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月刊，1984年创刊
主管：内蒙古自治区教育厅
主办：包头医学院
主编：赵云山
特邀主编：高长青
编辑出版：包头医学院学报编辑部
国际刊号：ISSN 1006－740X
国内刊号：CN 15－1182/R
邮发代号：16-292

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2021 Vol. 40, No. 5 Published: 2021-09-25

Research and Application Overview and Specific Topi

Research and Application

	651	Effects of Air Exposure Period on Antioxidant Function of Pacific White Shrimp Litopenaeus vannamei
		WANG Zhuoyu, YANG Chunqiao, WANG Qiuju, ZHOU Jingxiang, LIANG Jie, ZHANG Ruixue, YUAN Haiyan
		DOI: 10.16378/j.cnki.1003-1111.20049
		The antioxidant related indicators were determined in muscle, heart, and stomach, intestine, hepatopancreas and hemolymph of live healthy and vigorous Pacific white shrimp Litopenaeus vannamei with body length of (8.32±1.43) cm with air exposure on a closed laboratory table for 0, 5, 15, and 30 min at a room temperature of 25 ℃ to investigate the effects of air exposure on the activities of antioxidant function of Pacific white shrimp. It was found that there was significantly higher malondialdehyde content in Pacific white shrimp in 15 min air exposure than that in the control group (P<0.05), with downward trend of total antioxidant capacity (TAC) in hepatopancreas with the increase in air exposure time, compared with the control group. The TAC levels in the intestine, heart, and stomach were shown to be increase first and then decreased with the increase in air exposure period, and the activity of total superoxide dismutase in hepatopancreas and muscle tissues and γ-glutamylcysteine synthetase activity in hepatopancreas tissues were decreased, without significantly change in activity of muscle and intestinal tissues (P>0.05). It can be concluded that short-term (5 min) air exposure led to has less damage to the antioxidant function of Pacific white shrimp and that prolonged (30 min) air exposure can significantly reduce the antioxidant capacity of the tissue. The spatio-temporal changes in antioxidant capacity provide the basic information on auxiliary reference for the development of the air-exposure transportation technology of Pacific white shrimp.
		2021 Vol. 40 (5): 651-660 [Abstract] ( 306 ) HTML (1 KB) PDF (1489 KB) ( 219 )

	661	Molecular Cloning and mRNA Expression Analysis of Calcineurin B Homologous Protein 2 Gene in Black Porgy Acanthopagrus schlegelii
		CHEN Shuyin, ZHANG Zhiyong, SUN Ruijian, JIA Chaofeng, MENG Qian, ZHU Fei, ZHANG Zhiwei, WU Guojun
		DOI: 10.16378/j.cnki.1003-1111.19078
		Full length cDNA sequence of calcineurin B homologous protein 2 (CHP2) gene as a key molecule involved in regulation of intracellular pH and cell proliferation was amplified in black porgy Acanthopagrus schlegelii (AsCHP2) by RACE PCR, and the sequence characteristics and homology of the AsCHP2 were analyzed by bioinformatics. The expression of AsCHP2 mRNA was detected in whole black porgy larvae, and brain, heart, muscle, liver and gonads of 90 d or 180 d old black porgy hybrid F₂ (red sea bream Pagrus major ♂×black porgy ♀) and, backcross F₁ (black porgy♂×hybrid F₁♀) by real-time fluorescent quantitative PCR. It was found that the AsCHP2 cDNA was 1722 bp in length, including a 69 bp 5′-untranslated region (UTR), a 1069 bp 3′-UTR and a 585 bp open reading frame encoding a peptide of 194 amino acids. The protein contained two conserved EF-hand domains and a nuclear export sequence, the molecular weight of about 21. 87 ku, pI of about 4. 89. Secondary and three-dimensional structure of AsCHP2 was developed by homology modeling. Nuclear sequence alignment revealed that AsCHP2 shared higher identities (86%—81%) with other fishes, and the alignment of the predicted proteins sequence of AsCHP2 had 80%—72% of similarity with other fishes. The evolutionary relationships of AsCHP2 amino acid sequences with other kinds were analyzed using the methods of NJ tree and ML tree. Sequence alignment and structure comparison revealed that AsCHP2 were members of the conservative CHP2. The AsCHP2 appeared to be constitutively expressed in early larval development (5—35 d) and the 90-day and 180-day old individuals, and had high expression level in all tissues from the individuals of 90-day old. CHP2 mRNAs was ubiquitously expressed in all tested tissues, and far more abundant in the heart, as about several times as that in gonad in black porgy, the hybrid F₂ and the backcross F₁. These findings suggest that the CHP2 gene might be involved in the growth and development of sea fishes.
		2021 Vol. 40 (5): 661-669 [Abstract] ( 181 ) HTML (1 KB) PDF (7634 KB) ( 179 )

