Abstract:is rich in arachidonic acid (20:4 ω6, AA). The synthesis of AA is thought to begin with the conversion of oleic acid (18:1, oleic acid) to linoleic acid (18:2, linoleic acid, LA) and then proceeding along the ω6 pathway by the catalysis of Δ12, Δ6, Δ5 and other fatty acid desaturases (FADs), based on the fatty acids that have been detected in . We cloned the full length cDNAs and the corresponding DNAs of the genes (GenBank accession numbers: JN205757, JN205755, and JN205756, respectively). The full-length cDNAs for the genes were 1806 bp, 2674 bp, and 2318 bp, respectively, and their corresponding ORFs were 1 137 bp, 1 443 bp, and 1446 bp in length encoding putative proteins consisting of 378, 480, and 481 amino acids, respectively. Compared to their corresponding DNA sequences, the coding sequences of the genes were interrupted by 4, 5, and 7 introns, respectively, with all the splice sites matching the “GT-AG” rule. The encoded Δ12, Δ6, and Δ5 FAD proteins were rich in hydrophobic amino acids which accounted for 52.8, 46.6, and 50.9% of total amino acids, respectively. The codon preference of these . cDNA library. these three FADs had four transmembrane domains, while Δ5 FAD and Δ12 FAD had another hydrophobic but not transmembrane region. These FADs were conserved, having three histidine boxes similar to the FAD family. The neighbor-joining (NJ) phylogenetic tree inferred from the putative proteins of the incisa were clustered within their corresponding clades, the Δ12 and ω3 FADs were genetically closer, and the Δ6 and Δ5 FADs had a closer genetic relationship. relative transcription of these three FAD genes was estimated by quantitative real-time PCR (Q-RT-PCR) in during culture under nitrogen starvation for 96 h followed by nitrogen replenishment for 72 h. The relative transcription of these three genes increased under nitrogen starvation, then declined rapidly and significantly after were transferred to the nitrogen rich medium, suggesting that these genes were subject to regulation by nitrogen. Taking the known variation of fatty acids together, our results suggest that the increased transcription of these genes may play an important role in the synthesis and accumulation of AA is cultured in nitrogen deficient conditions, and that Δ6 FAD is more critical than the remaining FADs. Our observations provide a foundation for investigation of the metabolic pathway and molecular regulation mechanism for AA biosynthesis and accumulation in during nitrogen starvation.

Abstract:Apolipoproteins, the protein moieties of lipoproteins, participate in physical activities in different forms. A 14 kDa apolipoprotein (Apo-14 kDa) and apolipoprotein E (ApoE) are thought to be associated with embryonic development in animals. We analyzed the gene structure and phylogenetic evolution of these two types of apolipoprotein in the common carp (). In addition, we documented the pattern of expression using RT-PCR to provide insight into their function during the embryonic development of carp. , including and (identity=90%). Phylogenetic analysis revealed that Apo-14 kDa-a has a close relationship with that of most other teleosts and that Apo-14 kDa-b has the closest relationship with that of differentiation of the family yprinidae, although ApoE is characterized by four homologous genes. The expression of carp was highest in the liver and head-kidney, was very low in the intestine, and undetectable in the remaining tissues. Conversely, we were only able to detect expression of in the liver. We observed tissue specific differences in the expression of were only detected in the intestine whereas were present in the brain, skin, gill, liver, spermary, intestine, heart, muscle, body-kidney, and head-kidney. in the ovary. Our observations suggest there is considerable variation in the expression and function of . Furthermore, qRT-PCR analysis suggests that the expression of these six genes varies throughout embryonic development, both within and among genes. This is consistent with the molecular phylogeny of these genes. qRT-PCR analysis suggests that play an important role throughout different stages of embryonic development in common carp.

