Vaccination plays an important role in large-scale and intensive commercial marine fish farming. Vaccines can have significant positive impact on the reduced usage of antibiotics and have been a key reason for the successes of the healthy and sustainable development in marine fish aquaculture industries of developed countries and regions in the world. China, the world's largest fish producer, has been in the time of industrial transformation and upgrading on marine fish farming, however the increasing serious problems of fish diseases and food safety have been becoming one of the executing barriers for the greater progress in marine fish farming. With continuous technical breakthroughs in research and commercial development of marine fish vaccines funded by National industry system of flounder fishes, vaccination will be the core strategy of disease control and prevention in China's marine fish aquaculture.
With the rapid developments in marine aquaculture, the bacterial pathogen has been recognized as a serious cause of disease. The urgency of implementing diagnosis to control the spread of bacterial disease and safety of aquaculture products is presently the dominant issue to be concerned. The aim of this review is to compile the dispersed literature published about different aspects of the detection technology of bacterial diseases occurring in aquaculture worldwide. The current status in the development of rapid diagnosis of aquaculture bacterial diseases will provide useful information on the establishment of detection standards and development of diagnosis products.
Four monoclonal antibodies (mAbs) to immunoglobulin M (IgM) of turbot Scophthalmus maximus were produced and characterized. All the mAbs (denominated B1D1, D5C2, E1B2 and F4A1) are showed good anti-turbot IgM reactivity in enzyme linked immunosorbent assay (ELISA) and immunoblotting. Results of ELISA indicated that the titre of the mAb was 1:1.024×106 and the minimum detectable amount of IgM was 32 ng/mL. Results of immunoblotting showed that the mAb reacted with heavy chain of IgM. The mAb showed specificity for Scophthalmus maximus, light specificity for Paralichthys olivaceus, Takifugu rubripes, Sebastodes fuscescens, Hexagrammos otakii, Lateolabrax japonicas, and no specificity for Cynoglossus semilaevis, Cyprinus carpio, Carassius cuvieri, Ctenopharyngodon idellus, Aristichthys nobilis. The mAbs characterization should prove useful for studying the biology of IgM and its practical application.
In this study, formal dehyde was used to inactivate Edwardsiella tarda, Vibrio anguillarum, Vibrio harveyi, Vibrio vulnificus, Vibrio alginolyticus, Aeromonas caviae, Edwardsiella ictaluri, Aeromonas hydrophila, in order to preparethe inactivated vaccine. Then vaccine was used to immune turbot by intramuscular injection. In this way ,we got the antiserum of all bacterium above. Enzyme-linked immunosorbent assay was used to determine the content of antibody in serum. The antibody can be detect after four week in the immune, and the level of antibody is research highest in the tenth week which is inoculated inactivated vaccine of Edwardsiella tarda, and the highest titer of other vaccines are 1:102400, 1:6400, 1:6400, 1:12800, 1:12800, 1:6400, 1:6400, 1:12800. The results of cross reaction of the bacteria and their anti-serum shows that the effect is most intense when the bacteria react with its own antiserum, and it is very weak when the bacteria react with other antiserum.
Three third-generation of successive meiogynogenetic families (Meio-G3-1, Meio-G3-2 and Meio-G3-3) in Japanese flounder (Paralichthys olivaceus) were induced by artificially meiogynogenesis, which the eggs were activated by UV-irradiated red sea bream (Pagrus major) sperm, and followed with the cold-shock treatment. We evaluated the genetic structure of these three families using 30 microsatellite markers, and the efficiency of successive meiogynogenesis for producing highly inbred line was quantified by calculating the homozygosity and genetic similarity. The numbers of alleles detected were 35, 38 and 37 in Meio-G3-1, Meio-G3-2 and Meio-G3-3, respectively. And for these three families studied, the average numbers of alleles (A) were 1.17, 1.27 and 1.23; the average observed heterozygosity (Ho) were 0.1467, 0.2556 and 0.2056; the average homozygoisty among the 30 analyzed loci were 0.8533, 0.7444, and 0.7944. For the genetic similarity, the average similarity index between offspring within family was 0.9913, 0.9918 and 0.9838; between dam and offspring was 0.996, 0.9968 and 0.9923; and between families was 0.9717 (Meio-G3-1 and Meio-G3-2), 0.9810 (Meio-G3-1 and Meio-G3-3) and 0.9714 (Meio-G3-2 and Meio-G3-3), respectively. Our results indicate that the artificially induced successive meiogynogenesis can increase the homozygosity of individual, and also the genetic similarity of offspring within family and between families. And therefore, the artificially induced successive meiogynogenesis is a good method to establish inbred lines in fish.
