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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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2022 Vol. 41, No. 3 Published: 2022-05-25

Research and Application Overview and Specific Topic

Research and Application

	343	Effects of Four LED Light Sources on Growth and Gonadal Development in One-Year-Old Red Spotted Grouper Epinephelus akaara
		XU Wengang, LIU Liming, WANG Jiulong, YU Wensong, ZHANG Jianbai, SOYANO Kiyoshi, TANG Yongzheng
		DOI: 10.16378/j.cnki.1003-1111.20254
		This study used one-year-old red spotted grouper Epinephelus akaara as target species, aimed to investigate the growth and gonadal development of this species exposed to white (3000 K), red (590 nm), blue (480 nm), and green (520 nm) light emitting diodes (LEDs) for two months. The growth and gonadal development were compared. The gene expression of growth-related hormones such as PSS-Ⅰ, NPY and GH, and reproduction-related hormones such as Kiss1, Kiss2, GPR54, sbGnRH, FSHβ, and LHβ in the brain and pituitary was analyzed using qRT-PCR technology. The results showed that at the end of the experiment, the total length of fish in white group was significantly higher than that in blue and green groups (P<0.05), and the body weight was significantly higher than that in green group (P<0.05). There was no significant difference in GH gene level (P>0.05), contrarily, the PSS-Ⅰ gene level was significantly higher than that at the begining of the experiment, suggesting limited effects of PSS-Ⅰ on inhibition of GH synthesis. The significantly increased NPY gene levels in four light groups (P<0.05) indicated that four light quality were effective to stimulate food intake. After two months, the gonad developed from chromatin nucleolar-stage oocytes to perinucleolar-stage oocytes in four light groups. The GPR54 levels in four light groups and sbGnRH levels in white and blue groups were significantly increased when compared to the begining (P<0.05), without significant differences in FSHβ and LHβ gene expression in the four light groups, suggesting that the two genes may not play important roles on the development of reproductive system in the one-year-old red spotted grouper. In summary, the white light was more effective to accelerate the growth of the experimental fish, and may not induce the gonadal development.
		2022 Vol. 41 (3): 343-351 [Abstract] ( 308 ) HTML (1 KB) PDF (3640 KB) ( 371 )

	352	Effects of Lactobacillus helveticus on Gene Expression in Intestinal Transcriptome of Loach Misgurnus anguillicaudatus
		CUI Xiaolin, DING Zhiwen, MI Haoyu, MENG Wenrong, LIU Shu, YANG Guang, HOU Xiaoyue, DONG Zhiguo, FANG Yaowei
		DOI: 10.16378/j.cnki.1003-1111.20230
		In order to explore the effect of Lactobacillus helveticus HML037 on the growth and disease resistance gene expression of loach Misgurnus anguillicaudatus, the intestinal tissues of the loach from control group (C) and L. helveticus HML037 addition group (L) were double ended sequenced by Illumina hiseq 2500 high-throughput sequencing platform. The original data were quality controlled and de novo assembled, and 40 877 unigenes with an average length of 1218 bp and 1942 bp of N50. DEGseq was used to analyze gene expression difference, with 604 differential genes, of which 326 genes were significantly up-regulated and 278 genes were significantly down-regulated. All the differentially expressed genes were enriched in five pathways by GO functional enrichment analysis. The oxidation-reduction process pathway was the most abundant, followed by the oxidoreductase activity pathway, and the differentially expressed genes involved in these pathways were all up-regulated. Enrichment analysis of KEGG pathway showed that the differentially expressed genes were mainly concentrated in peroxidase proliferation-activation receptor signaling pathways, fatty acid prolongation and fat digestion and absorption. The findings provide an important reference for the improvement of intestinal growth and disease resistance performance of the loach by using L. helveticus HML037 instead of antibiotics.
		2022 Vol. 41 (3): 352-361 [Abstract] ( 173 ) HTML (1 KB) PDF (3626 KB) ( 262 )

