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Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To investigate difference in the quality of the different parts (back, tail muscles, and fish skin) of Opsariichthys bidens from pond and rice field cultures, a comparative study was conducted in terms of nutritional composition, volatile flavor profiles and gut microbiota. In detail, the texture, free amino acids, fatty acids were further assessed. The results suggested that the moisture content, crude protein and crude fat content in the skin of O. bidens are higher than those in the back and tail muscles, regardless of breeding modes. The fish cultured in the rice field had a higher protein content than those from the pond culture, while the fat content of the rice field-cultured fish was significantly low compared to the fish from the pond culture, especially in the back and tail parts. A total of 43 volatile components were detected by Gas Chromatography–Mass Spectrometry (GC-MS), with a maximum of 18 types of aldehydes and the highest concentration being nonanal. Compared to pond cultures, the fish from the rice field cultures showed more abundant flavor composition and odor-active compounds. The total content of DHA (Docosahexaenoic Acid) and EPA (Eicosapentaenoic Acid) in the rice field-cultured fish was higher than that of the pond group, while no significant disparity in amino acid composition was observed (p > 0.05). Comparative and clustering analyses of gut microbiota revealed notable discrepancies in the gut microbiota of O. bidens from two aquaculture systems. However, an inherent correlation between the gut microbiome and meat quality would be further emphasized in further studies. This study can offer a theoretical reference for the development of high-quality aquatic products by selecting the appropriate aquaculture models. [ABSTRACT FROM AUTHOR]

With the rapid development of aquaculture in China in recent decades, the country now faces environmental problems, such as high energy consumption and severe environmental pollution. The Yangtze River Basin is the most important area for freshwater aquaculture production in China, accounting for more than half of the total production. The environmental issues induced by aquaculture have received widespread consideration in this area. However, the freshwater farming-induced environmental issues in the Yangtze River Basin were rarely evaluated in prior research. Life cycle assessment (LCA) is a valid tool for assessing environmental impacts and resources and is widely deployed in the industrial sector. It can quantify the impact of a product or service on different environmental indicators at various stages of the production process, thereby aiding in the identification of the best measures to reduce environmental impacts. The LCA is more effective than traditional environmental impact assessment methods; thus, it has been gradually applied in other fields, such as agriculture and aquaculture, in recent years. In aquaculture, LCA has been used to evaluate the environmental impact of various farming models or species in a laboratory setting. However, little attention has been paid to large-scale systems, such as the Yangtze River Basin. The two most important farming models in China are the pond farming model and the integrated rice-fish farming model. Among them, the integrated rice-fish farming model is regarded as environmentally friendly and an important step towards realizing the sustainable development of aquaculture in terms of the efficient utilization of water and land resources. Therefore, in this study, the environmental effects of pond farming and integrated rice-fish farming models were investigated in the Yangtze River Basin using the LCA method. A total of 20 monitoring points were established in the Yangtze River Basin, including 5 for integrated rice-fish farming and 15 for pond culture. In the integrated rice-fish farming model, the life cycle consists of two stages: Feed supply and breeding. In pond culture, the life cycle consists of three stages: Feed supply, power supply, and breeding. We analyzed the values of energy use (EU), global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), and water use (WU) in the pond farming and integrated rice-fish farming models using the LCA method, assessed the contribution rate of each phase for environmental indices, and compared the environmental impact of the two farming models. In order to establish the inputs and outputs of an aquaculture system, experimental measurements and surveys were conducted to collect data. The collected data mainly included feed consumption, electricity consumption, water consumption, total phosphorus and total nitrogen emissions, and greenhouse gas (CH4 and N2O) emissions. The data were analyzed by the LCA software eBalance. In this study, the weight gain of 1 ton of aquaculture products served as the functional unit, and the results were standardized and evaluated in order to compare the environmental impacts of various impact indicators. The results showed that the standardized and weighted evaluation values of WU, EP, GWP, AP, and EU in the integrated rice-fish farming model were 11.650, 0.770, 0.141, 0.096, and 0.003, respectively, and the total environmental impact indicator was 12.660. In the pond farming model, the values of WU, EP, GWP, AP, and EU were 31.453, 1.187, 0.210, 0.174, and 0.007, respectively, and the total environmental impact indicator was 33.031. The environmental impacts of integrated rice-fish farming were lower than those of pond farming. The contribution rate analysis of the three stages of the life cycle to environmental impact showed that the contribution rates of EU, GWP, and AP in the feed supply stage were higher than those in the power supply and breeding stages. EP was primarily associated with the feed supply stage and pollutant discharge stages of the breeding process, and WU was principally concentrated on the breeding stage. Overall, the LCA results showed that the integrated rice-fish farming model had a more environmentally friendly effect than the pond farming model, which indicates that the Yangtze River Basin has considerable development potential. WU was the most influential environmental impact indicator and the main restriction factor in aquaculture; it was mainly associated with the breeding stage. Therefore, moderately increasing stocking density was an effective strategy for reducing water resource consumption and improving water resource utilization rates. In addition to WU, the main environmental impact index of the pond culture model and integrated rice-fish farming models comprised EP, followed by GWP, AP, and EU. The contribution rate analyses of the two models showed that the aquaculture-induced environmental impacts could be mitigated by improving feed production technology, establishing accurate feeding technologies, applying advanced effluent water treatment technologies, and appropriately increasing stocking density in the Yangtze River Basin. In summary, in this study, we compared the environmental impacts between the pond culture and integrated rice-fish farming models in the Yangtze River Basin using the LCA method. In addition, we analyzed the differences between environmental impacts at different production stages. These data served as a reference for the sustainable development and optimization of aquaculture in the Yangtze River Basin.

Simple Summary: Different culturing modes have adopted different living spaces, foods, shelter, substrates, and surroundings for and human actions regarding animals. The Chinese soft-shelled turtle (Pelodiscus sinensis) is one of most economically important turtles, and healthier culturing modes should be applied for high-quality aquatic products to remit serious environmental and health problems. The differences in growth performance, physiological indices, and related gene expression were compared between two culturing modes in the present study. The results indicated that rice–turtle-co-cultured turtles with limited natural foods grew slower than pond-cultured turtles fed with commercial feeds. The creatinine, uric acid, blood urea nitrogen, alkaline phosphatase, acid phosphatase, glutamic oxaloacetic transaminase, and catalase were higher in co-cultured turtles than pond-cultured turtles. More differentially expressed genes were related to environmental information processing, metabolism, and human diseases when comparing pond-cultured turtles and co-cultured turtles. P. sinensis can adapt to different culture modes by adjusting their growth and physiology over a short culture period, and rice–turtle co-culturing proves to be a healthier culturing mode for turtles within the proper culturing strategies. The Chinese soft-shelled turtle (Pelodiscus sinensis) is an important freshwater aquaculture turtle due to its taste and nutritional and medicinal value. More ecological culturing modes, such as rice–turtle co-culture, should be developed to meet the ecological benefit demand. We compared growth, physiological parameters, and transcriptome data to detect the physiological responses and regulatory mechanisms of pond-cultured turtles as compared to co-cultured turtles. The co-cultured turtles grew slower than pond-cultured turtles. The gonadosomatic index of co-cultured male turtles was lower than that of pond-cultured male turtles, and both the mesenteric fat index and limb fat index were lower in co-cultured turtles than in pond-cultured turtles (p < 0.05). The blood GLU of the co-cultured turtles was significantly lower than the GLU of the pond-cultured turtles (p < 0.05), while the values of CRE, UA, BUN, AKP, ACP, GOT, and CAT were higher in the co-cultured turtles than in the pond-cultured turtles (p < 0.05). In total, 246 and 598 differentially expressed genes (DEGs) were identified in the brain and gut from turtles cultured in the two different modes, respectively. More DEGs were related to environmental information processing, metabolism, and human diseases. In the brain, the top enriched pathways of DEGs included the longevity regulating pathway, glycerolipid metabolism, cytokine–cytokine receptor interaction, Toll-like receptor signaling pathway, and PI3K-Akt signaling pathway, while in the gut, the top enriched pathways of DEGs included the cell cycle, DNA replication, cellular senescence, and p53 signaling pathway. The turtles acclimated to the different culturing conditions by adjusting their growth, physiological, and biochemical characteristics and related gene expression during a short culture period. [ABSTRACT FROM AUTHOR]