	670	*Isolation, Identification and Pathogenicity of White-Nodules Disease in Internal Organs of Large Yellow Croaker Pseudosciaena crocea* in a Sea Cage**
		XU Chunxia
		DOI: 10.16378/j.cnki.1003-1111.20085
		In order to identify the pathogen causing white-nodules disease in internal organs of large yellow croaker Pseudosciaena crocea in sea cages in Ningde and its preliminary pathogenicity, we first took metagenomic analysis to identify the pathogen as Pseudomonas sp.. On the completion of isolation of the pathogenic strains on selective plates, one of the potential pathogenic strains, termed as ND2018, was used for artificial infection. The results confirmed that ND2018 was the pathogen causing white-nodules disease in internal organs, and that the strain was eventually identified as P. plecoglossicida by whole-genome analysis. P. plecoglossicida, as a conditional pathogen, caused the pathogenicity to large yellow croaker as its concentration reached above 1×10⁴ cfu/mL. The histopathological observation showed that cell disintegration and deposited hemosiderin occurred in liver, spleen and kidney of diseased large yellow croaker. Inflamed tissue formed visible white nodules with ND2018 in large yellow croaker. In addition, susceptibility test showed that ND2018 was sensitive to neomycin, kanamycins, furazolidone, ciprofloxacin, compound sulphonamids and polymyxin B, but resistant to enrofloxacin, gentamicin, florfenicol and 20 other antibiotics. The findings provide theoretical data for the healthy breeding, prevention and treatment of large yellow croaker farmed sea cages.
		2021 Vol. 40 (5): 670-678 [Abstract] ( 220 ) HTML (1 KB) PDF (5453 KB) ( 357 )

	679	Effects of Stocking Density on Growth, Metabolism and Immune Functions of Banana Prawn Fenneropenaeus meiguiensis
		LIU Huiling, GUO Wenjun, WANG Chenggui, NIU Xiaoyu, YANG Shiping, SUN Chengbo
		DOI: 10.16378/j.cnki.1003-1111.20062
		Juvenile banana prawn Fenneropenaeus meiguiensis with body weight of (1.89±0.26) g was reared in a 1 m³ fiberglass tank at stocking density of 60, 90, 120, 150 and 180 individuals/m², with triplication, for 15 days under conventional feeding management at water temperature of (28±1) ℃ to probe into the effects of culture density on the growth, metabolism and immunity in banana prawn. During the experiment, the banana prawn had survival rate of 100% in each group. However, the maximal activities of glutamic-oxalacetic transaminase, and glutamic-pyruvic transaminase in hepatopancreas and succinate dehydrogenase in the muscle were observed in the banana prawn at stocking density of 90 individuals/m². There was abnormal increase in the activity of acid phosphatase in the hepatopancreas and activities of alkaline phosphatase, acid phosphatase and superoxide dismutase in the muscle of banana prawn at the stocking density of 180 individuals/m². There was significant decrease in activities of glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase, succinate dehydrogenase, alkaline phosphatase, acid phosphatase and superoxide dismutase in the hepatopancreas and muscle of the banana prawn at the stocking density of 180 individuals/m² (P<0.05). The higher metabolic enzyme activities and immune enzymes indices were found in the banana prawn at the stocking density of 90 individuals/m² and considering the multiple benefit of the prawn culture, the proper breeding density of the banana prawn is less than 150 individuals/m².
		2021 Vol. 40 (5): 679-685 [Abstract] ( 202 ) HTML (1 KB) PDF (1379 KB) ( 230 )