	362	*Expression Analysis of Genes Related to Sex Differentiation in Tiger Puffer Takifugu rubripes* Juveniles**
		Juveniles JIANG Jieming, SHEN Xufang, LIU Ying, ZHANG Qi, ZHOU Huiting, WANG Jia, YAN Hongwei, WANG Chenqi, LIU Qi
		DOI: 10.16378/j.cnki.1003-1111.21046
		In order to clarify the expression patterns of sex differentiation-related genes during the critical period of sex differentiation in tiger puffer Takifugu rubripes, the histological characteristics of the gonads were observed in tiger puffer juveniles at 40, 60 and 80 d post hatching firstly. Then, after the genetic sex verification of individual, the expression patterns of amhr2, dmrt1, gsdf, cyp19a1a, foxl2 and dnmt1 genes were determined in the gonads of XX and XY tiger puffer juveniles by real-time quantitative PCR (qPCR). The results showed that the expression of the above genes showed sexual dimorphism obviously, without significant difference in the expression level of amhr2 gene in the gonads of XX and XY tiger puffer juveniles at 40 and 60 d post hatching (P>0.05), significantly higher expression level of amhr2 gene in the gonads of XX juveniles than that in XY juveniles at 80 d post hatching (P<0.05). The expression levels of dmrt1 and gsdf genes in the gonads of XY juveniles were increased significantly from 20 d, and the expression levels in the gonads of XY juveniles were significantly higher than that in XX juveniles at all the three sampling points (P<0.05). The expression levels of cyp19a1a and foxl2 genes in the gonads of XX juveniles were significantly higher than that in XY juveniles at the 40, 60 and 80 d post hatching (P<0.05). There was no significant difference in the expression level of dnmt1 gene in the gonads of XX and XY tiger puffer juveniles at 40 and 60 d post hatching (P>0.05), but the expression level of dnmt1 gene in the gonads of XY tiger puffer juveniles was significantly higher than that in XX juveniles at 80 d post hatching (P<0.05). The findings demonstrated that dmrt1 and gsdf genes played critical roles in testicular differentiation, while cyp19a1a and foxl2 genes played critical roles in ovarian differentiation in tiger puffer juveniles. The findings laid a foundation for functional analysis of the sex differentiation-related genes during the development of sex differentiation of tiger puffer.
		2022 Vol. 41 (3): 362-369 [Abstract] ( 200 ) HTML (1 KB) PDF (2123 KB) ( 243 )

	370	Cloning and Expression Analysis of E-Cadherin Gene of Nile Tilapia Oreochromis niloticus
		YANG Huiyuan, CHEN Honglin, LI Ruixue, YANG Zhihui, WU Yingrui, WU Xinzhong, CAI Xiaohui
		DOI: 10.16378/j.cnki.1003-1111.20106
		The E-cadherin gene of Nile tilapia Oreochromis niloticus (GenBank number: MT370500; named as On-ECdh gene) was cloned, and the bioinformatics characteristics of On-ECdh gene and its expression pattern were analyzed in different tissues of Nile tilapia under normal conditions and stimulation of Streptococcus agalactiae. The specific primers were designed to amplify On-ECdh gene. The characteristics of On-ECdh gene was analyzed by bioinformatics, and its expression pattern was detected by the fluorescence quantitative PCR. The On-ECdh gene had open reading frame of 2442 bp, encoding 813 amino acids. The theoretical molecular weight of On-ECdh protein was 89.9 ku and the isoelectric point was 4.81. Prediction of conservative domain showed that On-ECdh amino acids contained 1 cadherin pro domain, 4 cadherin re-like domain, 1 cadherin cytoplasmic region and 1 transmembrane domain. Homologous alignment showed that On-ECdh amino acids had the highest similarity with Haplochromis burtoni (79.04%), and lower similarity with other fish (42.44%—52.59%) and mammals (37.12%—44.62%). Fluorescence quantitative PCR analysis showed that On-ECdh gene was detected in all the examined tissues of healthy Nile tilapia, with the maximal expression level in liver, followed by gill, intestine, stomach, eye, muscle, spleen, brain, heart, head and kidney. After the stimulation of S. agalactiae, the expression of On-ECdh gene was significantly up-regulated in the head kidneys, eyes and intestines, while down-regulated in the stomach, gills and liver. The expression of On-ECdh gene reached peak at 1 h in eye, 3 h in head kidney and 12 h in intestine, and showed a downward trend after the peak. And its expression levels were the minimum at 1 h in stomach, 3 h in liver and 24 h in gills. Moreover, the expression level of On-ECdh gene showed a time-dependent wavy trend in the stomach and gills, while its expression level in the liver was continuously decreased. The findings showed that S. agalactiae induced the expression of On-ECdh gene, indicating that the On-ECdh gene may play a defensive role in Nile tilapia infected with S. agalactiae.
		2022 Vol. 41 (3): 370-378 [Abstract] ( 140 ) HTML (1 KB) PDF (4116 KB) ( 143 )

