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Neolissochilus benasi is an important aquatic germplasm resource, but there is a problem of large differences in growth rate among individuals during the breeding process.
The study aims to identify molecular markers significantly associated with the growth traits in N. benasi and promote the improvement of its growth characteristics.
The study focused on melanocortin-4 receptor (MC4R) gene, which are deeply related to ingestion, energy metabolism and growth development. Single nucleotide polymorphism (SNP) detection and genotyping were performed using PCR-Sanger sequencing technology, and association analysis was conducted between the SNP loci and growth traits to identify SNP markers related to the growth traits of N. benasi.
The results showed that there were 15 SNP loci in the two copies of MC4R gene, with one SNP locus in the first copy and 14 SNP loci in the second copy. Among the 15 SNP loci, only G227A was a missense mutation, with the amino acid type changed from valine (V) to isoleucine (I). The remaining loci were synonymous mutations. Population genetic analysis showed that, except for SNP locus G669C in the first copy with low genetic parameter values, the SNP loci in the second copy of MC4R gene had an expected heterozygosity (He) and observed heterozygosity (Ho) of 0.860 4±0.027 2 and 0.503 2±0.001 4, respectively, and their polymorphic information content (PIC) ranged from
This study preliminarily screens 15 candidate SNP loci associated with growth traits in N. benasi, providing a scientific basis for further analysis of growth-related mechanisms and molecular markers, as well as for the improvement of growth traits in this species.
Fishes and other aquatic products are important agricultural products, with typical nutritious, healthy and delicious food, and play an important role in ensuring the food and nutritional security in the world.
China has a long history of fish farming, featuring the world’s earliest treatise on the subject, “the Classics on Fish Breeding”, as well as the establishment of the oldest ecological farming method known as the “Mulberry Fish Pond”. In China, the artificial breeding technology of silver carp, bighead carp, grass carp, green carp and mud carp have been overcome, and have a complete theory of fish ecological farming—“the Eight Character Intensive Breeding Method” and richly fish culture. Since 1980s, China’s fish farming technology and farming model had been continuously innovating, and green transformation and upgrading, respectively. The variety, area, and output of fish farming have been continuously broken through which grass carp farming output have been taken the first place of a characteristic fishery. The pond farming mode have occupied an important position, and the characteristic development model of “variety research-integrated technology-industrial development” had been formed. Human have completed the structural adjustment from “difficulty in eating fish” to “consuming a large quantity of fish”, and even “consuming high-quality fish”, and make leapfrog development of fish farming from nearshore to deep sea. China is now a big country in fishery in world, the aquaculture yield is two-thirds of the world’s total aquaculture output.
With the promotion of the “Five Actions” in green and healthy aquaculture technology, “efficiency, quality, ecology, health, sustainability and safety” are the directions for the green development of China’s fish farming industry. It will be of great significance and play an important role in improving people’s living standards and promoting the strategy of rural revitalization.
This study aims to analysis the genetic diversity of Cyprinidae in South China, and provide reference for genetic breeding of freshwater fish.
The genetic diversity of Cyprininae fish in South China, a total of 156 samples from six populations of four species of Cyprininae fish, including Cyprinus carpiorubrofuscus Lacepede, Cyprinus acutidorsalis Wang, Cyprinus multitaeniata Pellegrin et Cheveyand, Carassioides cantonensis Heincke, were collected in Hainan Province, Guangdong Province, and Guangxi Zhuang Autonomous Region. The mitochondrial D-loop marker was used to analyze genetic diversity.
This study showed that the genetic diversities of Cyprinus carpio rubrofuscus Lacepede had higher genetic diversity. In which, the haplotype diversities based on D-loop were 0.814, 0.895 and 0.879, respectively. The haplotype diversities of Carassioides cantonensis Heincke, Cyprinus acutidorsalis Wang and Cyprinus multitaeniata Pellegrin et Chevey based on D-loop were in lower levels, which were 0.748, 0.794 and 0.536, respectively. Among which, the genetic diversity of Hainan population was lower a bit than that of the Pearl River population and Rongjiang population. This may be caused by the Ice Age and the separation of Qiongzhou Strait. The genetic diversities of Carassioides cantonensis Heincke, Cyprinus acutidorsalis Wang and Cyprinus multitaeniata Pellegrin et Chevey were in very low levels, which were related with their small distributions and low viabilities. This study found that Cyprinus acutidorsalis Wang, Cyprinus multitaeniata Pellegrin et Chevey, and Carassioides cantonensis Heincke did not share any haplotypes, indicating that there was no recent population exchange among these three taxa and suggesting significant population differentiation. Additionally, Cyprinus multitaeniata Pellegrin et Chevey and Carassioides cantonensis Heincke did not share haplotypes with Cyprinus carpiorubrofuscus Lacepede, indicating that there was no recent genetic exchange between these two taxa and Cyprinus multitaeniata Pellegrin et Chevey and Carassioides cantonensis Heincke have been separated from the population of Cyprinus carpiorubrofuscus Lacepede for a relatively long period of time.