	686	Application of a Compound Microbial Water Purification Agent in Culture of Sea Cucumber Apostichopus japonicus
		ZHOU Wenming, LI Liying, SUN Xinyu, LIU Yue, LI Ying, LIU Bingnan
		DOI: 10.16378/j.cnki.1003-1111.20074
		In order to study the purification capacity of the compound microbial preparations of photosynthetic bacterial Rhodopseudomonas palustris PSB1 and Bacillus BS1 isolated and preserved in the laboratory were taken as the research objects. After measuring the content changes in levels of ammonia nitrogen, and sulfide, and chemical oxygen demand (COD) in artificial sewage, the optimal density ratio of the two strains was 2∶1. Under this ratio, the ammonia nitrogen content in sewage was decreased from 4.68 mg/L to 0.39 mg/L, the sulfide content decreased from 0.62 mg/L to 0.26 mg/L, and the COD decreased from 4.02 mg/L to 2.35 mg/L. The safety test showed that the contents of arsenic and cadmium in the compound microbial water purification agent were 0.017 mg/kg and 1.634×10^-4 mg/kg, lower than the national standard, and no aflatoxin B₁, Shigella and other components were detected to meet the safety standard. In order to further explore the influence of composite microbial water purification agent on the quality of aquaculture wastewater, the microbial water purification agent was put into the sea cucumber Apostichopus japonicus culture to measure the concentration changes in COD, ammonia nitrogen and sulfide. It was found that the compound microbial water purifier had a good degradation effect on ammonia nitrogen, sulfide, and COD at pH of 7.0—8.5 and asalinity of 25—35.
		2021 Vol. 40 (5): 686-692 [Abstract] ( 182 ) HTML (1 KB) PDF (2702 KB) ( 159 )

	693	*Genetic Diversity of Wild Populations of Mantis Shrimp Oratosqilla oratoria* in Bohai Bay Using Microsatellite Markers**
		GU Dexian, WANG Ting, XU Yufu, WU Ning, WANG Na, HAO Yu, WANG Gang, LI Wenwen, LIU Guoshan
		DOI: 10.16378/j.cnki.1003-1111.20073
		The genetic diversity was analyzed in the back muscles of wild populations of mantis shrimp Oratosqilla oratoria sampled in the sea areas of Qinhuangdao, Tangshan, Changli, Tianjin and Huanghua by a single layer gill net in November 2019 by 12 pairs of microsatellite primers. The results showed that the five populations had from 3 to 16 in the allele number with the average effective alleles ranging from 2.9063 to 3.4102, the average observed heterozgosity (H_o) ranging from 0.5004 to 0.5342, average expected heterozgosity (H_e) from 0.5310 to 0.5491, and average polymorphic information content (PIC) ranging from 0.5422 to 0.6038. Hardy-Weinberger equilibrium test revealed that 81.67% position was in balance in the five populations. There was the maximal genetic distance between Tianjin and Tangshan populations, and the minimal genetic identity between Tianjin and Tangshan populations. The UPGMA phylogentic tree showed that the populations of Qinhuangdao and Tangshan were clustered together, Changli and Huanghua were clustered together, and then they got together with the Tianjin population. The findings indicated that the five mantis shrimp populations had high levels of genetic diversity, being the potential as breeding material and used as breeding material.
		2021 Vol. 40 (5): 693-699 [Abstract] ( 172 ) HTML (1 KB) PDF (960 KB) ( 198 )

	700	Cloning and Analysis of Extracellular Domain Expression of CD2-like Gene in Nile Tilapia Oreochromis niloticus
		CHEN Funuan, GAO Xiaolin, ZENG Xiaolian, XIE Caixia, WANG Zhiwen, LU Yishan, WU Zaohe, WANG Zhongliang, WANG Bei
		DOI: 10.16378/j.cnki.1003-1111.20032
		In this study, cluster of differentiation 2 (CD2) molecular homologous analogues (CD2-like) was cloned and identified in Nile tilapia Oreochromis niloticus with body weight of (150±50) g, and extracellular proteins of the molecule were obtained to provide a foundation for further research on the immune function of CD2-like molecule in Nile tilapia. Based on NCBI (Genbank: XM_005460661.4) predicted Nile tilapia CD2-like(OnCD2-like) gene sequences, OnCD2-like fragments were amplified by PCR. The prokaryotic expression plasmid pGEX-6P1-CD2L was constructed from its extracellular domain and the expression conditions were optimized to protein renaturation and purification. The openning reading frame (ORF) of OnCD2-like gene(GenBank: MN296489)was found to be 1110 bp and its extracellular domain was 558 bp in length. The extracellular domain molecular weight of target protein was about 20 ku, which was consistent with the expected results. The prokaryotic expression plasmid pGEX-6P1-CD2L of OnCD2-like gene extracellular domain gene was successfully constructed, and then the recombinant plasmid was introduced into BL21 and the OnCD2-like recombinant protein was successfully expressed, indicating that prokaryotic expression showed that the target protein was mainly in the form of inclusion bodies, and that the optimal expression of the inclusion body protein was observed under conditions of the induction of 0.2 mmol/L IPTG for 6 h at 37 ℃, and that finally the recombinant protein was successfully obtained after gradient dilution renaturation and purification.
		2021 Vol. 40 (5): 700-709 [Abstract] ( 152 ) HTML (1 KB) PDF (4576 KB) ( 228 )