	379	Postembryonic Development and Growth of Early Life Stages of Amur Ide Leuciscus waleckii
		YANG Peimin, JIN Guanghai, LIU Yixin, WANG Lei, XIE Han, HU Zongyun
		DOI: 10.16378/j.cnki.1003-1111.20224
		Postembryonic development and early growth were investigated in hatchery-reared Amur ide Leuciscus waleckii, from hatching to the juvenile stage at a temperature range of 12.7—26.7 ℃. The newly hatched larvae had total length (L) of (7.04±0.30) mm. The posterior swim bladder rudimentary appeared 2 days post hatching (dph) and was inflated one day later. Mouth opened 6 dph and the yolk sac was completely exhausted 8 dph. The notochord end started to curve upward 10 dph, followed by the anterior swim bladder appearance and the completion of notochord flexion 18 dph. In 39 dph larva, all fins were well developed. Scales were first found to be appeared on the caudal peduncle 55 dph, at which time the larvae reached the juvenile stage. The body was covered by scales 67 dph, meanwhile the fry reached the juvenile stage. Based on the external morphology, postembryonic development of Amur ide was divided into 3 periods: the yolk-sac stage (0—8 dph), the postlarval stage (9—54 dph) and juvenile stage (55—67 dph). From hatching until 67 dph, the specific growth rate of total length was 2.16%. Absorption of yolk sac was expressed by the equation: V=0.0057t²-0.2604t+1.723 (r²=0.8035), where V=yolk sac volume in mm³ and t=age in days. The appropriate equations for total length (L) for larval and juvenile Amur ide was exponential: L=7.6529e^0.0231^t(r² =0.9393), where t=age in days.
		2022 Vol. 41 (3): 379-387 [Abstract] ( 195 ) HTML (1 KB) PDF (7107 KB) ( 263 )

	388	Ecological Characteristics of Macrobenthos near Mai Island during Autumn
		JI Yinglu, ZHANG Naixing, WANG Lan, ZHANG Liang, PU Sichao, SUN Jingyi
		DOI: 10.16378/j.cnki.1003-1111.20190
		The present study aimed to reveal the status of macrofaunal community and diversity in the surrounding area of Mai Island in Qingdao. Samples were collected from 9 stations in October 2018. The biodiversity, macrobenthic community structure, and correlations between biotic and abiotic parameters were analyzed in this study. A total of 80 species of macrobenthic fauna were identified, including 57 species of annelids, 15 species of crustaceans, 3 species of mollusks, 2 species of echinoderms and 3 species of other taxa. The mean total biomass was 65.42 g/m², of which crustaceans contributed most; and the mean total abundance was 474 ind./m², of which polychaetes contributed most. The result of CLUSTER analysis showed that, at the 25% similarity level, the 9 surveyed stations were divided into 3 groups. The Shannon-Wiener diversity index (H′) and abundance and biomass comparison (ABC) curve showed that the sediment environment from partial stations were slightly polluted, while the other stations were relatively clean. The key environmental parameters affecting the characteristics of macrobenthic community and biodiversity of macrofauna in this area were the content of silty sand.
		2022 Vol. 41 (3): 388-397 [Abstract] ( 155 ) HTML (1 KB) PDF (1562 KB) ( 216 )

	398	Analysis of Nutritional Composition and Quality Evaluation of Chinese Minnow Rhynchocypris oxycephalus
		REN Yanhua, ZHANG Junmei, SUI Xiulei, ZHOU Chuanjiang, MENG Xiaolin, NIE Guoxing, ZHANG Yuru
		DOI: 10.16378/j.cnki.1003-1111.20143
		Morphological index and COⅠgene sequencing for species verification in wild Chinese minnow Rhynchocypris oxycephalus in Guanshan Geopark, Henan Province, and the nutritional composition and quality of Chinese minnow was evaluated by the analysis of conventional nutrients method and gas chromatography analysis method. The results showed that there were moisture of (79.59±2.92)%, crude protein of (16.62±2.73)%, crude fat of (1.15±0.45)%, ash of (0.93±0.05)%, pH of 6.91±0.16 and dressing rate of (61.50±3.35)%. A total of 17 kinds of amino acids were found in the muscle of Chinese minnow, with essential amino acid index (EAAI) of 96.24, the amino acid score (ASS) standard close to or greater than 1, the chemical score (CS) standard greater than 0.5, and the lysine content of 705 mg/g, which was 2.07 times as that as the FAO/WHO score and 1.60 times as that as the whole egg protein mode. There were 11 kinds of fatty acids in dorsal muscle, abdominal muscle, liver, intestine, brain, kidney and spleen of Chinese minnow. The content of EPA+DHA was 18.07% and PUFA 39.21% in muscle. The findings indicate that Chinese minnow in Henan Province is high in protein and PUFA (especially EPA and DHA), which can be used as high quality food source.
		2022 Vol. 41 (3): 398-408 [Abstract] ( 142 ) HTML (1 KB) PDF (1663 KB) ( 127 )

