Aquaculture Fisheries
As an important economic shrimp species, the Litopenaeus vannamei is frequently affected by bacterial diseases, especially Vibriosis (including Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio harveyi, Vibrio cholerae, etc.) during intensive aquaculture. This represents a significant risk to the long-term sustainability of aquaculture. With the widespread use of antibiotics, resistance genes of pathogenic bacteria are prevalent and widespread in the aquatic environment, posing new challenges to the prevention and treatment of Vibriosis. Therefore, it is extremely important to emphasize the maintenance of aquaculture environment and water quality monitoring. This review describes a series of biological control measures, including the use of biofloc technology, probiotics, antimicrobial peptides, quorum sensing inhibitors, and the use of biological control methods such as Bdellovibrio and like organisms and bacteriophage. The combination of biofloc technology and probiotics can improve water quality and enhance immunity. However, it is greatly affected by the environment, making it difficult to control the stability of bacteria flora. Antimicrobial peptides exhibit a broad spectrum of antibacterial activity, and they are safe and not easily resistant to drugs. However, they are difficult to preserve and have a high cost. Quorum-sensing inhibitors provide precise prevention and treatment with minimal environmental impact, but the mechanism research on them is limited. Bdellovibrio are effective at lysing Gram-negative bacteria but have a poor effect on Gram-positive bacteria and grow slowly. Bacteriophages are highly specific but have a narrow host range. Although these biological control measures are less effective than antibiotics, they are environmentally friendly, less prone to drug resistance, and aim to reduce chemical drug dependency, protect the ecosystem, and improve aquaculture efficiency. In the future, innovative and sustainable biological control technologies should be developed to address the challenges posed by pathogenic bacterial resistance and environmental protection.
Tissue section staining observation technology and physiological and biochemical detection methods were used to study the hepatopancreas histopathological and blood biochemical indicators of acute poisoning of Eriocheir sinensis under high concentration nitrite farming conditions, five experimental concentrations were set: 10.16, 21.13, 30.06, 41.11, and 51.04 mg/L. The results showed that acute intoxication caused shrinkage of the basement membrane of the hepatopancreatic tubules in crabs, with severe cases resulting in rupture. The hepatopancreatic cells were separated from the basement membrane to form a large gap. The cell boundary was not obvious, and the arrangement was disordered and fell off to the lumen. Some hepatic tubules were broken, the tissue dissolved, and the stromal cells infiltrated; the hemocyte density (DHC) in the blood increased. In haemolymph of acute poisoning crabs, glutamic oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT) and the glucose content (GLU) increased, the activities of triglyceride (TG) decreased. Immunological indexes showed that superoxide dismutase (SOD) and catalase (CAT) decreased but the activity of galkaline phosphatase (ALP) increased. The research indicated that acute high concentration nitrite poisoning caused great damage to the hepatopancreas and reduced the immunity of the crab, ultimately affecting the normal feeding and activities of the crab. When the concentration of nitrite in the water of Eriocheir sinensis aquaculture is 41.11 mg/L, the mortality rate is 50% at 20 hours and 60% at 24 hours; when the concentration of nitrite is 51.04 mg/L, the mortality rate is 50% at 8 hours and 80% at 24 hours.
In order to further understand the application of Integrated Multi-Trophic Aquaculture (IMTA) in aquaculture industry, the paper sorted out the development history of IMTA, and outlined the main aquaculture species of IMTA, including fishes, crustaceans, bivalves, echinoderms and algae, et al. It summarized land-based and marine IMTA, and pointed out that freshwater and brackish water IMTA were part of the land-based aquaculture models, while seawater and offshore IMTA belonged to marine IMTA. The article also outlined the advantages of IMTA in terms of aquaculture environment, energy utilization, economic benefits, and reduction of waste discharge. At present, IMTA still has problems in the aspects of technical implementation, ecological impacts and sustainable development. Future research should focus on the interactions among different species components, system optimization, and disease control to promote the sustainable development of aquaculture.