Abstract The aim of the present study was to develop low‐cost techniques for culturing seahorses in extensive shrimp ponds to foster a legal and more sustainable production chain to meet market demand for traditional Chinese medicine. In the present article, the results of two‐year experiments of seahorse culture in cages and extensive shrimp ponds are reported. We found that juveniles of the lined seahorse survived in cages and ponds very well, and the juvenile survival generally was >70% during the experimental periods. The survival and growth of the juveniles were similar to or even better than that reported in indoor tank culture. Additionally, the lined seahorse survived well (>60%) at temperatures up to 34.6°C which is the highest recorded temperature for the species in the field. For large ponds of >5 ha, cage culture may be a better way. For small ponds of

To investigate difference in the quality of the different parts (back, tail muscles, and fish skin) of Opsariichthys bidens from pond and rice field cultures, a comparative study was conducted in terms of nutritional composition, volatile flavor profiles and gut microbiota. In detail, the texture, free amino acids, fatty acids were further assessed. The results suggested that the moisture content, crude protein and crude fat content in the skin of O. bidens are higher than those in the back and tail muscles, regardless of breeding modes. The fish cultured in the rice field had a higher protein content than those from the pond culture, while the fat content of the rice field-cultured fish was significantly low compared to the fish from the pond culture, especially in the back and tail parts. A total of 43 volatile components were detected by Gas Chromatography–Mass Spectrometry (GC-MS), with a maximum of 18 types of aldehydes and the highest concentration being nonanal. Compared to pond cultures, the fish from the rice field cultures showed more abundant flavor composition and odor-active compounds. The total content of DHA (Docosahexaenoic Acid) and EPA (Eicosapentaenoic Acid) in the rice field-cultured fish was higher than that of the pond group, while no significant disparity in amino acid composition was observed (p > 0.05). Comparative and clustering analyses of gut microbiota revealed notable discrepancies in the gut microbiota of O. bidens from two aquaculture systems. However, an inherent correlation between the gut microbiome and meat quality would be further emphasized in further studies. This study can offer a theoretical reference for the development of high-quality aquatic products by selecting the appropriate aquaculture models.

This study investigates the water-saving and emission-reduction effects of biofilm technology on the pond culture of largemouth bass (Micropterus pallidus) and Japanese eel (Anguilla japonica) using a combination of biofilm water purification grids and a complex microbial preparation. The results show that during the 150-day largemouth bass aquaculture trial, the TN, TAN, TP, nitrite, and LP in the treatment group were significantly lower than those in the control group by 26.2%, 74.7%, 53.9%, 30.7%, and 59.1% (p < 0.01), respectively. During the 145-day aquaculture trial of Japanese eel, the TN, TAN, and TP levels in the treatment group were significantly lower than those in the control group by 30.1%, 68.6%, and 18.7% (p < 0.01), respectively. The nitrite and COD levels were also significantly lower in the treatment group than in the control group by 18.3% and 16.0% (p < 0.05). In addition, largemouth bass and Japanese eel tailwater nitrogen and phosphorus discharges were significantly reduced and culture yields were significantly increased. This biofilm pond culture technology has advantages such as low cost, water saving and emission reduction, increased production, ease of operation, and a wide range of applications. [ABSTRACT FROM AUTHOR]

The aim of the present study was to develop low‐cost techniques for culturing seahorses in extensive shrimp ponds to foster a legal and more sustainable production chain to meet market demand for traditional Chinese medicine. In the present article, the results of two‐year experiments of seahorse culture in cages and extensive shrimp ponds are reported. We found that juveniles of the lined seahorse survived in cages and ponds very well, and the juvenile survival generally was >70% during the experimental periods. The survival and growth of the juveniles were similar to or even better than that reported in indoor tank culture. Additionally, the lined seahorse survived well (>60%) at temperatures up to 34.6°C which is the highest recorded temperature for the species in the field. For large ponds of >5 ha, cage culture may be a better way. For small ponds of <0.3 ha, culturing the seahorse in a pond is recommended. A 1000 m2 pond could support around 7000 of the juveniles of the lined seahorse. In conclusion, culturing the lined seahorse in an extensive shrimp pond is technically feasible. [ABSTRACT FROM AUTHOR]

Rice flower carp (Cyprinus carpio rubrofuscus) has high economic value because of its tender meat. However, a comprehensive scientific evaluation of the meat quality and nutritional value of rice flower carp is still needed. At the same time, because of its fast growth and strong disease resistance, rice flower carp is widely popularized in rice field culture but without any research comparing its quality with the pond culture method. Although rice farming has high ecological value, the fish yield is low and its specifications are abnormal, which cannot guarantee the stability and safety of the commercial fish supply and limit the potential rice flower carp industrial benefits. In addition, some studies have shown that fish muscle quality can be affected by environmental conditions. This study aimed to comprehensively evaluate the muscle quality and nutritional value of the rice flower carp and investigate the relationships between the nutritional values and its culture conditions, providing data to increase the rice flower carp yield, economic efficiency, and farmed varieties available. Therefore, 6 000 Quanzhou rice flower carp (2.35±0.08 g) were randomly divided into ponds and rice field groups for the experiment (three replicates per group, with a density of 15 000/hm2). The pond culture group was fed with 3% of the commercially established everyday food per fish weight, while the rice field group was not fed. After 12 weeks, the fish were submitted to a 24 h period without food and anesthetized using MS-222 (USA, Sigma). The length and weight of 100 fish were measured for each treatment. For the rice field group and pond group, respectively, the lengths were (13.56±0.49) cm and (14.10±0.23) cm, and the weights were (73.19±7.02) g and (101.20±4.57) g. The muscle quality of 30 fish from each treatment was measured, including basic nutritional components, texture characteristics, and amino acid and fatty acid compositions. The nutritional level was compared between the pond and rice field groups using the FAO/WHO amino acid score, whole egg protein comparison, protein amino acid score (AAS), chemical score (CS), and essential amino acid index (EAAI). Moreover, no significant differences between the two culture methods were observed in relation to the total ash (P > 0.05). The crude protein and crude fat contents in the rice field group were significantly lower than in the pond group (P < 0.05), while moisture was significantly higher (P < 0.05). The viscosity of the rice field group was significantly lower than that of the pond group (P < 0.05), but the cohesion and shear force were significantly higher than those of the pond group (P < 0.05). There was no significant difference in the other texture indexes (P > 0.05). Essential amino acids (EAA) in both groups met the FAO/WHO standard. Among the 18 amino acids measured, the total amino acids (TAA), delicious amino acids (DAA), essential and nonessential amino acids (NEAA) were significantly lower in rice field conditions than in pond (P < 0.05), while the EAA/TAA and EAA/NEAA ratios were significantly lower in the pond group (P < 0.05). According to the amino acid score (AAS) and chemical score (CS), glutamic acid (Glu) was the most common amino acid in both groups, while the first and second limiting amino acids were tryptophan (Trp) and valine (Val). Among the 22 fatty acids observed, the contents of tridecanoic, pentadecanoic, palmitoleic, heptadecanoic, and docosatetraenoic acids were not significantly different between the two groups (P > 0.05). In contrast, the contents of linoleic, linolenic, and arachidonic acids in the pond group were significantly higher than those in the rice field group (P < 0.05), while 14 other fatty acids showed significantly lower contents in the pond group (P < 0.05). The monounsaturated fatty acid (MUFA) contents in the pond group were significantly higher (P < 0.05), while the EPA+DHA and n-3PUFA/n-6PUFA were significantly lower than those in the rice field group (P < 0.05). Overall, the contents of four main flavor amino acids (glutamic acid, glycine, alanine, and aspartic acid) in the rice field group were significantly lower than those in the pond group (P < 0.05). In conclusion, rice flower carp reared in both pond and rice field is a high-quality protein source. However, different cultural environments significantly influence the rice flower carp muscle nutritional value and quality, wherein a higher nutrient composition and amino acid score were observed in the pond environment. Concerning the fatty acids content, the muscle of rice flower carp reared in rice fields had higher EPA+DHA content and N-3/N-6 polyunsaturated fatty acid ratio, which is more suitable for people with hyperlipidemia and cardiovascular diseases. In addition, in terms of texture, the muscle of rice flower carp is chewier under the rice field rearing condition. Nevertheless, N-3PUFA shortages were observed in both culture conditions. Besides, fish in the pond group had better muscle nutrition than the rice field group. Different culture conditions can change rice flower carp's fatty acid composition and content to a certain extent, but none of the two conditions tested here could completely allay the lower N-3PUFA problem. Therefore, increasing the N-3PUFA content of rice flower carp is the key to improving its nutritional value, and pond culture conditions make this process easier to be manually controlled.