	409	Heat Pump Drying Characteristics and Kinetic Model of Sea Cucumber Apostichopus japonicus
		ZHANG Jingfeng, ZHAO Haibo, QIAO Lingmin, DAI Jiaao, WANG Haixiang, QU Yong
		DOI: 10.16378/j.cnki.1003-1111.20219
		In order to establish the drying kinetic model of sea cucumber Apostichopus japonicus and to investigate its heat pump drying characteristics, fresh sea cucumber with uniform size were selected for pretreatment. After pretreatment, the sea cucumber had dry basis moisture of 550%—650%. Six groups of sea cucumber in drying tests were carried out under different dry air temperature of 30, 35, 40 ℃ and 45 ℃, and relative humidity of 10%, 15% and 20%, and the drying wind speed of 2 m/s for 20 h in each test. The quality of sea cucumber was measured every 30 minutes. When the drying was terminated, the moisture of the dry basis of sea cucumber was varied from 30% to 75%. Based on the experimental data of heat pump drying of sea cucumber, eight commonly used drying models were improved. The coefficients in the drying model were fitted as the function of air temperature and relative humidity, and the coefficients in different models were obtained under four conditions. The fitting degree of different models was compared by using four evaluation indices. The results showed that the temperature and relative humidity of the drying air affected the heat pump drying process of sea cucumber. The higher the drying air temperature was, the lower the relative humidity and the faster the drying rate were. Page model was most suitable to describe the drying process of sea cucumber heat pump, and the simulation accuracy was higher when considering the influence of dry air temperature and relative humidity at the same time than when no considering or considering the influence of only one parameter.
		2022 Vol. 41 (3): 409-416 [Abstract] ( 121 ) HTML (1 KB) PDF (1612 KB) ( 133 )

	417	Path Analysis of Effects of Morphometric Traits on Body Length in Giant River Prawn Macrobrachium rosenbergii
		XIONG Zhaodi, GAO Xiang, DENG Pingping, DAI Xilin
		DOI: 10.16378/j.cnki.1003-1111.20126
		In order to explore the effect of morphological characteristics of giant river prawn Macrobrachium rosenbergii on body length, 391 individuals of five-month-old prawn were randomly sampled, ten morphometric characters such as total length, body length, carapace length, carapace width, first segment length and second segment width were measured. After correlation analysis and path analysis, the correlation coefficient, path coefficient, determination coefficient and common determination coefficient among various morphological traits were calculated; the morphological traits with significant path coefficients were selected to calculate the complex correlation index to determination the key morphological traits that affect body length; finally, the stepwise regression analysis equations for morphological traits were established to estimate body length. The results showed that the correlation coefficients between the measured morphological traits and body length had very significant level (P<0.01); the correlation coefficients between total length and body length, path coefficients, and determination coefficients were all the maximam; the regression coefficient of equations reached the significant level (P<0.05), r²=0.958; except that the partial regression coefficients of the first segment length and second segment width were significant (P<0.05), the partial regression coefficients of other traits reached very significant levels (P<0.01). It was seen that the total length was the most important morphological trait that affected the body length. The second segment width and sixth width segment had significant direct effect on the body length; and total length, second segment width and sixth width segment as a directional breeding index, which were applied to the production practice of establishing a fast-growing specialized strain of giant river prawn.
		2022 Vol. 41 (3): 417-423 [Abstract] ( 191 ) HTML (1 KB) PDF (1374 KB) ( 165 )

