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JI Qun, ZENG Lin, XIONG Yifei, WANG Yonghong, SONG Wei
2024,31(10):1141-1150, DOI: 10.12264/JFSC2024-0013
Abstract:
The large yellow croaker (Larimichthys crocea) is one of the most economically important marine fish species in China. Reducing water salinity can effectively prevent white spot disease, but it can also cause low-salinity stress and damage to fish. Low-salinity acclimation can improve the body’s tolerance to low salinity; therefore, it is necessary to explore the specific physiological mechanisms of low-salinity acclimation in fish under low-salinity stress. This study aimed to investigate the effects of low-salinity acclimation on energy metabolism and mitophagy in the large yellow croaker under low-salinity stress. Juvenile large yellow croakers with a body weight of (53.46±1.47) g were transferred from natural seawater (salinity 25) to water with a salinity of 20 and were cultured for 7 d and then exposed to low-salinity (salinity 12) water for 24 h. The results showed that low-salinity stress increased reactive oxygen species (ROS), adenosine triphosphate (ATP) content, tricarboxylic acid (TCA) cycle enzyme activities, and mitophagy gene expression levels, indicating that L. crocea improved aerobic metabolism and mitophagy under low-salinity stress but still suffered from oxidative damage. Compared with the low-salinity group, the low-salinity acclimation with low-salinity group showed increased ATP content, TCA enzyme activities, and mitophagy gene expression levels but reduced ROS content, indicating that low-salinity acclimation reduced oxidative damage by improving energy metabolism and mitophagy in large yellow croaker under low-salinity stress. During low-salinity stress, adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) activity was positively correlated with TCA and fatty acid β oxidation enzyme activities and negatively correlated with fatty acid synthesis enzyme activity, indicating that AMPK promoted energy-yielding metabolism and inhibited energy-consumptive metabolism in L. crocea, thereby improving energy generation efficiency. Forkhead box class O3 (FoxO3) mRNA levels were positively correlated with the expression levels of mitophagy genes, indicating that FoxO3 participates in the regulation of mitophagy gene expression during low-salinity adaptation. In summary, low-salinity acclimation improved aerobic metabolism and mitophagy, inhibited lipid synthesis, and enhanced the tolerance of L. crocea to low-salinity stress.
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Hydrodynamic performance of a semi-submersible aquaculture platform during wet towing transportation
LIU Changfeng, ZHANG Yu, XIN Yu, YIN Jing, CHEN Changping, HAO Jian
2024,31(10):1151-1162, DOI: 10.12264/JFSC2024-0123
Abstract:
As marine aquaculture expands from coastal regions to the deep seas, large-scale semi-submersible aquaculture platforms have become the primary engineering equipment in recent years because of their high stability and ease of installation. To reduce the difficulty of offshore construction, these platforms are typically installed on land and towed to the operating areas by tugboats. However, owing to the high center of gravity of the platform, there is a risk of capsizing during long-distance towing. In this study, a numerical analysis model was developed to assess the hydrodynamic performance of an aquaculture platform, including its frame and net, during wet-towing transportation. For a large-scale frame, including pontoons and columns, a three-dimensional potential flow theory was applied to solve the diffraction and radiation problems. For the thin net, a semi-empirical Morison equation was used to calculate the wave loads and a mesh group method was implemented to decrease the computational cost and time. The motion equation was solved in the time domain using the impulsive response function method, and analysis of nonlinear catenary towline was performed using the lumped-mass method. This model examines the impact of significant wave height, wave direction, towing speed, towline length, and mooring point position on the motion response and towline tension of a semi-submersible aquaculture platform. The results indicate that as the significant wave height rises from 1.25 m to 4.00 m, the heave acceleration and pitch angle of the aquaculture platform increase by 293% and 750%, respectively, whereas the towline tension increases by 358%. The aquaculture platform experienced more severe pitch motion in the following waves than in the head waves although the towline tension decreased. Furthermore, increasing the towing speed from 2.0 kn to 5.0 kn leads to a 56% reduction in heave acceleration and an 112% increase in towline tension. Tripling the towline length results in a 43% decrease in the pitch angle and 31% decrease in the towline tension. The height of the towing point has a significant impact on the pitch motion. For practical engineering applications, it is recommended to limit the maximum sea condition for towing aquaculture platforms to level 4, keep the towing speed below 5.0 kn, avoid towing in following waves, and instead opt for quarter head waves. Additionally, appropriately increasing the tow line length can improve the towing stability.
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WANG Kexiang, TIAN Tao, YUE Yue, YU Xiaoming, WU Zhongxin, LI Qingxia
2024,31(10):1163-1173, DOI: 10.12264/JFSC2024-0165
Abstract:
The purpose of this study was to examine how Sebastes schlegelii responded to acute pH stress in terms of group behavior and physiological variations. The pH of the water column is lowered during industrial aquaculture due to the high shellfish mortality, excessive algae cultivation, and seawater red tides. Water’s pH rises as a result of the massive consumption of carbon dioxide in the water caused by photosynthesis. Numerous enzymes, including those involved in immunology, antioxidant, and metabolism in aquatic organisms, are impacted by pH variations. Under stress, fish frequently run, reduce their metabolism, and increase the activity of related enzymes such as SOD and CAT. When fish are subjected to external stimuli, physiological and biochemical indices can represent their overall health ability to adapt to their environment. In this study, the effects of acute pH stress on the immunity, liver function, antioxidant activity, and group behavior of juvenile S. schlegelii were investigated. Different pH values (pH 6.5, pH 7.5, pH 8.5, and pH 9.5) in seawater were studied to identify the effects of pH stress on immunity, liver function, antioxidant activity, and group behavior of juvenile S. schlegelii, The results show that S. schlegelii CAT activity significantly increased in the pH 7.5 and pH 9.5 experimental groups at 48 h (P＜0.05), SOD enzyme activity increased significantly (P＜0.05) at 72 h compared to 24 h in all experimental groups and started to decrease after 72 h. ACP activity showed a gradual decrease in the pH 6.5 and pH 9.5 experimental groups, with a rebound in the pH 9.5 experimental group at 96 h but the change was not significant (P＞0.05). At 48 h, AKP fell dramatically in the pH 6.5 and pH 9.5 experiment groups (P＜0.05), but rebounded somewhat in the pH 6.5 group at 72 h (P＞0.05). GPT decreased and then increased in all experimental groups with a significant drop in the pH 6.5 group after 24 h (P＜0.05). There was no significant difference among the pH 7.5 experiment groups (P＞0.05). Throughout the 48 h–72 h period, GOT activity gradually increased in the pH 7.5 and pH 9.5 experimental groups, although it significantly decreased at the start of the 72 h (P＜0.05). In comparison to the control group, S. schlegelii’s degree of aggregation increased greatly and its activity dramatically decreased under pH 6.5 and pH 9.5 (P＜0.05). The results showed that different pH levels influenced S.schlegelii’s physiological processes and behavioral decisions. The immunity of juvenile S.schlegelii was lower in the pH 6.5 and pH 9.5 experimental groups.