The nutritional quality of three edible parts (gonads, hepatopancreas and muscles) of Chinese mitten crabs (CMCs) from rice field culture and pond culture was firstly compared in our current study. It was found that the contents of mineral elements and volatile compounds in rice CMCs were superior to those in pond CMCs, and the antioxidant enzyme activities of rice CMCs were markedly higher than those of pond CMCs. Besides, the total free amino acid levels in the edible parts of pond CMCs were higher than those of rice CMCs. Compared with other tissues, the nucleotide and equivalent umami concentrations of the gonads in female rice CMCs were the maximum. Overall, both types of crabs demonstrated good nutritional quality, which met human nutrition and dietary needs. In comparison, the quality of rice CMCs was better than that of pond CMCs.

In order to achieve accurate and reliable prediction of the dissolved oxygen in ponds and mitigate aquaculture risks, we propose a predictive model based on Feature Construction (FC) pretreatment and Temporal Convolutional Network (TCN) coupled with Bidirectional Gate Recurrent Unit (BiGRU). By constructing statistical features, environmental factor features and seasonal features from the samples, deep-level correlations between variables are explored. Then, the structural feature sequences are processed using multiple layers of convolution and dimensionality reduction through TCN, while preserving the global temporal characteristics and removing redundant information. By integrating BiGRU to model the reduced features, accurate prediction of dissolved oxygen levels is achieved. Furthermore, the Sand Cat Swarm Optimization (SCSO) algorithm is employed to optimize the non-parametric Kernel Density Estimation (KDE) for estimating the distribution range of dissolved oxygen prediction errors. The experimental results indicate that the proposed model achieves superior performance compared to other comparative models, with respective values of 0.027 5 for Mean Squared Error (MSE), 0.143 2 for Mean Absolute Error (MAE), 0.165 8 for Root Mean Squared Error (RMSE), and 0.94 for the Coefficient of Determination (R²). Meanwhile, the interval estimation effectively covers the fluctuation range of dissolved oxygen, thereby quantifying the uncertainty in the prediction process. In the short-term prediction of dissolved oxygen levels in ponds, this model demonstrates notable accuracy and robustness. It is instructive for water quality monitoring in aquaculture and the enhancement of farming efficiency. [ABSTRACT FROM AUTHOR]

In response to the current situation that most of the bait feeders in pond culture rely on manpower, which is labor-intensive, and it is difficult to feed the baiting boats on steep sloping banks, an energy-saving feeding truck without power discharging has been designed. The truck uses a rotating discharging valve for feeding, and a scissor lift platform for adjusting the height of feeding. Through the design of the spherical limit rotating connector located at the discharge port of the rotating discharging valve to adjust the inclination angle of the feeding tube to realize the non-powered discharging, a new type of telescopic feeding tube is designed based on cylindrical cam. The feeding truck can realize directional, fixed-distance and fixed-point feed addition through the movement of the truck body, the lifting and lowering of the scissor lift platform, and the adjustment of the inclination angle and length of the feeding tube. The prototype of the feeding truck was made, and the feeding test was carried out with the baiting boat and stationary baiting machine as the feeding target, and the test results show that the feeding truck has the universality for different specifications of feeds, and the telescopic length of 1.2 m and the lifting height of 1.5 m can satisfy the feeding needs of the baiting boat and stationary baiting machine, and the adjusting is flexible, and the rate of feeding is 6.2 kg/min. The designed feeding truck is flexible in use, and it can replace the manual feeding to the baiting boat and stationary baiting machine. It can replace manual feeding for baiting boat and fixed baiting machine, reduce manual labor intensity, improve the mechanization level of breeding process, and lay the foundation for further automation and intelligence. [ABSTRACT FROM AUTHOR]

To analyze the composition of norfloxacin-resistant bacteria and norfloxacin-degrading bacteria in pond water and sediment in subtropical China, the composition of antibiotic resistant bacteria in pond water and sediment enriched with norfloxacin-containing medium was analyzed by high-throughput sequencing. Sediment and water samples were collected from 3 fish ponds in subtropical China, and domesticated with norfloxacin, subsequently norfloxacin-resistant bacteria through high-throughput sequencing of 16S rDNA, and isolated norfloxacin- degrading bacteria. Our results showed that the pond sediment and water contain a variety of norfloxacin-resistant bacteria, mainly from Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, and Chloroflexi. Moreover, we isolated two norfloxacin-degrading bacteria (NorXu-2 and NorXu-3). The norfloxacin-degrading rate by NorXu-2 and NorXu-3 in the culture mediums with 200 μg/mL was the highest, which was up to 49.71% and 35.79%,respectively. When the norfloxacin concentration was 200 μg/mL, NorXu-2 and NorXu-3 had the best norfloxacin-degrading effect at pH of 6, and the degradation rates were 53.64% and 45.54%, respectively. Moreover, NorXu-3 exhibited a good tolerance to high NaCl concentration. These results not only provided basic data for the follow-up study of the molecular mechanism of antimicrobial microbial degradation, but also provided potential norfloxacin degrading bacteria for norfloxacin removal and bioremediation in aquaculture environment.