Abstract:We evaluated the factors regulating the secretion of digestive juices in fish. We cloned two intestinal hormone genes, gastrin (GAS) and cholecystokinin (CCK), from mandarin fish (cDNA consists of 581 bp nucleotides, including a 100 bp 5′ untranslated region (UTR), a 336 bp open reading frame (ORF) encoding 111 amino-acid residues, and a 145 bp 3′ UTR. The , consisting of 843 bp and 846 bp nucleotides, respectively. The gene consists of a 60 bp 5′ untranslated region (UTR), a 414 bp ORF encoding a polypeptide of 137 amino-acid residues and a 369 bp 3′ UTR, while the gene consists of a 112 bp 5′ UTR, a 403 bp ORF encoding a polypeptide of 134 amino-acid residues and a 332 bp 3′ UTR. The C-terminal of the GAS polypeptide has a similar octapeptide structure (DYQGWVDF/ DYLGWMDF) to that of CCKs’. The only differences occur Val₃ (GAS) and Glu₆ (GAS) are replaced by Met₃ (CCK) and Leu₆ (CCK), respectively. Real-time PCR analysis revealed that mRNA was primarily expressed in the intestine and pyloric caecum. The expression of CCK1 and mRNA was highest in the brain, but expression was also detected in intestine and pyloric caecum. Our results suggest that GAS and CCKs may be involved in regulating digestion, while CCKs appear to be associated with digestive and neurosecretory processes. The genes are constitutively expressed during larval development (022 days post hatching, DPH). Expression was higher during the early stage (4–8 DPH for GAS and 2–4 DPH for CCK), possibly linked to development and growth of the digestive tract, then gradually decreased to a stable level during the later stages of development.

Abstract:20E) plays a role in the direct regulation of crustacean molting and growth. The synthesis and degradation of 20E is catalyzed by cytochrome P450 enzymes (CYP enzymes). We attempted to determine the molecular mechanism for the growth promoting effect of KK-42 in) (body length 3.55.0 cm) were exposed to a solution containing KK-42 (1.95×10 ^{mol/L) or to a control solution without KK-42 then cultured normally. A single was cloned and its spatiotemporal expression was analyzed using real-time PCR. The hemolymph 20E titer was measured by reverse-phase high performance liquid chromatography. The full-length cDNA contained a 1 545 bp open reading frame encoding a predicted protein of 515 amino acids which shares common characteristics with the cytochrome P450 superfamily. The expression of mRNA was highest in the hepatopancreas. Following KK-42 treatment, expression of hepatopancreas decreased significantly to >72.3 % that of the control group and was that of the control on day 6. Administration of KK-42 resulted in an increase in hemolymph 20E titers compared to that of control animals. Our results suggest that the inhibition of hepatopancreas expression and the increase in hemolymph 20E titer following KK-42 administration may explain the growth promoting effect of KK-42 in}

Abstract:). We then analyzed the combining ability and heterosis of 6 reproductive traits in the F1, including male gonadosomatic index (_GSIelative fecundity (RF), fertilization rate (FR), and hatching rate (HRWe observed obvious differences among the reproductive traits between the different mating combinations. The highest were found in combinations in which the mother was “whole red with small black spots” (RS). The highest and RF were observed in combinations in which the mother was “whole red” (WR). Conversely, the values for these reproductive traits were low for combinations in which the mother was “whole white with big black spots” (RB). The phenotypic correlations among . We detected significant specific combining ability (SCA) for RF. Ten combinations were detected with predicted specific combining ability (SCA) and heterosis ( correlation between SCA and heterosis for M_GSI, F_GSI, AF, RF, and HR<0.01). Our results provided baseline data to guide breeding of complete set lines of Oujiang color common carp.

Abstract:wo inbred groups, SS (S♀×S♂) and TT (T♀×T♂), and two hybrid groups, ST (S♀×T♂) and TS (T♀×S♂) were established. We measured the following traits in the offspring of each group: body length, body weight, carapace length, carapace width, and carapace height. The order of growth performance was ST>TS>TT>SS based on the five traits. Prior studies of gene diversity have documented strong differentiation between populations from the western Pacific Ocean and the south China Sea, providing a theoretical basis for heterosis between the Sanya and Thailand populations. Heterosis of the hybrid combination for the five traits ranged from 2.13% to 19.7% and was highest for body weight. The heterosis of the hybrid group ST was higher than that of the hybrid group TS for all traits (<0.05). There was a significant difference in body length, body weight, carapace length, and carapace height of the offspring among the four groups (>0.05). Multiple covariance analysis suggested that length, body weight, and carapace length were significantly different between the hybrid group ST and both inbred groups (<0.05). Our results provide an important reference for hybrid breeding of .