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FENG Dejun, GUO Xiaokun, QU Xiaoyu, GUI Fukun, YANG Xu
2024,31(10):1174-1185, DOI: 10.12264/JFSC2024-0352
Abstract:
Phenotypic parameter measurement is one of the most important methods for monitoring the growth of Larimichthys crocea and estimating its economic benefits. However, most current studies on phenotypic parameter measurements focus only on the length of the fish body, with few studies focusing on essential details such as the measurement of parameters at the caudal peduncle. Also, manual measurement is time-consuming and laborious. This study designed and developed an L. crocea phenotypic parameter measurement system using computer vision technology to measure the phenotypic parameters of L. crocea. First, an improved segmentation model, Mask-RCNN, was constructed to remove the fin from L. crocea. The improvement in the model includes two aspects: detection speed and accuracy. The model replaces the backbone network of the original network model with the MobileNetV2 network to improve detection speed. Subsequently, a hybrid attention module, CBAM, is introduced into the backbone network, and PointRend is imported into the head network. These improvements have enhanced the extraction accuracy of fish body edges. The accuracy of the optimal model was 87.94%, mAP was 83.21%, and average single-image detection time was 70.5 ms. We developed a L. crocea parameter measurement system for the greater amberjack based on PyQt5, which realized the fusion of fin removal images and complete contour images with the location of the key points and calculated the phenotypic parameters through the positional information. The average relative error for systematic measurements of the six parameters was 4.04%. The average absolute percentage error of each parameter for different sizes of L. crocea was under 7%. Overall, the process designed in this study provides a new method for measuring the phenotypic parameters of L. crocea and a new way of thinking to improve the efficiency of measuring these parameters.
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JIN Zhixin, XU Yongjiang, CUI Aijun, JIANG Yan, WANG Bin, LIU Xinfu
2024,31(10):1186-1203, DOI: 10.12264/JFSC2024-0219
Abstract:
Copper is an important heavy metal and an essential trace element for aquatic organisms and is found at low concentrations in aquatic ecosystems. In aquaculture, copper sulfate is used as a therapeutic agent to reduce parasitic infections in cultured fish. However, exposure to heavy metals beyond a safe concentration range can cause a series of physiological and biochemical stresses in aquatic animals, including death. Fish are generally most sensitive to the effects of Cu2+ exposure during early life stages, especially during embryonic and larval development, which can result in reduced fertilization success, chromosomal abnormalities, DNA injury, increased incidence of yolk membrane ruptures, reduced hatching success and survival, altered time to hatching, embryonic and larval teratogenicity, inhibited growth, abnormal larval behaviors. Yellowtail kingfish (Seriola aureovittata) is a fast-growing marine species widely distributed in temperate and subtropical regions of the oceans. It has a large body size, superior flesh quality, high economic value, and can be cultured in sea cages, indoor recirculating aquaculture systems, aquaculture crafts, and other culture modes. Therefore, S. aureovittata is a promising candidate for open-ocean aquaculture in China. To investigate the effects of copper exposure on the early life stages of S. aureovittata, embryos and yolk sac larvae were exposed to copper concentrations of 0, 0.034, 0.060, 0.107, 0.192, 0.340, 0.600, and 1.070 mg/L for 60 h and 5 d under laboratory conditions in the present study. The half-lethal concentration (LC50) and safe concentration (SC) were determined for embryos and newly hatched larvae of S. aureovittata, respectively. In addition, differential gene expression patterns and related signaling pathways were investigated in embryos and yolk-sac larvae to elucidate possible molecular mechanisms. The results showed that: (1) Low hatching rate of embryos, high malformation rate of newly hatched larvae, and high utilization speed of yolk sacs during the early developmental stage of S. aureovittata under copper exposure stress. (2) The 48 h-LC50 of copper for S. aureovittata embryos was 0.08 mg/L, which was much lower than that of yolk sac larvae (48 h-LC50 = 0.60 mg/L). The SC of Cu2+ in S. aureovittata yolk sac larvae was 0.034 mg/L. (3) Transcriptome sequencing analysis revealed that differentially expressed genes (DEGs) were mainly enriched in the oxidative phosphorylation pathway during the embryonic development stage of S. aureovittata, whereas in the yolk sac larval stage, DEGs were mainly enriched in the cell cycle and phototransduction pathways, indicating that excessive copper exposure may injure the antioxidative ability of embryos and cause DNA injury and phototransduction inhibition in larvae. The present study determined the safe concentration of copper sulfate during the early developmental stages of S. aureovittata and revealed the molecular responses of embryos and yolk sac larvae to copper exposure stress. These results could provide theoretical support for the scientific and staged application of copper agents in the aquaculture of S. aureovittata and technical guidance for monitoring aquaculture and marine environments.
