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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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2023 Vol. 42, No. 2 Published: 2023-03-25

Research and Application Overview and SpecificTopi

Research and Application

	175	Molecular Cloning and Expression Analysis of LvML1 Gene in Pacific White Shrimp Litopenaeus vannamei
		LIU Hongtao, WANG Kun, YANG Mingqiu
		DOI: 10.16378/j.cnki.1003-1111.21182
		ML (MD-2-related lipid-recognition) genes are a class of proteins with important functions in innate immunity and lipid metabolism in invertebrates. In this study, we cloned a novel ML gene from Pacific white shrimp Litopenaeus vannamei named LvML1. The full-length cDNA sequence of LvML1 consists of a 254 bp 5'-untranslated regions (5'-UTR), a 913 bp 3'-UTR and a 462 bp open reading frame (ORF). The deduced amino acid sequence is composed of 153 amino acids. LvML1 has seven cysteine residues, which are predicted to form three pairs of disulfide bonds, with a typical ML family structural domain. Multiple sequence alignment revealed that both the ML structural domain and cysteine residue positions were relatively conserved. Phylogenetic tree showed that LvML1 clustered with ML proteins of crustaceans including tiger shrimp Penaeus monodon, kuruma shrimp Marsupenaeus japonicus and spiny lobster Homarus americanus. Real-time quantitative PCR results showed that LvML1 was expressed in hepatopancreas, eyestalk, intestine, stomach, heart, gill, muscle and blood, with the highest expression level in the heart. Expression in larval developmental stages showed that LvML1 was already expressed from the nauplius of Pacific white shrimp and was upregulated at each metamorphosis transition to zoea, mysis and postlarva, indicating that it is involved in the larval developmental processes of shrimp. Expression of LvML1 in hepatopancreas and gills exposed to artificial injection of Decapod iridescent virus 1(DIV1) for 0 h and 24 h was significantly down-regulated with P<0.01, indicating that it is involved in the regulation of innate immunity against the virus in shrimps. The finding provides basic data for understanding of the structure and function of the ML protein family in Pacific white shrimp and its important role in the innate immunity and larval developmental processes of the shrimp.
		2023 Vol. 42 (2): 175-184 [Abstract] ( 206 ) HTML (1 KB) PDF (3729 KB) ( 161 )

	185	Serum Proteins Profile and Bioinformatics Analysis of Silver Crucian Carp Carassius auratus gibelio
		PI Qiaomu, WANG Qiannan, LIU Youhua, WANG Weixia, AN Xianhui, LI Fuhou
		DOI: 10.16378/j.cnki.1003-1111.21036
		Silver crucian carp Carassius auratus gibelio is one of the excellent varieties of freshwater aquaculture in China. In recent years, the disease problems are becoming more and more serious, and thus have greatly affected the breeding efficiency. Fish infected with diseases can cause changes in the expression levels of some proteins in serum. Therefore, screening some specific proteins as biomarkers is helpful to the identification and control of fish diseases. In the paper, the serum proteins of silver crucian carp were isolated and identified using blue-native polyacrylamide gel electrophoresis and LC-MS/MS. A total of 721 serum proteins were identified. Bioinformatics analysis showed that these proteins were mainly involved in complement and coagulation cascade, metabolic pathway and bacterial infection pathway. A lot of non-specific immunity related proteins including complement C3 proteins and α2-macroglobulin were identified. intensity-based absoluteprotein-quatification (iBAQ) analysis showed that different kinds of complement C3 proteins and α2-macroglobulin had different expression levels. Moreover, some potential biomarkers such as serum transferrin, creatine kinase, α2-enolase and complement factor HF were also determined. The finding provides a new method for the study of serum proteins function, protein-protein interaction and serum biomarker screening for silver crucian carp, which is of great significance for disease prevention of fish.
		2023 Vol. 42 (2): 185-194 [Abstract] ( 139 ) HTML (1 KB) PDF (2442 KB) ( 114 )