Abstract:one of the oldest extant cold-water fish species in the world, are of considerable research and economic value. We documented the postembryonic development of the Siberian sturgeon by monitoring morphological characteristics and cell types in retina, taste buds, olfactory sac, and ampullary organs in the larvae. The stages of postembryonic development were defined based on both the external morphology and the internal organ characteristics. Larvae were reared at a water temperature of (18.0±1.0)7.5. The newly hatched larvae (day 0) were (9.05±0.14) mm long. During the early-stages of development (days 0–7), the larvae were nurtured by a large yolk sac and the eye was the primary sense organ. The late-stage larvae (day 8­–22) were characterized by the disappearance of the yolk sac and initiation of active feeding, the formation of fins and fin rays, a shift in habitat use towards the bottom of the water column, and the completion of organ differentiation. As larvae reached the juvenile stage (day 23–57), the begin to form, the organs tended to become fully developed, and the external morphology and body color pattern gradually matured into the adult pattern. We observed some differences in the development characteristics of the primary sensory organs in Siberian sturgeon relative to other teleosts. Our observations suggest that Siberian sturgeon is an ancient species that occupy a unique position during the evolution of teleosts.

Abstract:were fed at different temperature (15) to study the effects of water temperature on feeding, growth and activities of digestive enzymes using morphological and biochemical methods. The results showed that, the specific growthsignificantly increased with the increasing temperature between 15<0.05), and reaches the maximum at 24. The feed conversion ratio (FC) decreased significantly and reached the minimum at 24then greatly increased. In addition, the feed ration (FR) increased remarkablely with the temperature increasing ( < 0.05).The growth rate in the different temperature group were in the order of group 24. The water temperature had significant effects on the protease activity in the foregut( < 0.05), the protease activity in the foregut of the group 24 < 0.05), and the water temperature had no striking effects on the protease activity in the midgut and hindgut(> 0.05). The temperature had no striking effects on lipase activity in > 0.05), and the lipase activity of midgut was higher than the hindgut and foregut in every temperature group. The temperature had no striking effects on amylase activity in intestinal tract (> 0.05), and the amylase activity were in the order of midgut > hindgut > foregut. Taken together, the growth rate was fastest in the group 24, but the activities of intestinal digestive enzyme were lower than the group 21. In the temperature range juvenile can reaches the maximum growth rate and survival rate.

Abstract:was staged by the method of Darch. We then measured the three digestive enzymes in hepatopancreas throughout the molt cycle. Based on the setogenesis and the morphological changes to the epidermis of the third maxilliped, we identified four molting periods (postmolt, intermolt, premolt and ecdysis). In addition, the premolt period was further divided into three substages (D₀, D₁, and D_3-4). Both amylase and tryptase activities increased in the hepatopancreas during the A-B stages, peaking in the early premolt D₀ stage (3_{<0.05). There were no obvious changes in peptase activity during the majority of the molt cycle, though levels were significantly lower ( stage. In summary, we identified five periods (C, D0, D1, D3-4, A-B)in the molt cycle of during which the activities of amylase, trypsase, and peptase changed periodically.}