	424	*Indoor Biofloc Culture of Pacific White Shrimp Litopenaeus vannamei* in Low Temperature Season**
		ZHOU Hui, HAN Manqiang, TANG Baogui, WU Xumin, DU Shumin, TAN Ruihua, GONG Hanfu, LIN Zhihao, HE Yixun, ZHONG Yuqi, LIN Guiteng
		DOI: 10.16378/j.cnki.1003-1111.20168
		In low temperature season, the growth index and body composition of Pacific white shrimp Litopenaeus vannamei cultured in the indoor biofloc system were studied. In the experiment, clean water culture (CW, fed ad libitum) was set as the control group, and biofloc culture (BF, 70% feeding amount of the CW group) was set as the experimental group. There were 3 tanks in each group and 18 individuals of Pacific white shrimp (3.17±0.37) g per tank cultured for 42 days, recorded the feeding rate of Pacific white shrimp, measured the body weight and body composition of the Pacific white shrimp, and calculated the growth index. The results showed: (1) the average water temperature in the CW group was (21.3±2.0) ℃, the average daily food intake rate of Pacific white shrimp was (1.87±0.30)%, which did not change significantly (P>0.05), and there was no significant correlation between water temperature and the average daily food intake rate of Pacific white shrimp (P>0.05). (2) From 31 to 42 days, the water temperature of the BF group was significantly higher than that in the CW group (P<0.05). (3) With the food intake rate only 70% in the CW group, the final body weight, weight gain rate, specific growth rate and body composition of Pacific white shrimp in the BF group and the CW group were not significantly different (P>0.05). There were significantly higher feed conversion efficiency and protein efficiency in the Pacific white shrimp in the BF group than those in the CW group (P<0.05). It was found that in the low temperature season, compared with clean water culture, the indoor biofloc culture mode effectively improved the feed conversion ratio of the Pacific white shrimp and maintained higher water temperature, while the growth rate of the Pacific white shrimp did not showed significant difference.
		2022 Vol. 41 (3): 424-430 [Abstract] ( 131 ) HTML (1 KB) PDF (1827 KB) ( 153 )

	431	Effect of Composite Feed Additives on Growth and Health Status of Largemouth Bass Micropterus salmoides
		ZHANG Qi, YANG Jun, LIAO Weijian, LI Zijin, ZHENG Lianchun, HE Xugang
		DOI: 10.16378/j.cnki.1003-1111.20070
		In this study, feed additives of astragalus polysaccharide, Eucommia ulmoides, yeast cell wall, bile acid and L-carnitine were used to study the effects of the new compound feed on the growth performance, serum biochemical indices and liver antioxidant capacity of largemouth bass Micropterus salmoides for eight weeks. A total of 270 largemouth bass juveniles with average body weight of (50.42±6.43) g were randomly divided into blank control group (basic feed), test group (basic feed + 0.01% compound feed additive), and positive control group (functional feed) and fed different diets, with three replicates in each treatment. The results showed that the body weight gain rate and specific growth rate were shown to be higher in test group and positive control group than those in blank control group, and the difference was significant in test group(P<0.05); compared with blank control group, the hepatosomatic index and crude fat content in liver in test group were significantly lower(P<0.05), while the survival rate, condition factor and nutritional compositions of whole fish and muscle were not significantly different among groups(P>0.05); the activities of serum glutamic oxaloacetic transaminase and alanine aminotransferase were significantly higher in test group and positive control group than those in blank control group (P<0.05).The activities of superoxide dismutase and catalase in liver in test group were significantly higher than those in blank control group and positive control group(P<0.05), and the concentration of malondialdehyde in test group was significantly lower than that in blank control group(P<0.05). The findings indicated that the appropriate amount of compound feed additives effectively promoted the growth of largemouth bass, reduced the liver fat content and improved the antioxidant capacity of tissues.
		2022 Vol. 41 (3): 431-437 [Abstract] ( 144 ) HTML (1 KB) PDF (2129 KB) ( 200 )

	438	Effects of Different Dissolved Oxygen Levels on Respiratory Metabolism and Related Gene Expression in Mandarinfish Siniperca chuatsi
		SONG Yindu, ZENG Mengdong, ZHOU Haotian, ZHOU Yunhong, ZHANG Chengshuo, ZHAO Jinliang
		DOI: 10.16378/j.cnki.1003-1111.20183
		In order to study the respiratory metabolism level of mandarinfish Siniperca chuatsi under different dissolved oxygen levels, the activities of pyruvate dehydrogenase (PDH), and lactate dehydrogenase (LDH) and the content of lactic acid (LA) in heart, brain, liver and muscle tissues, as well as the relative expression levels of related genes in each tissue were measured at different dissolved oxygen levels of 5 mg/L, 4 mg/L, 3 mg/L, 2 mg/L and 1 mg/L, and the oxygen consumption rate at each stage was calculated. The results showed that as the level of dissolved oxygen was decreased from 5 mg/L to 1 mg/L, the PDH activity and LDH activity in each tissue showed a downward and upward trend respectively, and the activities of PDH in liver and muscle were decreased significantly at 3 mg/L (P<0.05); while the activities of LDH in heart, muscle, brain, and liver were increased significantly at 2 mg/L (P<0.05); when the dissolved oxygen levels were reduced to 1 mg/L, the LA concentration in each tissues except liver was raised to the maximum level. In addition, expressions of LDH-A gene were significantly up-regulated in each tissues (P<0.001). Expression of PDH-E1α gene was significantly decreased in all tissues except heart (P>0.05). When the dissolved oxygen levels were reduced to 3 mg/L, the oxygen consumption rate was decreased very significantly (P<0.01). When the dissolved oxygen level was decreased, the mandarinfish reduced aerobic respiration, increased anaerobic respiration, and reduced the oxygen consumption rate to adapt to the hypoxic environment. When the dissolved oxygen level was less than 3 mg/L, the mandarinfish was under hypoxia.
		2022 Vol. 41 (3): 438-444 [Abstract] ( 139 ) HTML (1 KB) PDF (1322 KB) ( 153 )