This study aims to investigate the physiological and molecular responses of Corbicula fluminea to salt-alkali stress. Corbicula fluminea was subjected to varying concentrations of salt-alkali stress to monitor and analyze survival rates and ATPase activity, thereby assessing its tolerance to sodium chloride-induced salinity, sodium bicarbonate-induced alkalinity, and the combined effects of salt-alkali interaction stress. The findings indicated that the median lethal concentrations (LD50) of sodium chloride at 24, 48, 72, and 96 h were 70.22, 44.86, 22.87, and 9.92 g/L, respectively, with a safe concentration (SC) of 5.5 g/L; the median lethal concentrations (LD50) of sodium bicarbonate alkalinity at 24, 48, 72, and 96 h were 309.56, 188.03, 86.4, 35.97 mmol/L, and SC was 20.81 mmol/L. The interaction of salt-alkali stress exhibited an antagonistic effect on Corbicula fluminea, with the toxicity of the combined stress being less than that of either salinity or alkalinity alone. Following exposure to saline-alkali water at a safe concentration, the activities of Ca2+-Mg2+-ATPase and Na+/K+-ATPase in the gills demonstrated a significant increase within the first 12 hours (P<0.05). These activities continued to rise, reaching normal levels after 24 hours and peaking at 72 hours (P<0.05). The study indicates that Corbicula fluminea exhibits a degree of tolerance to saline-alkaline water conditions, indicating its potential for cultivation in environments where salinity does not exceed 5.5 g/L or alkalinity remains below 20.81 mmol/L.
The team adopted the model of two dams and three zones to carry out ecological transformation of ponds in the Yangtze River Delta. In order to explore whether the transformation can improve the immune ability of fish, this study compared the changes of several immune factors in the serum of genetic improvement of farmed tilapia (GIFT) in the untreated and treated groups of waste water, and solved the key industrial problem of cost accounting in the application of the two dam and three zone model. Results showed that the treated aquaculture waste water would not affect the SGR and HSI of the tilapia, and had no significant effect on the growth index of the fish (P>0.05). The levels of immune factors α1-AT and LYS in GIFT were significantly increased, and the contents of pro-inflammatory factors (IFN-γ) and anti-inflammatory factors (IL-10 and TGF-β) were significantly increased (P<0.05). Significant changes in the levels of several immune factors have been observed in tilapia serum after treatment of aquaculture wastewater.
To investigate the effects of salinity stress on the growth and antioxidant capacity of channel catfish fry, we established six salinity groups (3.0, 3.8, 4.7, 5.9, 7.3, 9.0) and one control group using the equidistant spacing method, the tolerance of each group to different salinity levels was assessed by measuring growth indexes, four physicochemical indexes, and H&E stained sections. The findings demonstrated that the growth performance and survival rates of fish fry at salinities of 3.0, 3.8, and 4.7 did not differ significantly (P>0.05). The growth rate and survival rate of fish fry gradually slowed down with the increase of salinity. The survival rate fell to 71% when the salinity hit 9.0. As salinity increased, the activity of three antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX)—in liver tissue first increased and then decreased. SOD and CAT activities were considerably increased (P<0.05) at a salinity of 4.7, with values of 1163.918 U/mg prot and 88.039 U/mg prot, respectively. The Hematoxylin and Eosin (H&E) stained sections results revealed significant alterations in a variety of tissues under varying salinity settings. These findings suggest that both low and high salt stress can cause damage to fish bodies, with liver tissue being particularly sensitive to salt stress. This research provides a theoretical foundation and essential data for the scientific cultivation of channel catfish fry in coastal mudflats.
