyzed by using ANOVA. The results showed that there were highly significant differences in growth rate, fullness and growth index of the four groups(P<0.01). Both the body weight and body length of four groups were JH>HH>HJ>JJ. Both AGR and SGR of the four groups decreased with the culturing time. During the culturing, SGR of HJ group was the maximum and that of JJ group was the minimum. At 198 d and 588 d, AGR of JH group was the maximum, and at 198 d, that of JJ group was the minimum, but at 588 d, AGR of HH group was smaller than the others. This indicated that the growth performance of the hybrid groups was better than the inbred groups. At 198 d and 588 d, the fullness of JJ group was greater than the other groups. The fullness of HH, JJ and HJ group increased with time, while JH group was the opposite. The growth indexes of four groups increased and the growth index of JH was the highest during the whole culturing. The analysis of heterosis showed that the body type of HJ group was between C. carpio haematopteru and C. carpio var. Jian. The JH group showed positive heterosis during the whole culturing(except for body height and width at 588 d). The body weights of the four groups at 588 d were significantly positive-correlated with those at 198 d (P<0.01). The correlation coefficient of body length and body height of JH group between 588 d and 198 d were highly significant (P<0.01), meanwhile the correlation coefficient of body width of HH group between 588 d and 198 d was also highly significant(P<0.01).

Abstract:This research compared growth performance and nutritional components in the muscles of Centropristis striata juveniles feeding on artificial diet only (Group A), artificial diet mixed with fresh fish (Group B), and fresh fish only (Group C) respectively. The results showed that the contents of nutrition in the artificial diet were much higher than those in the fresh diet, and the artificial diet had a certain advantage in terms of diet utilization, fish growth and development. The protein content in the artificial diet was 45.4%, which was 3.66 times of the fresh diet. Relative to the fresh diet, artificial diet provided adequate protein nutrition. The protein content in muscles of C.striata of Group A (20.3%) was higher than that of other two groups, and Group C was the lowest. The essential amino acid index (EAAI) of the three groups was 54.93（Group A）, 66.40（Group B）, and 61.02（Group C）. The content of PUFA in Group C was higher than Group A（5.94% higher） and Group B（7.84% higher）. The content of EPA and DHA in Group C were higher than Group A（13.26% higher）and Group B（9.61% higher）. The five delicious amino acids were detected, including Glu, Asp, Gly, Ala and Arg. The content of five delicious amino acids in Group C was 5.9%, and the ratio of total delicious amino acids in total amino acids ( DAA/TAA) was 42.66%, which was higher than Group A（8.8% higher） and Group B（10% higher）. In terms of the growth effect and nutrient, Group C is better than Group A and Group B. This research result will provide a reference for nutritional properties, feed development and feeding strategy.

Abstract:An eight-week experiment was conducted to investigate the effects of dietary protein level on the growth performance, body composition, and protease activity of Japanese seabass Lateolabrax japonicus at average weight of (34.15±0.33)g. Fish meal and casein were used as the main dietary protein， and five diets containing 35%, 40%, 45%, 50% and 55% protein were prepared.Feed experiment on the Japanese seabass showed no significant difference in survival rate (91.7%-96.7%) among dietary treatments(P＞0.05). As the dietary protein level increased, the specific growth rate (SGR) increased. Diets at protein level of 45%, 50%, and 55% obtained significantly higher SGR than the diet with 35% protein (P<0.05). The protein productive value (PPV) of fish fed diet with 45% protein was significantly higher than that of other groups. In the experiment, with the increase of dietary protein level, the content of crude protein of whole body increased, but the crude fat and ash decreased. There was no significant difference in whole body moisture content among all groups(P＞0.05). As dietary protein increased, activities of pepsin, trypsin and glutamic-oxaloacetic transaminase (GOT) increased significantly(P<0.05), but for activity of glutamic-pyruvic transaminase (GPT),there was no significant differences among all groups(P＞0.05). The optimal dietary protein level of Japanese seabass was 45.00%-45.89%.