	710	Isolation, Identification and Pathological Observation of Ulcerative Disease Syndrome in Xenocypris davidi
		WANG Ronghua, LIU Yisha, FU Yanchun, ZHANG Runchun, ZHOU Yong, LUO Yushuang, LIU Fei, CHEN Zhongyuan
		DOI: 10.16378/j.cnki.1003-1111.20058
		Ulcerative disease syndrome in Xenocypris davidi occurred in a fish farm of Zhuzhou city in Hunan Province during the breeding season for the past few years, causing ulcers in different positions of broodstock fish body surface. To determine the pathogenesis and histopathological changes in the ulcerative disease syndrome of X. davidi and explore the prevention and control measures of this disease, the traditional methods of bacterial isolation and histopathology were used in the research, and the sensibility of the pathogenic bacteria to antibiotics and Chinese herbal medicines were detected by the KB paper method. In this study, the dominant strain HZ0416 was isolated from the liver of the morbid X. davidi with typical symptom of ulcerative disease syndrome and identified as Aeromonas schubertii through 16S rDNA gene sequencing and biological identification. The artificial infection test verified that HZ0416 caused the ulcerative disease syndrome in yellow catfish Pelteobagrus fulvidraco. The drug susceptibility analysis showed that HZ0416 was significantly sensitive to gentamicin, florfenicol and nutgall, and sensitive to 8 drugs such as ciprofloxacin, herba houttuyniae, herba andrographitis, but low sensitive or resistant to 22 drugs such as kanamycin, polymyxin B, Cortex Fraxini, and Folium Artemisiae Argyi. Pathological section showed that the diseased fish suffered from multiple organ tissue hyperemia and hemorrhage, accompanied by inflammatory cell infiltration, substantial cell vacuolization and necrosis. A. schubertii was the potential pathogen of ulcerative disease syndrome in X. davidi, and prevented during the breeding process by feeding florfenicol and Galla Chinensis.
		2021 Vol. 40 (5): 710-717 [Abstract] ( 193 ) HTML (1 KB) PDF (3924 KB) ( 293 )

	718	Path Analysis of Effects of Phenotypic Traits Attributes on Abdomen Meat Weight of Red Swamp Crayfish Procambarus clarkii
		PENG Bo, TAN Yunfei, PENG Guohui, XIONG Lijing, BAI Xufeng
		DOI: 10.16378/j.cnki.1003-1111.20037
		Abdomen meat percentage as one of the important economic traits for red swamp crayfish Procambarus clarkii is positively related with abdomen meat weight. To identify the phenotypic traits that can reflect abdomen meat weight, 904 samples of red swamp crayfish including 397 males and 507 females were collected, and divided into 8 different groups (body weight of 10 g, 15 g, 20 g, 25 g, 30 g, 35 g, 40 g and 45 g) for both sex based on body weight, respectively. Eight traits including chela weight, chela length, body weight, body length, abdomen meat weight, abdomen meat percentage, carapace length and carapace width were measured and statistically analysed. The results showed that six traits were increased with increase in body weight except for abdomen meat percentage. For the same body weight individuals, body length, abdomen meat weight and abdomen meat percentage of female were significantly more than those of male, but they were opposite to the traits of chela length and chela weight. There was a significantly negative correlation between chela weight and abdomen meat percentage in both medium individuals (body weight: 25—35 g) and large individuals (body weight: 40—45 g). Multiple stepwise regression and path analysis indicated that chela weight and body weight contributed the direct effects to abdomen meat weight, negatively and positively, respectively. Together these findings indicated that it was an important breeding strategy to improve abdomen meat percentage of red swamp crayfish by reducing chela weight.
		2021 Vol. 40 (5): 718-725 [Abstract] ( 151 ) HTML (1 KB) PDF (1464 KB) ( 241 )