Abstract:We evaluated the effect of glucose injection on and glycolytic enzymes in GIFT (=150, mean weight 80±5 g) wererandomly assigned to one of two groups, a control group that was injected with sterile 0.7% saline and a treatment group that was injected intraperitoneally with glucose (30 mg/100 g wet weight). The fish in both groups were euthanized 1–12 h after injection. Glucose injection resulted in hyperglycemia with maximum glucose levels observed 1 h after injection (<0.05) and a return to normal levels after 3 h. Cholesterol content also increased significantly (<0.05) after glucose injection. Conversely, triglycerides, glutamic-pyruvic transaminase (GPT) levels were unaffected by glucose injection. The level of glutamic-oxalacetic transaminase (GOT) decreased significantly (<0.05) after injection. Liver glycogen peaked 6 h after injection with glucose, then decreased significantly (<0.05). Glucose injection had no effect on muscle glycogen levels. Insulin levels increased significantly (<0.05) in the plasma and muscle, but not in the liver, following glucose injection. Pyruvate kinase levels peaked 6 h after glucose injection (<0.05). Conversely, there was no change in hexokinase activity after injection. Our results suggest that metabolic adjustment caused by glucose administration is reflective of the regulatory action of insulin and pyruvate kinase. The levels of insulin and pyruvate kinase (PK) were unable to maintain pace with the absorption speed of carbohydrates in fish and a shortage in hexokinase (HK) activity limited glucose utilization, leading to higher concentrations of cholesterol.

Abstract:Hybridization is the most widely used and effective method of artificial breeding in aquaculture. To develop grouper species that were fast growing and tolerant of low temperatures, we conducted hybridization between (♂) by artificial methods. We documented embryonic development and the growth and morphological characteristics of larva, juveniles, and young fish in the hybrid was divided into cleavage stage, blastula stage, gastrula stage, neurula stage, and organogenesis stage. In sea-water (minembryonic development. The 2-cell stage occurred 1 h post fertilization (pf); the 16-cell stage at 2 h 25 min pf; the multi-cell stage at 3 h 50 min pf; the high blastula stage at 5 h 10 min pf; the middle gastrula stage at 12 h 40 min pf; the embryo body stage at 16 h pf; the closure of blastopore stage at 17 h 50 min pf; the muscle burl stage at 20 h 50 min pf; the brain vesicle stage at 24 h 50 min pf; the crystal stage at 31 h 05 min pf; the heart-beating stage at 32 h 40 min pf; the hatching stage at 35 h 10 min pf; and the newly hatched larvae stage at 35 h 20 min. There was no obvious difference in embryonic development between crossbreed F1 by except the time of the heart-beating stage. Based on the features of the yolk sac, second dorsal fin spine, pelvic fin spine, scales, and body color, the post-embryonic development of the hybrid was divided into larval, juvenile, and young fish stages. The larvae relied on their yolk for nourishment up to 4 d after hatching, at which time the mouth opened. Metamorphosis was completed ~42 d after hatching at which time the fish were classified as juveniles. The juvenile stage lasted for ~58 d, after which the juveniles became young fish. Our results suggest that the hybrid F1 grows more rapidly than either parent species.

Abstract:Within recirculating aquaculture systems (RAS), the bio-filter plays a critical role by removing dissolved inorganic nitrogen, intercepting suspended matter, and constantly recycling the culture water. The nitrifying performance of the bio-filter is heavily influenced by bio-fillers and as such the optimal method for removal of deleterious substances remains a focus of research. Microbial water purified agents are often used as a water amendment in artificial culture systems. Their use is thought to promote water purification and disease prevention in fishes, though few studies have evaluated the use of microbial water purified agents as strains for bio-film cultivation. RAS allows high culture density and rapid growth of cultured species, though compared with the traditional flowing water culture, little is known about the effect of fish culture in RAS. We evaluated bio-film cultivation and the dissolved inorganic nitrogen removing efficiency of three kinds of bio- young black sea bream, We tested the effect of using agents as a strain for (pottery ring, elastic brush, and biochemical cotton fiber) during bio-film maturation time for the three was 25, 32, and 28 d, respectively. Our results suggested that maintaining high dissolved oxygen concentrations, changing the water, and adding nutrients and NaCO₃ promoted the growth and propagation of nitrifying bacteria. Conversely, NO₂-N concentrations cannot be held at high levels for an extended period because ammonia-oxidizing bacteria and nitrifying bacteria require dissolved oxygen and alkalinity for survival. grew well in the simple recirculating aquaculture systembody weight and feed conversion rate of in the three experimental groups differed significantly from that in the control group (<0.05).The survival rates in all groups were >95%. The activity of serum LSZ and liver SOD was significantly higher in the experimental groups than the control group (<0.05). Similarly, the quantity and diversity of digestive tract flora was significantly higher in the experimental groups than the control group. different kinds of beneficial bacteria in the three experimental groups, relative to the control. Our results suggest that these beneficial bacteria are dominant, and thus inhibited the survival of pathogenic bacteria. During circulation of the water, the beneficial bacteria are able to enter the fish body during respiration and ingestion, thereby enhancing the nonspecific immunity of the fish. Our results suggest that different filter materials have different bio-film maturation times under the same operating conditions. A recirculating aquaculture system can not only improve fish growth, but also enhance their