This research provides important insights into the natural resource status of Cyprinidae fish in South China and offers a reference for future conservation and genetic breeding.
This study aims to understand the growth, gonadal differentiation process and regulatory mechanism of juvenile Thamnaconus modestus under artificial breeding conditions.
After 10 days post-hatching, 30 fish were sampled every 5 days. The growth indices such as body mass, total length (TL), body length (BL), preanal length (PL), head length (HL), body height (BH), snout length (SL), and eye diameter (ED) were measured. Paraffin-embedded sections and hematoxylin-eosin staining were used to observe the development of gonads. At the same time, the samples were homogenized, and the changes in the content of 17β-estradiol (E2) and testosterone (T) were determined.
There were no significant differences in the growth indices such as body mass, TL, and BL of juvenile T. modestus among 10−20 days (P>0.05), while they increased significantly from 25 days (P<0.05). There was no significant difference in PL between 10 and 15 days (P>0.05), while it increased significantly from 20 days (P<0.05). There were no significant differences in HL, BH, SL and ED between 10 days and 20 days (P>0.05), but they began to increase significantly at 30 days (P<0.05). In addition, at 25−35 days, the undifferentiated gonads were observed to appear in pairs near the intestine and connect with the mesentery, and the blood vessels were observed in the gonads. At 60 days, oogonia or spermatogonia were observed in some juvenile T. modestus, indicating that the gonads had differentiated into females and males. In the process of sex transition to female, the E2 content was low, when the gonads were undifferentiated. However, the E2 content significantly increased after the finish of sex differentiation at 60 days (P<0.05). In the process of sex transition to male, the T content was lower when the gonads were undifferentiated and increased after the finish of sex differentiation at 60 days.
These results suggested that the growth turning point of juvenile T. modestus may occur at 20−30 days, and the age of sex differentiation may be 35−60 days. Estrogen and testosterone may be the key factors that induced juvenile T. modestus to change their gender to female and male, respectively. This study clarifies the process of sex differentiation and the changes in hormone content during the differentiation process, which may provide the theoretical basis for the sex regulation and artificial reproduction in T. modestus.
Fujian Province is one of the most potential coastal provinces for fishery development. Conducting a comprehensive evaluation of fishery development quality has great significance for promoting high-quality development of fisheries.
This paper provides a comprehensive evaluation of the fishery development quality in different cities of Fujian Province, exploring effective ways to improve the overall quality of fishery development.
Based on the panel data of nine cities’ fishery development in Fujian from 2017 to 2022, this paper constructed an integrated evaluation index system from four dimensions for the quality of fishery development in various cities of Fujian. Using the entropy weighted TOPSIS method, the quality of fishery development in various cities was measured.
The fishery development quality evaluation index of different cities was quite different in the two dimensions of production benefits and technology. In terms of production benefits, the coastal evaluation index of Fuzhou, Xiamen, Quanzhou, Zhangzhou and Ningde was much higher than the inland cities of Sanming, Nanping and Longyan. In terms of technology, Fuzhou, Xiamen and Quanzhou, the gathering cities of colleges and universities, ranked highly in the index. For the single city, Fuzhou was the city with the highest quality in fisheries development in Fujian Province; Xiamen and Quanzhou ranked the second, with promising future in fisheries; Zhangzhou, Putian, and Ningde cities were located in inland areas, then their overall level of quality development in fisheries was not high.
There were differences in the quality of fishery development in various cities in Fujian Province, and the differences were increasing. Based on the advantages and disadvantages of the fishery development in various cities, it is proposed to construct a “one core, two wings, three points, and three regions” development pattern with Fuzhou City as the “core”, Xiamen and Quanzhou cities as the “wings”, Zhangzhou, Putian, and Ningde cities as the “driving points”, and Sanming, Nanping, and Longyan cities as the main areas of freshwater fisheries. In addition, it is suggested to extend the fisheries industry chain.