	726	Analysis of Morphological Differences between Differential Body Colors Groups of Hybrid Yellow Catfish
		ZHOU Huaxing, DUAN Guoqing, HU Yuting, WANG Huan, JIANG He, LING Jun, PAN Tingshuang, CHEN Xiaolei
		DOI: 10.16378/j.cnki.1003-1111.20060
		In this study, 26 measurable traits were measured in two differential groups of hybrid yellow catfish Pelteobagrus fulvidraco ♀ × P. vachellii ♂ in order to analyze the morphological differences between two groups. Subsequent comparative analyses of the morphological characteristics were performed using the one-way analysis of variance, discriminant analysis, principal component analysis and cluster analysis. The results showed that 6 traits including adipose-caudal fin distance, caudal peduncle length, eye diameter, interorbital width, dorsal-fin spine length and pectoral-fin spine length were segregated significantly. Almost all individuals were divide into two groups using cluster analysis based on the morphological characters. The corrected eye diameter and caudal peduncle length were the most discriminative traits to differentiate these two groups. Significant negative correlation between caudal peduncle length and spine length was detected and significant positive correlation between eye diameter and interorbital width was detected. We inferred that the coevolution between different traits was of importance for the adaptation of yellow catfish. The finding provides novel insights into the breeding and identification of hybrid yellow catfish.
		2021 Vol. 40 (5): 726-732 [Abstract] ( 167 ) HTML (1 KB) PDF (2460 KB) ( 168 )

	733	*Vibration Sensitivity and Suitable Hatching Mode of Schizothorax waltoni* Eggs**
		ZENG Benhe, LIU Haiping, Wangjiu, MU Zhenbo, WANG Wanliang, WANG Jinlin, ZHOU Jianshe, ZHU Chengke, YANG Ruibin
		DOI: 10.16378/j.cnki.1003-1111.19062
		The fertilized eggs (with fertility of 91.23%, 64.26% and 45.65%) of Schizothorax waltoni derived from the same batch of eggs were randomly divided into three parts and incubated in three types of incubators to compare three incubation patterns of S. waltoni eggs and the embryos of different developmental stages were oscillated at frequency of 0, 50 r/min (0.157 m/s), 100 r/min (0.314 m/s), 150 r/min (0.471 m/s), 200 r/min (0.628 m/s) and 250 r/min (0.785 m/s) for 5 minutes to explore the sensitivity of the embryos to shock. The results showed that the descending order of hatching rate was expressed as horizontal incubator (fertilization rate of 91.23%, 64.26%, and 45.65%; hatching rate of 81.74%, 40.30%, and 6.08%)>vertical incubator (91.23%, 64.26%, and 45.65%; 32.77%, 2.59%, and 0)>cylindrical incubator (91.23%, 64.26%, and 45.65%; 5.42%, 0, and 0). The minimal mortality [(0.22±0.15)%] was found in the embryos exposed to flowing rate of 0, without significantly different from that in the embryos exposed to flowing rate of 0.157—0.471 m/s, There was no significant difference in themortality of fertilized eggs between groups with flowing rates of 0.157—0.628 m/s. The maximal mortality was found in the 0.785 m/s group, which was significantly higher than that in the other groups. Under the condition of 0—0.471 m/s, the maximal mortality [(10.00±5.61)%] was found in the late gastrula stage, followed by the multicellular stage [(5.83±2.85)%]. Under the condition of 0.157—0.628 m/s, the maximal mortality [(26.67±23.45)%] was found in the 64-celled stage, which was not significantly different from that in the late gastrula stage and multicellular stage. The minimal mortality (0) was found in the rudimental heart and heart beating stages in 0.785 m/s group,which was lower than that in the other developmental stages. S. waltoni embryos was sensitive to flowing rate at different developmental stages. It is suggested to hatch the fertilized eggs in a horizontal incubator with a low flowing rate.
		2021 Vol. 40 (5): 733-739 [Abstract] ( 144 ) HTML (1 KB) PDF (2040 KB) ( 382 )