The aim was to explore the differences in nutritional components of muscle between male and female Opsariichthys bidens, providing theoretical basis for breeding selection and nutritional evaluation of Opsariichthys bidens. Using biochemical analysis methods, nutrient contents in muscle of 2-year-old male and female Opsariichthys bidens with body weights of (32.48±5.78) g and (78.31±8.79) g were determined, and the nutritional value of them was analyzed and compared. The results showed that the content of crude fat in females was significantly higher than that of males (P<0.05); There were no significant difference in moisture, crude protein and crude ash content between the two groups (P>0.05). The mineral content had significant difference. The contents of potassium and iron in the detected minerals were significantly higher in males than those in females (P<0.05), and the contents of other minerals in females were significantly higher than those in males. 16 kinds of amino acids were detected in both female and male fish, and there was no significant difference in the contents of various amino acids; the essential amino acids, total amino acids and flavor amino acids in females were higher than those in males, but there was no significant difference. According to amino acid score (AAS) and chemical score (CS), the first limiting amino acid for both females and males was Met+Cys, and the second limiting amino acid was Val. The essential amino acid index (EAAI) of females (90.15) was higher than that of males (86.10). Total of 24 and 22 fatty acids were detected in female and male. The contents of saturated fatty acids and monounsaturated fatty acids in males were significantly higher than those in females (P<0.05), and the polyunsaturated fatty acids in females were significantly higher than those in males (P<0.05). Among the detected fatty acids, the content of oleic acid (C18:1) was the highest, followed by linoleic acid (C18:2). Erucic acid (C22:1) and tetracosenoic acid (C24:1) were not detected in male fish. During the growth process of male and female Opsariichthys bidens, the composition and content of some nutrients were different. On the whole, the nutrients of female are more abundant than those of male. However, in actual production, due to the rapid growth of male, the breeding cycle is short, the growth rate of male fish is 2-3 times faster than that of female, and the body mass is more than 50% higher than that of female. Therefore, the all-male breeding of fish still has certain significance.
In order to quickly detect the soil water content and achieve timely monitoring of tomato plant growth, the average spectral reflectance of 304 soil samples was extracted using hyperspectral imaging technology. The original spectra underwent preprocessing and optimization by removing outliers, dividing the sample set, applying three preprocessing methods, successive projections algorithm (SPA), uninformation variable elimination (UVE), iterative retained information variable (IRIV), genetic partial-least-squares algorithm (GAPLS) to extract the feature wavelengths. Following this, a partial-least-squares regression (PLSR) model was established based on the identified feature wavelengths. Utilizing these preferred feature wavelengths, multiple models were then constructed, including the PLSR model, multiple linear regression (MLR) model, principal component regression (PCR) model, and convolutional neural network (CNN) model. The results showed that: the preferred moving average smoothing (MAS) preprocessing of soil water content was applied, and the quantitative prediction model of soil water content, which was established using the characteristic wavelength extracted by the IRIV method, proved to have the best effect (Rc=0.7167, RMSEc=0.0193; Rp=0.6631, RMSEP=0.0272). Additionally, the model of soil water content based on IRIV-CNN also demonstrated good performance (Rc=0.7655, RMSEc=0.0172). This study holds great practical significance and usefulness for the development of water utilization efficiency in the facility vegetable industry, as well as the scientific management of water in tomato crops. It currently provides technical support for online monitoring of tomato plant growth.
To understand the microbial composition and structure of the intestinal tract of three fish species in the Nujiang River basin in Xizang, the study was conducted to analyze the species composition, abundance and diversity of intestinal microorganisms of three fish species in the Nujiang River basin by sequencing of the V3-V4 region of 16S rRNA. A total of 1153446 valid sequences and 1754 OTUs were obtained from all samples. These microorganisms of Schizothorax nukiangensis were determined to belong to 27 phyla, 56 classes, 154 orders, 297 families and 634 genera. The microorganisms of Schizopygopsis thermalis were determined to belong to 29 phyla, 59 classes, 165 orders, 308 families and 659 genera. The microorganisms of Triplophysa stenura were determined to belong to 29 phyla, 62 classes, 161 orders, 306 families and 647 genera. At the phylum level, Proteobacteria and Firmicutes were the dominant microflora of all three species of fishes, accounted for more than 70% of the total. At the genus level, Aeromonas was the dominant genus in the intestinal microbiota of S. nukiangensis, Pseudorhodobacter was the dominant genus in the intestinal microbiota of S. thermalis, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium was the dominant genus in the intestinal microbiota of T. stenura. Diversity analysis showed that Shannon's index was higher in the samples of S. thermalis than in the samples of S. nukiangensis and T. stenura, but the difference was not significant (P>0.05). The community composition and proportions of the three fishes were relatively similar at the phylum level. However, at the genus level, although the community structure was similar, the species proportions were significantly different. PCoA analysis showed even smaller differences between S. nukiangensis and S. thermalis in gut microflora.