	445	Effects of Dietary Methyltestosterone on Growth and Body Pigmentation of Female Sciaenochromis fryeri
		JIANG Jufeng, LIU Keming, LI Chunyan, LIU Xiaolian, ZHOU Yong, HAN Xianqin, SHI Dongjie, MA Lin, SONG Hongmei, ZHAO Liming
		DOI: 10.16378/j.cnki.1003-1111.20205
		In order to study effects of methyltestosterone on growth and body colour in female Sciaenochromis fryeri, 450 individuals of female S. fryeri with initial body weight of (5.78±1.05) g were randomly divided into 5 groups and fed diets containing methyltestosterone at a dose of 0 (control group), 4, 8, 12, and 16 mg/kg for 8 weeks, and then all fishes were fed the control diet for 4 weeks. Growth performance and body pigmentation of female S. fryeri were determined every 2 weeks during the 12 weeks experimental period. The results showed that there was significantly higher average body weight in the female S. fryeri in 12 mg/kg group than that in the other groups (P<0.05), even though with 100% of average survival rate in each group. There was no significantly difference in body pigmentation between 12 mg/kg group and 16 mg/kg group(P>0.05), significantly higher than that in the other groups (P<0.05). The fish colour was all elevated somewhat in all groups, and then decreased slightly, being remained at stable level constantly after the colouration of female S. fryeri for 8 weeks was enhanced. The findings indicated that the methyltestosterone had adaptive reaction to female S. fryeri, and that the optimal methyltestosterone dose was of 12 mg/kg.
		2022 Vol. 41 (3): 445-451 [Abstract] ( 152 ) HTML (1 KB) PDF (1364 KB) ( 106 )

	452	*Analysis of Drug-Resistance and Cross Resistance in Vitro of Vibrio alginolyticus* Induced by Enrofloxacin**
		ZHANG Kai, ZHANG Mingming, XIE Xi, WANG Rong, HU Wenting
		DOI: 10.16378/j.cnki.1003-1111.20201
		Enrofloxacin-sensitive Vibrio alginolyticus strains collected from the marine aquaculture area in Hainan province were induced by concentration-increasing method on the medium containing sub-inhibitory concentration of enrofloxacin in vitro to evaluate the occurrence of drug resistance. The minimal inhibitory concentration (MIC) of the induced bacterium to induced drugs and 6 non induced drugs was compared before and after drug resistance induction, and the genetic stability of the induced drug resistance strains was investigated on the media without drugs. The results showed that 24 enrofloxacin-sensitive strains were screened out of 30 strains of V. alginolyticus after 30 generations of induction in vitro. The sensitive strains were all resistant to enrofloxacin, and the MIC was 64—1024 times as large as before induction. The induced strains had severe cross-resistance to the non-induced quinolone drugs ciprofloxacin and norfloxacin, increase in resistance to tetracycline, a certain degree of enhancement to florfenicol and sulfadiazine, and no significant changes in sulfadiazine resistance. The cross resistance rates of 14 strains were over 50%, and that of HNVA21 was 83.3%. After 20 successive passages of drug-resistant progeny, the MIC value of 21 strains remained unchanged, and 3 strains were decreased by 1/2, with relatively stable drug resistance. Enrofloxacin led to induce drug resistance of V. alginolyticus with secondary inhibitory concentration, and cross-resistance to a variety of non-induced drugs, with good genetic stability of the resistant strains.
		2022 Vol. 41 (3): 452-458 [Abstract] ( 134 ) HTML (1 KB) PDF (1067 KB) ( 108 )