	740	Aquatic Ecological Health Assessment of Qiantang River Basin in Zhejiang Province by Phytoplankton Index of Biotic Integrity
		XIAO Shanshi, HAO Yabin, LIU Jindian, ZHANG Aiju, WANG Jun, LUO Wei, HE Haisheng, ZHOU Zhiming
		DOI: 10.16378/j.cnki.1003-1111.20031
		In order to learn more about the aquatic ecosystem health in Qiantang River basin in Zhejiang, phytoplankton and water quality data were collected and analyzed from 16 sites (3 reference points and 13 impaired points) for four times in May, July, September and December, 2018 by a series of methods including the distribution analysis, the Mann-Whitney nonparametric test and Spearman correlation analysis to obtain the main metrics. Finally, five main parameters (abundance of Dinophyta and Cryptophyta, relative abundance of Bacillariophyta, Centrales abundance/Pennales abundance, relative abundance of Bacillariophyta and Chlorophyta, and relative abundance of Cymbella) were screened out from 37 candidate parameters. Then a phytoplankton index of biotic integrity (P-IBI) value was obtained to evaluate the aquatic ecological health by summing up the scores of every metrics calculated by the ratio method.The results showed that 1 of the 16 sections was healthy, three were in medium health condition, 9 was fair, and three were in poor health. It can be seen that the aquatic ecosystem was relatively damaged slightly in larger area of the Qiantang River in Zhejiang province. Therefore, the treatment capacity of industrial, agricultural and domestic sewage was further improved and hydrophyte was planted for water remediation to avoid further deterioration of its water. The findings indicated that the evaluation system reflected the health status of the Qiantang River appropriately, and that the range of its application was relatively narrow due to P-IBI being greatly affected by climate and geographical region in study basin. In conclusion, different P-IBI should be established for the water area with obvious habitat differences.
		2021 Vol. 40 (5): 740-749 [Abstract] ( 163 ) HTML (1 KB) PDF (1685 KB) ( 183 )

	750	Large-Scale Breeding Techniques of Rough Sea Cucumber Holothuria scabra
		FENG Yongqin, WENG Wenming, FANG Zaiguang, WANG Huaihong, WANG Shifeng, LIAO Jingqiu, ZHOU Yongcan
		DOI: 10.16378/j.cnki.1003-1111.18215
		In order to increase the resources of rough sea cucumber Holothuria scabra in tropical sea, key techniques of large-scale breeding were established. From June 2014 to May 2015, the rough sea cucumber collected from the sea of Lingshui county, Hainan province were used as broodstock ones. The techniques of transporting broodstock, broodstock rearing, inducing broodstock to spawn, and culturing larval and juvenile rough sea cucumber were explored. Results showed that the survival rate of broodstock rough sea cucumber reached 99.8% when they were transported in aerating plastic bags. The survival rate of breeding broodstock rough sea cucumber in this study was above 97.1%. The success rate for inducing broodstock rough sea cucumber to spawn was 93.3% using the combination of cool drying and flowing water methods. In this study, 12 batches of early auricularia and seedling cultivation experiments were carried out, and a total of 54.74 million early auricularia were cultured and 4.459 million juveniles with body length of 1.0—5.5 cm were cultivated with total survival rate of 8.1% from early auricularia to juvenile. The large-scale production of rough sea cucumber seedlings was preliminarily realized.
		2021 Vol. 40 (5): 750-756 [Abstract] ( 146 ) HTML (1 KB) PDF (960 KB) ( 193 )

	757	*Overwinter and Culture of “Zebra” Strain of Manila Clam Ruditapes philippinarum* in Seawater Ponds**
		LI Yongren, ZHANG Chao, LIANG Jian, GUO Yongjun
		DOI: 10.16378/j.cnki.1003-1111.20066
		To increase economic performance and production efficiency, the overwinter culture experinment was conducted from Oct, 2018 to May, 2019 in Tianjin, during the idle time of seawater ponds(1.334 hm²) with 2 stocking density groups(low density group: 1000 ind./m²; high density group: 2000 ind./m²) of “Zebra” strain of Manila clam Ruditapes philippinarum. Results showed that the clam grown from 324 ind./kg to 152 ind./kg; in the trial, clam obviously grown in 2 periods(autumn: Oct. to Nov., 2018; spring time: Mar. to May, 2019).Though clam grew faster in spring in shell length each month, there was no significant difference. By the end of the experinment, the survival rate was higher in high density group than that in low density group. During the experinment, the levels of suspended solids, nitrite nitrogen, nitrate nitrogen, ammonia nitrogen, inorganic phosphorus, and COD in the ponds were declining with pH of 7.68—8.33. This new strain of Manila clam could be overwinter culture in seawater ponds in Tianjin.
		2021 Vol. 40 (5): 757-761 [Abstract] ( 163 ) HTML (1 KB) PDF (938 KB) ( 223 )