	195	Effects of Different Sets of China's Tuna Purse Seine Fishery on Cetaceans Bycatch
		LU Siqi, DAI Xiaojie, GAO Chunxia, LI Junyi
		DOI: 10.16378/j.cnki.1003-1111.21049
		Cetaceans are the top predators of the marine ecosystem in the Central and Western Pacific, and bycatch in tuna purse seine fisheries has been one of the most interesting hotspot in cetaceans conservation in recent years. In this study, the effects of two-type setting operations including free swimming school (FSC) and fish aggregation devices (FADs) on cetacean bycatch were analyzed by different fishing areas, by different fishing time, by months and years of setting, based on the data from the Chinese tuna purse-seine fishery in the Western and Central Pacific Ocean (N 10°—S 13°, E 144°—W 149°) from 2016 to 2019. A total of 15 species of cetaceans bycatch were recorded with total of 219 individuals. The results showed that the main distribution area of cetacean bycatch in the Western and Central Pacific Ocean was the Kiribati exclusive economic zones; the time period of cetacean bycatch under FSC operation was more evenly distributed and the difference was not significant (P>0.05), while the time period of cetacean bycatch under FADs operation was mainly concentrated in 16:00—19:00 and the difference was significant (P<0.05 ); the bycatch of cetaceans was high in January, July and November, and the variability of cetacean bycatch in different months under FSC operations and FADs operations were not significant (P>0.05); the average mortality rate of cetaceans caused by FSC and FADs operations was 43.04% and 33.33%, respectively, and the variability of cetacean mortality between the two operation methods was not significant (P>0.05), while there were some differences in bycatch mortality rates of different species affected by the two operations. The finding indicated the effects of FSC and FADs on cetacean bycatch and proposed recommendations for cetaceans conservation, aiming to provide a scientific reference for cetaceans conservation and management in the western and central Pacific Ocean.
		2023 Vol. 42 (2): 195-205 [Abstract] ( 121 ) HTML (1 KB) PDF (4230 KB) ( 92 )

	206	Effect of Five Aquaculture Chemicals on Ammonia Nitrogen Removal Efficiency of Bioflocs
		LUO Guozhi, WU Huifang, HAO Yaning, YAO Miaolan, TAN Hongxin
		DOI: 10.16378/j.cnki.1003-1111.20022
		In order to probe for the effect of addition of aquaculture drugs on the ability of bioflocs to remove ammonia nitrogen, conventional doses of florfenicol (0.45 mg/L), doxycycline (1.5 mg/L), sulfamethoxacin (4.8 mg/L), sulfadiazine (4.5 mg/L) and enrofloxacin (15 mg/L) were added into a 10 L plexiglass reactor with a diameter of 20 cm, a height of 50 cm, and a conical bottom containing the biofloc suspension of the tilapia aquaculture system. The dynamics of total ammonia nitrogen (TAN), nitrite nitrogen and nitrate nitrogen in the process of removing 20 mg/L ammonia nitrogen by biological flocs were measured, and the bacterial community structure in each experimental group was compared for 20 days. The reactor containing only the biological floc suspension without the addition of fishery drugs was used as a ontrol group. No significant effect was found in TAN removal for all the five chemicals with their current concentrations under the experimental conditions.. There were significantly higher nitrite nitrogen concentration in reactors with florfenicol and doxycycline than that in the control group (P<0.05), with less nitrite nitrogen concentrations in reactors with sulfamethoxacin, sulfadiazine and enrofloxacin than that in the control group, without significant differences in the richness and diversity of bacterial community in the reactors with sulfamethoxacin, florfenicol and doxycycline, and in the control group (P＞0.05 ). Significantly higher diversity of bacterial community was observed in the reactors with sulfadiazine and enrofloxacin than that in the control reactors (P<0.05),with significantly less richness of bacterial community in these two reactors than that in the control reactors (P<0.05). Among the five chemicals,the most significant difference in the bacterial community was found in the reactors with enrofloxacin (15 mg/L), followed by doxycyclinev (1.5 mg/L) and florfenicol (0.45 mg/L), wihtout significant differences in bacterial community on phylum, class and genus levels between the reactors with the other two chemicals compared to the control group (P＞0.05).
		2023 Vol. 42 (2): 206-213 [Abstract] ( 146 ) HTML (1 KB) PDF (7099 KB) ( 68 )