Abstract:In this study, the fatty liver model for sturgeon Acipenser baeri was successfully established by analyzing hepatosomatic index, serum biochemical indexes, triglyceride in liver, color of liver and pathologic tissue section of sturgeon fed with high-fat diets. Sturgeons at similar body weight (8.41±0.82)g and length (10.12±0.44)cm, were divided into three groups and fed with three diets at oil contents of 8%(control group), 12%(mid-fat), and 16%(high-fat), respectively. After cultured for 42 d, their body length and body weight were measured, and blood was sampled from the caudal vein, then dissection was performed. The growth, serum and liver biochemical indexes and liver biopsy were employed to evaluate the model. Results showed that the final body length, body weight and hepatosomatic index of high-fat treatment was significantly higher than the other treatments (P＜0.05), but the survival rate showed no significant difference (P＞0.05). In high-fat treatment, the serum biochemical indexes, including aspartate aminotransferase, alanine transaminase, triglyceride and total cholesterol were significantly higher than those of control(P＜0.05). Also, the liver triglyceride in high-fat treatment was significantly higher than the other treatments (P＜0.05). The colour of the fish liver was dark-red in control, light red in mid-fat treatment and grey-white in high-fat treatment. Necrosis and ruptured liver cells were found in high-fat treatment, with fat particles merged into bigger fat droplets, cells became transparent and the nucleus were ruptured or dissolved.

Abstract:VP110, an envelope protein of white spot syndrome virus (WSSV), with a molecular weight of 110 kDa, has an Arg-Gly-Asp (RGD) structure domain and the ability of binding gill cells of the host. In order to study the role of VP110 in the WSSV infection of Litopenaeus vannamei, we designed a pair of primers according to the partial sequence of the gene vp110 (vp110-b). The vp110-b was then amplified by PCR and cloned into Escherichia coli expression vector pET-28a successfully. The pET28a-vp110b was transformed into E. coli BL21 cells, and a fusion protein rVP110-B (50 kDa) was expressed. The rVP110-B was injected into L. vannamei, and the protecting effect against WSSV infection was evaluated. The results showed that the half lethal time (LT50) of L. vannamei treated with rVP110-B was prolonged by 20% compared to the control. Rabbit anti-VP110 polyclonal antibody, which was prepared with the expressed and purified rVP110-B, was used in the Far-Western analysis of gill cell membrane protein of L. vannamei and renatured rVP110-B. The Far-Western showed a protein band at MW of 41 kDa besides the band of hemocyanin at 90 kDa. Analysis of protein band by MALDI-TOFMS (matrix-assisted laser desorption ionization-time of flight mass spectrometry) proved that this 41 kDa protein is actin.

Abstract:The genetic structure for two generations of cultured Marsupenaeus japonicas was investigated using eight pairs of microsatellite primers. In this study, a total of 108 alleles were tested, and the length of the alleles ranged from 196 bp to 528 bp; the number of alleles per locus ranged from 6 to 23 with an average of 13.5. For the parents and offspring populations, the average number of alleles was 8.5 and 11.5, respectively; the observed heterozygosity was 0.721 and 0.632, respectively; the average expected heterozygosity was 0.775 and 0.764, respectively; and the average polymorphism information content was 0.732 and 0.729, respectively. The pedigree structure for the parents and progeny populations was inferred by maximum likelihood method according to the microsatellite marker information. The parent population was divided into six groups, and the genetic distance among them ranged from 0.277 to 2.356 with an average of 1.510. The offspring population was divided into 17 groups, and the genetic distance among them ranged from 0 to 2.593 with an average of 1.113. The genetic distance between parents and offspring sub-groups ranged from 0 to 3.089 with an average of 1.238. An evolutionary tree for the 23 sub-group populations was drawn by unweighted pair-group method with arithmetic means (UPGMA) according to Nei′s genetic distance. Eighteen sub-groups aggregated into the main stretch after forming three sub-stretches. However, five sub-groups (O15, O12, O13, P21 and P18) were obviously away from the main stretch. In this study, the heterozygosity and polymorphism of the offspring population were lower than their parents. The result showed that the heterozygosity of the parents have partially lost during the genetic inbreeding.