We studied the gonadogenesis, gender differentiation and early stage development of doubled haploid Japanese flounder (Paralichthys olivaceus) by using histological sections. The results indicated that there were some female, male and also undifferentiated individuals in the doubled haploid population, and the ratio was 56%: 38%: 6%. The gender differentiation in female doubled haploid was later than the normal one. At 100 days, the ovarian cavity was still not closed; and at 110 days, there were a large number of transitional cells from oogonium to oocyte on the spawning board, and the stageⅠoocyte was not observed. For the male double haploid, the gender differentiation was basically the same in time with the normal one. With the development of gonad, there were some abnormal oocytes in the ovaries of double haploids, and some ovaries degenerated. There were also some degeneration appeared in the testes of male doubled haploids. At 9-11 months old, the testis of doubled haploid was at stage Ⅲ, while the testis of normal Japanese flounder develop into stage Ⅳ. From 11 months, the testes of some doubled haploid begun to degenerate. At 13-15 months old, there were only spermatogonium in the seminiferous lobules, and the primary spermatocyte disappeared, like the testis in stageⅡ.
In this study, the full length of turbot NPY cDNA was cloned using RT-PCR and rapid-amplification of cDNA ends (RACE). Turbot NPY cDNA is 729bp with a 5´-untranslated region (UTR), 135bp 3´-UTR and 299bp ORF. The open reading frame encodes a 99 amino acid NPY. The first 28 amino acids constitute the signal sequence followed by the 36 amino acid mature peptide. Turbot NPY share a 53.9–98.0% identity with NPY from other fish, especially, Turbot NPY share a 97–98.0% identity with NPY from other flounder (Japanese flounder, winter flounder).Using real-time PCR to analysis NPY expression in turbot. Tissue distribution studies show that NPY mRNA is expressed in brain, in particular the hypothalamic, and in peripheral tissues. During food deprivation, the NPY undergo significant change in expression (P<0.05), with NPY levels being elevated first, then decreased, and being significantly increased, maintain a high level of expression, then decreased again during food deprivation. Expression level was significantly higher with refeeding after fasting than the normal feeding, the longer of food deprivation, the higher of expression level. But the expression level of 2h after refeeding will fall again to a similar level. Our results suggest that NPY is conserved peptides that might be involved in the regulation of feeding and other physiological functions in turbot.
The full length cDNA of LH has been cloned from pituitary of half smooth tongue sole C. Günther by using RACE technology for the first time. The cDNA of LH is 670 bp，and the open reading frame is 477 bp encoding peptides of 158 amino acid. Multiple amino acid sequences alignments were performed among vertebrates，and the results showed that tongue sole LH mature peptide was the most similar to their orthologs of Pleuronectiformes and Perciformes which was 58 %～68 % identity. And 12 conserved cysteine residues and 1 N-linked glycosylation site were found in the deduced amino acid sequence. Real-time PCR analysis showed that LH mRNA was expressed in all twelve tissues including brain，pituitary，ovary and so on. The highest expression level was in pituitary. And the stronger amplification signals were detected in the brain and gonad than all other non- pituitary tissues. It suggested that LH may had the more physiological functions because LH mRNA of tongue sole expressed widely in non-pituitary tissues. Quantitative real- time PCR was used for analyzing the expression of female C. semilaevis LH mRNA in the reproductive cycle. The results showed that LH mRNA was expressed in all three tissues including brain，pituitary and ovary from the stage Ⅱto stage Ⅵ， and the highest expression level appeared on the stage Ⅳ and stage Ⅴwhich suggested that the main function of LH is to promote eggs finally mature and discharge. Radio immunoassay （RIA）marked by 125I was used to detect the concentration of plasma LH in C.semilaevis. The results showed that the biggest plasma LH concentration appareed on the stage of Ⅴwhich also suggested that the main function of LH was to promote eggs finally mature and discharge.
Scophthalmus maximus was a kind of dietary supplement and ideal healthy and beauty product. The cold-smoked processing technology of Scophthalmus maximus was studied, and the results showed that the product in best taste had a better colour, thicker odour, more compact tissue, less 3,4-Benzo(a)pyrene and Clostridum botulinum in the condition of smoking time of 7d, salt content of 10%, pickling time of 18h and spices content of 1.0%. The smoking, worthy of promotion, was a complex processing and storing method at the same time of heating, smoking and drying to raise its flavour and added value.
To study the effects of salt concentration，curing time and curing methods on the quality of salted turbot，the texture and physicochemical property changes were analyzed. Results showed that the effect of salt concentration and curing time on salted turbot chewing was significant (P<0.05)；while the hardness，elasticity and gumminess was insignificant. Significant effect (P<0.05) of curing methods was also seen in hardness，elasticity and gumminess. During curing process，when the salt concentration increased 2 %，the acid value decreased 1.03 mg/g and the peroxide value decreased 0.1 g/100 g. With the curing time increasing，the acid value and peroxide value enhanced；also，the curing time had significant effects on sensory evaluation (P<0.05). In summary，pickling process had significant impact on the quality of turbot products. Based on the effects of various parameters，this work will provide basic data for further optimization of salted turbot process.