	214	Effects of Acute Hypoxia Stress on Gill Structure, Physiology and Biochemistry of Hybrid F₃ of Blunt Snout Bream Megalobrama amblycephala ♀× Culter Culter alburnus ♂
		CHEN Songlin, LIN Xin, ZHENG Guodong, ZOU Shuming
		DOI: 10.16378/j.cnki.1003-1111.21205
		By adjusting the amount of nitrogen or air in the water, hybrid F₃ of blunt snout bream Megalobrama amblycephala (♀) × culter Culter alburnus (♂) was exposed to normal [dissolved oxygen concentration = (7.16±0.20) mg/L], low oxygen [dissolved oxygen concentration = (1.04±0.12) mg/L] and recover [dissolved oxygen concentration = (7.19±0.23) mg/L]. Gills of hybrid F₃ of normal, hypoxia 12 h, hypoxia 24 h, hypoxia 72 h and recovery were used as samples. Hematoxylin-Eosin staining, Alcian blue-Periodie acid Schiff staining, antioxidant enzyme activity determination, qRT-PCR and other techniques were used to explore the adaptability of gill tissue of hybrid F₃ to hypoxia. The results showed that after 72 h of hypoxic treatment, the area of intercellular cell mass in gill tissue of hybrid F₃ was significantly reduced, the length of gill lamellae was prolonged, and the contact area between gill lamellae and water was increased, so as to adapt to hypoxic environment. The area of interlamellar cell mass was recovered after reoxygenation. Hypoxic stress led to significantly reduce the density of mucus cells in gill tissue of hybrid F₃, and reduce the secretion function of mucus in gill tissue. Under hypoxia stress, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in gill tissue of hybrid F₃ were the maximum at 72 h, and catalase (CAT) activity was the maximum at 24 h. Hypoxia stress significantly changed the mRNA expression levels of caspase-3 and Bcl-2 genes in gill tissue, with the different trends. In the 72 h hypoxia treatment group, the expression level of caspase-3 gene was the maximum and that of Bcl-2 gene was the minimum. After 24 h of reoxygenation treatment, the structure, physiological and biochemical indices of gill tissue was recovered. In summary, hypoxia environment significantly affected the morphological structure, mucus secretion function, and antioxidant enzyme activity of gill tissue of hybrid F₃, but did not completely destroy its self-regulation ability.
		2023 Vol. 42 (2): 214-221 [Abstract] ( 185 ) HTML (1 KB) PDF (2914 KB) ( 233 )

	222	Molecular Cloning and Expression Analyses of Foxo3a and Foxo3b Genes in Gobiocypris rarus
		QIAN Jiaming, MIN Qianwen, DONG Ranran, ZENG Sheng, ZHANG Xianbo
		DOI: 10.16378/j.cnki.1003-1111.21094
		The full-length cDNA of forkhead protein O3a (Foxo3a) and forkhead protein O3b (Foxo3b) genes were cloned from the ovary of Gobiocypris rarus by using RACE. RT-PCR, qRT-PCR and in situ hybridization were employed to detect the expression of the pair of paralogous genes. A 2562 bp full-length cDNA of Foxo3a gene was abtained, containing a 1953 bp open reading frame (ORF) that encoded a protein of 650 amino acids, 242 bp 5' untranslated terminal region (UTR), 367 bp 3' UTR; a 2804 bp full-length cDNA of Foxo3b gene, containing a 1959 bp ORF that encoded a protein of 652 amino acids, 470 bp 5' UTR, 375 bp 3' UTR. Foxo3a gene was only expressed in brains and ovaries with a high level among all detected tissues. Foxo3b gene was highly expressed in brains and ovaries, and also found to be expressed in all other detected tissues. Foxo3a gene mRNA was detected in the ovaries with high levels from 2 month onward and slightly increased from 4 to 5 months. There was no significance in Foxo3b gene expression level in ovaries at all developing stages. In situ hybridization results showed that both Foxo3a and Foxo3b genes were expressed in the germ cell and follicular cell of Ⅱ, Ⅲ, and Ⅳ stage oocytes. Foxo3a gene expression was affected, but Foxo3b gene not, after the treatment by rapamycin. These findings indicate that Foxo3a and Foxo3b genes may play some roles in the oogenesis of G. rarus.
		2023 Vol. 42 (2): 222-232 [Abstract] ( 183 ) HTML (1 KB) PDF (11328 KB) ( 86 )