Abstract:The composition of bacterial community in the intestine of white shrimp Litopenaeus vannamei under industrial culture conditions was investigated by 16S rDNA-based molecular methods of denaturing gradient gel electrophoresis (DGGE) analysis and restriction fragment length polymorphism (RFLP) analysis. Sequencing results of cloned 16S rDNA amplicons revealed that unculturable bacteria were the dominant species, Ruegeria spp., and Rhodobacterales spp. were subdominant species in samples collected in August 2011. The coverage rate by the 16S rDNA clone library was 97.5%. Eight different RFLP patterns of the clones were obtained by restriction RFLP analysis from samples collected in October 2011. Sequencing results of cloned 16S rDNA amplicons revealed that unculturable bacteria, Bacillus spp. and Vibrio spp. were the dominant species; Photobacterium spp. and Neptunomonas spp. were subdominant species. The coverage rate by the 16S rDNA clone library was 90.8%. DGGE analysis was also carried out for the samples. Sequencing results of cloned 16S rDNA amplicons revealed that unculturable bacteria and Vibrio spp. were the dominant species. Comprehensive analysis of PCR-RFLP and PCR-DGGE experimental results would be helpful to understand the microbial components in the intestine of the white shrimp, and to comprehensively and objectively reveal the structure and diversity of white shrimp microbial community.

Abstract:An experiment was carried out to investigate the effects of temperature on the respiratory metabolism of swimming crab Portunus trituberculatus. Oxygen consumption rate, ammonia excretion rate of juvenile（1.17±0.03g）and adult (57.57±1.16g) crabs and activity of energy metabolism enzymes, pyruvate kinase(PK)，hexokinase(HK) and succinate dehydrogenase (SDH) in muscle and liver of adult crab， were measured at 15℃,18℃,21℃,24℃and 27℃. The results were as follows:with the increase of temperature, both oxygen consumption rate and ammonia excretion rate increased significantly（P<0.05）. Oxygen consumption rate of juvenile crab at various temperatures and adult carb at 15-18℃ and 21-27℃ had significant difference （P<0.05）. Ammonia excretion rate of both juvenile and adult crabs had significant difference at 15-18℃ and 21-27℃（P<0.05）.The ratio of oxygen to nitrogen (1.38-3.02)demonstrated that the metabolic substrates of crab P.trituberculatus was protein-dominant and it displayed a decreasing trend as the temperature increased. Activity of PK in liver had an upward trend as temperature increased. However, activities of PK and HK in muscle displayed a decreasing trend（P<0.05）. Activity of SDH in liver increased as temperature increased （P<0.05）and reached the highest level at 27℃. In summary,the rate of glycolysis increased in the liver of swimming crab， and a gradual decreasing glucose-utilizing capability in muscle was observed. Activity of SDH in liver was enhanced as temperature increased （P<0.05）, which indicated a strengthed aerobic metabolism of swimming crab at high temperature.

Abstract:Voltammetric method for determining nitrofurazone and its metabolite semicarbazide was developed by employing grapheme-based electrode as working electrode. When the scan rate was 0.10 V/s, an irreversible adsorption-controlled redox reaction of nitrofurazone occurred in the NaAc-HAc buffer of pH 6.0. Under the conditions of optimized parameters, including buffer solution, pH, accumulation time, etc, the dependence of the ipc on the concentration of nitrofurazone in the range of 20.0-800.0 nmol/L was linear with a detection limit of 12.0 nmol/L (S/N=3). At the same scan rate, semicarbazide also had an irreversible adsorption-controlled redox reaction in the NaAc-HAc buffer of pH 4.1. Under optimized conditions, linear relationship between ipa and the concentration of semicarbazide was obtained in the range of 1.3-39.9 μmol/L with a detection limit of 0.2 μmol/L. Under the other set of optimized parameters, nitrofurazone and semicarbazide could be detected in the same buffer solution subsequently, with the detection limit of 71.0 nmol/L and 0.3 μmol/L, respectively, and the average recovery was found to be 87% and 83％, respectively. The concentrations of the two molecules in real fishery water samples were successfully determined using this method.

Abstract:The bacteriostatic activity of potassium monopersulfate powder on five strains of common pathogenic bacteria in aquaculture was studied, and the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) in vitro and protection rate in vivo were determined respectively. Results of in vitro bacteriostatic experiments showed that Edwardsiella, Aeromonas sobria, A. hydrophila, Edwardsiella tard, and Psudomonas fluorescens were significantly inhibited by potassium monopersulfate powder. The MIC for these bacteria were 1, 0.25，0.125，0.25 and 0.5 μg/ml respectively, and the MBC were the same as the MIC. While for in vivo experiments, with the increase of concentration of potassium monopersulfate powder, mortality of Carassius auratus caused by the five pathogens decreased gradually. Statistical analysis showed that dipping C. auratus in 0.25 μg/ml potassium monopersulfate was effective in treating disease caused by the five pathogens in C. auratus.