	762	Fishing Ground Forecast Model of Albacore Tuna Based on LightGBM in the South Pacific Ocean
		GONG Peng, WANG Dexing, YUAN Hongchun, CHEN Guanqi, WU Ruoyou
		DOI: 10.16378/j.cnki.1003-1111.19292
		Since traditional fishery forecasting methods cannot accurately analyze the key factors in the face of increasingly complex ocean data, the light gradient boosting machine (LightGBM), an integrated learning model, was used to predict albacore tuna Thunnus alalunga fishery via the albacore tuna longline fishing production data in the south Pacific ocean from 2000 to 2015, combined with the sea surface temperature, concentration of chlorophyll a and sea surface height, latitude and longitude in marine environment factor and spatio-temporal data, and then the results were compared with naive bayes, XGBoost and BP neural networks. Meanwhile, the optimal parameters of LightGBM model were obtained by grid search method, and the stability of the model was verified by cross validation method. Results showed that the best prediction accuracy of the LightGBM model for albacoren tuna fishery in the south Pacific reached 72.6%, and the accuracy of the LightGBM model was significantly improved compared with other models. Finally, analysis of the importance of each input factor in the prediction of fishery revealed that sea surface height and sea surface temperature were important factors influencing the distribution of fisheries.
		2021 Vol. 40 (5): 762-767 [Abstract] ( 158 ) HTML (1 KB) PDF (1461 KB) ( 220 )

	768	*Synthesis and Antiparasitic Activity against Protozoan Parasite Ichthyophthirius multifiliis* of N-Substituted-Tetrahydroisoquinoline Derivatives**
		YAO Jiayun, ZHANG Chengsai, YIN Wenlin, LIN Lingyun, PAN Xiaoyi, CAO Zheng, LIU Yihan, XIA Yanchun, SHEN Jinyu
		DOI: 10.16378/j.cnki.1003-1111.19234
		Three N-substituted-tetrahydroisoquinoline derivatives were designed, synthesized, and evaluated for their antiparasitic activity against protozoan parasite Ichthyophthirius multifiliis in vitro. The toxicity of the synthesized N-substituted-tetrahydroisoquinoline derivatives was also evaluated to develop novel antiparasitic agents against the protozoan parasite. The results showed that there was promising antiparasitic activity against I. multifiliis theronts and encysted tomonts in vitro in all the three synthesized compounds, with the maximal activity against I. multifiliis in compound 1 (2-methylamino-1,2,3,4-tetrahydroisoquinoline-formonitrile). The compound 1 had 100% effective against theronts at concentration of 20.0 mg/L in 4 h, with the median lethal concentration (LC₅₀) of 11.6 mg/L. All dead encysted tomonts were observed in compound 1 at concentration of 40.0 mg/L, with the compound 1 48 h LC₅₀ of 62.78 mg/L for topmouth culter Erythroculter ilishaeformis. The findings indicated that compound 1 (2-methylamino-1,2,3,4-tetrahydroisoquinoline-formonitrile) was useful in aquaculture for control of I. multifiliis due to high antiparasitic efficacy against I. multifiliis with low toxicity.
		2021 Vol. 40 (5): 768-773 [Abstract] ( 122 ) HTML (1 KB) PDF (1320 KB) ( 132 )