	233	Gonadal Development and Changes in Concentration of Serum Sex Hormones in Schizothorax irregularis
		ZHAO He, ZHAO Nianhua, LI Li, QIANG Zhuang, NIE Zhulan, WEI Jie
		DOI: 10.16378/j.cnki.1003-1111.21177
		To investigate the annual development of testis and ovary of Schizothorax irregularis and the changes in sex hormone content in serum, samples were taken monthly in the Kizil River from August 2020 to August 2021, and a total of 194 samples were obtained. Their testis and ovary were observed by conventional histological method. The otoliths were used as identification material to determine the minimum age at sexual maturity of the fish. The eggs were selected to depict the distribution of egg diameter to determine the spawning type. The results showed that S. irregularis testis and ovary development was divided into six periods; the minimum age at sexual maturity was 2 years for males and 3 years for females, and testis development was earlier than ovary development; S. irregularis spawn from March to May, and the number percentage of egg peaked at 2.9—＜3.1 mm in diameter, and very few mature eggs were present in the ovary at stage Ⅵ after spawning, which was judged to be a fully synchronized spawning type. The maximal serum concentrations of estradiol and testosterone were observed at stage Ⅴ in both females and males. The findings showed that S. irregularis gonads matured and spawned from March to May 2017, and the concentrations of estradiol and testosterone were increased significantly during the reproduction of S. irregularis.
		2023 Vol. 42 (2): 233-240 [Abstract] ( 130 ) HTML (1 KB) PDF (6597 KB) ( 149 )

	241	Effects of Light Spectrum on Intestinal Microbial Composition of Juvenile Tiger Puffer Takifugu rubripes
		LU Hongbo, LIU Ying, SHEN Xufang, WANG Jia, ZHOU Huiting, JIANG Jieming, LI Zequn, LIU Qi, YAN Hongwei, SUN Qunwen
		DOI: 10.16378/j.cnki.1003-1111.21101
		In order to explore the influence of different light spectra on the gut microbial composition of tiger puffer Takifugu rubripes, in the experiment the juvenile tiger puffer was taken as the research object. The fertilized eggs were hatched and bred for a total of 90 days under 5 different light spectrum conditions (blue, green, red, white, and yellow). After the feeding trail, the body length of juvenile fish was measured in each group, and the composition of their gut microbes was analyzed using Illumina HiSeq high-throughput sequencing technology. The results showed that the body length of juvenile fish was found to be significantly higher in the green light group, yellow light group and white light groups than that in the blue light group and the red light group (P<0.05 ). The survival rate of each group was from high to low described as blue light group> red light group> yellow light group> white light group> green light group, without significant difference between the groups (P>0.05). A cluster analysis with a similarity of 97% showed that the number of operational taxonomic units (OTUs) of the intestinal microbes in the blue light group, green light group, red light group, white light group, and yellow light group were found to be 631, 508, 530, 513, and 418, respectively, with the total OTUs number of 87, the unique OTUs number of 0, were found to be but the number of OUTs shared by the blue light group and the red light group was 13. The Ace and Chao1 indices of the blue light group were significantly higher in the blue light group than those in the yellow light group (P<0.05), and there was the maximal abundance of microbial flora in the blue light group, while the minimal abundance in the yellow light group. The Shannon index of blue light and red light group was significantly higher than that in green light and yellow light groups (P<0.05 ), that is, the diversity of gut microbial flora in blue light and red light groups was greater than that in green light and yellow light groups. According to the distribution of the intestinal flora at the level of the genus, the genera Arcobacter, Vibrio, mycoplasma, Rhodococcus, Brevinema, Brevibacterium, Cetobacterium, Pseudoalteromonas and Ochrobactrum were the main genus of the intestinal tract of tiger puffer, among which Arcobacter was the absolute dominant bacteria in the intestinal microbe genus. In summary, the spectrum can affect the growth of tiger puffer, and the spectrum has a micro-regulatory effect on the homeostasis of juvenile gut microbes, but the effect on the gut microbial structure of juvenile fish is not obvious.
		2023 Vol. 42 (2): 241-249 [Abstract] ( 130 ) HTML (1 KB) PDF (2874 KB) ( 466 )