Abstract:A high performance liquid chromatography (HPLC) method for determination of adenosine triphosphate (ATP) and its breakdown products, adenosine diphosphate (ADP), adenosine monophosphate (AMP), inosinic acid (IMP), inosine (HxR) and hypoxanthine (Hx) was studied. The samples were extracted with perchloric acid, and pH value was adjusted to 6.0-6.4 with sodium hydroxide. The six ATP-related compounds were then separated on an AQ-C18 column (250 mm×4.6 mm, 5 μm) with 0.02 mol/L KH2PO4-0.02 mol/L K2HPO4 (V/V=1/1) buffer as the mobile phase. At wavelength of 254 nm, ATP-related compounds were detected and quantified by external standard method. The calibration curves were linear in the range of 0.2-40.0 μg/ml for ATP, ADP, AMP, IMP and HxR, and 0.1-20.0 μg/ml for Hx, with all correlation coefficients above 0.999. The detection limit for ATP, ADP, AMP, IMP, and HxR was 5.00 mg/kg, and was 2.50 mg/kg for Hx, with S/N=3. The average recoveries of ATP compounds in Pagrosomus major, Seriola quinqueradiata, Oncorhynchus keta, Litopenaeus vannamei and Portunus trituberculatus samples at three spiked levels varied from 85.5% to 105%, and the relative standard deviation (RSD) was less than 12.9%. The results indicated that this method is rapid and reliable, and it is suitable for simultaneous determination of the six ATP-related compounds in aquatic products.

Abstract:Nowadays, the function of Enteromorpha polysaccharide has attracted widespread attentions. However, due to the lack of test methods, the product quality and efficacy evaluation of Enteromorpha polysaccharide were compromised. In this study, the optimal conditions under which the samples of Enteromorpha polysaccharide were completely hydrolyzed by trifluoroacetic (TFA) acid without loss. Based on the optimization of the mobile phase elution procedures and other chromatographic conditions, the pre-column derivatization- high performance liquid chromatography (HPLC) using 1-phenyl-3-methyl-5-pyrazolone (PMP) to analyze the composition and content of monosaccharides in Enteromorpha polysaccharide was established. Monosaccharides in Enteromorpha polysaccharide were determined by HPLC under 250 nm wavelength, and were quantified by external standard method. It was found that 8 species of monosaccharides in Enteromorpha polysaccharide can be completely separated under the chromatographic condition. The monosaccharides had good linear relation in the range of 1-100μg/ml, and its correlation coefficient was equal to or greater than 0.999. The average recovery rate was between 76% and 108%, and the relative standard deviation (RSD) was below 10%. The strength of this method is the ability to analyze the composition of Enteromorpha polysaccharide, and it is found in this study that the most important monosaccharides in Enteromorpha polysaccharide were rhamnose; glucuronic acid, glucose, xylose, galactose, and small amounts of mannose, galacturonic acid and fucose were also detected.

Abstract:A method was established for determining the polybrominated diphenyl ethers (PBDEs) in sediment. The sediment samples were subjected to ultrasonic extraction using n-hexane/acetone as solvent. The extract was concentrated and combusted in the combustion flask which was filled with oxygen. Polybrominated diphenyl ethers were decomposed into bromine ion which was then determined by bromide ion selective electrode. The result showed that, when the addition level was 100 μg/kg, 1000 μg/kg and 5000 μg/kg, the recovery was in the range of 70.27%-97.49%, and the relative standard deviation(RSD) was less than 15%. The quantification limit of the method was 100 μg/kg.

Abstract:Phospholipid is the predominant polar lipid which plays a central role in growth performance, survival, salt-resistance, and temperature tolerance for fish, especially for the larvae. The biological characters of phospholipid, its digestion, absorption and transport in fish, its synthetic pathways, and the interactions between phospholipid and cholesterol were introduced in this review. Moreover, differences in the requirements of phospholipid between fish and crustacean were compared, in order to provide a theoretical guidance for the applications of phospholipid in fish culture.