In order to realize the pond culture of Opsarüchthys bidens in northern China, the autumn fingerling breeding experiment of Cpsariichthys bidens was carried out in two ponds in Liaoyang area of Liaoning Province from May to October 2021. The results showed that the average body length of summerlings in the two ponds was 31.85 mm and the average body mass was 0.28 g after 30 and 33 days of cultivation, respectively. After 123 and 125 more days of cultivation, the average body mass of autumn fingerlings in the two ponds reached 36.50 g and 46.25 g, respectively. The total mass of autumn fingerlings was 12 300 kg, the average survival rate was 61.9%, and the average feed coefficient was 1.62. In July, the maximum value of the specific growth rate of the total length of the juvenile was 4.00%/d, and the maximum value of the daily mass growth of the juvenile was 0.49 g in Septem- ber. There was a power function relationship between the total length and body mass of juvenile fish from fry to au- tumn fingerling. It is suggested that the water temperature should be maintained at 20-25 °C and the density should be controlled at about 225 000 fishes per hectare under the condition of pond culture. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

E. sinensis, normally harvested in October and November, is an economic aquatic product in China. Pond culture has been widely applied for the production of E. sinensis, wherein a stable food supply for crabs is provided. In order to improve the nutritional quality of E. sinensis products, this study evaluated the effect of the local pond culture on the nutritive profiles of E. sinensis and screened out the best harvest time for the nutrient-rich crabs, thereby guiding the local crab industry to improve its aquaculture mode and harvest strategy. The results indicated that pond culture enhanced the levels of protein, amino acids, and specific organic acid derivatives, and reduced the levels of peptides and polyunsaturated fatty acids (PUFAs). Compared with E. sinensis harvested in October, peptide levels were significantly increased, whereas sugar, phenolic acid, and nucleotide levels were decreased in those harvested in November. Overall, the study revealed that the nutritive profile of the pond-reared E. sinensis was significantly modulated by a high-protein diet, thus lacking the diversity of metabolites. Additionally, October could be more appropriate for harvesting E. sinensis than November. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Chinese soft-shelled turtle (Pelodiscus sinensis) is an important freshwater aquaculture turtle due to its taste and nutritional and medicinal value. More ecological culturing modes, such as rice–turtle co-culture, should be developed to meet the ecological benefit demand. We compared growth, physiological parameters, and transcriptome data to detect the physiological responses and regulatory mechanisms of pond-cultured turtles as compared to co-cultured turtles. The co-cultured turtles grew slower than pond-cultured turtles. The gonadosomatic index of co-cultured male turtles was lower than that of pond-cultured male turtles, and both the mesenteric fat index and limb fat index were lower in co-cultured turtles than in pond-cultured turtles (p < 0.05). The blood GLU of the co-cultured turtles was significantly lower than the GLU of the pond-cultured turtles (p < 0.05), while the values of CRE, UA, BUN, AKP, ACP, GOT, and CAT were higher in the co-cultured turtles than in the pond-cultured turtles (p < 0.05). In total, 246 and 598 differentially expressed genes (DEGs) were identified in the brain and gut from turtles cultured in the two different modes, respectively. More DEGs were related to environmental information processing, metabolism, and human diseases. In the brain, the top enriched pathways of DEGs included the longevity regulating pathway, glycerolipid metabolism, cytokine–cytokine receptor interaction, Toll-like receptor signaling pathway, and PI3K-Akt signaling pathway, while in the gut, the top enriched pathways of DEGs included the cell cycle, DNA replication, cellular senescence, and p53 signaling pathway. The turtles acclimated to the different culturing conditions by adjusting their growth, physiological, and biochemical characteristics and related gene expression during a short culture period.

Positive cases of Streptococcus in tilapia cause serious economic losses, however, there are no reports on the prevalence of Streptococcus in tilapia farmed within ponds and cages in the tropics, this is the first report about it. The goal was to compare the prevalence of beta-haemolytic streptococci in tilapia (Oreochromis niloticus) from pond and cage culture farming, in Chiapas, Mexico, also, evaluate the susceptibility to antibiotics. 155 fish between 250-300 gr were collected in 31 farms (12 ponds and 19 cages). The highest prevalence (45.16%, P<0.05) of beta-haemolytic streptococci was in fish with clinical manifestations from cages, compared to fish from ponds. S. agalactiae and S. alactolyticus were identified. Signs in fish infected with Streptococcus agalactiae included exophthalmia, ascites, cerebral congestion, hemorrhages, and melanization. 100% of the S. agalactiae strains were susceptible to beta-lactams, clindamycins, among others. There is a higher prevalence of beta-haemolytic streptococci in fish farming in cages compared to pond culture. The information generated in this study favors the implementation of sanitary strategies to optimize tilapia farming in tropical regions. [ABSTRACT FROM AUTHOR]

【Objective】The study was conducted to understand the growth and development law of Siniperca chuatsi Guangqing No.1 (hereinafter called mandarin fish) fed with compound diet and cultivated in pond so as to provide references for the breeding and large-scale culture of mandarin fish.【Method】The morphological parameters and growth performance of mandarin fish fed with compound diet at different month-ages in a whole cultivation period were measured. Three nonlinear models, Logistic, Gompertz and Bertalanffy, were used to construct the growth curves of both body mass and body length of the mandarin fish.【Result】The maximum absolute body weight gain and absolute body length gain were found at 5-month-age fish, and 3-month-age fish, respectively. While the relative body weight gain and body length gain began to decrease from 4 months age. Morphological parameters, including condition factor (CF), viscerosomatic index (VSI) and mesenteric fat index (MFI) increased while hepatosomatic index (HIS) and intestine & stomach index (ISI) decreased as the fish month ages increased. The three models could simulate the growth curve of mandarin fish well, with a degree of fit R2 ≥ 0.97. Correlation analysis between the model predicted value and the measured value showed that the Logistic model was better than the other two models. The growth models for body mass and both length were as follows respectively, Wt=1230.808/(1+39.666e-0.760t), R2=0.989; Lt=40.871/(1+3.076e-0.387t), R2=0.990. The growth inflection point for body mass was at 4.843 months, corresponding to body mass and both length of 615.404 g and 20.436 cm, respectively.【Conclusion】Logistic model is more suitable to describe the growth process of mandarin fish, and it can predict the growth data of different stages, which will provide theoretical basis for further breeding and large-scale culture of mandarin fish fed with compound diet.

Color preference testing for animals is a prerequisite for optimizing facilities and ensuring animal welfare in aquaculture. Swimming crabs (Portunus trituberculatus) are aggressive, and shelters are often installed in ponds to reduce the high mortality rate caused by their agonistic behavior. To test the preference of juvenile crabs for the color of shelters, this study observes the preferences of crabs for shelters of different colors (white, yellow, blue, and black). The counts and duration of crabs occupying different colored shelters were quantified. The probability of fighting and the probability of abandoning the shelter were also calculated. The results revealed that: (i) when all colors were presented simultaneously, the z-scores of the blue shelters were far higher than others during the day; (ii) when only one color was present, crabs occupied the blue shelter significantly more often and for longer periods of time than others during the day, with invasive crabs exacerbating this preference; and (iii) the probability of fighting between crabs was relatively low in the presence of the blue shelter, and the probability of abandoning the shelter was significantly lower than that of others. Based on these results, blue shelters are recommended for use in swimming crab ponds. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study investigated the effects of different dietary protein levels on the growth and survival of milkfish Chanos chanos for 90 days feeding trial. Milkfish with an average body weight of 10.81 ± 0.07 g were collected from the coastal zone using a manual dragnet. The study tested four diets, 10% (T1), 15% (T2), 30% (T3) and 38% (T4) of proteins containing feed with triplicates. These diets were offered to the milkfish juveniles in triplicate earthen ponds (1.5 ha). Juveniles were stocked at 10,000 ind./1.5 ha, and initially feeding rate of 10% biomass per day. The feeding rate adjusted according to fish biomass on a weekly basis. The present results showed that fishes fed 30% of proteins-containing feed have the highest weight gain (WG), specific growth rate (SGR), average daily weight gain (ADWG), survival, and the best feed conversion ratio (FCR) compared to the other treatments. The present study suggested that 30% crude protein is the optimum level for the best growth performance and for obtaining a high yield of milkfish C. chanos reared in the brackish water ponds.