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MA Bin, XU Yongjiang, JIANG Yan, ZHENG Jichang, JIAO Kaili, LIU Hang, LI Tengkun
2024,31(10):1204-1217, DOI: 10.12264/JFSC2024-0295
Abstract:
This study investigated the behavioral and physiological adaptation characteristics of Lateolabrax maculatus to different light colors at both population and individual levels. We analyzed the liver enzyme activity, retinal tissue morphology, and eye transcriptomics under preferred light colors. Five light colors (red, yellow, blue, green, and white) were used to explore population and individual color peference behavior. The results showed that the population color trend index (PCTI) and population retention time (PRT) of Lateolabrax maculatus were significantly higher under blue and white lights than those of other (P＜0.05). However, differences were observed in light-color preferences between populations and individuals; populations showed a stronger preference for blue light, whereas individuals preferred white light. Additionally, higher tail beat frequency (PTBF) was observed in red and yellow light regions. Physiological analysis indicated that hepatic antioxidant parameters such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), alkaline phosphatase (AKP), acid phosphatase (ACP), and malondialdehyde (MDA) content were significantly lower (P＜0.05) under blue light than those under green light. Retinal analysis showed an increased number of cone cells (C. C) under blue light compared to green and white light, though the pigment index (PI) was lower. The KEGG annotation of the eye transcriptome showed that differentially expressed genes (DEGs) in the green light group were mainly enriched in the calcium signaling pathway compared with that in the white light group, in which genes such as α7nAChR and casq were up-regulated within the pathway. Furthermore, green light upregulated motor protein signaling pathway genes (myh, tnn2, and tpm1) in the eyes of periwinkles compared to the blue and white light. In summary, Lateolabrax maculatus populations displayed a stronger tendency toward blue light and experienced lower stress levels under blue light compared to other light colors.
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XUAN Zhongya, YANG Yanping, HUA Zhong, MA Fengjiao, WANG Yinping, LIU Kai
2024,31(10):1218-1229, DOI: 10.12264/JFSC2024-0156
Abstract:
Coilia nasus, a historically significant fish species in the Yangtze River, has experienced a significant decline because of overfishing and habitat degradation. As an anadromous fish, C. nasus traverses different habitats over large geographic areas, making effective conservation difficult. Tracing their natal origin and lifelong habitat useage at the individual and population levels will enhance our ability to protect critical habitats of this anadromous fish. The migratory life history of C. nasus across freshwater, estuarine, and marine environments can be determined by analyzing otolith Sr/Ca ratios. However, difficulties remain in tracking their natal origins and identifying transitions between freshwater habitats during the early stages of their development. The use of otolith 87Sr/86Sr isotopic ratios offers a robust approach for tracing the natal origins and migration patterns of C. nasus. The Sr isotope (87Sr/86Sr) composition of the otoliths was analyzed using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) to confirm the hatching grounds and life histories of C. nasus in the Poyang Lake. In July and August 2023, a total of ten adult C. nasus and three adult C. brachygnathus were collected from the Duchang area of the Poyang Lake, Jiangxi Province, China. The otolith 87Sr/86Sr profiles from the core to the edge displayed minor fluctuations of approximately 0.71448, indicating that the three C. brachygnathus individuals reside in the Poyang Lake. The 87Sr/86Sr ratio of the otolith core region of nine C. nasus was close to 0.71448, indicating that they hatched in the Poyang Lake and subsequently returned to the lake (because they were caught in the Poyang Lake). Among these individuals, four migrated out of the Poyang Lake during their larval stage and five migrated during their juvenile stage. One individual exhibited an average 87Sr/86Sr ratio of 0.71078 in its first segment, suggesting that it was born in the main channel of the Yangtze River and then strayed into Poyang Lake after its sea life history. The results demonstrated the objectivity, accuracy, and stability of otolith 87Sr/86Sr ratio as a reliable geographical indicator for identifying the natal origin of C. nasus in the Poyang Lake. Furthermore, these findings shed light on habitat shifts between the Poyang Lake and the main Yangtze River channel, emphasizing the diverse timing of early life migration from the Poyang Lake. Consequently, despite being a preliminary study, this study demonstrates the potential of using Sr isotopes to distinguish between natal origins and freshwater habitats. This approach is significant within the context of a decade-long fishing prohibition in the Yangtze River, as it facilitates the assessment of species recovery and management while contributing to broader ecological and conservation insights.
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YAN Jin, FANG Jinghui, WANG Renjie, WANG Wenjun
2024,31(10):1230-1239, DOI: 10.12264/JFSC2024-0163
Abstract:
Kelp (Saccharina japonica) is one of the main seaweed aquaculture species in China and is crucial for environmental carbon sequestration and the development of the marine economy. However, longline aquaculture technology of kelp has been used for many years and there are many problems in the kelp aquaculture industry. Owing to the lack of mechanization modes, such as high labor costs and low profits, the mechanization of production operations is difficult. Rongcheng, in Shandong Province, is a prominent kelp aquaculture area. In the present study, longline aquaculture of kelp was the experimental object in the Sanggou Bay, Rongcheng, and a preliminary study on the mechanization of kelp aquaculture was conducted. There were two different single-rope aquaculture modes with kelp-seeding rope hanging spaces of 1 m and 2 m (A1 and A2) in the Sanggou Bay; the traditional aquaculture mode (zone B) was used as the control. By analyzing the differences in kelp growth under different aquaculture modes and the relationship between light intensity, water depth, and kelp growth in the single-rope aquaculture mode, we explored the optimal hanging space for kelp growth under this mode, which will provide important references for the mechanization and sustainability of kelp aquaculture. The results showed that the specific growth rate of kelp in the traditional aquaculture mode was higher than that in the single-rope aquaculture mode during the aquaculture period. The kelp in the upper layers of A1 and A2 grew well, with an average wet weight of 1005.35 g in the upper layer of A2, whereas the average wet weight of kelp in the traditional mode was 1254.09 g which was approximately 1.25 times of A2. The experiment lasted until the kelp was harvested. The temperature in the kelp aquaculture area was within the suitable range for the growth of kelp. Light intensity in zone A was mostly higher than that in zone B, which effected the growth of kelp to a certain extent, resulting in a lower wet weight of the kelp harvested in zone A compared to the traditional aquaculture mode. By analyzing the relationship between light intensity and water depth and the experimental results, it was found that insufficient light intensity in the lower layers of A1 and A2 led to poor growth of kelp, compared with those in the upper and middle layers. In this study, the average yield of A1 raft frame was about 690 kg whereas that of A2 raft frame was about 900 kg, which was 1.3 times that of A1; the average yield per raft under the traditional aquaculture mode was about 1420 kg, which was about 1.5 times that of A2. However, the maximum wet weight of a single kelp in the single rope aquaculture area could reach 1729.07 g, which is consistent with the maximum wet weight of a single kelp in traditional aquaculture. Although the yield of kelp in the single-rope aquaculture mode was not as high as that in the traditional aquaculture mode, the labor cost of the longline aquaculture mode was significantly reduced, which could compensate for the reduced yield. It is necessary to maintain a balance between kelp growth and improvement of comprehensive efficiency in aquaculture production. Therefore, by appropriately increasing the hanging spacing and reducing the water layer of the range, thereby allowing all kelp to receive uniform light intensity, the quality of kelp can be improved, technical support for kelp aquaculture can be provided, and the foundation for the realization of mechanized production operations for kelp aquaculture can be laid.
