Effect of Two Substrate Types on Feeding Efficiency by Juvenile Chinese Sturgeon Acipenser sinensis on Barcheek Goby Rhinogobius giurinus

We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby Rhinogobius giurinus was not affected by sand vs. smooth glass substrate. Gobies are among the most common prey eaten by wild juvenile A. sinensis in the estuary. Test results found neither substrate type significantly affected feeding efficiency by juveniles. Previous research found a strong innate habitat preference of A. sinensis for sand substrate. The present results indicate that the preference for sand is not related to efficiently capturing R. giurinus on sand, but is an adaptation predisposing juvenile A. sinensis to seek sandy substrate where R. giurinus and other benthic forage are the most abundant in the Yangtze Estuary.

铅暴露致中华鲟(Acipenser sinensis)幼鱼弯曲畸形与畸形恢复

铅是一种常见的污染物,在水环境中广泛分布并在水生食物链中富集,具有持久的生态效应.中华鲟(Acipenser sinensis)是我国特有的珍稀濒危大型洄游性鱼类,极具学术价值和生态价值.为了探索中华鲟在生命早期接触铅后的损伤和自我修复机制,采用水溶液静态置换法,从中华鲟受精卵发育至96h开始,进行了16周的Pb2+暴露试验,随后继续6周的排放试验.结果显示:经0.8mg·L-1和1.6mg·L-1的Pb2+暴露16周,中华鲟幼鱼会发生弯曲畸形,而0.2mg·L-1Pb2+暴露组未出现畸形个体.畸形弯曲位置主要发生在近胸鳍起点处以及背鳍起点至尾鳍末端之间,多伴有尾鳍末端下垂.Pb2+暴露浓度越高,畸形弯曲越严重,但未见椎骨变形.畸形个体的自主活动能力和摄食能力明显降低.Pb2+排放后,畸形个体的弯曲程度由重度向轻度转变而恢复正常,弯曲程度越轻恢复越快,畸形恢复个体的自主活动能力和摄食能力均明显得到恢复并逐渐复原.表明中华鲟幼鱼具有较强的排铅能力和铅损伤后的自我修复能力.

史氏鲟(Acipenser schrenckii)两种促性腺激素β亚基的原核表达

采用遗传工程方法,重组表达史氏鲟两种促性腺激素β亚基蛋白。选用原核表达载体pET-22b(+),分别插入史氏鲟GtHⅠ&Ⅱβ亚基成熟肽cDNA序列,构建成C端含有6个组氨酸(6-His)融合蛋白标签的表达质粒;分别转化大肠杆菌表达菌株BL21(DE3)并诱导表达2个基因。SDS-聚丙烯酰胺凝胶电泳显示重组融合蛋白相对分子质量分别为:GtHⅠβ亚基大约14 000,GtHⅡβ亚基15 000左右。分别用抗6个组氨酸融合标签的单克隆抗体及兔抗鲟鱼GTH多克隆抗体对2个表达蛋白进行Western-Blot分析,结果显示重组蛋白表达正确且有较高的免疫活性。GTHⅠβ重组蛋白在2 h就有明显的表达,6 h后随着时间增加表达量不再增加;25℃诱导重组蛋白产量比37℃诱导产量低。获得的重组蛋白质将可用于建立鲟鱼GtH的放射免疫测定方法。

碱胁迫下“鲟龙1号”(Huso dauricus♀×Acipenser schrenckii♂)鳃组织结构变化及转录表达特征

为探究碱胁迫下杂交鲟“鲟龙1号”(Huso dauricus♀×Acipenser schrenckii♂)的响应机制,本研究设置了淡水组(3.13~3.20 mmol/L)与胁迫组(14.4~16.67 mmol/L),采集鳃进行了组织病理分析,并利用转录组测序技术,进一步分析转录组表达特征。结果显示:高碱胁迫下“鲟龙1号”鳃组织出现明显损伤,鳃小片末端发生肿胀、卷曲和融合,鳃上细胞出现增生和膨大。转录组测序共获得80422条Unigene,富集到GO数据库的差异表达基因为371个,其中87个基因表达上调,284个基因表达下调,富集到KEGG的代谢通路主要为矿物吸收、近曲小管碳酸氢盐重吸收和胃酸分泌等通路,其中近曲小管碳酸氢盐重吸收为主效应途径,该途径的Nhe3、Atp1a、Atp1b和Gdha基因显著表达下调。综上所述,碱度为14.4~16.67 mmol/L的条件下,“鲟龙1号”幼鱼已发生鳃组织损伤,且矿物质重吸收、钾/钠离子转运与排氨等功能受到影响。