The mangrove red snapper Lutjanus argentimaculatus (Forsskål 1775) is a high value, euryhaline marine fish with potential as a species for freshwater aquaculture. This study evaluated the growth and cost efficiency of the species in a freshwater pond in two experiments with three replications: (a) comparing stocking densities: (1) 0.5; (2) 1; and (3) 3 fish fish•m-2 reared for six months fed three times a day with trash fish to apparent satiation; and (b) comparing feed types: (1) trash fish; (2) moist diet; and (3) formulated dry pellet at a stocking density of 1 fish•m-2 fed to apparent satiation three times a day for seven months. The stocking density (SD) experiment showed significantly higher weight gain, absolute growth and specific growth rate (P0.05). Survival rate (SR) and feed conversion ratio (FCR) were not statistically different between treatments (P>0.05), which ranged from 78% to 92% and 5.0 to 5.9, respectively. Cost analysis showed high net returns for 1 and 3 fish•m-2 SD but low in 0.5 fish•m-2 SD. The feeding experiment study showed that feed types significantly affected weight gain, SGR, and SR (P

E. sinensis, normally harvested in October and November, is an economic aquatic product in China. Pond culture has been widely applied for the production of E. sinensis, wherein a stable food supply for crabs is provided. In order to improve the nutritional quality of E. sinensis products, this study evaluated the effect of the local pond culture on the nutritive profiles of E. sinensis and screened out the best harvest time for the nutrient-rich crabs, thereby guiding the local crab industry to improve its aquaculture mode and harvest strategy. The results indicated that pond culture enhanced the levels of protein, amino acids, and specific organic acid derivatives, and reduced the levels of peptides and polyunsaturated fatty acids (PUFAs). Compared with E. sinensis harvested in October, peptide levels were significantly increased, whereas sugar, phenolic acid, and nucleotide levels were decreased in those harvested in November. Overall, the study revealed that the nutritive profile of the pond-reared E. sinensis was significantly modulated by a high-protein diet, thus lacking the diversity of metabolites. Additionally, October could be more appropriate for harvesting E. sinensis than November.

Nitrification and denitrification are important for nitrogen (N) cycling in fish ponds culture, but the effects of nitrifying and denitrifying bacteria concentrations on pond water and sediments remain largely unknown. Here, we used 0, 0.15, 0.30, 0.60 mg/L different concentrations of mixed nitrifying and denitrifying bacteria to repair the pond substrate through an enclosure experiment lasting 15 days. The results showed that the purification effect of nitrifying and denitrifying bacteria was most obvious on pond nitrogen from day 4 to day 7. The optimal relative concentration was 0.60 mg/L for nitrifying and denitrifying bacteria; NH4+-N (ammonia nitrogen) decreased by 75.83%, NO2−-N (nitrite) by 93.09%, NO3−-N (nitrate) by 38.02%, and TN (total nitrogen) by 45.16% in this concentration group on pond water. In one cycle, C/N (carbon/nitrogen) ratio of both water body and bottom sediment significantly increased, but C/N ratio of water body increased more significantly than that of sediment. Water C/N ratio increased by 76.00%, and sediment C/N ratio increased by 51.96% in the 0.60 mg/L concentration group. Amplicon sequencing of pond sediment showed that the change in nitrifying and denitrifying bacterium diversity was consistent with that in water quality index. Dominant nitrifying bacteria had a relatively high percentage, with significant differences in dominant bacterium percentage across different bacterial addition groups, while dominant denitrifying bacterium percentage was not high without significant differences among different groups. The dominant species of nitrifying bacteria were, respectively, Nitrosomonas, Nitrosovibrio, Nitrosospira, and Aeromonas, and the dominant species of denitrifying bacteria were Thauera, Azoarcus, Magnetospirillum, Azospira, and Idiomarina. The correlation analyses showed an aerobic nitrification and facultative anaerobic denitrification in pond sediments. Research shows that the addition of exogenous nitrifying and denitrifying bacteria can effectively reduce the nitrogen load of pond water and sediment. At the concentration of 0.6 mg/L, the nitrogen load of pond water and sediment decreased most obviously, which had the best effect on pond purification. [ABSTRACT FROM AUTHOR]

The growth efficiency, productivity and economic viability of Indian white shrimp (Penaeus indicus) fed with diet containing 40% (CPhigh) and 34% (CPlow) crude protein (CP) levels were determined in a 90‐day grow‐out culture trial. Growth parameters including average body weight (ABW), specific growth rate (SGR), survival and feed conversion ratio (FCR) were not statistically different. CPlow had lower overall shrimp production (797.53 kg/ha, DOC 90), but was not significantly different from CPhigh (843.78 kg/ha, DOC 90). The mean values for the water parameters of both treatments, such as DO, pH, salinity, temperature, TAN, NO2‐N, NO3‐N and PO4‐P, also showed no significant differences. However, the TAN values of CPhigh were consistently higher from day of culture (DOC) 63 and increased significantly (p =.048) at DOC 90. Furthermore, the total bacterial and Vibrio counts in both treatments were not significant throughout the culture period. The economic analysis revealed that CPlow obtained higher net profits (6093 USD/ha/year), return on investment (72%) and discounted benefit–cost ratio (1.73). The current study found that feeding a low protein diet to P. indicus is economically viable and profitable and results in improved growth efficiency and productivity while also improving water quality and lowering nitrogen discharge. [ABSTRACT FROM AUTHOR]

Cost-effective reefs improve the yield of sea cucumber Apostichopus japonicas cultured in ponds. The reaction to reef models was studied in laboratory experiments regarding selectivity and fitness-related behaviors (crawling, feeding and defecation) in different roughness (rough and smooth), angles (30°, 60° and 90°) and heights (3.5, 7, 10.5 and 14 cm). The present study found that significantly more sea cucumbers selected the rough model, with significantly better crawling frequency, tentacles activity frequency and defecation behavior compared with those on the smooth model. This indicates that rough materials in artificial reefs are appropriate for the fitness-related behaviors of sea cucumbers. Regarding the angles, the 30° model attracted significantly more sea cucumbers than those of 60° and 90°. Among the three angles, sea cucumbers in the 30° model showed significantly better defecation behavior, while showed higher frequencies of crawling and tentacles activity in comparison with the 90° model. In other words, the models of 30° and 60° serve as the ''toilet'' and the ''kitchen'' of sea cucumbers better in defecation and food intake. No significant difference was found in the number of sea cucumbers selecting any model of three heights. The 7-cm model sees significantly higher frequencies of crawling and tentacles activity than the ones of 3.5 and 14 cm. These results indicate that the higher reef may not necessarily be valuable in the pond culture and a shorter one may help boost the feeding efficiency of sea cucumbers.

Placing shelter is an effective way to mitigate cannibalism in the pond culture of swimming crab (Portunus trituberculatus). However, it is still unclear what shape of shelter the crabs prefer. To determine their preference for shelter shapes (circular, square, semicircular, and triangular), we quantified the counts and duration of the crabs occupying the different shelters. We also calculated the probability of fighting and abandoning these shelters. The results reveal that: (1) The z-scores for circular shelters were significantly higher than others, but the differences among the z-scores for square, semicircular, and triangular shelters were not significant. These indicate that the crabs had a significant preference for circular shelter when all four shapes were present in the same area. (2) When only one shape was present, the crabs spent more time occupying circular shelters and had a higher count of occupations. The differences in the counts and durations of occupation among the non-circular shelters were also not significant. (3) When the invasive crab was present, the occupancy counts and duration of the focal crab significantly increased, but its preference for the circular did not substantially change. (4) When only circular shelter was available, the aggression of the crabs was reduced, and the probability of abandoning shelter was also the lowest. These results suggest that swimming crabs have a preference for circular shelter and exhibit a relatively low willingness to fight in the arena with the circular shelter. The structural properties of circular shelters account for the observed preference of the crabs. The circular shelters are recommended to be used to reduce cannibalism and improve survival rates in swimming crab pond cultures.