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QU Yaoqi, WANG Peng, MA Yihong, LI Yingdong, YANG Shicheng, REN Yiping, XU Binduo
2024,31(10):1240-1248, DOI: 10.12264/JFSC2024-0166
Abstract:
The size spectra of fish communities can reflect the characteristics of their biomass, abundance, and size structure, and these parameters can be used to explore the effects of environmental changes and human disturbance on the ecosystem. Therefore, it is important to construct reasonable size spectra of fish communities to study their community structures. However, there are differences in the quantity and quality of data collected from different survey designs, which further affects the construction of the size spectra of fish communities. This simulation study examined the effects of sampling design on the estimation of parameters of normalized biomass size spectra of fish communities using a computer resampling method based on data collected from seasonal bottom trawl surveys in the southern waters off the Shandong Peninsula from 2016 to 2017. Simple random sampling (SRS), stratified random sampling with strata defined by depth (StRS_depth), and stratified random sampling with strata defined by size (StRS_size) were chosen as potential sampling designs for sample sizes ranging from 5 to 60. The relative estimation error (REE) and relative deviation (RB) were used to measure the performance of the different sampling designs. The results showed that under the three sampling methods, REE values of the slopes of the normalized biomass size spectra of the fish communities decreased with an increase in the sample size. As the sample size increased, the range of absolute values of RB decreased and gradually approached zero. Under the three sampling methods, the distribution of simulated values of the slopes of the normalized biomass size spectra of fish communities became more concentrated, and the estimation accuracy improved with an increase in sample size. StRS_size performed better compared with those of the other two sampling methods, which had lower REE and absolute RB values. In addition, different seasonal data showed different effects on the slope estimation of the normalized biomass size spectra of fish communities. Considering the sampling effects of different sample sizes during the four seasons under the three sampling methods, StRS_size was the optimal sampling method suitable for the estimation of biomass size spectra parameters of fish communities, and the number of sampling stations could be optimized.
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ZOU Jinghua, SHI Huilai, PING Hongling, ZHANG Tao, LIN Hui, YANG Shuyue, ZHOU Qun
2024,31(10):1249-1258, DOI: 10.12264/JFSC2024-0182
Abstract:
To investigate the pathological characteristics and pathogenesis of visceral white spot disease in Hapalogenys mucronatus, anatomical observations, tissue sectioning, and ultra-thin section electron microscopy were used to conduct a pathological analysis of the thymus, spleen, gills, liver, kidneys, intestines, and ovaries of affected fish. The results showed that clinical symptoms in H. mucronatus included ulceration and hemorrhage on the body surface, ulceration and bleeding at the base of the pectoral, caudal, and dorsal fins, visible whitish nodules in the gills, thickening and severe fibrosis of the ovarian membrane in females, and numerous white nodules in visceral organs such as the spleen, liver, and kidneys. Histopathological examination revealed that the spleen, thymus, liver, and kidneys were the main target organs for infection and injury, showing severe tissue degeneration and necrosis with pronounced vacuolation. Pathological nodules were observed in all the affected tissues. Ultrastructural pathology results showed severe damage to the cellular ultrastructure of the spleen, thymus, liver, and kidneys of the affected fish, particularly mitochondrial and nuclear damage. Mitochondrial swelling, cristae disruption, and vacuolization were observed, along with nuclear shrinkage, chromatin marginalization, and clustering of numerous pathogenic bacteria. The results indicate that tissue cellular pathology and ultrastructural pathological characteristics of visceral white spot disease in H. mucronatus demonstrate the invasion and harm caused by pathogenic bacteria, primarily resulting in damage to respiratory-, immune-, and reproductive-related tissue organs, ultimately leading to death, while potentially exerting a negative impact on reproductive capacity.
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LI Fei, HUA Chuanxiang, SONG Liming, ZHU Qingcheng
2024,31(10):1259-1272, DOI: 10.12264/JFSC2024-0049
Abstract:
Numerical computer simulation is an important method to study the hydrodynamics of fishing gear, providing visualization of motion, morphology, loading, and surrounding flow characteristics under different operating conditions. Here, the research progress of hydrodynamics and the application of fishing gear based on numerical simulation were reviewed. Additionally, the development and simulation methods of numerical models, as well as solving algorithms and efficiency improvement approaches of numerical analyses were summarized in detail. Finally, the disadvantages and suggestions of numerical research on fishing gear hydrodynamics were put forward. The summary showed that the numerical analysis of fishing gear primarily involves the dynamics model based on the topology of physical structure and the hydrodynamic model based on computational fluid dynamics (CFD) software. Both explicit and implicit algorithms were used to calculate the rigid motion equations and reducing the number of elements and optimizing the programming algorithm were the main methods used to improve the computational efficiency. The review suggests that the numerical model and related parameters could be improved by combining with actual working conditions such as non-constant currents or irregular waves at sea, the accumulation of catch in the codend, as well as the mechanical properties affected by the braided structure and non-linear deformation of the mesh. Moreover, numerical computation efficiency could be improved by the modification of solution algorithms, optimization of node topology, and improvement of calculation frameworks. In addition, the coupled motion and flow simulation of fishing gear, fishing methods, sea condition, and catches should be strengthened, providing an efficient approach for designing netting configurations, improving operational technology, and optimizing fishing gear hydrodynamics.