Sex-Based Variation of Gene Expression in the Gonads and Fins of Russian Sturgeon (<i>Acipenser gueldenstaedtii</i>)

Russian sturgeon (Acipenser gueldenstaedtii) is a primitive freshwater fish and a source of black caviar. The genes involved in sexual determination and differentiation are still unknown and there are no molecular markers for sex identification in this species. Studying the variation of the sex-based differences in genomic sequences and in gene expression in the sturgeon may lead to markers of sex in early stages of development and advances in aquaculture, as well as provide novel insights about the evolution of reproduction, sex determination, and sexual differentiation mechanisms in vertebrates. Previous studies by our and other groups have identified differentially expressed genes in the gonads of adult female and male sturgeon. The current study aimed to test whether these genes were also differentially expressed in non-gonadal tissue, namely fins. We measured by qRT-PCR the mRNA levels of 29 known and novel sex-related genes in the gonads and fins of males (4 years old) and females (7 years old;sexual maturation is earlier in males than in females). Six genes (ATP6, IGFRM, LIA1A, S1A, NPL1A, GAPDH and SOX9) showed higher expression in female fins. However, only ATP6 mRNA levels differed in fins of males and females of the same age (4 years old). These findings underscore the impracticality of sex identification based on gene expression in non-gonadal tissue and the need for genetic sex markers in the Russian sturgeon.

Physiological, Enzymatic and Molecular Changes of Acipenser schrencki Induced by Heat Exposure

[Objective] The paper was to understand the physiological, enzymatic and molecular changes of Acipenser schrencki induced by heat exposure. [Method] The effects of heat exposure on A. schrencki were investigated. The temperature was increased from(18± 0.5) ℃ by 0.08 ℃/min and respectively kept at(32±0.5) ℃ for 2, 4 and 6 h. The respiration rate, related biochemical indicators and heat shock protein 70(Hsp 70) mR-NA expression were investigated. [Result] At(32±0.5) ℃, the activities of total protein, albumin, globulin, urea nitrogen, ceatinine, malondialde-hyde, aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase fluctuated dramatically from 2 h to 6 h. Meanwhile, the respi-ration rate and Hsp 70 m RNA expression in heart, liver and spleen were significantly increased from 2 h to 6 h. In comparison, the lower respira-tion rate and tiny fluctuations in activities of biochemical indicators were consistent with the lower Hsp 70 expression. [Conclusion] During the process of heat stress, A. schrencki seems to be sensitive to such temperature, and manifests generally consistent gill breathing, biochemical indica-tors and Hsp70 gene expression, implying better heat tolerance.

Gut Peculiarities of Feed Deprived White Sturgeons (<i>Acipenser transmontanus</i>, Richardson 1836)

In the White sturgeon fish farms, some individuals have difficulty in getting access to food: such sturgeons are called "runts", and they result in a slower growth rate than normally feeding fish. In this paper, we have studied the gut peculiarities of runt sturgeons. Utilizing in paralleling an analysis of diatom populations in both the fish gut tissues and the rearing tank waters, we hypothesized a causative relation between the occurrence of runt sturgeons and periodic diatom blooms. In fact, we have observed that the diatom species identified in the aquatic environment were also detected in organs (Fragilaria spp and Rhoicosfenia spp for both glandular body, mid-intestine) of the runt sturgeon's gut, but not in tissues of normally feeding individuals. Owing to their siliceous wall, diatoms can be responsible for areas of epithetlial detachment in the mucosal surfaces of the alimentary canal and a catharral inflammation in both the gastric pits and intestinal folds which may be the cause of secondary bacterial diseases. We suggest that diatom blooms may contribute to the occurrence of runt sturgeons in the studied Italian fish farm.