This article provides a reference and help for comprehensively and quantitatively evaluating the quality of fishery development in various cities in Fujian Province, putting forward development strategies based on local conditions, and promoting high-quality development and advancement of fisheries in Fujian Province.
Grass carp reovirus (GCRV) infection can cause leakage bleeding by increasing vascular endothelial permeability.
To investigate the functional mechanism of adenylate cyclase 3 (AC3) mediated GCRV infection, a series of studies were conducted in Ctenopharyngodon idella kidney (CIK) cells.
AC3 overexpression was successfully achieved in CIK cells. Real-time fluorescent quantitative polymerase chain reaction (qPCR) was used to detect the relative expression of ac3, claudin c, claudin 15, claudin 18, irf3, irf7, ifn1 and ifn2 at different time points (0 h, 12 h, and 24 h) of GCRV infection. The protein level of GCRV VP7 was detected by Western blot (WB). The transendothelial electrical resistance (TEER) of the CIK cell layer under various conditions was measured using a cell resistance meter, while the connections between CIK cells were examined using a transmission electron microscope.
The results showed that AC3 overexpression significantly enhanced the expression of tight junction molecules claudin 15 and claudin 18 in CIK cells, but had no significant effect on the expression levels of interfering semaphorin pathway genes irf3, irf7, ifn1 and ifn2. However, the protein amount of GCRV VP7 was inhibited. The transepithelial electrical resistance assay demonstrated that AC3 overexpression significantly increased the resistance of the CIK cell layer. Transmission electron microscopy results indicated that AC3 overexpression reduced the extent of damage to CIK cell-to-cell junctions caused by GCRV infection.
In summary, AC3 can influence the relative expression of claudin molecules and the barrier function of cells, inhibiting GCRV proliferation within these cells.
This study introduces a novel approach for discovering GCRV resistance-related molecules from the perspective of cell permeability.
Marine fouling organisms pose severe problems to aquaculture. However, the metal-based antifoulants pollute marine environment. Thus, environmentally friendly alternatives are urgently needed. Natural antifouling products are important sources of environmentally friendly antifoulants.
The aim of this study is to screen out the deep-sea microbial resources with antifouling activity.
Here the microorganisms from the different sediments of the deep sea were isolated and the antifouling activity of their fermentation broth extracts was tested using the settlement assays with the mussel Mytilopsis sallei juveniles and the bryozoan Bugula neritina larvae. Furthermore, the residual effect of the bacterial extracts on M. sallei juveniles were examined.
The results showed that 15 microorganisms of 10 genera were isolated from 6 types of the deep-sea sediments. Marinobacter was the dominant bacterial group. The extracts of strains B2 (Alteromonas sp.), C1 (Marinobacter sp.), C2 (Escherichia sp.), E1 (Pseudoalteromonas sp.), E2 (Marinobacter sp.) and F2 (Flagellimonas sp.) inhibited settlement of M. sallei juveniles, and the extracts of the strains B1 (Marinomonas sp.), B2 (Alteromonas sp.), C2 (Escherichia sp.), C3 (Marinobacter sp.) and E2 (Marinobacter sp.) inhibited settlement of B. neritina larvae. The bacterial extracts of strains F2 (Flagellimonas sp.) and fermentation broth extracts of C1 (Marinobacter sp.) and E2 (Marinobacter sp.) showed no residual effect on M. sallei juveniles, indicating their low toxicity.
Eight strains of antifouling bacteria are isolated from deep-sea sediments, among which strains F2, C1, and E2 demonstrate potential in the field of environmentally friendly marine antifouling.
The white spot syndrome virus (WSSV) is a highly infectious and lethal pathogen that poses a significant threat to the global shrimp farming industry. WSSV can spread rapidly through both horizontal and vertical transmission, leading to mortality rates of up to 100% within 3−10 days post-infection. Due to the absence of effective prevention and treatment measures, developing rapid, accurate, and sensitive detection technologies for WSSV is crucial for timely diagnosis and implementation of control measures to prevent disease spread.
This study aimes to establish a sensitive and specific duplex real-time fluorescent quantitative PCR (qPCR) method for the simultaneous detection of WSSV and an endogenous control gene in shrimp.
First, specific primers and TaqMan probes were designed based on the conserved sequences of the WSSV genome, establishing a single WSSV qPCR detection system. Specificity and repeatability tests confirmed that the method had excellent specificity for WSSV without cross-reactivity, with the coefficient of variation for different gradients of plasmid standards being less than 1.5%, indicating high repeatability. Subsequently, primers and probes for the endogenous control gene of Litopenaeus vannamei were designed and synthesized, and the primer sequences were optimized to establish a duplex qPCR detection system.