Volume 31,2024 Issue 10
深远海养殖渔业专题
研究论文
综述
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Characteristics and influencing factors of CH4 and NO2 emissions from pond culture and rice-crab co-culture models of Chinese mitten crab (Eriocheir sinensis)
xuke, xiaolin, sunyunfei, chengyongxu
Abstract:
为研究中华绒螯蟹(Eriocheir sinensis)池塘养殖与稻蟹共作两种模式下水-气界面温室气体的排放特征及其影响因素,本实验使用静态箱-气相色谱仪法分别测定两种养殖模式下的温室气体排放通量,同时采集两种养殖模式下相关环境因子,并进行对比分析。结果表明,稻蟹共作模式N2O排放通量是池塘养殖的2.8倍,波动范围为34.94~126.90 μg.m-2.h-1,平均值为85.41±5.78 μg.m-2.h-1,CH4排放通量是池塘养殖的1.19倍,波动范围为1.32~39.50 mg.m-2.h-1,平均值为13.69±1.42 mg.m-2.h-1。池塘养殖和稻蟹共作的全球增温潜势分别为10.73±1.16 t.hm-2和13.07±1.62 t.hm-2,两种模式的排放高峰期均出现在8月高温期。多元逐步回归表明,池塘养殖模式CH4的排放量主要受水温和总氮 TN 的影响,N2O排放量则主要受到硝态氮 NO3--N 的影响；稻蟹共作模式CH4排放量主要受到总磷 TP 含量的影响,而N2O排放量则主要受到溶解氧 DO 和水温的影响。本研究为中华绒螯蟹不同养殖模式下温室气体的排放提供一定数据支持,同时为稻蟹共作养殖模式的推广示范提供了一定的理论依据。
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The analysis and comparison of circadian behavioral rhythm between Hippocampus kuda and Oryzias melastigma
lijiawei, Lin Penghong, Xu Yongjian
Abstract:
为了探究不同鱼类昼夜行为节律差异及其变化规律，提升人工养殖技术。本文针对管海马和海水青鳉在人工养殖条件下的昼夜行为节律进行分析与比较，结果表明：在光强2000lx、温度25±1℃、盐度25±0.5及光周期14L:10D的条件下，管海马和海水青鳉的行为节律均表现出昼强夜弱。管海马在08:00-10:00间活动节律最强，行为组成最丰富。其中，宏观行为组成包括游动占比47.40%±1.1%、爬行3.0%±0.6%、移动4.80%±0.7%以及摆动32.50%±2.1%和静止12.30%±0.8%等；细微行为组成包括：鳃盖运动38.77±1.14次/min、吻盖运动38.77±1.14次/min、眼球运动108.50±5.52次/min、背鳍运动116.87±0.64次/min和胸鳍运动67.81±2.27次/min。次强节律时间段为12:00-14:00，主要为摆动行为，占比为59.20%±5.1%。海水青鳉也在08:00-10:00时间段有最强烈的活动节律，其中，游动占比88.0%±1.1%、鳃盖运动407.88±3.8次/min、颌运动407.88±3.8次/min、眼球运动7.38±0.9次/min、背鳍运动373.17±2.5次/min、胸鳍运动400.83±6.8次/min、尾鳍运动416.58±7.7次/min。因此，不管是管海马还是海水青鳉，作为视觉性鱼类，均存在明显的昼夜行为节律表现。其中，8:00-10:00时间段是两种鱼类行为的活跃期，活动节律强、行为组成丰富，因此可以选择该时间段作为相关行为学研究的适宜观察时段。
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Evaluation of the Effectiveness of Molecular Marker-Based Release for Chinese Shrimp in the Yellow Sea off the Southern Coast of the Shandong Peninsula
qiujingyaun, lvding, huyulong, wangweiji, lvguanzheng, shanxiujuan
Abstract:
中国对虾(Fenneropenaeus chinensis)是我国黄渤海重要的增殖放流物种,其放流效果的评估对黄渤海中国对虾资源的养护具有重要意义。为开展此项研究,本研究先后于2023年春季在山东半岛南部海阳黄海水产有限公司,收集生产完成的中国对虾亲虾404尾,作为放流苗种；当年9月份中国对虾秋汛期间在黄岛、海阳和崂山海域,回捕中国对虾个体共计461尾；于2024年春季,在崂山和日照海域,分别采集中国对虾生殖洄游个体110尾和399尾。实验采用微卫星分子标记和线粒体COI基因序列信息相结合的亲子溯源方法,对山东半岛南部黄海海域中国对虾放流效果进行了评估。结果显示,2023年秋汛回捕样本以及2024年生殖洄游的回捕样本,共计监测到放流个体112尾,其中,秋汛回捕样本和生殖洄游样本中各监测到56尾来自放流的个体。上述结果表明,山东半岛南部黄海海域增殖放流的中国对虾,无论对当年黄海秋汛生物量和翌年生殖洄游的亲虾资源量均有显著贡献。
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pIgR gene in Aristichthys nobilis: Molecular characterization and immune response to Aeromonas hydrophila challenge
Xia Hu, Ding Cheng, Liu Liang-guo, YANG Xin-Yue, BU Jian-Chao, Chen Fu-yan, and YANG Pin-Hong