Abstract:DNA vaccine, We constructed a baculovirus transfer vector pFastBac™Dual-derived DNA vaccine vector pFastBac-FA-VP6-ph-VP6 in which one gene was controlled by the baculovirus polyhedron (Ph) promoter, and another -actin promoter of grass carp, at the downstream of the baculovirus p10 promoter. Grass carp (weight 60−120 g, length 14−20 cm) were injected with 10, 30, or 60 μg of the vaccine vector, the negative control group was inject with 30 μg of pFastBac™Dual, and the unvaccinated control group was injected with 0.4 mL of sterile water. We then analyzed the pattern of expression in vaccinated fish using RT-PCR, measured antibody titers in the blood by indirect agglutination at 14, 21, 28, 49, and 70 d post-vaccination and evaluated immune efficacy by challenging GCRV at 21 d post-vaccination. The specific antibodies were detected in all vaccinated groups, and its levels peaked at 28^th day after immunization. The mortalities were 0, 0, and 5% in the vaccinated groups injected with 10, 30, and 60 μg of DNA vaccine, and 30 % and 100% in the negative control group and the unvaccinated control group, respectively. Our results suggest that the DNA vaccine had strongly immunoprotective efficacy against GCRV.

Abstract:Small-size fishes that have a short lifespan and high growth rate are important members of aquatic communities. Despite having relatively low commercial value, they often serve as forage fish for more commercially important species. Furthermore, small fish species are potentially key determinants of aquatic ecosystems. We evaluated the species composition, density, and biomass of small-size fishes in Niushan Lake, a typical shallow macrophytic lake along the middle reach of the Yangtze River. Based on macrophyte cover conditions, the lake was divided into three major habitat types: P. maackianus habitat (H2), and uncovered/ habitat (H3). Fish were sampled quantitatively in the three types of habitat using block nets that were placed seasonally between September 2002 and August 2003. We captured a total of 12 636 individuals comprising 27 fish species, among which 20 species were classified as small-size fishes. The tBased on an index of relative importance (IRI), Paracheilognathus imberbis, Toxabramis swinhonis, were the dominant small fish species, collectively accounting for 91.1% of the total catch. The Zippin’s removal method was used to estimate density and biomass of the eight dominant small-size fishes in each season and throughout the whole year. We observed seasonal variation in the calculated density and biomass. For the entire year, average total density and average total biomass of the eight dominant small-size fishes were 3.992 ind/(m²·year) and 6.073 g/(m²·year), respectively. Our results provide baseline information that is essential to the long-term monitoring of small-size fish communities in the shallow lakes in the Yangtze River basin. We suggest that targeted stocking of piscivorous fishes (Culter mongolicus) and optimization of the fish community structure may provide means to exploit and utilize