	250	Effects of Plant Growth Regulators on Growth and Biochemical Components of Green Microalga Dunaliella viridis
		DAI Mengyi, ZHANG Jing, XU Yangcang, ZHANG Fu
		DOI: 10.16378/j.cnki.1003-1111.21144
		Green microalga Dunaliella viridis has strong salt tolerance, can survive in 5.5 mol/L saturated salt solution, and has rich cellular material composition. It can be used as aquatic initial weaning food and health food. In this experiment, the green microalga was used as material and Walne's medium as culture substrate to compare the effects of different concentrations of natural plant growth regulator indole-3-acetic acid (IAA) and synthetic growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D) as microalgae culture additives on the growth and biochemical components of the green microalga. The results showed that at the end of the culture period, the optimal application concentrations of indole-3-acetic acid and 2,4-dichlorophenoxyacetic acid were 0.2 mg/L and 0.05 mg/L respectively, the cell density was increased by 20.74% and 9.37% respectively compared with the control group, and the harvested biomass was 1.25 times and 1.09 times higher than that in the control group respectively (P<0.05). At the end of the culture period, the photosynthetic rate was increased first and then decreased with the increase in growth regulator concentration, and the respiratory rate increased. At the end of the culture period, the content of extracellular polysaccharide under the action of 0.20 mg/L indole-3-acetic acid was increased by 33.00%, the content of soluble protein under the action of 0.05 mg/L 2,4-dichlorophenoxyacetic acid was increased by 43.21%, and the content of glycerol under the action of 0.02 mg/L indole-3-acetic acid increased by 68.11%. Under the action of 0.20 mg/L indole-3-acetic acid and 0.50 mg/L 2,4-dichlorophenoxyacetic acid, the total lipid content was increased by 46.16% and 53.25% respectively compared with the control group, and the lipid yield was increased to 1.46 and 1.54 times as that in the control group, respectively. Considering the economic cost and ecological feasibility, 0.20 mg/L indole-3-acetic acid is more suitable as a plant growth regulator of the green microalga D. viridis.
		2023 Vol. 42 (2): 250-259 [Abstract] ( 107 ) HTML (1 KB) PDF (1385 KB) ( 225 )

	260	Seasonal Variations in Community Structure of Nekton in the Bohai Sea
		XU Yanzhao, SHAN Xiujuan, TENG Guangliang
		DOI: 10.16378/j.cnki.1003-1111.21200
		Based on the bottom trawl survey data of nekton in the Bohai Sea in May (spring) and August (summer) of 2015 and January (winter) of 2016, the seasonal variations in the community structure of nekton were analyzed. The results showed that 96 species of nekton were captured in the survey, including 55 species of fish, 37 species of crustaceans, and 4 species of Cephalopods. There were 2 to 5 dominant species [index of relative importance (IRI)>500] in the survey. The dominant species were Oratosquilla oratoria, and Crangon affinis in spring, Engraulis japonicus, Oratosquilla oratoria, Chaeturichthys stigmatia, Loligo sp. and Palaemon gravieri in summer, C. affinis, C. stigmatia, P. gravieri, Alpheus japonicus, and Acanthogobius ommaturus in winter. There was the minimum (244 ind./h) relative abundance of nekton was in spring and maximum (11 391 ind./h) in summer. The relative biomass was minimum in spring (1.56 kg/h) and maximum in summer (38.57 kg/h). From spring to winter, the relative abundance and biomass of nekton were increased firstly and then decreased. Margalef species richness index (D) was varied from 3.61 to 4.99, with the maximum in spring and the minimum in winter. Shannon-wiener's diversity index (H') was ranged from 1.83 to 2.40, with the minimum in winter and the maximum in spring. Pielou evenness index (J') was ranged from 0.49 to 0.59, with the minimum in winter and the maximum in spring. Cluster analysis and multidimensional scaling analysis showed that there was inapparent seasonal variation in similarity of community structure among subseas of the Bohai Sea. SIMPER analysis revealed that the seasonal variations in community structure in spring, summer and winter were involved in the seasonal variations of resources of O. oratoria, Loligo sp. and E. japonicus.
		2023 Vol. 42 (2): 260-267 [Abstract] ( 140 ) HTML (1 KB) PDF (1365 KB) ( 169 )