Sensitivity tests revealed that the detection limit of the duplex system for WSSV was 15 copies·µL−1, with a strong linear relationship between the logarithmic value of the initial template amount and the cycle threshold (Ct) value of WSSV plasmid standards within the range of 6.6 to 6.6×105 copies·µL−1(R²=0.998). Furthermore, the incorporation of the endogenous control gene effectively distinguished false-negative results caused by nucleic acid extraction or operational issues in the samples.
In conclusion, the established duplex qPCR detection method for WSSV and the shrimp endogenous control gene exhibits high sensitivity, strong specificity, and good repeatability. This method provides a reliable technical approach for the rapid diagnosis and epidemiological investigation of WSSV, which is crucial for controlling WSSV outbreaks and ensuring the sustainable development of the shrimp farming industry.
Coelomactra antiquata is an economically important marine shellfish species that is valued for both its culinary and medicinal properties. In recent years, the artificial breeding of C. antiquata along the coast of Zhanjiang has been successful, and large-scale proliferation and release have been carried out in the coastal areas. The large amount of precipitation in summer in the coastal area of Zhanjiang has caused a significant decrease in the salinity of the coastal waters, which poses a great threat to C. antiquata.
The changes of low salinity tolerance and related enzyme activities of C. antiquata were investigated.
C. antiquata, collected from the Xuwen sea area of Zhanjiang, was used as experimental materials. The gradual and acute dropping salinity groups were set up to explore the low salinity tolerance of C. antiquata through comparing the 50%CSMin (the salinity at which half of the C. antiquata survived) during the gradual dropping salinity process and the 72 h LS50 (the salinity at which the survival rate was 50% within 72 hours) during the acute dropping salinity process. The gill tissues of acute dropping salinity groups at 0 h, 6 h, 12 h, 24 h and 48 h were taken to investigate the immune indicators under low salinity stress, including Na+/ K+-ATPase (NKA), superoxide dismutase (SOD), catalase (CAT), alkaline phosphatase (AKP), acid phosphatase (ACP) and lysozyme (LZM).
The minimum survival salinity (SSMin) was 18.22, the minimum critical salinity (CSMin) was 10.18, and the salinity at which the survival rate was 50% (50%CSMin) was 13.07. The median lethal salinity after 72 h (72 h LS50) was 16.86. The NKA, CAT, SOD, AKP, ACP and LZM of gill tissue were significantly affected by acute dropping salinity stress for 48 h (P<0.05). CAT, SOD, ACP, AKP and LZM all showed a trend of increasing first and then decreasing, and their minimum values were 75.36 U/mL, 293.8 U/mL, 0.292 U/L, 0.321 U/L and 5.283 U/mL, respectively. NKA showed an upward trend, and the minimum value within 48 h was 0.339 U/mL.
At the same salinity, the survival rate of the acute dropping salinity groups were significantly lower than that of the gradual dropping salinity groups. This study provides an important theoretical basis for the further study of the low salinity antioxidant response mechanism in C. antiquata, and also offeres an important guiding for the artificial breeding of C. antiquata.
In light of escalating anthropogenic activities impacting aquatic ecosystems and global climate change, the frequency and magnitude of red tide occurrences have been steadily increasing year after year. Red tide has evolved into a marine ecological catastrophe that poses a grave threat to oceanic ecological environments, socio-economic development, and public health. Fujian Province possesses abundant marine resources; however, the rapid progress of marine aquaculture is hindered by the occurrence of red tide. Therefore, the development of precise, rapid, and specific detection techniques for harmful algae is imperative to enable early monitoring and warning systems for red tides.
The study evaluated a rapid detection method that combined recombinase aided amplification (RAA) with LbCas12a nuclease. This method was tested using field red tide samples and pilot applications, with Karenia mikimotoi, Karlodinium veneficum, and K. brevis serving as representative species. The core principle of the RAA-LbCas12a method involved designing amplification primers and crRNA that specifically targets the internal transcribed spacer (ITS) region unique to the desired algal species, which enabled rapid amplification of the target nucleic acid, followed by analysis of the amplification products. Additionally, lateral flow strips were utilized for visual interpretation of the detection results.