Sturgeon (Acipenser gueldenstaedtii) Acclimatization to Optimal Growth Conditions—A Case Study of Adaptation, Nutrition, Reproduction, and Sex Determination

The development of new agricultural industries is an important challenge for a region’s economic establishment. The connection between a research department at MIGAL Institute and biotechnology in aquaculture is an example (case study) of the interrelationships that also exist in other departments. This article describes the research conducted by the institute supporting the development of the aquaculture industry in Israel through the introduction of a relatively new fish species—the Russian sturgeon (Acipenser gueldenstaedtii), with the relevant information to be used for acclimatization to aquaculture conditions in northern Israel. Many aspects related to bringing a new species to Israel and working with this new industry to study its adaptation to existing conditions in the north of the country influenced the economic success of this new type of precision agriculture. This article describes the research on various aspects affecting the successful acclimatization of Russian sturgeon in northern Israel: introduction, food development, reproduction, hormone systems that control reproduction and growth, gonadal development, and molecular markers for sex determination, differentiation, and economic assessment of caviar production.

Artificial enhancement of sturgeon stock in freshwater reservoirs:A case study on sterlet Acipenser ruthenus of the Kama reservoir

The paper presents the results of the sterlet sturgeon Acipenser ruthenus reintroduction into the Kama Reservoir(Perm Krai,Russia)by sterlet fry from hatcheries into the reservoir since 2001.The effectiveness of hatchery releases was evaluated by monitoring gillnet sampling 2014-2020.The results showed that the species was reported throughout entire Kama Reservoir,which contrasts with 1988-1994 data,when the species was registered only at the upper part of the reservoir near the Kama River mouth.The highest number and biomass values of catch per unit effort(CPUE)of the sterlet were found in submerged river channels-the deepest habitats with flow conditions which are close to the ecological requirements of the species.The distribution of the sterlet within the channel biotopes of the reservoir is defined by reduced variability.The biggest individuals and the widest size range of the sterlet were typical for the upper area of the reservoir and Chusovskoy Bay,which have the greatest flow.The smallest sizes were typical for fish from catches near the dam of the reservoir,which is consistent with the published data on the distribution of sterlet in reservoir conditions.The presented results may indicate the artificial formation of the sterlet stock in the Kama Reservoir maintained by hatchery releases.The revealed distribution of the sterlet in the reservoir determines the direction of further research on natural reproduction and thus formation of an artificially formed population.Also,future studies are required to assess the possibility of hybridization of the sterlet of artificial origin with natural populations of the species,since the low genetic diversity of the sterlet released into the Kama Reservoir which can lead to irreversible loss of genetic individuality of the natural stocks of the species in the catchment of upper course of the Kama River.

北鲟Acipenser schrencki Brandt骨骼系统解剖

分类地位脊索动物門 Chordata 脊椎动物亚门 Vertebrata 魚形总綱 Pisces 硬骨魚綱 Osteichthyes 輻鰭亚綱 Actinopterygii 硬鳞总目 Chondrostei 鱘形目 Acipenseriformes 鱘科 Acipenseridae 鱘属 Acipenser 北鱘 A. schrencki

Gluconeogenesis during starvation and refeeding phase is affected by previous dietary carbohydrates levels and a glucose stimuli during early life in Siberian sturgeon(Acipenser baerii)

Gluconeogenesis responses was assessed during a short starvation period and subsequent refeeding in Siberian sturgeon(Acipenser baerii) previously fed different dietary carbohydrates levels and experienced to a glucose stimuli during early life. The sturgeon larvae were previously fed either a high glucose diet(G) or a low glucose diet(F) from the first feeding to yolk absorption(8 to 12 d post-hatching [dph]). Each group of fish was sub-divided into 2 treatments at 13 dph and was fed either a high-carbohydrate diet(H) or a low carbohydrate diet(L) until 20 wk. In the current study, the fish in 4 groups(GL, FL, GH and FH) were experienced to starvation for 21 d following by re-feeding of their corresponding diets for 21 d.Fish were sampled at postprandial 6 and 24 h before starvation(P6 h and P24 h), starvation 7,14 and 21 d(S7, S14 and S21) and 1, 7,14 and 21 d during refeeding(R1, R7, R14 and R21). Plasma samples during refeeding were taken at P6 h at each time point. Glycaemia levels, liver and muscle glycogen contents,activities and mRNA levels of hepatic gluconeogenic enzymes were examined. We found that both dietary carbohydrate levels and early glucose stimuli significantly affected the metabolic responses to starvation and refeeding in Siberian sturgeon(P < 0.05). During prolonged starvation, Siberian sturgeon firstly mobilized the liver glycogen and then improved gluconeogenesis when the dietary carbohydrates were abundant, whereas preserved the liver glycogen stores at a stable level and more effectively promoted gluconeogenesis when the dietary carbohydrates are absent to maintain glucose homoeostasis.During refeeding, as most teleostean, Siberian sturgeon failed controlling the activities and mRNA levels of phosphoenolpyruvate carboxykinase cytosolic forms(PEPCK-C), fructose-1,6-bisphosphatase(FBPase),but particularly controlled phosphoenolpyruvate carboxykinase mitochondrial forms(PEPCK-M) activities and mRNA expression of glucose-6-phosphatase(G6 Pase, except in GL group). Siberian sturgeon has a full compensatory ability on growth, but this ability would be obstructed by early glucose stimuli when refeeding the low carbohydrate diet after S21.