	268	Isolation, Identification, and Pathogenic Analysis of Klebsiella pneumoniae from Large Yellow Croaker Larimichthys crocea
		PAN Yuanxia, WANG Wenji, CHEN Qingtao, HU Gaowei
		DOI: 10.16378/j.cnki.1003-1111.21041
		Klebsiella pneumonia is the second largest conditioned pathogen after Escherichia coli and infects a wide range of hosts, including humans and a variety of animals. In recent years, diseases caused by K. pneumoniae infection of aquatic animals have occurred frequently, which has seriously hindered the healthy development of aquaculture. In this study, the method of bacterial isolation, culture and morphological observation were used to isolate a suspected pathogenic bacterium (designated as KPLYC2) from the liver of cultured diseased large yellow croaker Larimichthys crocea for identification. Large yellow croakers were infected by injection with KPLYC2, which caused the same symptoms and death of natural infection. The medial lethal dose of KPLYC2 was 6.8×106 cfu/mL, and caused obvious pathological damage to the liver, kidney and spleen in large yellow croaker. KPLYC2 also infected mice and caused systemic pathological damage. Through the physiological and biochemical characteristics detection, 16S rRNA sequence analysis and construction of phylogenetic tree, it was found that the genetic identity was more than 99% between the isolated strain and K. pneumoniae, so KPLYC2 was identified as K. pneumoniae. The drug sensitivity test showed that KPLYC2 was not sensitive to ampicillin, penicillin G and tetracycline. A strain of K. pneumoniae was isolated from large yellow croaker for the first time and its drug resistance and pathogenicity was explored. The finding will provide reference and foundation for the prevention and control of this disease.
		2023 Vol. 42 (2): 268-278 [Abstract] ( 139 ) HTML (1 KB) PDF (4517 KB) ( 155 )

	279	Comparison of Nutritive Composition in Muscle of Wild and Domesticated Goby Acanthogobius ommaturus
		ZHU Fei, XU Dafeng, JIA Chaofeng, MENG Qian, GAO Bo, SUN Ruijian, ZHANG Zhiyong, ZHANG Zhiwei, CHEN Shuyin, WU Guojun, SHA Shibing, YU Mingwei
		DOI: 10.16378/j.cnki.1003-1111.21067
		The purpose of this study was to understand the changes in nutrient composition and quality of the goby Acanthogobius ommaturus fed compound diet throughout the whole course, after several generations of acclimation and breeding of artificial formula feed, F₃ generation muscles of the goby were selected as samples in this experiment. The approximate nutritional composition, amino acid composition, fatty acid composition in muscles of wild and farmed goby were analyzed by conventional methods. The results showed that compared with wild goby, the contents of crude protein and crude fat in muscle of cultured goby was significantly higher (P<0.05), while the crude ash content of cultured group was significantly lower than that of wild goby (P<0.01), without significant differences in the moisture in muscle (P>0.05 ). The amino acid composition of the two was basically the same, sixteen types of amino acids were found in the muscle of the goby, which included seven types of essential amino acids. Four types of delicious amino acids were found in the muscle, the content of the cultured and wild group were 39.47% and 31.74% respectively (P<0.05). The essential amino index (EAAI) of cultured goby (73.65) was higher than that of wild goby (66.76); the total contents of polyunsaturated fatty acids (PUFA)in muscles of cultured and wild goby were 39.58% and 40.91%, respectively. A total of 25 fatty acids were detected in cultured goby and 24 in wild goby. The total content of saturated fatty acids (SFA) in muscle of wild goby was significantly higher than that in cultured goby (P<0.05) while the total content of monounsaturated fatty acids (MUFA) was significantly lower than that in cultured goby (P<0.05). No significant difference was found in the total content of polyunsaturated fatty acids (PUFA) between wild and cultured goby. The total content of n-3 PUFA in muscle of wild goby, however, was significantly higher than that of farmed goby (P＜0.05). The total content of n-6 PUFA in muscle of wild goby was significantly lower than that of farmed goby (P＜0.05). The findings indicated that goby muscle is nutritional and delicious,and featured by high protein content and low fat content, and that the dietary supplementation of n-3 fatty acids can improve the meat quality and nutritional value of the goby.
		2023 Vol. 42 (2): 279-287 [Abstract] ( 128 ) HTML (1 KB) PDF (1001 KB) ( 112 )