The RAA-LbCaas12a assay demonstrated high accuracy in detecting target microalgae in field red tide samples, even at concentrations as low as 10 cells/mL (representing only 0.1% of the total cells present in red tide samples). While the target microalgae in environmental samples were consistently detected multiple times during the 65-day pilot application, it demonstrated a large level of concordance with the results obtained from colloidal gold immunoassay strips and microscopic observations. Importantly, no significant instances of false positives were observed.
Field application data demonstrate that the RAA-LbCas12a technology exhibits remarkable sensitivity, specificity, reliability, and operational simplicity. Additionally, this technology has proven to be highly applicable for the field detection of various red tide algae species. The RAA-LbCas12a technology only requires a portable rapid detection toolkit, enabling field inspectors to promptly perform on-site microalgae testing, which holds immense significance in enhancing red tide monitoring and early warning capabilities, as well as strengthening measures for preventing and controlling marine ecological disasters.
Stock enhancement has been widely used as an important resource restoration measure in global fisheries management. However, its long-term impact on the genetic characteristics of target species still requires further investigation. Acanthopagrus latus, an important commercial fish species in the coastal waters of Xiamen, Fujian Province, has genetic stability that is crucial for maintaining the health of its population.
This study aims to evaluate the impact of recent stock enhancement on the genetic characteristics of A. latus in the coastal waters of Xiamen and to determine whether it has caused any significant effects on the germplasm resources of the population.
Mitochondrial DNA control region sequences were used to sequence samples of A. latus collected at different time points in the coastal waters of Xiamen. Genetic diversity analysis, phylogenetic tree construction, and analysis of molecular variance (AMOVA) were employed to assess the genetic variation within the populations.
The analysis revealed 66 mitochondrial DNA control region sequences obtained from 3 A. latus populations, with 82 polymorphic sites, defining 58 haplotypes, 54 of which were unique. The overall genetic diversity level of the populations was high. The NJ-Tree based on 58 mitochondrial control region haplotypes showed that all A. latus clustered into one group. AMOVA analysis indicated that the majority of genetic variation in the populations came from within the groups, with only 1.23% of the variation attributed to differences between groups.
The recent stock enhancement activities in the coastal waters of Xiamen have not significantly affected the genetic diversity of A. latus, and the population’s genetic structure remains stable. This finding supports the optimization of future stock enhancement strategies and the sustainable management of A. latus resources.
At present, domestic and foreign scholars have used morphology, spectroscopy, mass spectrometry, molecular biology and other technologies to identify sea cucumber from the morphology, chemical substances contained, nucleic acid differences and other aspects of sea cucumber, but considering the technical requirements and time cost, morphology is still the main identification method of sea cucumber.
The dermis surface layer of sea cucumbers contains ossicles, which constitute the distinguishing feature of this class. The types and relative proportions of these ossicles can facilitate rapid identification of different sea cucumber species.
In this study, NaClO and protease K methods were employed to extract and process tissues of sea cucumbers (Apostichopus japonicus) aged 1 to 3 years from the Pingtan sea area (Fujian, China). Tissue samples included spines, body walls, tentacles, tube feet, longitudinal muscles, respiratory trees, and intestines. Ossicle images obtained through these methods were compared, and the relative proportions of each type of ossicle were analyzed using SPSS software.
The results revealed seven types of ossicles: table-shaped, button-shaped, rod-shaped, rosette-shaped, long hole-like body ossicles, composite discoid ossicles, and C-shaped ossicles, observable under both light and electron microscopes, with significant differences (P<0.05). Comparing the images obtained by NaClO and protease K methods, NaClO-extracted ossicles displayed clearer types and approximate numbers, free from tissue attachment, but were brittle and prone to damage, resulting in incomplete structures. In contrast, protease K-extracted ossicles showed better structural integrity under the microscope, facilitating more accurate counting and analysis, although they retained some tissue. Additionally, the relative proportions of ossicle types significantly differed (P<0.05) across different ages and tissues. For instance, in one-year-old specimens, button-shaped ossicles constituted the highest proportion in the body wall 83.28%±9.33%, while table-shaped ossicles dominated in the body cavity 35.02%±10.84%, and long hole-like body ossicles were most prevalent in tentacles 7.23%±2.50%. Relative proportions in the body wall and tube feet at one year (20.28%±7.29% and 35.02%±10.84%, respectively) were significantly higher than in the second year (3.80%±1.35% and 17.21%±1.87%, respectively) and third year (3.40%±1.43% and 11.23%±1.01%, respectively) (P<0.05).
The results show that the relative proportion of ossicle types of sea cucumber have a difference in different ages and tissues, and can be obtained by various methods stability, which is an important index to identify sea cucumber species.