Abstract:
多聚免疫球蛋白受体(polymeric?immurnoglobulin?receptor，pIgR)是一种重要的鱼类黏膜免疫因子，在介导多聚免疫球蛋白向黏膜免疫组织的黏液中分泌和转运中起着关键的作用。本研究利用PCR与RACE技术克隆获得鳙（Aristichthys nobilis）pIgR基因cDNA全长序列，鳙pIgR基因cDNA序列全长1885 bp，其开放阅读框长1008bp，编码336个氨基酸，鳙pIgR具有1个信号肽序列，之后为胞外区、跨膜区和胞内区，胞外区包括2个免疫球蛋白样功能域（Ig-like domains, ILD），其三级结构呈扭曲的“L”型。系统进化树分析发现鳙pIgR基因与同属鲤形目鱼类的pIgR聚为一支。实时荧光定量PCR检测结果显示鳙pIgR基因的表达量在肝脏中最高，其次为脾、肠、头肾、鳃及皮肤，在中肾、心及脑中具有较低的表达量，其表达水平最低的组织是肌肉。鳙被嗜水气单胞菌感染5 d，通过组织切片与HE染色观察pIgR基因表达水平高的免疫相关组织病理变化，发现肠绒毛宽度增宽，黏液细胞增多，肠壁增厚，表现出明显的肠道炎症症状；头肾与脾脏组织出现大量的炎症细胞，脾脏中观察到大量的空泡细胞；肝脏肝窦増宽；鳃丝变形缩短，鳃丝细胞凋落。鳙被嗜水气单胞菌感染，头肾、脾脏、鳃、肠和肝中pIgR基因的表达量在感染28 d内呈先上升后降低的趋势，鳃和肠中pIgR基因的相对表达量在感染5 d达到峰值，头肾、脾脏与肝中分别在感染7 d和14 d达到最大值，且鳙pIgR基因在肠（18.63倍）和鳃（16.53倍）中达到峰值时的相对表达量高于其在头肾（9.38倍）、脾脏（15.98倍）和肝（12.28倍）中在峰值时的相对表达量。实验结果表明嗜水气单胞菌感染鳙不仅导致其免疫相关组织发生病变，诱导产生炎症反应，且对呼吸系统和消化系统也具有影响，在鳙抵御细菌感染的免疫反应中pIgR可能在黏膜免疫系统中起着关键的作用。
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Analysis for ovarian metabolome between hybrid sturgeon population (Huso dauricus♀×Acipenser schrenckii♂) with differential fertility
LI Yutao, WANG Ruoyu, MA Bo, CAO Dingchen, SUN Zhipeng, WANG Nianmin, XU Shijian, ZHANG Ying
Abstract:
本研究旨在通过鉴定高/低繁殖力雌性杂交鲟成年个体性腺组织间差异代谢物并对其进行信号通路富集分析以确定影响鲟鱼繁殖力的关键代谢物种类及生理代谢途径。本研究测量90尾处于性成熟期的雌性杂交鲟个体（达氏鳇 Huso dauricus♀×施氏鲟 Acipenser schrenckii♂）体重及卵重后计算相对卵重系数（卵重/体重），定义相对卵重系数小于0.15为低繁殖力个体，大于0.20则为高繁殖力个体。本试验共计选取高/低繁殖力杂交鲟个体各8尾，采集卵巢组织进行非靶向代谢组学分析。结果表明，与低繁殖力组相比，高繁殖力组杂交鲟个体相对卵重系数显著提高76.92%（P<0.05），说明本试验设定的分组标准合理 。另外发现，在高/低繁殖力组杂交鲟卵巢组织中共计鉴定到14大类小分子代谢物，其中主要代谢物类别为脂质/类脂质分子、有机酸及衍生物以及有机杂环化合物。基于差异代谢物筛选阈值，本试验在高/低繁殖力组之间共计鉴定到11种差异代谢物，分别隶属于五大类别。与低繁殖力组相比，高繁殖力组个体卵巢中（-）维生素B2、维生素B2、亚精胺、腺苷以及溶血磷脂酰肌醇22：6等8种差异代谢物显著下调（P<0.05）。随后对差异表达代谢物进行通路富集分析，发现氨基酸代谢相关通路（“精氨酸和脯氨酸代谢”、“β-丙氨酸代谢”）和维生素代谢相关通路（“维生素B2代谢”、“维生素消化与吸收”）被显著富集（上述4条通路P值分别为0.0019、0.0247、0.0001、0.0004）。另外发现，差异代谢物腺苷可参与14条代谢途径，推测其可能对于杂交鲟繁殖力具有核心调控作用。本研究初步阐明了影响雌性杂交鲟产卵量性状的关键分子信号通路并筛选了高繁殖力表型的候选生物标志物，这将为早期选育高繁殖力杂交鲟群体提供理论基础。
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Molecular cloning and mRNA expression analysis of Msck8 gene in largemouth bass (Micropterus salmoides)
yuerongyan, qufengyu, wuhaiqing, linshimei, chenyongjun, luoli, zhouxinghua, heyuanfa
Abstract:
细胞角蛋白8(cytokeratin 8, ck8)是一种细胞骨架蛋白,属于角蛋白家族成员,在调控上皮细胞粘附与运动、介导免疫反应等过程中发挥重要作用。为了探究ck8在大口黑鲈(Micropterus salmoides)免疫反应中的作用,本研究利用cDNA末端快速扩增(RACE)技术克隆获得大口黑鲈Msck8基因的全长序列2 424 bp,其中5"非编码区有570 bp,3"非编码区有195 bp,开放阅读框有1 659 bp,可编码552个氨基酸,预测其分子量为61.30 kD,理论等电点为5.17。系统进化树中大口黑鲈与小口黑鲈Msck8蛋白聚为一支,显示了较高的同源性(99.10%)。荧光定量PCR分析显示,Msck8在健康大口黑鲈9个组织中均有表达(P<0.05),其表达量由高到低依次是心脏、肌肉、鳃、肾脏、肝脏、后肠、前肠、中肠和脾脏。经脂多糖免疫刺激后,Msck8在大口黑鲈心脏、肌肉和后肠组织中的表达量均呈时序性变化(P<0.05),心脏和肌肉中均在6 h出现表达高峰,后肠中于48 h出现表达高峰。此外,大口黑鲈经高水平豆粕饲料响应后发现,豆粕替代50%鱼粉组的Msck8基因表达水平显著低于鱼粉组(P<0.05)。综上所述,Msck8可能在鱼体抵御细菌入侵和营养调控的炎症反应中发挥重要作用。