	288	Isolation and Identification of Pathogen of Bacterial Gill Disease in Brown Trout Salmo trutta
		SUN Shuaijie, ZHOU Jianshe, WANG Wanliang, CHEN Meiqun, ZHANG Chi, LI Ming, TASHI Lhamo
		DOI: 10.16378/j.cnki.1003-1111.21052
		In September 2020, gill disease of brown trout Salmo trutta was developed at a breeding base in Yadong County, Xigaze City, Xizang Autonomous Region. The sick fish had main clinical symptoms including open gill cover, gill filament congestion, lonely, and difficult breathing. In order to explore the cause of the disease and to find its treatment, a dominant strain (YDX-1) was isolated from the gill tissue of brown trout with gill disease, using conventional bacterial analysis, 16S rRNA gene sequence comparison analysis and artificial infection test. At the same time, the drug resistance of strain YDX-1 was explored. The results showed that the strain YDX-1 was a gram-negative bacterium, and its phylogenetic tree constructed based on the sequence alignment of 16S rRNA gene clusters with Aeromonas salmonicida, with the similarity of more than 99%. Combined with the morphological characteristics of the bacteria, biochemical properties and the results of sequencing identification, it was comprehensively identified as A. salmonicida. The artificial infection test showed that strain YDX-1 was infectious and had a higher lethality to brown trout. The results of the drug susceptibility test showed that strain YDX-1 was generally sensitive to 6 types (21 types) of drugs used, and was only insensitive to compound trimethoprim. The finding provides guiding significance for the prevention and treatment of bacterial gill disease of brown trout in Xizang.
		2023 Vol. 42 (2): 288-295 [Abstract] ( 136 ) HTML (1 KB) PDF (2336 KB) ( 146 )

	296	Effects of Different Environmental Factors on Infection of Enterocytozoon hepatopenaei in Ridgetail White Prawn Exopalaemon carinicauda
		DUAN Jiancheng, HU Jihui, MU Jinxin, DENG Gaowei, GAO Wei, MU Hua, ZHANG Qingqi, GAO Huan
		DOI: 10.16378/j.cnki.1003-1111.20280
		The spread of Enterocytozoon hepatopenaei (EHP) is related to the host physique and water environment. Environmental factors such as temperature, salinity, and ammonia nitrogen concentration are extremely important influencing factors in the breeding process. It is shown that too high or too low temperature and salinity have a greater impact on the specific growth rate and non-specific immunity of ridgetail prawn Exopalaemon carinicauda. In this study, the EHP capacity in ridgetail prawn was used as an indicator to determine the transmission rate of EHP. The interaction of temperature, salinity and ammonia nitrogen on the transmission of EHP were discussed. In this experiment, three factors and three levels of orthogonal culture experiment were designed, including temperature (22 ℃, 24 ℃, 26 ℃), salinity (20, 24, 28) and ammonia nitrogen concentration (2 mg/L, 4 mg/L, 6 mg/L). Through a ten-day artificial infection experiment, real-time fluorescence quantitative PCR was used to detect EHP load under different environmental factors. The results showed that under the experimental conditions, the EHP capacity increased significantly (P<0.05). The influence of environmental factors on EHP transmission in the shrimp was temperature, ammonia nitrogen and salinity. The optimum propagation conditions were temperature 24 ℃, ammonia nitrogen 2 mg/L and salinity 28, and the unsuitable conditions were temperature 26 ℃, ammonia nitrogen 4 mg/L and salinity 20. The findings ascertained the environmental conditions for the transmission of intestinal worms in shrimp, and provided data reference for the prevention and control of intestinal cysts in shrimp in marine aquaculture.
		2023 Vol. 42 (2): 296-302 [Abstract] ( 122 ) HTML (1 KB) PDF (1124 KB) ( 151 )