This study provides the basic data for the biological identification of the A. japonicus and the reference for the age identification.
The genetic and evolutionary variation of different Opsariichthys bidens poputions were explored, which would provide a theoretical basis for the further protection and the maintenance of genetic diversity of breeding populations.
In this study, 136 O. bidens individuals were collected from Mudanjiang River (MDJ), Futunxi River (FTX), Jianxi River (JX), Tingjiang River (TJ) and Nandujiang River (NDJ). The mitochondrial DNA (mtDNA) Cyt b gene and D-loop region sequences from each individual were identified and analyzed.
The results showed that the total haplotypes defined by Cyt b gene and D-loop region in all populations were 35 and 37, respectively; the corresponding overall haplotype diversity (Hd) and nucleotide diversity (π) were 0.922 and
Overall, obvious genetic differentiation among the five populations were observed with the NDJ and TJ populations having the higher genetic diversity, but MDJ, FTX and JX populations having the lower genetic diversity. The results could provide scientific evidence for the conservation, sustainable development, and commercial utilization of germplasm resources of O. bidens.
Crustaceans are a type of biological resource with significant commercial value in fisheries and aquaculture. In recent years, due to the decline of certain traditional fisheries and the increasing demand for high protein foods, resources of crustaceans such as crabs, lobsters, shrimp, and krill have been extensively developed. Therefore, it is necessary to develop stock assessment and management of crustaceans to maintain their sustainable development. However, for crustaceans, the challenge of determining age hampers the development of accurate stock assessments. At present, there are many methods for identifying the age of crustaceans, mainly including feeding method, marker recapture method, body length frequency method, lipofuscin analytical method, radioisotope method, and hard tissue growth band counting method. In recent years, the hard tissue growth band counting method has gained widespread use and significant attention.
Based on the above background, this article first introduces the biological characteristics and hard tissue structure of crustaceans, describes on the experimental process of using the hard tissue growth band counting method to identify the age of aquatic crustaceans, compares it with other methods for identifying the age of aquatic crustaceans, analyzes the advantages and disadvantages of this method, and reviews the research progress of using hard tissue growth zones to analyze the age and growth of aquatic crustaceans. Perspectives are provided on the future challenges that need to be addressed and the development direction of this method.
It is pointed out that in the future work on age determination of aquatic crustaceans, it is necessary to further understand the sedimentation mechanism of growth zones, accurately grasp the counting of hard tissue growth zones, conduct in-depth analysis of the experimental data obtained, and conduct relevant verification experiments.
This paper may provide a systematic reference for future age determination of aquatic crustaceans.
Sea cucumber (Apostichopus japonicus) is a significant species in marine aquaculture, valued for its nutritional and medicinal properties. Ensuring the health and vitality of sea cucumber seedlings is crucial for the success of the industry. Water quality and disease prevention are two key factors that directly influence seedling survival and growth rates. Disinfectants play a vital role in preventing and controlling diseases during the seedling cultivation process. When selecting disinfectants for sea cucumber cultivation, it is essential to strike a delicate balance between their efficacy against pathogens and potential toxicity to the target species. Excessive or inappropriate use of disinfectants can lead to adverse effects on seedlings, including mortality, growth retardation, and physiological stress. Therefore, it is imperative to conduct scientific studies to assess the toxicity profiles of various disinfectants and determine their safe concentrations for use.
This research project aims to comprehensively evaluate the acute toxicity effects of four commonly used disinfectants on A. japonicus seedlings, with the primary objective of providing practical and actionable guidance to growers.
Acute toxicity experiments were conducted on four disinfectants commonly used in aquaculture, employing the static water experiment method. Juvenile A. japonicus were used as the experimental subjects. The experiments were taken place in controlled environments, ensuring consistent water quality parameters such as temperature, pH, and dissolved oxygen. Seedlings were exposed to the disinfectants for a specified duration, during which their behavior, survival rates, and any visible signs of toxicity were closely monitored. After the exposure period, data were collected and analyzed to determine the median lethal concentration (LC50) for each disinfectant.