In order to understand hydrodynamic characteristics of circular gravity cage in varied flow-field, and obtain both the flow-velocity variations and flow-field distribution inside and around cages, four models(C1,C2,C3,C4) were designed to be measured at specific measurement points at a velocity of 0.068m/s,0.105m/s,0.143m/s,0.182m/s by particle image velocimetry (PIV) technique and acoustic Doppler velocimeter(ADV).The experimental data showed that the measurement result of ADV was basically same with that of PIV. The ratio of flow-velocity reduction inside a cage remained approximately the same in different current. On the effect of the flow-velocity reduction ,the cages with small mesh did better than the cages with big mesh and the cage with diamond mesh did better than the cage with round mesh at the same velocity. As current flowed through multiple cages, the flow velocity was gradually reduced. The flow velocity inside and downstream from the cages decreased with increasing number of net cages. The flow-velocity reduction was 67.6% inside the second cage, 88.2% inside the forth cage,72.1%downstream from multiple cages. This research can provide a reference to a suitable type of net cages used in production practice.
This study presents how the UV device affecting the Cynoglossus semilaevis’s RAS environment and its growth by arranging the device in the front end and rear end of biofilter.The results showed that ：a. the change of positions of UV device has no significant effects on sterilize the bacteria and Vibrio，but it has huge impact on the number of bacteria and Vibrio in culture pond；b. when the UV device was placed on the rear end，the biofilter’s removal rate of NH4+ -N，NO2- -N，COD was 35.81 %，6.67 %，12.00 %，lower than when it was set on the front end，which is 51.51 %，11.54 % 42.45 %；c. when the device was in the front end，the mean concentration of ammonia nitrogen and nitrite nitrogen was down by 9.7 %，21.6 % than it was on the rear end；d. the change of positions of UV device affects the growth rate of the fish remarkably，The special growth rate (SGR) for the two group respectively were 0.99，0.21，The lead of fish weight gain rate was 4.27 % significantly below the rear of 21.71 %；e.the difference between the two groups was obvious；the number of erythrocyte，leucocyte and hemoglobin of the fish were much lower than the rear group.
In this study, the morphological changes of ovary development and variation of correlated plasma sex steroids levels were detected in Alosa sapidissima. The result shown that Alosa sapidissima belongs to the non-synchronized multiple batch spawner; based on size, shape and external color, the development of ovary was divided into six stages; according to changes of inner structures, yolk accumulating and development of follicle cells, the oogenesis could be divided into six phases. There were no significant differences about hepatosomatic index (HSI) and condition factor (CF) during the ovarian maturation cycle, but gonadosomatic index (GSI) and 17β- estradiol (E2) were found to increase during the peak phase of vitellogenic growth corresponding to the ovary development.
These studies were focused on second and third industry, cluster of aquaculture was rarely explored and reported. Using Location Quotient and Spatial Gini Coefficient methods, the cluster of lefteye flounder Farming Industry of China from 2003 to 2012 was estimated and in this paper. The results showed that industrial cluster does exist in flounder aquaculture of China, mainly clustered in Shang Dong and Liao Ning. Its cluster degree in Shang Dong has been highest since the development of this industry, but it has decreased since 2005. Contrarily, its cluster degree in Liao Ning has kept on increasing. This study suggest that: the industry cluster of flounder aquaculture is influenced not only by resource endowments and demand factors, but also by technological innovation and industrial policies; if one want to promote the industrial clusters of this industry, industrial policy and technological innovation should be paid more attention, at the same time, industrial culture, which can help to create demand and lead the development of this industry, should be forged.
Stocking density is widely recognized as a critical husbandry factor in modern intensive aquaculture and inappropriate stocking density is a potential source of chronic stress that may affect the welfare of farmed fish, and increase breeding risk. So far the effect of stocking density on the fish welfare was studied widely. In order to provide reference for selecting suitable stocking density and further researching, this review will focus on the fish welfare indicator such as growth performance, health status, stress response and behavior, to explore how stocking densities affect fish welfare.
With the hot problem of the deepening of water shortage, environmental degradation, efficient development of aquaculture, food safety and security, etc, which makes that the "resource-based" factory farming water is gradually an urgent need to "efficient type" recirculating aquaculture change. In this paper, industrialized farming concept as a guide, energy saving and emission reduction targets to agro-industrial technology research of flatfish system has been based on the model-based recirculating aquaculture systems (RAS) design principles to build accurate "conserving facility type" RAS, optimize their breeding process, and preliminary exploration of marine fish in this integrated system. Low build the system for the majority of aquaculture enterprises to provide a construction cost, the system is stable, practical farming model is easy to manage, but also for the further development of aquaculture in the establishment of modern precision engineering system to provide basic theory.