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Effects of phytosterols on growth, digestion, intestinal, liver morphology, antioxidant and immune levels in Procambarus clarkia
YANG Zhigang, WANG Xiao, Ren shengjie, LIU Yongjian, GU Xiaolong, WANG Aiming
Abstract:
本实验旨在探究饲料中添加植物甾醇对克氏原螯虾（Procambarus clarkii）生长消化、抗氧化、免疫及肠肝形态的影响。在基础饲料中分别添加0%、0.10%、0.19%、0.38%、0.76%的植物甾醇，制备5组等氮等脂饲料，分别命名为CON、P1、P2、P3和P4饲料组，对体均重为（9.37 ? 0.02 g）的克氏原螯虾进行6周的养殖实验。结果显示：P1和P2组的增重率、特定生长率显著高于CON组（P < 0.05），且P2组实验虾的生长性能最佳。P3组实验虾肠道蛋白酶活性显著高于CON组，脂肪酶活性显著低于CON组（P < 0.05）。肝胰腺中P1组酸性磷酸酶和碱性磷酸酶活性最高，血淋巴中P2组酸性磷酸酶和碱性磷酸酶活性最高，但与CON差异均不显著（P > 0.05）。随着植物甾醇水平提高，肝胰腺和血淋巴总超氧化物歧化酶活性与过氧化氢酶活性呈上升趋势，丙二醛含量呈下降趋势。相较CON组，P1组肠道结构更加健康完整，植物甾醇水平到0.19%及以上时，克氏原螯虾的肝胰腺与肠道组织形态出现不良影响。随着植物甾醇水平提高，肝胰腺的NF-κB相对表达水平升高。P1组Hsp70相对表达水平显著高于其他组（P < 0.05）。研究表明，本实验条件下添加0.10%?0.19%植物甾醇可以促进克氏原螯虾的生长消化、改善肠肝组织形态，提高克氏原螯虾抗氧化和免疫能力。
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Effects of two Bacillus probiotics on growth, digestion, immunity and intestinal microbial communities of largemouth bass (Micropterus salmoides)
WANG Shigui, YAN Fajun, ZHANG Minglei, MAO Shuquan, ZHU Yongan, FU Chaosong, SONG Liping, LIU Feng
Abstract:
本文选取热带芽孢杆菌(Bacillus tropicus)和传染病研究所副芽孢杆菌(Metabacillus idriensis)为潜在益生菌，探讨它们对大口黑鲈(Micropterus salmoides)生长、消化、免疫及肠道菌群的影响。将初始体重为(92.95±2.36)g的大口黑鲈随机分为5组，每组设3个重复，分别饲喂基础饲料(对照组)和4种试验饲料[于基础饲料中分别添加104和106 CFU/g的B. tropicus(标记为BT4、BT6)或M. idriensis(MI4、MI6)]，饲喂期为60 d。生长试验结果表明，各菌处理组大口黑鲈的终末体重、增重率及特定生长率均高于对照组，但差异不显著(P>0.05)，而饲料系数均显著低于对照且随菌株添加浓度增加呈显著降低变化(P<0.05)。消化方面结果显示，各菌处理组的肠道淀粉酶和蛋白酶活性均高于对照组，其中BT6和MI6对肠道消化性能具有显著提高效果(P<0.05)。免疫方面结果表明，各菌处理组的血清酸性磷酸酶、碱性磷酸酶及溶菌酶以及肠道溶菌酶、超氧化物歧化酶活性均得到显著的提升(P<0.05)，说明菌株对血清和肠道免疫功能均有显著提高作用，但比较发现，总体以BT6与MI6的免疫增强效果最佳。肠道菌群高通量测序结果显示，支原菌属(Mycoplasma)、邻单胞菌属(Plesiomonas)和鲸杆菌属(Cetobacterium)为大口黑鲈肠道优势菌群；各组比较发现，BT6、MI6与对照之间在OTU数量、多样性指数及菌群结构上差异最明显，BT6可降低主要优势菌支原菌属(P<0.05)和多数劣势菌群的丰度来提高菌群均一性进而提高菌群多样性，而MI6可促进多数劣势类群的生长来提高菌群丰富度和均一性进而提高菌群多样性，这反映了不同菌株对肠道菌群作用方式的差异。本研究表明，热带芽孢杆菌和传染病研究所副芽孢杆菌皆可作为益生菌株应用于大口黑鲈养殖，在本实验条件下最佳使用量均为106 CFU/g，它们具有促进大口黑鲈生长、增强消化和免疫力、促进肠道菌群平衡及提高肠道菌群多样性等作用。本研究为大口黑鲈的益生菌开发与应用提供理论支撑。
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1.3 RT-qPCR
zhanghui, zenglin, xiongyifei, songwei
Abstract:
毒物兴奋效应是指有机体经历低剂量胁迫后,可以提高其对相同或不同高剂量胁迫因子的耐受性。由此探讨盐度驯化改善大黄鱼(Larimichthys crocea)盐度胁迫耐受性的作用机制,实验设置六个盐度梯度(25、25+12、25+40、20、20+12、20+40,分别记为C组、CL组、CH组、A组、AL组、AH组),大黄鱼盐度暴露24 h后取样。结果显示,CL vs C中大黄鱼肝脏的丙二醛(malondialdehyde,MDA)、脂质过氧化物(Lipid oxidation,LPO)、超氧化物歧化酶(superoxide dismutase,SOD)、溶菌酶(lysozyme,LZM)活力显著上升,过氧化氢酶(catalase,CAT)活力显著降低(P<0.05),碱性磷酸酶(alkaline phosphatase,AKP)的活力变化不显著(P>0.05)。CH vs C中MDA和LPO含量显著上升,SOD、 LZM的活力显著上升,CAT和AKP显著降低(P<0.05)。