The results showed that the 24, 48, 72, and 96 hours median lethal concentrations (LC50) of chlorine dioxide were 2.97, 2.06, 1.56, and 0.96 mg/L, respectively, with a safe concentration of 0.43 mg/L at 48 hours. For potassium hydrogen persulfate, the LC50 values at 24, 48, 72, and 96 hours were 9.66, 6.53, 5.50, and 5.07 mg/L, respectively, with a 48-hour safe concentration of 1.32 mg/L. The LC50 values for dibromohydantoin were 12.80, 7.84, 7.01, and 6.02 mg/L at 24, 48, 72, and 96 hours, respectively, with a 48-hour safe concentration of 1.44 mg/L. For povidone-iodine, the LC50 values were 11.95, 9.30, 8.51, and 8.13 mg/L at the same time intervals, with a 48-hour safe concentration of 2.17 mg/L.
The virulence of the disinfectants to A. japonicus manifested as chlorine dioxide > potassium hydrogen persulfate > dibromohydantoin > povidone-iodine. Considering the antibacterial ability of different disinfectants, potassium hydrogen persulfate can be preferred as the disinfectant. The results of this study will offer valuable insights into the safe use of disinfectants in sea cucumber aquaculture.
The study aims to analyze the effects of different feeding frequencies on growth performance of largemouth bass (Micropterus salmoides), culture water quality and bacterial community structure under land-based round drum.
This study conducted experiments with two feeding frequencies: 2 times/day and 3 times/day.
The results showed that the final body mass and specific growth rate of the group fed 3 times/day were higher than those of the group fed 2 times/day. Feeding frequency had a significant impact on the levels of ammonia nitrogen (TAN), nitrite (NO2-N), suspended solids (SS), and chemical oxygen demand (COD) in the water (P<0.05), with the group fed 2 times/day having higher levels than the group fed 3 times/day. The bacterial community structure of the culture water was similar in both groups, with the dominant phyla being Proteobacteria and Bacteroidetes, and the dominant genera being Plesiomonas and Rhodobacter. Statistical analysis of the abundance of common pathogenic bacteria during the culture process of largemouth bass revealed that the average abundance of Aeromonas caviae in the 3 times/day group (0.08%) was significantly lower than that in the 2 times/day group (0.14%) (P<0.05). The results of the correlation analysis between environmental factors and bacterial community structure showed that TAN, total nitrogen (TN), and total phosphorus (TP) had a significant impact on the bacterial community structure of the water (P<0.05).
Based on the aforementioned findings, within the context of a land-based round barrel culture model for M. salmoides, a feeding frequency of 3 times/day has advantages over 2 times/day. These benefits include accelerated growth rates of the bass, reduced levels of critical water quality parameters in the culture medium, and diminished abundance of pathogenic bacterial populations. The research outcomes furnish tangible support for the scientific feeding practices of M. salmoides within land-based round barrel culture systems.
China is a major aquaculture country. In the context of carbon peak and carbon neutrality, it is necessary to accelerate the establishment of management systems for the carbon footprints (CFP) and enrich the practice of CFP barcodes for products, in order to adapt to the trend of low-carbon economy of the future.
The present study aims to establish and optimize the CFP accounting method for aquatic products, as well as to compare the CFP of major oyster products in Fujian Province.
Here, the CFP of diploid oyster (Crassostrea angulate) and triploid oyster (C. angulate ♂ × C. gigas ♀) were compared by life cycle assessment. The inventory analysis included the periods of breeding in the factory, farming in the sea and cultivation marketing.
The results showed that the “cradle-to-gate” CFP of 1 ton diploid and triploid oysters were −210.79 kg CO2eq and −37.92 kg CO2eq, respectively. The “cradle-to-grave” CFP of 1 ton diploid and triploid oyster were −93.89 kg CO2eq and 78.98 kg CO2eq, respectively. The main carbon emissions of cultured oyster products came from the power consumption in the breeding period and the emission of farming facilities in the aquaculture period. In the future, carbon emissions can be further reduced by increasing renewable energy and using new materials in farming facilities.
Compared with other aquaculture products, oysters have lower carbon emissions than most seafood, suggesting its environment-friendly superiority.
This study will supporting the scientific management of aquaculture product carbon emissions and development of CFP assessment methods, which is conductive to the green transformation of aquaculture under the background of carbon peaking and carbon neutrality.