	459	Antibacterial Analysis of Coelomic Fluid from Echiuran Worm Urechis unicinctus
		GAN Hongtao, LIU Tonghao, DING Ziyuan, YAO Haiyang, CUI Nan, MENG Xiao, XU Guocheng, CAO Lixin, XU Xinghong
		DOI: 10.16378/j.cnki.1003-1111.20140
		The coelomic fluid of echiuran worm Urechis unicinctus with body weight of (18.03±1.35) g was centrifuged at 4 ℃, 3000 r/min (centrifugal radius of 13.5 cm) for 20 min, and the supernatant was taken, and then centrifuged the blood cell pellet by centrifugation. After resuspending in sterile normal saline, it was crushed by ultrasonic disintegrator at 4 ℃ for 5 min, and the supernatant was taken as the supernatant of the coelomic cell crushing liquid. The antibacterial effects of the coelomic fluid supernatant, and coelomic cell crushing liquid on Aeromonas hydrophila, Escherichia coli, Vibrio parahemolyticus, V. anguillarum, A. veronii, V. harveyi, Staphylococcus aureus, and Micrococcus lysodeikticus were determined by the methods of Oxford cup and bacterial growth curve determination. Meanwhile, the influence of environmental factors including temperature, salinity, air exposure and fast on the antibacterial activity of coelomic fluid of the echiuran worm were investigated. The results showed that coelomic fluid supernatant had significant inhibiton on V. anguillarum and V. parahaemolyticus (P<0.05), while the coelomocyte ocytelysate supernatant had a significant bacteriostatic effect on V. anguillarum, V. parahaemolyticus and A. fragilis (P<0.05). There was slightly higher significant inhibition in the supernatant of the coelomic cell crushing liquid in the treatment group of salinity 25 than that in salinity 20 and 30 groups. However, the antibacterial activity of the coelomic cell crushing supernatant was found to be decreased significantly at salinity of 15 and 35, low salinity (15) showing more significant effect than at high salinity (35) (P<0.01). The coelomic cell crushing supernatant led to higher bacteriostatic effect under the temperature of 22—26 ℃, while the inhibition effect was declined significantly with the temperature below than 12 ℃ or more than 26 ℃ (P<0.01). The significantly lower antibacterial activity was observed in the coelomic fluid of echiuran worm exposed to the stress of air exposure for 8 h or more (P<0.05), and to be fasten for 2 days or more (P<0.01).
		2022 Vol. 41 (3): 459-466 [Abstract] ( 126 ) HTML (1 KB) PDF (5994 KB) ( 141 )

	467	Community Structure Characteristics of Phytoplankton and Estimation of Fish Productivity in Dahushi Reservoir
		SHAO Xudong, LI Yichao, BAI Lujun, ZHOU Bobo, WANG Fangfang, LIU Qing
		DOI: 10.16378/j.cnki.1003-1111.20214
		In order to explore the phytoplankton community structure characteristics such as species composition, density and biomass in Dahushi Reservoir, and to evaluate the water trophic status and estimate the fish productivity in the reservoir by using the phytoplankton diversity indices, the phytoplankton was investigated and analyzed in May, July and September 2018. The results showed that there were 57 species/genera of phytoplankton in the reservoir, among which Chlorophyta was the most abundant, with 22 species/genera accounting for 38.60%. The average density and biomass of phytoplankton were 7.5465×10⁶ cell/L and 3.11 mg/L, respectively. A total of 39 species/genera of zooplankton were detected, among which rotifers were the most abundant, accounting for 48.72%. The average density and biomass of of zooplankton were 1924.54 ind./L and 1.34 mg/L, respectively. The water quality of Dahushi Reservoir was moderate trophic status according to Shannon Wiener diversity index (H′), Pielou evenness index (J) and Margalef richness index (d). The fish productivity was estimated to be 336.63 kg/hm² based on the results of plankton survey. The findings showed that the utilization rate of food organism in the reservoir was low, and that the stocking amount of silver carp Hypophthalmichthys molitrix and bighead carp Aristichthys nobilis was appropriately increased to control the increase in plankton quantity and biomass in the reservoir and further to prevent the eutrophication of water.
		2022 Vol. 41 (3): 467-474 [Abstract] ( 152 ) HTML (1 KB) PDF (1690 KB) ( 246 )