Abstract:Marine vibrio is a causative agent of vibriosis, a disease that results in severe losses to the aquaculture industry. The development of vaccines would likely lower the abuse of antibiotics that are currently used to ensure the safety of aquatic products. We prepared and characterized a FlaA-OmpK enteric microsphere vaccine and evaluated the effectiveness of oral vaccination. We cloned the V. parahaemolyticus. by overlap extension PCR. The expression systems OmpK, FlaA, and FlaA-OmpK were then constructed. The recombinant proteins were expressed in large scale in BL21 and purified. OmpK, FlaA-OmpK, and mixed OmpK and FlaA were administered as antigens to immunize . Vaccination with FlaA-OmpK protected against the infection by C. striata against FlaA-OmpK were highest 40 d after immunization, and were two times that of the OmpK group and four times that of the OmpK group. The serum titers of the FlaA-Ompk were significantly lower in fish that were treated orally relative to those that were injected. The fish immunized with r-FlaA-OmpK had high survival (80%) compared with the control group. Similarly, the oral FlaA-OmpK protection rate (50%) was lower than that in the injection group. Our results suggest that FlaA-Ompk is an ideal candidate for development of a Vibriosis vaccine.

Abstract:Marine vibrio is a causative agent of vibriosis, a disease that results in severe losses to the aquaculture industry. The development of vaccines would likely lower the abuse of antibiotics that are currently used to ensure the safety of aquatic products. We prepared and characterized a FlaA-OmpK enteric microsphere vaccine and evaluated the effectiveness of oral vaccination. We cloned the V. parahaemolyticus. by overlap extension PCR. The expression systems OmpK, FlaA, and FlaA-OmpK were then constructed. The recombinant proteins were expressed in large scale in BL21 and purified. OmpK, FlaA-OmpK, and mixed OmpK and FlaA were administered as antigens to immunize . Vaccination with FlaA-OmpK protected against the infection by C. striata against FlaA-OmpK were highest 40 d after immunization, and were two times that of the OmpK group and four times that of the OmpK group. The serum titers of the FlaA-Ompk were significantly lower in fish that were treated orally relative to those that were injected. The fish immunized with r-FlaA-OmpK had high survival (80%) compared with the control group. Similarly, the oral FlaA-OmpK protection rate (50%) was lower than that in the injection group. Our results suggest that FlaA-Ompk is an ideal candidate for development of a Vibriosis vaccine.

Abstract:Larimichthys crocea). We observed daily periodicity in growth increment formation in the sagittal otoliths. The first daily increment was formed 2 days after hatching (dah), corresponding to the time of first feeding. The sagittas were uring the yolk-sac larval and pre-flexion larval stages, on the long Following this, the sagitta became ellipsoidin shape during the post-flexion larval stage. During the early juvenile stage, the first secondary primordium began to form between 29−39 dah (32±0.39), corresponding to the timing of from larvae to juvenile. The number of secondary primordium ranged from 5 to 7 in 47–­­78-day-old juveniles, and the secondary growth zone (SGZ) structure”. During this stage, the sagittas were nearly peltate in shape. The radius () of the sagitta was significantly and linearly related to standard length (S) (b), calculated based on the width of the daily increment on the sagitta of juveniles, were significantly and linearly related to the time of formation of the first secondary primordium ((<0.01). This suggests that the secondary primordium was formed much earlier and metamorphosis was more rapid in faster growing larvae. In summary, the pattern of elarge yellow croaker can be back-calculated based on sagitta size, morphology, and microstructure for measuring early and documentinglarge yellow croaker in the field.

Abstract:We used ecological simulation to study changes in the population structure of bacteria in water during the decomposition of into a 500 L glass tank and measured chemical oxygen demand (COD) and heterotrophic bacteria and analyzed the structure of the bacteria population at different stages using PCR-DGGE. We observed an initial increase in DO, COD, and the abundance of aerobic heterotrophic bacteria as the degree of decomposition of increased, followed by a decrease in COD and aerobic heterotrophic bacteria abundance. The bacterial population in the water consisted primarily of ) and Proteobacteria (60.61. We observed a significant change in the species structure during the decomposition process. During the initial stage of decomposition, were dominant, but were replaced by α-, γ-, and ε-Proteobacteria during the latter stages of decomposition. Our results provide insight into predicting the influence of breakouts in marine environment.