Color preference testing for animals is a prerequisite for optimizing facilities and ensuring animal welfare in aquaculture. Swimming crabs (Portunus trituberculatus) are aggressive, and shelters are often installed in ponds to reduce the high mortality rate caused by their agonistic behavior. To test the preference of juvenile crabs for the color of shelters, this study observes the preferences of crabs for shelters of different colors (white, yellow, blue, and black). The counts and duration of crabs occupying different colored shelters were quantified. The probability of fighting and the probability of abandoning the shelter were also calculated. The results revealed that: (i) when all colors were presented simultaneously, the z-scores of the blue shelters were far higher than others during the day; (ii) when only one color was present, crabs occupied the blue shelter significantly more often and for longer periods of time than others during the day, with invasive crabs exacerbating this preference; and (iii) the probability of fighting between crabs was relatively low in the presence of the blue shelter, and the probability of abandoning the shelter was significantly lower than that of others. Based on these results, blue shelters are recommended for use in swimming crab ponds.

The present study investigated the effects of different dietary protein levels on the growth and survival of milkfish Chanos chanos for 90 days feeding trial. Milkfish with an average body weight of 10.81 ± 0.07 g were collected from the coastal zone using a manual dragnet. The study tested four diets, 10% (T1), 15% (T2), 30% (T3) and 38% (T4) of proteins containing feed with triplicates. These diets were offered to the milkfish juveniles in triplicate earthen ponds (1.5 ha). Juveniles were stocked at 10,000 ind./1.5 ha, and initially feeding rate of 10% biomass per day. The feeding rate adjusted according to fish biomass on a weekly basis. The present results showed that fishes fed 30% of proteins-containing feed have the highest weight gain (WG), specific growth rate (SGR), average daily weight gain (ADWG), survival, and the best feed conversion ratio (FCR) compared to the other treatments. The present study suggested that 30% crude protein is the optimum level for the best growth performance and for obtaining a high yield of milkfish C. chanos reared in the brackish water ponds. [ABSTRACT FROM AUTHOR]

This study evaluated the individual effects of microcystin-LR (MC-LR) with different concentrations (0, 10, 20, 30, 40 and 50 μg L−1) and the combined influences with astaxanthin (10 and 100 μg L−1) from Haematococcus pluvialis on the survival and oxidative stress of zebrafish embryos. Results showed that the reactive oxygen species (ROS), malondialdehyde (MDA), mortality and deformity rate were increased in the presence of MC-LR accompanied with the reduction of the glutathione peroxidase (GSH), superoxide dismutase (SOD), the total antioxidant capacity (T-AOC) and hatching rate of the zebrafish embryo. The higher the MC-LR concentration was, the stronger the developmental and oxidative stress response (p < 0.05). This study confirmed that the supplementation of astaxanthin could significantly alleviate the toxic effects of MC-LR on zebrafish embryos. The mortality and deformity rates decreased significantly in the combined exposure group compared with the only MC-LR exposure group, and the decreasing rates were positively correlated with the astaxanthin concentration. Astaxanthin could also significantly improve the oxidative stress response and damage caused by MC-LR. The ROS and MDA contents of juvenile fish decreased, whereas GSH, SOD and T-AOC increased significantly with astaxanthin supplementation. Therefore, astaxanthin might be a suitable diet supplement against the MC-LR contamination of pond aquaculture. [ABSTRACT FROM AUTHOR]

Copyright of Gazdalkodas is the property of Herman Otto Intezet Nonprofit Kft. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pikeperch (Sander lucioperca L.) possesses great potential for diversifying European aquaculture. However, studies on the genetic risk of stocking natural waters with farmed individuals of this species have been limited. Even the effect of pond culture on the genetic composition of stocks with natural-origin has not yet been determined. Our study aimed to compare the genetic variability of a wild living pikeperch population, a pond cultured broodstock (originating from the wild population) and its offspring generation. We also aimed to detect the potential signs of selection using three different methods. By analyzing the molecular data with 14 microsatellite markers, we illustrated that the impact of pond culture on the genetic diversity of fish stocks is similar to hatchery rearing due to its diversity reducing effect caused by using lower effective population sizes. Although the heterozygosity was similar in all populations (Ho = 0.68–0.71), the average number of alleles and allelic richness were significantly lower in the pond cultured stocks (NA = 7.5 and 6; AR = 7.5 and 5.9) compared to the wild population (NA = 11.00, AR = 10.47). Despite the semi-natural conditions of the present study, we detected changing selection pressure in one of the 14 microsatellite markers.

An efficient aerobic denitrifying bacteria species was isolated from water in a Ctenopharyngodon idellus culture pond in Zhongshan City, Guangdong Province in March 2018. The bacteria were identified as Pseudomonas furukawaii by morphological observation, physiological and biochemical characteristics, and 16S rDNA sequence analysis. This strain was named Pseudomonas furukawaii ZS1. The denitrification characteristics of the strain and the effects of the carbon source, temperature, pH, C/N ratio and shaking speed on the denitrification ability of strain ZS1 were investigated. The results showed that P. furukawaii ZS1 was an efficient denitrifier under aerobic conditions. The content of nitrate nitrogen (NO3-) decreased from 48.93 mg/L to 1.27 mg/L, the removal efficiency of -N was 97.40%, and the removal rate was 0.993 mg/L/h; the content of total nitrogen (TN) decreased from 52.04 mg/L to 8.40 mg/L, the removal efficiency was 83.86%, and the removal rate was 0.909 mg/L/h. Single-factor experiments indicated that the optimal conditions for denitrification activity in P. furukawaii ZS1 were a carbon source of sodium acetate, sodium citrate or glucose; temperatures ranging from 25 to 35°C; a pH of 7.0 to 10.0; a C/N ratio of 15 to 25; and a shaking speed of 100 to 200 r/min. The above results showed that the strain could quickly and effectively remove nitrogen through aerobic denitrification. Therefore, the P. furukawaii ZS1 strain can be used as a candidate strain for the treatment of pond culture wastewater through biological denitrification. [ABSTRACT FROM AUTHOR]

The pikeperch (Sander lucioperca L.) possesses great potential for diversifying European aquaculture. However, studies on the genetic risk of stocking natural waters with farmed individuals of this species have been limited. Even the effect of pond culture on the genetic composition of stocks with natural-origin has not yet been determined. Our study aimed to compare the genetic variability of a wild living pikeperch population, a pond cultured broodstock (originating from the wild population) and its offspring generation. We also aimed to detect the potential signs of selection using three different methods. By analyzing the molecular data with 14 microsatellite markers, we illustrated that the impact of pond culture on the genetic diversity of fish stocks is similar to hatchery rearing due to its diversity reducing effect caused by using lower effective population sizes. Although the heterozygosity was similar in all populations (Ho = 0.68-0.71), the average number of alleles and allelic richness were significantly lower in the pond cultured stocks (NA = 7.5 and 6; AR = 7.5 and 5.9) compared to the wild population (NA = 11.00, AR = 10.47). Despite the semi-natural conditions of the present study, we detected changing selection pressure in one of the 14 microsatellite markers. [ABSTRACT FROM AUTHOR]