	303	Reconstruction and Identification of Beak Morphology in Purpleback Flying Squid Sthenoeuthis oualaniensis
		LI Qingying, LIU Bilin, OU Liguo, GU Xinyu, CHU Moxian, BU Xinyu
		DOI: 10.16378/j.cnki.1003-1111.21058
		Purpleback flying squid Sthenoeuthis oualaniensis is a kind of marine cephalopod with abundant resources. Understanding of the population structure of purpleback flying squid is beneficial to the evaluation and management of fishery resources. Beak as hard tissue is a good material for identifying the populations of purpleback flying squid, so 161 squid samples collected from the Middle East Pacific, northwest Indian Ocean and East Indian Ocean were used to analyze and distinguish the upper and lower beaks by Fourier transform. The three views of upper and lower beaks were transformed into 20 sets of elliptic Fourier descriptors by software. The three views of upper and lower beaks were reconstructed, and then principal component analysis and stepwise discriminant analysis were carried out. The results of principal component analysis showed that the first two principal components of elliptic Fourier descriptors explained 67.4%, 70.8%, 65.8%, 80.7%, 63.0% and 57.8% of the total variation for lateral, ventral and oral view of upper beak and lower beak, respectively; the results of discriminant analysis showed that the success rates of discriminant analysis were 87.0%, 82.6%, 83.2%, 85.7%, 88.8% and 72.0% respectively; the contour of the six views reconstructed by Fourier analysis reflected the differences among the populations of squid in the three sea areas. Therefore, it is suggested that the geographic population of purpleback flying squid can be identified by analyzing the contour morphology of the six views of the beaks with Fourier transform, and the correct rate of population identification can be improved by using three views.
		2023 Vol. 42 (2): 303-312 [Abstract] ( 98 ) HTML (1 KB) PDF (3305 KB) ( 133 )

	313	Identification and Drug Sensitivity Analysis of Pathogenic Plesiomonas shigelloides Isolated from Diseased Mandarin Fish Siniperca chuatsi
		ZHANG Shuangming, JIANG Ziyan, ZHANG Zirui, TANG Huanyu, ZHU Xinhai, ZHOU Yifan, JIANG Qun, ZHANG Xiaojun, GAO Xiaojian
		DOI: 10.16378/j.cnki.1003-1111.21114
		Outbreaks of mass mortalities occurred in mandarin fish Siniperca chuatsi farms in Yangzhou City, Jiangsu Province of China in 2019. The diseased fish had clinical symptoms of haemorrhaging on surface, gills rotting, and the presence of ascitic fluid in the abdominal cavity, enlarged gallbladder and hemorrhagic liver. The bacterial isolates from the diseased fish exhibited the same phenotypic traits and biochemical characteristics, and were identified as Plesiomonas shigelloides. In challenge test, the mandarin fish infected with the representative P. shigelloides SN1 developed similar pathological signs to the naturally diseased fish, and the LD50 value of the strain SN1 to S. chuatsi was 1.05×105 cfu/mL. Detection of virulence-associated genes by PCR indicated that P. shigelloides SN1 was positive for astA, astB, astD, astE, actP and aphA. According to the antibiotic resistant assay, P. shigelloides SN1 was sensitive to ampicillin, erythromycin and cephalosporins, and resistant to penicillin G and clindamycin. These findings will provide theoretical support for prevention and control of the diseases caused by P. shigelloides in mandarin fish.
		2023 Vol. 42 (2): 313-320 [Abstract] ( 123 ) HTML (1 KB) PDF (2433 KB) ( 218 )

Overview and SpecificTopi

	321	Microbial Function and Application in Marine Recirculating Aquaculture Systems
		SUN Yongxin, TIAN Bin, REN Tongjun, LIU Xianjie, WANG Qingzhi
		DOI: 10.16378/j.cnki.1003-1111.21112

		2023 Vol. 42 (2): 321-330 [Abstract] ( 193 ) HTML (1 KB) PDF (1026 KB) ( 206 )

	331	Research Progress on Stress Response Observation Techniques of Live Fish: a Review
		YUAN Yuanyue, CEN Jianwei, LI Laihao, YANG Xianqing, HUANG Hui, WEI Ya, HAO Shuxian, ZHAO Yongqiang, WANG Yueqi, LIN Zhi
		DOI: 10.16378/j.cnki.1003-1111.21170

		2023 Vol. 42 (2): 331-338 [Abstract] ( 157 ) HTML (1 KB) PDF (1263 KB) ( 137 )

	339	Research Progress on Biological Activity of Common Saponins from Marine Animals: a Review
		JIANG Pingzhe, GAO Shan, JIANG Jingwei, XIAO Yao, ZHANG Gaohua, ZHAO Liang, CHEN Zhong, XU Yongping, LI Shuying, ZHOU Zunchun
		DOI: 10.16378/j.cnki.1003-1111.21246

		2023 Vol. 42 (2): 339-346 [Abstract] ( 193 ) HTML (1 KB) PDF (997 KB) ( 129 )