Abstract:We evaluated the spatial and temporal variation in the eco-environment of a mariculture area in Dapeng Cove, China using chemometric techniques and principal component analysis (PCA), clustering analysis (CA), and categorical principal component analysis (CATPCA). PC1 was associated with temperature, salinity, dissolved inorganic nitrogen (nitrate, nitrite, and ammonium), water sulfide, chlorophyll a and particulate organic matter, reflecting the influence of the seasonal transition of climate and hydrology. PC2 was characterized by phosphorus and sediment sulfide, primarily due to self-pollution from fish cage farming. PC3 was characterized by dissolved oxygen and chemical oxygen demand, related to the oxygen metabolism of cultured animals. PC4 was characterized by sediment organic matter, related to the biodeposition effect of oyster raft farming. The spatial-temporal variation in the eco-environment of the mariculture area were primarily affected by the subtropical monsoon climate combined with spatial and seasonal changes in the artificial production of caged fish and oysters.

Abstract:We analyzed the hydrodynamic properties of a gravity cage for flatfish culture during exposure to wave action. We constructed a numerical model to simulate the hydrodynamic behavior of the float collar, the base frame system, and the mooring system, the primary sections involved in withstanding waved-induced forces acting on the net cage structure. We conducted a series of experiments to validate the numerical model. The numerical model appeared to predict the experimental behavior well (mean relative error was <9%), suggesting our model can be used to accurately predict the primary hydrodynamic behavior of gravity cages in waves. After validating the numerical model, we evaluated the effect of the weight of the base frame and the height of the net pen on mooring line tension and cage motion. The mooring-line tension increased by 13% and 19% and the inclination decreased by 8.8% and 9.3% as the weight of base frame increased from 80 to 100 g and from 80 to 140 g, respectively. Thus, increasing the weight of the base frame in favor of decreasing the inclination results in an increase in the tension on the mooring lines of ~15%. The values for these parameters decreased by <10% when the height of net pen was increased from 20 to 30 cm. The motion of the base frame was reduced slightly due to an increase in the forces acting on the float collar and the base frame of the cage net. Based on our observations, we offer suggestions regarding the design and optimization

Abstract:We measured the total selenium content in aquatic product samples after oxidation of organic selenium into inorganic selenium using a nitric acid, perhydrol mixed system. Simultaneously, we measuredinorganic selenium content by HG-AFS following extraction of the sample in a HCL(50%) solution and digestion of the water phase in HNO₃ and H₂O₂. Using these data we calculated the organic selenium content of the samples. Under optimal conditions, the detection limit of selenium by this method was 7.1 ng/mL and the linear range was between 0–20 μg/L. The recovery rate of total selenium was 93.88%–107.65% and the RSD was 0.82%­­­­­–4.97%. Similarly, the recovery rate of organic selenium was 82.88%–90.10% and the RSD was 2.33%–7.73%. In summary, this method has a wide linear dynamic range and good precision and accuracy, so is suitable for the determination of organic and inorganic selenium in aquatic products.

Abstract:We compared the muscle constituents and quality of age 2, 4, and 6 wild and cultured Heilongjiang Province. There was no significant difference in muscle components between wild and cultured populations of>0.05). However, the moisture and crude protein contents were significantly higher in the wild population than in the cultured population. Conversely, the crude fat content was significantly lower in wild population than in the cultured population (<0.05) for both age 2 and age 4 fish. Compared with the common farmed fish, the Ca and P content of wild in Xingkai Lake was high and there was no difference in amino adid composition in wild and cultured populations. Of the amino acids, glycine was the most common, followed by glutamate and lysine. The total amino acid (TAA), EAA), and delicious amino acid contents were significantly higher in the wild population than in the cultured population for age 4 and 6 individuals (<0.05). Our results suggest that theproteincontentis highin both the wildandculturedpopulationsof in Xingkai Lakeand that these fish have highnutritionalandedible value. Compared with the cultured population, the nutritional value and taste of the meat was superior in the wild population, and this advantage increased with the age of the fish. Our data provide a basis for evaluating the nutritional value of and for developing manufactured feed for cultured fish. Based on our observations, artificial feeds for in Xingkai Lake should include methionine and cystine to improve the nutritional value whereas glycine and glutamic acid should be added to improve the flavor of cultured fish.