	774	Effect of Culture Water Levels on Growth in 2-Year-Old Asian Yellow Pond Turtle Mauremys mutica
		YANG Guiqiang, LI Wentong, WANG Zhanquan, HE Jie, LIN Quan, ZHENG Huang, MA Junfeng, YUAN Ding
		DOI: 10.16378/j.cnki.1003-1111.19279
		In order to promote water-saving aquaculture, the effects of three aquaculture water levels on the growth of 2-year-old Asian yellow pond turtle Mauremys mutica were investigated. One turtle was reared in a box (16.9 cm×10.5 cm×7.4 cm), 30 animals in each water level group including 1 control group and 2 test groups, which were 350 mL (high water level), 260 mL (medium water level), and 110 mL (low water level). Under the same conditions of feeding and management, the growth index and morphological characteristics were measured after 7 months at water temperature of 20.7—30.1 ℃. The results showed that the body weight was significantly higher in turtle in the middle and high water levels than that in the low water level (P<0.05). Turtle carapace length, carapace height, plastron length and carapace bridge length were significantly higher in the high and middle water levels than those in the low water level at the later stage of the test (P<0.05). The final carapace width of the turtles was significantly lower in the high water level test group than that in the low water level test group (P<0.05). The flatness of the middle and high water level groups was shown to be significantly lower than that in the low water level group (P<0.05). In this article, low water level significantly affected the weight, traits and body shape of the tested turtles, while the medium water level did not significantly affect the weight, traits and body shape of the tested turtles. It can be seen that the low water level significantly affects the body weight, morphological characteristics and flatness index of the tested turtles. The low water level group can macroscopically showed the adjustment mechanism of the turtle′s body growth in the absence of water, which had a significant water-saving effect. The mid-water level group was considered to be both water-saving efficiency and growth advantages. There was only significant growth advantages in high water level group. After comprehensive consideration of perspective of growth performance and water saving efficiency, it is concluded that the middle water level is suitable for water-saving aquaculture of the Asian yellow pond turtle.
		2021 Vol. 40 (5): 774-779 [Abstract] ( 232 ) HTML (1 KB) PDF (1581 KB) ( 211 )

	780	Fighting Behavior of Red Swamp Crayfish in Different Culture Conditions
		XU Yunling, PU Xueyin, XU Zhongqi, HUANG Cheng, HUANG Yahong
		DOI: 10.16378/j.cnki.1003-1111.19253
		In order to explore the fighting behavior of red swamp crayfish Procambarus clarkii under different culture conditions and enrich the behavioral research content of red swamp crayfish, two trails were designed in this study. In the first stage, 50 red swamp crayfish in the isolation group were put into the non isolation group domestication boxes (single-group), and 50 red swamp crayfish in the non isolation group were put into other domestication boxes (group-group). After 24 hours, the survival number of red swamp crayfish in each box was recorded. In the second stage, the same-sex red swamp crayfish in the isolation group and the non isolation group, whose body weight and body length were close to each other, were paired in two groups (the non isolation group was not paired with the original partner) to form 36 pairs of fighting groups, recorded the fight with the camera. The time of the first fight between red swamp crayfish (the length of hesitation period), the time of each fight, the total fighting time and the number of fighting rounds were recorded. The ratio of the total fighting time to the number of fighting rounds, i.e. the average fighting time, was taken as the standard to measure the fighting strength. The results of the first phase of the experiment showed that the single-group mortality was significantly higher than that in the group-group (P<0.05). The results of the second experiment showed that the fighting rate, the number of fighting rounds, the total fighting time and the fighting intensity of the red swamp crayfish kept in isolation were significantly greater than those in the non-isolated state (P<0.05). However, after eliminating the no fighting samples, there was no significant difference in the fighting behavior parameters of red swamp crayfish in the two feeding conditions (P>0.05). The results revealed that red swamp crayfish raised in an isolated environment were more aggressive, but isolation did not enhance the fighting capacity of red swamp crayfish. When a red swamp crayfish entered an unfamiliar environment from an isolated environment, death was more likely to occur (invaders died, or native died, or both died).
		2021 Vol. 40 (5): 780-785 [Abstract] ( 195 ) HTML (1 KB) PDF (1229 KB) ( 248 )

Overview and Specific Topi

	786	A Review: Research Advances on Molecular Basis and Artificially Induced Regulation of Astaxanthin Accumulation in Green Alga Haematococcus pluvialis
		DOU Yong, WU Lin, YAN Yongfang, REN Hongye, CHEN Jiayu, QIAO Zhiyi, ZHAI Shengli, ZHOU Wenli
		DOI: 10.16378/j.cnki.1003-1111.20029

		2021 Vol. 40 (5): 786-793 [Abstract] ( 222 ) HTML (1 KB) PDF (1015 KB) ( 271 )

	794	Research Progress on C1q Domain-Containing Proteins in Aquatic Animals: a Review
		GAO Yuanyuan, ZHU Lei, KONG Xianghui
		DOI: 10.16378/j.cnki.1003-1111.20027

		2021 Vol. 40 (5): 794-800 [Abstract] ( 213 ) HTML (1 KB) PDF (995 KB) ( 450 )