In order to explore the stress of water environment changes on cultured fish in the development of intensive aquaculture, the effects of environmental factors such as temperature, pH, dissolved oxygen, ammonia nitrogen and heavy metals on fish body were studied. From the five aspects of growth performance, blood biochemistry, digestive enzyme activity, antioxidant capacity and immunity, the related mechanism of environmental stress factors affecting fish health was reviewed, and the importance of environmental stress factor research was revealed. It was suggested that comprehensive methods such as field investigation, long-term monitoring and calculation models should be more widely used in the future to comprehensively explore and evaluate the coping strategies and health status of fish in the actual environment, and to explore the molecular mechanism of environmental stress factors on fish health. Future experiments need to study the whole process of fish growth in different periods, which is helpful to predict the impact of future environmental changes on fish community structure and ecosystem function. By studying the adverse effects of environmental stress factors on fish health, the occurrence of stress can be avoided or weakened, which provides a reference for ensuring efficient and healthy aquaculture of fish.
In order to carry out artificial breeding and germplasm resource protection of Callista chinensis, we used correlation analysis and path analysis to evaluate the relationship between quantitative traits and live body weight. 70 wild individuals were sampled randomly in Haitan Bay, Pingtan, Fujian Province. Shell length, shell width, shell height and live body weight were respectively measured. Multiple regression analysis and path analysis were used for investigating the morphological variation. The result showed that there was extremely significant correlation among the 4 traits (P<0.01). Through stepwise multiple regression analysis, shell height was removed, then optimum multiple regression equations were obtained. Path analysis revealed that, the direct effects of morphological parameters on live body weight were in order of shell width>shell length. Shell width had the maximum direct effect on the live body weight with a direct path coefficient of 0.665. The coefficient of determinant (R2) of morphological parameters against the live body weight was 0.970, which was more than 0.850, indicating that shell width and shell length were the major factors associating live body weight.
To investigate the effects of different salinity conditions on physiological indices and analyze the physiological regulation mechanism of Urechis unicinctus Juvenile in the face of salinity stress, the salinity of aquaculture water were maintained at 15‰, 20‰, 25‰, 30‰ and 35‰ in five experimental groups. Serum, intestinal homogenate and body wall samples were collected at 0h, 6h, 12h, 18h, 24h, 48h and 72h and the activities of SOD, CAT, ACP, intestinal lipase and glycogen content were measured. In conclusion, salinity stress has a significant effect on antioxidant capacity and nonspecific immunity of Urechis unicinctus. A certain degree of salinity stimulation can activate the activities of digestive enzymes and accelerate metabolism; the increase rate of digestive enzyme activity under low-salt stimulation is slower than that under high-salt stimulation; the time of digestive enzymes and muscle glycogen reaching the highest value in the medium-high salinity group was earlier than that in the low-salinity group. However, when the salinity of water exceeds the limit tolerance range of Urechis unicinctus or the stress time is too long, the regulatory load of osmotic pressure will increase, which will inhibit the activities of the immune system and digestive enzymes, and even cause severe damage to the body. In contrast, the changes of each index in salinity 25‰ group are relatively stable, which are suitable for Urechis unicinctus cultivation.
Through comparative experiments in different breeding periods of crayfish from April to October, 34 quality factors such as conventional nutritional components, texture properties, amino acid composition and content of 25-30 g crayfish meat were analyzed and compared. The results showed that 32 quality factors of crayfish in different breeding periods were significantly different (P<0.05, the same below). The conventional nutritional components and texture properties of crayfish increased first and then decreased, and those of shrimp from June to August were significantly higher than those in other months. The total amino acid (TAA) was 16.57%-19.72%, the highest was in April, followed by July, and the lowest was in October, showing an overall downward trend. The ratio of essential amino acids (EAA) to TAA was 32.63%-36.58%, and the ratio of EAA to non-essential amino acids (NEAA) was 59.67%-73.51%, which was the highest in shrimp from September to October, showing an upward trend. The essential amino acid index (EAAI) was 68.34-90.14, with the highest in April and the lowest in August, showing a downward trend. The correlation analysis between 32 quality factors and meteorological factors in breeding period showed that 23 quality factors were significantly correlated with meteorological factors in breeding period, among which the most quality factors were significantly correlated with the number of cloudy days, sunshine hours and temperature suitability index. They were mostly positively correlated with the number of cloudy days, mostly negatively correlated with the number of sunshine hours, and positively correlated with the temperature suitability index. The optimum temperature of the temperature suitability index related to the conventional nutrients were 22℃, the texture properties were 24-26℃, and the amino acids were 20℃. Therefore, under the appropriate temperature, the appropriate shade was conducive to improving the quality of crayfish. Analyzing the correlation between meteorological factors and quality factors in different periods, the results showed that the early stage of breeding was the critical impact period of meteorological factors on conventional nutrients and amino acids, and the middle and late stages of breeding was the critical impact period of meteorological factors on texture properties.