	475	*Spatial Distribution of Fishing Ground of Jumbo Flying Squid Dosidicus gigas* in the Equator in Eastern Pacific Ocean**
		FANG Xingnan, YU Wei, CHEN Xinjun
		DOI: 10.16378/j.cnki.1003-1111.20088
		The spatial and temporal changes in the gravity centers of the fishing ground of jumbo flying squid Dosidicus gigas were investigated according to the fishing data of jumbo flying squid and the sea surface temperature (SST) and chlorophyll a concentration (Chl-a) in the equatorial waters in the Eastern Pacific Ocean in different months from January to July in 2017 by the longitudinal and latitudinal gravity centers of the fishing ground method. The effects of SST and Chl-a on catch per unit effort (CPUE) were evaluated by generalized additive model (GAM), and the suitable range of SST and Chl-a and monthly changes were determined for jumbo flying squid based on the relationship between fishing effort and SST as well as Chl-a concentration. The results showed that the gravity centers of the fishing ground gradually were shifted southeastward from January to July. GAM results indicated that there was significant effects of the two environmental factors on CPUE (P<0.05). The suitable SST ranges were initially increased and then decreased with the month, with the maximal suitable SST ranging from 26.8 to 27.2 ℃ in April. The optimal Chl-a concentration range was basically the same in the first five months, ranging from 0.14 to 0.16 mg/m³, 0.16—0.18 mg/m³ in June and 0.18—0.20 mg/m³ in July. The fishing ground of jumbo flying squid in the equator was a new fishing ground which was exploited by Chinese squid fisheries in recent years. These findings led to understand spatial distribution of jumbo flying squid in this region, which provided scientific basis to look for fishing grounds with high squid abundance.
		2022 Vol. 41 (3): 475-483 [Abstract] ( 188 ) HTML (1 KB) PDF (2788 KB) ( 205 )

	484	Analysis of Catch Composition and Deepwater Fishing Ground of Bottom Trawl in the Gulf of Oman
		CHEN Feng, ZHU Wenbin, XU Guoqiang, FENG Weidong, GUO Ai, ZHANG Hongliang, LI Dewei
		DOI: 10.16378/j.cnki.1003-1111.20162
		The Gulf of Oman is one of new fishing grounds for distant-water fishery of China. Fishing ground distribution of bottom trawler, catch composition and development status of main species were based on fishing production data from bottom trawlers in the Gulf of Oman of Iran in 2016, which provided references for the sustainable utilization of fisheries resources in the deep waters of the Gulf of Oman. The results showed that the deepwater fishing ground was mainly distributed in N 25°25′—25°40′,E 57°00′—57°25′. Twenty-nine species were identified in the catch composition and the main target species were hairtail Trichiutus lepturus, conger pike Muraenesox cinereus, and blackmouth croaker Atrobucca alcocki whose size was generally large. The catch per unit effort (CPUE) of hairtail was 3.89 t/d in 2016. The high fishing season was observed from January to March and from October to November, with the maximum CPUE of 5.57 t/d for hairtail, the off-season was December and April to June, with the minimus CPUE of 1.00 t/d hairtail in April. However, at present the deep water fishing ground of the Gulf of Oman was narrow and fishing effort was limited, the Chinese fishing vessels must have access fishing in the fishery in the framework of China-Iran fishery agreements. Meantime fisheries resources will be reasonably and orderly developed and utilized in the Gulf of Oman in the future, and the number of fishing vessel must be strictly controlled.
		2022 Vol. 41 (3): 484-490 [Abstract] ( 149 ) HTML (1 KB) PDF (1530 KB) ( 100 )

Overview and Specific Topic

	491	A Review of Research Progress and Application of Biofloc Technology
		HAN Jiamin, SU Shengqi
		DOI: 10.16378/j.cnki.1003-1111.20228

		2022 Vol. 41 (3): 491-503 [Abstract] ( 217 ) HTML (1 KB) PDF (1478 KB) ( 331 )

	504	*Research Progress on Detection and Control Technology of Enterocytozoon hepatopenaei:* a Review**
		CAO Haipeng, XIA Tingting, XU La, GAI Chunlei
		DOI: 10.16378/j.cnki.1003-1111.20167

		2022 Vol. 41 (3): 504-508 [Abstract] ( 198 ) HTML (1 KB) PDF (974 KB) ( 251 )

	509	A Review: Research Progress on Role of NF-κB Signaling Pathway in Teleost Immunity
		LIU Nian, ZHOU Junhao, YANG Ying
		DOI: 10.16378/j.cnki.1003-1111.20153

		2022 Vol. 41 (3): 509-516 [Abstract] ( 161 ) HTML (1 KB) PDF (2256 KB) ( 280 )