Feeding activity of pikeperch (Sander lucioperca) under winter and spring photothermal conditions of pre-spawning period Keywords: feeding behaviour; pond culture; predation; prey selection; trophic ecology; wintering Size-dependent prey selection in piscivorous pikeperch Sander lucioperca and Volga pikeperch Sander volgensis haped by bimodal prey size distribution. Effect of gonadotropin hormonal stimulation on out-of-season propagation success of different year classes of indoor-reared pikeperch (Sander lucioperca (L.)). [Extracted from the article]

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Seasonal Artemia pond production has been practiced for several decades by rural salt producing communities in the Mekong Delta, Vietnam, with more success than elsewhere in the world. In spite of this success, yields have been stagnating for a long time due to suboptimal feeding conditions. As feeding is one of the most important factors affecting Artemia production, the aim of this article was to review the studies that have been done so far on the development and application of appropriate Artemia feeds and feeding protocols in this area. So far, there are three main approaches. Traditionally, phytoplankton blooming is stimulated by the use of fertilizers in so‐called fertilization ponds. This green water is supplemented by the use of cheap agriculture waste products and chicken manure, directly applied in Artemia ponds. As this technique, however, often results in suboptimal feeding levels and comes with high nutrient charges in pond effluents, recently a formulated feed has been developed specifically for Artemia pond production which allows further increasing production levels. Finally, also the biofloc technology can be applied in Artemia culture by adding tapioca flour or molasses as carbon source to obtain the ratio C/N ≥ 10 in order to stimulate biofloc development as feed for Artemia in ponds. The limitations of the above techniques are discussed. It is envisaged that the future success and further expansion of Artemia pond production, also outside Vietnam, will increasingly be determined by a flexible use of a combination of these techniques. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A feeding trial was conducted to evaluate the effects of different ratios of fish meal (FM) to a fermented blend (FB: fermented soybean meal and squid by-product blend) on growth and economic performance of climbing perch, Anabas testudineus (Bloch, 1792), in earthen ponds. Five diets were prepared where FB was substituted for 0 (D1), 25 (D2), 50 (D3), 75 (D4), or 100% FM protein (D5), while a commercial diet (D6) was used for comparison. Triplicate groups of fish (1.03 ± 0.07 g) were fed twice daily up to satiation for 70 days in earthen ponds. No significant (P > 0.05) differences were found in growth performance of fish fed D1, D2, D3, and D6 diets, while fish growth decreased significantly (P < 0.05) in D4 and D5 groups. Feed intake decreased (P < 0.05) with the increasing levels of FB with no significant difference in the feed conversion ratio, which ranged from 1.98 to 2.08. The fish survival decreased significantly in D5 alone. While considering the overall production, the total yield and economic return were found to be highest in D2 (64176.7 TK ha−1) and lowest in D5 (14418.3 Tk. ha−1). Based on the present experimental condition, it is concluded that FB can economically be included in aquafeed as a substitute for up to 50% of FM protein from the diets of climbing perch. [ABSTRACT FROM AUTHOR]

The nutritional quality of three edible parts (gonads, hepatopancreas and muscles) of Chinese mitten crabs (CMCs) from rice field culture and pond culture was firstly compared in our current study. It was found that the contents of mineral elements and volatile compounds in rice CMCs were superior to those in pond CMCs, and the antioxidant enzyme activities of rice CMCs were markedly higher than those of pond CMCs. Besides, the total free amino acid levels in the edible parts of pond CMCs were higher than those of rice CMCs. Compared with other tissues, the nucleotide and equivalent umami concentrations of the gonads in female rice CMCs were the maximum. Overall, both types of crabs demonstrated good nutritional quality, which met human nutrition and dietary needs. In comparison, the quality of rice CMCs was better than that of pond CMCs., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

An experiment was conducted for six months to evaluate the effects of artificial substrates on the survival, growth and production of Macrobrachium rosenbergii juveniles. The treatment T1 contained locally available bamboo-made substrate both vertical and horizontal and treatment T2 received no substrate. Juvenile prawns (0.40±0.13 g) were stocked at the rate of 19,760 prawns ha-1. The water quality parameters range such as temperature, pH and DO were 22.06-33.45°C, 7.70-8.40 and 4.75-6.15 mgl-1 respectively which was no significant difference (P0.05) than T2 (56.87%). The specific growth rate, food conversion ratio and protein efficiency ratio were 1.19 % and 1.14 %, 3.15 and 4.39, 0.98 and 0.71 in T1 and T2 respectively which were not significantly different (P0.05) than T2. Thus growth and survival of prawn juveniles improved in presence of artificial substrate which could be economically viable technique for the freshwater prawn culture.

Pond aquaculture plays a very important role in China's aquaculture industry and is the main source of aquatic product supply. To improve the effect of pond aquaculture, a partitioned recirculating aquaculture pond system (PRAPS) was designed and built based on the characteristics of pond aquaculture in freshwater, which consisted of feeding fish culture zone (20% of water surface) and filter-feeding fish culture zone (80% of water surface). The structure of facilities and equipment of PRAPS was optimized by setting up the overflow weir, propeller flow device, paddlewheel device, and pollutant absorption and collecting device. Tests on the mechanical properties revealed that both propeller flow device and paddlewheel device could achieve the design demand; the energy efficiency of the propeller flow device was about 340 m3/(kW·h), the flow rate was around 204 m3/h, and the no-load running noise was 60 dB; the energy efficiency of the paddlewheel device was about 360 m3/(kW·h), the flow rate was around 180 m3/h, and the no-load running noise was 67 dB; the total flow rate of the overflow weir was about 331 m3/h. The exchange capacity was totally about 7 900 m3/day, accounting for about 50% of the pond water capacity. Additionally, the system could reduce the total energy consumption and farming pollution and effectively improve the pond aquaculture ecological effect, which met the production requirement of energy saving and environmental protection. It was conducive to improve the water quality of the pond though the impeller disturbed the water. The pollutant could be gathered into the middle of bottom by the collecting device, and removed out of system by the pollutant absorption device, in which way the transparency of water was improved, and the content of TN (total nitrogen) and TP (total phosphorus) in the system was decreased. The propeller flow device and paddlewheel impeller stirring water could realize water convection in large scale, so the water was exposed to sunshine and air, which could increase the dissolved oxygen in the water. Tests showed that the dissolved oxygen of the middle and lower layer in the test pond was 59.5% higher than the control pond; the content of TN in the test pond was 21.4% lower than the control pond; the content of TP was 53.1% lower than the control pond; the chlorophyll a concentration in the test pond was lower than the control pond. Because the breeding density in the test pond was higher than the control pond, the content of ammonia nitrogen and nitrite nitrogen in the system was increased. Overall the water quality in the test pond was better than the control pond. For the PRAPS, the one-time investment was big at the beginning and it needed professional and technical personnel to maintain, while the PRAPS had a high economic efficiency. The yield of bream in the test pond was 10 280 kg, and the food coefficient was 1.7; the yield of bream in the control pond was 8 488 kg, and the food coefficient was 2.1. The result showed that the yield of bream increased by 21.1% using the PRAPS, the feed coefficient decreased by more than 23.5%, and the annual output value increased by 6%. The result provides the reference for the model establishment of healthy breeding pond system, which is helpful to make PRAPS become a more mature and reliable novel pond aquaculture system. [ABSTRACT FROM AUTHOR]