The transcription profile of Micropterus salmoides against LMBV infection was analyzed to reveal the immune response mechanism of Micropterus salmoides in response to LMBV infection. The head kidney tissues of largemouth bass infected with LMBV 72h were analyzed by transcriptome sequencing using Illumina NovaSeq 6000 sequencing platform. A total of 5953 differentially expressed genes (DEGs) were obtained, of which 1704 were up-regulated and 4249 were down-regulated. Through GO function annotation, DEGs were mainly related to single-organism process, metabolic process, membrane, cell, binding, catalytic activity, etc. The KEGG enrichment analysis showed that DEGs were mainly enriched in metabolic pathways such as glycolysis, primary bile acid biosynthesis. There were 4 immune response-related signaling pathways enriched including cytokine-cytokine receptor interaction, ECM-receptor interaction, phagosome and intestinal immune network for IgA production. The immune-related increased DEGs were cxcr4, il10, mrc, ncf4, itgb2, il27, ccl25, etc. while the decreased degs were cxcl12, tgfb3, il20ra, col4a5, itgb1, etc. PPI analysis showed that itgb1, itga8 and itgb6 were the hub genes of immune-related DEGs. This study analyzed the transcription profile of largemouth bass infected with LMBV to provide a theoretical basis for the molecular mechanism and disease prevention of largemouth bass immunity against LMBV.
In order to understand the regulation factors that may be involved in gonadal differentiation of P. Procambarus, in this study, the proteome of exosomes in the hemolymph before and after androgenic gland ablation of P. clarkii was sequenced and analyzed. The results showed that a total of 469 proteins were identified in hemolymph exosomes, and 98 differentially expressed proteins were screened. Among which two differentially expressed proteins, 14-3-3 zeta and cell division cycle protein 27 homolog, may be involved in the sex regulation of P. clarkii.
In order to investigate the different effects brought by MABR membrane and microecological preparation in the process of Eriocheir sinensis culture, we used MABR membrane and microecological preparations in Eriocheir sinensis culture ponds under the background conditions of juvenile crabs cultivation stage, and investigated the effects and potential mechanisms of the two water treatments on the water quality and nutritional quality of Eriocheir sinensis in the culture ponds through the determination of physical and chemical indexes of water quality, quantitative analysis of phytoplankton, and nutritional quality analysis of Eriocheir sinensis. The results showed that compared with the CK group, the group II approach had the best effect on the improvement of water quality, and reduced the content of ammonia nitrogen, nitrite, total phosphorus, total nitrogen, and COD in the pond water to different degrees; meanwhile, crude protein of the cultivated river crabs and crude fat contents were significantly higher than those of the control group (P<0.05), and the contents of total amino acids and essential amino acids were the highest (P<0.05). While the group I approach significantly increased the plankton biomass (P<0.05), and the content of essential amino acids/total amino acids was significantly higher than that of the control group (P<0.05). In conclusion, the use of MABR membrane and microecological agents can improve the water quality of Eriocheir sinensis culture ponds to a certain extent, and can also improve the nutritional quality of the cultivated Eriocheir sinensis.