In this study,juvenile A.japonicus (experimental group) were purchased from northern China and reared in southern China under natural water temperature for one year.The same age seedlings of juvenile A.japonicus (control group) were directly collected from northern China to compare their thermal resistance with those of the experimental group.The study of thermal limits showed that the sublethal temperature of A.japonicus in the experimental group was 32 ℃,significantly higher than the 30 ℃ in the control group.The ULTs50 of A.japonicus in the experimental and control groups were 33.1 ℃ and 31.9 ℃,respectively.These results demonstrated that the thermal history influenced the upper thermal limit of A.japonicus,and A.japonicus undergoing continuous thermal shock would possess stronger thermal resistance.Additionally,the expression patterns of HSP90a,gp96,HSP70,HSP26,and proeintl(2)efl genes after heat shock for 1,2,and 3 hours between the experimental and control groups were analyzed using qRT-PCR.The expression patterns of HSP90a,gp96,HSP70,HSP26,and proeintl(2)efl genes were different between the experimental and control groups.At 30 ℃ heat shock,the gene expressions of HSP90a,gp96,HSP70,and HSP26 in the control group did not noticeably increase after stimulation for 1 and 2 hours but were significantly up-regulated at 3 hours,with expression values reaching (9.801±1.303),(2.508±0.910),(8.649±1.936),and (34.787±4.978),respectively.However,all of the HSP90a,gp96,HSP70,and HSP26 gene expressions in the experimental group were dramatically up-regulated at 1 hour at 30 ℃,with expression values reaching (42.000±8.798),(20.019±6.224),(218.750±78.701),and (93.710±5.674),respectively.These four temperature-tolerant related genes detected in the present study in the experimental group were up-regulated earlier than those in the control group,indicating a higher ability of A.japonicus in the experimental group to respond adaptively to heat shock than that in the control group.Therefore,the research showed that A.japonicus undergoing high temperature acclimation could respond earlier to external environmental heat conditions.
This study aims to examine the interannual variation in the species diversity of crabs in the waters around Zhongjieshan Islands, Zhejiang Province during spring.
Based on the bottom trawl fishery resource survey data in spring (April) from 2016 to 2020, the abundance density index, relative importance index, biodiversity index, species turnover rate, abundance density contribution rate, and redundancy analysis method (RDA) were applied to study the species composition, species turnover, dominant species, abundance density status, community stability, contribution of dominant species to the abundance density of crabs during spring, and their relationships with environmental factors, respectively.
The study showed that a total of 14 species of crabs, belonging to 1 order, 6 families and 9 genera, were caught in spring over the five years, among which, 8 species were caught in 2016, 6 species were caught in 2017, 10 species were caught in 2018, and 9 species were caught in each of 2019 and 2020. The turnover rate of the number of species between the adjacent years ranged from 36.36% to 44.44%. Both biomass and number density were the highest in 2018, with the lowest biomass occurring in 2016 and the lowest number density in 2019. Portunus trituberculatus, Charybdis japonica and C. bimaculata were all co-dominant species over the five years, in which the total contribution of P. trituberculatus and C. japonica to crab biomass was more than 54% in each year. The richness and evenness were both the highest in 2018, while the highest diversity occurs in 2019, and both diversity and evenness were the lowest in 2017, while the richness was the lowest in 2020. The abundance of P. trituberculatus and C. japonica showed a significant positive correlation with dissolved oxygen (DO) at the bottom of seawater (P<0.05), and a significant negative correlation with water depth and bottom seawater salinity (P<0.05), while the abundance of C. bimaculata showed a significant positive correlation with bottom seawater temperature (P<0.05).
The crabs community in the waters around the Zhongjieshan Islands in spring of 2016—2020 was lightly disturbed.
The study aims to develop a practical, effective, simple and feasible wastewater treatment technology for Litopenaeus vannamei aquaculture, in order to promote the green and healthy development of the industry.
On the basis of the traditional sulfur limestone autotrophic denitrification system (SLAD), an autotrophic denitrification system was composed of pyrite and volcanic rock. The wastewater of shrimp farming was taken as the research object to investigate the effect of different hydraulic retention times (HRT) on nitrogen and phosphorus removal in the system. The reactor was continuously operated for 40 days to observe the denitrification and phosphorus removal efficiency and stability of the system. The morphology and structure of the material surface were observed using scanning electron microscope (SEM), and the microbial community structure on the filler surface was analyzed using high-throughput sequencing.
The removal efficiencies of nitrogen and phosphorus in the reactor increased with the increase of hydraulic retention time. By the end of the experiment, the removal efficiencies of total nitrogen and total phosphorus remained stable at around 90% and 50%, respectively, with a pH value between 6.4 and 7.0. The microbial types on the surface of the system packing were mainly Thiobacillus and Halothobacillus, which were distributed in all four types of packing.
The reactor exhibits efficient denitrification and phosphorus removal capabilities, with the autotrophic denitrification system based on pyrite emerging as a promising approach for treating aquaculture wastewater.
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