To be profitable, producers must reduce diet costs, which can be as high as 80% of the variable costs of an aquaculture expense. As vitamin and mineral premixes represent a significant cost, eliminating addition of these premixes could reduce diet costs if no adverse effects were observed for growth and production parameters. A 105-day feeding trial was conducted with juvenile Australian red claw crayfish ( Cherax quadricarinatus) to evaluate the effects of growth, survival, body composition, processing traits and water quality when red claw were fed a supplemental diet containing 28% crude protein ( CP) without vitamin and mineral premixes (and supplemented alfalfa hay) compared with red claw fed a diet (control diet) containing 42% CP, vitamin and mineral premixes, and with supplemented alfalfa hay, and compared with red claw only fed alfalfa hay when grown in ponds. Juvenile red claw (mean weight of 15.7 ± 1.0 g) were randomly stocked into nine 0.02-ha ponds at a rate of 640 per pond (3.2 per m2), and each treatment was used in three ponds. There were two feedings per day, each consisting of one-half of the total daily ration. At harvest, individual weight, percentage weight gain, specific growth rate, survival and total yield of red claw fed a control diet was significantly higher ( P < 0.05) (83.0 g, 398%, 1.53% day−1, 65.1%,and 1708 kg ha−1 respectively) compared with red claw only fed alfalfa hay (44.9 g, 202%, 1.04% day−1, 30.3% and 431 kg ha−1, respectively), but not different ( P > 0.05) from red claw fed the supplemental diet without vitamin and mineral premixes (76.2 g, 367%, 1.47% day−1, 57.2% and 1378 kg ha−1). There were no significant differences ( P > 0.05) in feed conversion ratio ( FCR) among treatments, which averaged 5.0 (based on prepared diet input). These results indicate that vitamin and mineral supplementation in a diet is not necessary when diet containing 28% CP and alfalfa hay are used in combination for pond grown red claw. These results may help reduce diet costs and possibly increase producers' profits which might allow for industry expansion. [ABSTRACT FROM AUTHOR]

Crustaceans select shelters non-randomly, and their preferences may be mediated by the structural properties of shelters. Providing shelters is an effective approach to improving the survival of pond-raised crabs, but the structural properties of shelters that would significantly benefit the survival rate remain unclear. Here, a laboratory experiment was conducted to examine the preference of swimming crabs (Portunus trituberculatus) for three types of shelter with different depths, heights, and widths using an animal behavioral observation system. The residence time of crabs in each shelter was calculated, the changes in their preference were described by the program PFunc, and the correlations between the carapace width and preference function traits were analyzed. The results showed that juvenile swimming crabs (carapace width = 5.08 ± 0.34 cm) preferred shallow, high, and wide shelters, and the strongest preferences observed were for depth and height. There was a correlation between crab carapace width and preference function traits, which suggests that preferences became stronger as the carapace width increased. Height and width are the two major dimensions that need to be controlled when designing a shelter, and their value should be determined by the carapace width of the crabs. Providing the crabs with shelter at their preferred dimensions in the pond can prolong the residence time, which may help to reduce the frequency of agonistic encounters and improve the survival of the crabs. • Swimming crabs have preference for shallow, tall, and wide shelters • Swimming crabs have strongest preferences for the depth and height of shelters • There is a correlation between crab carapace width and shelter preference • Providing shelters with various properties is recommended in pond culture [ABSTRACT FROM AUTHOR]

A high-latitude seawater pond system was restarted after 10 years absence of controlled biological production. Water supply systems for emptying and refilling the 25,000m3 pond were installed along with a wheel filter plankton collection unit which enabled fractionation and concentration of live zooplankton, consisting mainly of various stages of copepods. A raft was centrally located in the pond, serving as a platform for hydrographical and biological sampling, water mixing, and delivery of inorganic nutrients to boost primary production. No copepod resting eggs seemed to have survived the 10-year resting period, and copepod eggs and nauplii were reintroduced with the refilling of seawater to the pond. Abundances of copepod nauplii increased about 5 months after refilling, with subsequent generations of copepodids and adult copepods. The plankton was dominated by the calanoid copepods Acartia longiremis and Centropagus hamatus. The pond was managed according to a distinct year cycle, with the natural production season limited from March to October followed by cooling, quiescence, and complete draining before refilling in February and July to prevent establishment of other planktonic organisms than copepods. About 4.6 and 45.4 billion copepod resting eggs were estimated to be ready to hatch from the pond sediment at refilling in February the second and third year of operation, respectively. Thus, the operational procedures enabled synchronous hatching of copepod nauplii during spring season for use in large start-feeding experiments with marine fish larvae. Further, 2.7 and 1.6 billion copepods of various stages were harvested during 40 and 66 days periods in 2012 and 2013, respectively. The pond has proven itself a reliable supplier of copepods which sustained complete feed delivery through the whole larval period in large-scale start-feeding trials with marine fish larvae. [ABSTRACT FROM AUTHOR]

Study on growth culture of chocolate mahseer, Neolissochilus hexagonolepis was conducted to adopt this mahseer as a new candidate species in hills. Growth performance was studied in terms of specific growth rate, net weight gain and net length gain. It attained an average weight of 55.19 gm (164.6 ± 11.30 mm) in the experimental pond at the early developmental stage. The physico-chemical parameters were found to be optimum. The specific growth rate (SGR) was low during the winter from November to January but an o increasing trend was observed from January onwards (SGR = 3.0%). Temperature range of 19.0-23.0°C (during March -April) was found to be suitable for maximum growth. The study concludes that the chocolate mahseer could be considered as a new candidate species in hills. [ABSTRACT FROM AUTHOR]

Abstract: Tropical sea cucumber mariculture has potential to become a profitable industry and contribute towards natural population replenishment. Here, we synthesise the fields of progress, current impediments and research opportunities in tropical sea cucumber aquaculture arising from recent studies and an Indo-Pacific symposium. We present novel comparisons of data from hatcheries, earthen ponds and sea pens from published and unpublished studies in various countries. Of the few tropical species to have been cultured, only the sandfish Holothuria scabra has been bred extensively. While risks from hatchery-produced sea cucumbers are recognised, more genetic research is needed in farming and sea-ranching programmes. Advances have been made in the culture and nursery rearing of tropical sea cucumber juveniles but few have been published. Sandfish larvae have now been grown successfully on just one microalga species, but experimental studies to optimise culture conditions are needed urgently. Disease of tropical sea cucumbers in culture is infrequent but the treatment of disease and parasites is understudied. Earthen ponds are currently most effective for nursery rearing of juvenile sandfish to a size for stocking. Growth rates and survival of sandfish in ponds to market size are also favourable, and should improve via studies on stocking density, feeding regimes and pond management. Sea pens confer ownership of released stock and can provide a means of limiting predation in natural habitats but the costs of materials, maintenance and surveillance against poaching can diminish profitability. Sea ranching has minimal material costs but needs a large leased area and may require juveniles to be marked prior to release. Retail prices of sandfish in Hong Kong increased exponentially with body size. A cost-benefit analysis illustrated that labour and utility costs in pond farming will preclude profitability of monoculture in some cases, forcing proponents to look towards co-culture or gamble with uncertain survival in sea ranching. Better governance and consultation regarding the stocking of sea cucumbers have been advocated. We conclude that well-designed experiments and meta-analyses are needed to fill critical knowledge gaps if sea cucumber mariculture is to expand in the tropics as it has in temperate Asia. Co-culture remains a burgeoning frontier despite poor success of initial studies. Sea cucumbers have superb potential to diversify mariculture industries in the tropics and potentially ameliorate the detrimental effects of mariculture on coastal ecosystems. [Copyright &y& Elsevier]