To study the effects of Bacillus on the growth performance, digestion, non-specific immunity and disease resistance of Procambarus clarkii, a total of 270 P. clarkii with body weight of (9.36±1.40) g were selected and divided into 3 groups of CK (without Bacillus) group, T1 (with B. coagulans) group and T2 (with B. subtilis) group, for a 4-week culture experiment. The results showed that there were no significant differences in final body weight among all groups (P>0.05), while WGR, SGR, SR and HSI in groups T1 and T2 were significantly higher than those in group CK (P<0.05). The activities of ACP, ALP, LZM and SOD in groups T1 and T2 were significantly higher than those in group CK (P<0.05). The LPS and TPS activities of groups T1 and T2 were significantly higher than those of group CK (P<0.05), and the AMS activity of group T1 was significantly higher than that of groups CK and T2 (P<0.05), but there was no significant difference between groups T2 and CK (P>0.05). After WSSV challenge, the survival rate of P. clarkii in groups T1 and T2 was significantly higher than that in group CK (P<0.05). In conclusion, the two species of bacilluscan significantly improve the growth performance of P. clarkii, increase intestinal digestive enzyme and serum non-specific immunoenzyme activity, enhance disease resistance and reduce mortality when infected with WSSV.
In order to scientifically prevent the overwintering syndrome of freshwater fish and reduce the risk of disease outbreaks, this study, based on recent surveys of disease occurrence and data collection, deeply analyzed the meteorological background differences in the occurrence of overwintering syndrome diseases and established a meteorological assessment method for the onset of freshwater fish wintering syndrome. By statistically analyzing key meteorological elements, such as the first day when the temperature stably passes 12℃, the temperature before the cooling process, the time of cooling process occurrence, the cooling amplitude and accompanying precipitation amount, rainy days, etc., we identified the meteorological factors affecting fish overwintering syndrome. The study found that in addition to cooling and precipitation, the meteorological conditions before cooling were also important factors affecting the degree of fish disease occurrence. Based on this, we constructed a warming trap index based on risk trap theory and a precipitation index that comprehensively considers rainfall and rainy days, and developed a comprehensive meteorological index for fish overwintering syndrome. The results show that this comprehensive meteorological index can accurately reflect the timing and degree of disease occurrence, which is highly consistent with the actual disease situation. In addition, the study also determined the cumulative comprehensive meteorological index thresholds for different disease grades. This assessment method provides a scientific basis for meteorological monitoring and forecasting of freshwater fish overwintering syndrome.
This study aims to estimate crab yield by using meteorological factors. The crab yield and meteorological factors were acquired at five key growth stages (stocking period, 1st-3rd shelling period, 4th shelling period, 5th shelling period and mature fishing period) from 2010-2022 in Xinghua of Jiangsu. Meanwhile, the meteorological factors were used as the inputs for the three machine learning algorithms for the crab yield estimation. The three machine learning algorithms included the Random Forest Regression (RFR), Support Vector Regression (SVR), and Partial Least Squares Regression (PLSR). Finally, the estimation models were developed using Leave-One-Out cross validation under different growth stages. The results showed that the precision of estimating crab yield by different meteorological factors was significantly different at different growth stages. For the three machine learning algorithms, the SVR was found to be superior to the RFR and the PLSR (coefficient of determination, R2=0.95-0.98, RMSE=24.07-35.14 kg/hm2). In the single growth stage, the highest estimation accuracy was observed at the stocking period (R2=0.98, RMSE=24.07 kg/hm2). In the whole growth period, the estimation accuracy was (R2=0.92, RMSE=44.31 kg/hm2). Therefore, the meteorological factors can be expected to estimate crab yield under the different growth stages.
In Tai'erzhuang District National Aquatic Germplasm Resources Reserve of Pelteobagrus Fulvidraco, the catch was obtained by setting up three multi-mesh compound gill nets and setting series cage pots, and the data of the catch were measured and analyzed. The present composition of fish, dominant species, biodiversity and the stock of yellow catfish (Pelteobagrus Fulvidraco) were investigated. A total of 22 species, belonging to 5 orders and 9 families, were detected, of which 14 species (64%) were cyprinoid, one species (4%) catfish and one species of herring (4%), three species of perch (14%) and three species of crustaceans (14%). For the protected species Pelteobagrus Fulvidraco, the total DNA was extracted by column genomic DNA extraction kit. The results show that the population structure is stable and the genetic diversity is at a high level, the wild germplasm resources are in good condition. This finding confirms that the biodiversity within the reserve is effectively maintained, and that positive outcomes have been achieved in the conservation efforts of pelteobagrus fulvidraco.
Aquaculture Fisheries