A vs C中MDA和LPO含量显著上升,SOD、LZM和AKP的活力未发生显著变化(P>0.05),CAT活力显著降低(P<0.05)。 AL vs CL与AH vs CH中MDA和LPO含量显著降低,SOD、 CAT 、LZM和AKP的活力显著上升(P<0.05)。铜锌超氧化物歧化酶(Cu/Zn-SOD)、锰超氧化物歧化酶(Mn-SOD)、CAT、非特异性免疫酶［c型溶菌酶(c-type LZM)、g型溶菌酶(g-type LZM)和AKP］基因表达水平与其酶活成正相关；核转录因子NF-E2相关因子2(NF-E2-related factor 2,Nrf2)和核转录因子-κB(nuclear transcription factor-κB,NF-κB)基因表达水平均分别与其目的基因(抗氧化酶基因和非特异性免疫酶基因)表达水平呈正相关(P<0.05),表明Nrf2和NF-κB可能分别参与了抗氧化和非特异性基因表达调控。综上所述,基于毒物兴奋效应原理,盐度驯化可以通过提高大黄鱼抗氧化和非特异性免疫能力来缓解盐度胁迫所带来的氧化损伤,从而改善大黄鱼的盐度耐受性。
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Development of vertebral column and appendicular skeleton in Collichthys lucidus larvae and juveniles
WU Chenyan, TANG Pengyan, ZHONG Junsheng, WANG Xiaodong, HUANG Jieli
Abstract:
本研究基于2014年6-7月在杭州湾北部水域用大型仔稚鱼网（口径1.3m、网目0.5mm）进行表层拖网所采集的棘头梅童鱼（Collichthys luncidus）仔稚鱼样本，采用软骨-硬骨双染色技术，探讨了棘头梅童鱼仔稚鱼（体长范围为3.3-12.7mm）脊柱及附肢骨骼的早期发育和骨化特征。研究结果表明：脊柱骨化之前不分节，而是由前向后逐渐长出的一个个骨环把脊柱分节，硬骨化出现的顺序大体上为由前向后。髓弓在脊柱骨化之前完全形成，相对于一些低等鱼类髓弓等的生成方向是从中间向头尾和从后向前进行，棘头梅童鱼的髓弓由前向后生长，属于相对高等鱼类的生长类型。胸鳍支鳍骨是最先发育的附肢骨骼，为能够自由地游泳摄食和从内源性营养转变为外源性营养提供了保障。后颞骨的形状十分特殊，具有四枚向不同方向突起的棘；背鳍支鳍骨由体中部开始向前后生长，尾鳍支鳍骨的骨化晚于其他附肢骨骼，侧尾下骨与其相邻的两枚尾下骨的基部融合，为其游泳提供了强劲的动力。该研究结果不仅可以为早期形态学分类提供骨骼发育学方面的科学依据，对棘头梅童鱼人工繁殖过程中结合骨骼发育进行技术上的契合也具有重要的参考价值。
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Detection of Nile tilapia specific antibody secreting cells induced by human IgG by ELISPOT assay
Huang Yu, Pang Bijian, Li Qi, Wu Zaohe, Jian Jichang
Abstract:
通过酶联免疫斑点法(ELISPOT)检测了经人IgG免疫后尼罗罗非鱼(Oreochromis niloticus)头肾、外周血和脾脏中的特异性抗体分泌细胞(antibody secreting cell,ASC)数量。结果表明：首次免疫1天后可在头肾中检测出ASC,而外周血和脾脏第3天才能检测出ASC；头肾、外周血以及脾脏中的ASC均在第12天达到峰值,随后头肾,外周血中的ASC数量显著减少,而在脾脏中ASC数量减少不显著。二次免疫1天后在头肾、外周血和脾脏中均可检测到ASC,ASC数量均在第9天达到峰值,时间早于首次免疫,且在首次免疫和二次免疫中,头肾组织的ASC数量均是三个组织中最高的。酶联免疫吸附试验(ELISA)分别对首次免疫和二次免疫后血清中的抗体水平检测发现,其变化趋势与ASC数量变化规律相同。研究结果表明,尼罗罗非鱼在初次免疫后产生了免疫记忆,在二次免疫过程中产生了更多的ASC和抗体,头肾是ASC的主要来源组织。该结果为鱼类的免疫记忆研究提供重要的科学依据。
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Effects of Cu acclimation on oxidative damage in the large yellow croaker under cold stress based on transcriptome analysis
Zeng Lin, Wang Yong Hong, songwei
Abstract:
为探讨铜驯化对低温胁迫下大黄鱼氧化损伤和基因表达水平的影响,本实验将体质量为(48.92±3.62) g的大黄鱼暴露在铜浓度为0和10 μg L?1的水体中14 d,再暴露在温度为8°C的水体中24 h。结果显示,低温胁迫显著增加了活性氧(ROS)和脂质过氧化物(LPO)含量。尽管铜驯化对ROS和LPO含量不产生影响,但铜驯化显著增加了低温胁迫下大黄鱼ROS和LPO含量,表明铜驯化加剧了低温胁迫对大黄鱼的氧化损伤。从铜驯化vs.对照组、低温胁迫vs.对照组和铜驯化+低温胁迫vs.低温胁迫中分别筛选到2 288个、1 425个和1 382个差异基因。GO和KEGG分析发现差异基因主要富集在与脂肪酸代谢、糖类有氧代谢、谷胱甘肽代谢、内质网应激、自噬和凋亡等相关的通路中。聚类分析表明,低温胁迫上调了不饱和脂肪酸合成、内质网应激、自噬和凋亡等相关通路中的大部分基因表达,而铜驯化则对低温胁迫下大黄鱼的这些基因表达调控产生了拮抗效应,表明铜驯化通过抑制不饱和脂肪酸合成、内质网应激、自噬和凋亡来降低大黄鱼的低温胁迫耐受性。研究结果为深入研究铜污染物对大黄鱼低温胁迫耐受性的影响及其分子机制提供科学依据。
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