Characterization of hematopoiesis in Dabry's sturgeon(Acipenser dabryanus)

The hematological indices of Dabry's sturgeon(Acipenser dabryanus)were investigated in this paper.The results showed that the count of Red blood cell(RBC)was(0.60±0.02)
1012/L,and the blood glucose(GLU)was 9.32±1.00 mmol/L.Glutamic-pyruvic transaminase(ALT)and glutamic-oxalacetic transaminase(AST)were 13.75±6.65 U/L and 359.50±40.07 U/L,respectively.Smears of peripheral blood and imprints of four tissues were studied in the trial with Wright's staining method.The results indicated that Dabry's sturgeon's blood cells could be divided into five cell types,and included erythroid,granuloid,monocytoid,lymphoid and other cells.In addition,the developmental stage of each cell lineage could be subdivided into:primitive,young and mature.In the three developmental stages,the size of each cell type was similar and gradually decreased from primitive,young to mature blood cells.Among the blood cells,the monoblast and macrophage were the biggest,while the thrombocyte was the smallest.All stages of the primitive cells and young cells were observed in head kidney and all cell types,except granuloblasts,were identified in the head kidney.In contrast,primitive cells and young cells were not observed in the spleen or liver,and few orthochromatic erythroblasts were found in peripheral blood.It can be concluded that head kidney and trunk kidney are the primary organs of hematopoiesis in the Dabry's sturgeon.

Differential expression of fertility genes boule and dazl in Chinese sturgeon(Acipensersinensis):A basal fish

With the support by the National Natural Science Foundation of China,Prof.Wei Qiwei’s laboratory at Yangtze River Fisheries Research Institute,Chinese Academy of Fishery Sciences,reported the differential expression of fertility genes boule and dazl in Chinese Sturgeon(Acipenser sinensis),a basal fish,which was published in Cell and Tissue Research(2015,360(2):413—25).

饲料中添加酵母硒对史氏鲟幼鱼生长性能、肌肉品质和抗氧化能力的影响

以酵母硒(总硒含量2000 mg/kg)的形式分别向基础饲料(硒含量0.78 mg/kg)中添加0、2、4、6 mg/kg(饲料中硒总含量为0.78、2.42、4.26和6.73 mg/kg)的硒,研究饲料中添加酵母硒对史氏鲟(Acipenser schrenckii)幼鱼(25.89±0.74)g生长性能、肌肉品质及抗氧化能力的影响。实验选取360尾体质健康的史氏鲟幼鱼,随机分配至12个养殖缸(30尾/缸),养殖周期为10周。结果显示:(1)饲料中添加酵母硒对史氏鲟幼鱼肌肉硒含量、水分、粗灰分、粗蛋白质、粗脂肪含量及饲料转化率(FCR)、内脏比(VSI)、肝重比(HIS)没有显著性影响,但肥满度(CF)显著升高;与对照组相比,6.73 mg/kg添加组的史氏鲟幼鱼增重率(WGR)和特定增长率(SGR)显著升高,肌肉蒸煮损失、冻融损失和滴水损失均显著降低;(2)对史氏鲟幼鱼投喂添加2.42~6.73 mg/kg的酵母硒饲料,其肌纤维密度显著增加、肌纤维直径显著降低;(3)添加6.73 mg/kg的硒显著提升了肝脏谷胱甘肽过氧化物酶(GP X)活性。结果表明,饲料中以酵母硒的形式添加6.73 mg/kg的硒可以显著地促进史氏鲟幼鱼生长、改善肌肉品质、增强机体抗氧化能力。

低盐驯化对西杂鲟幼鱼生长发育的影响

为探讨低盐环境对西杂鲟幼鱼(西伯利亚鲟♀×施氏鲟♂)(Acipenser baerii♀×A.schrenckii♂)生长发育的影响,本研究设置了3个盐度组(0‰、4‰、8‰),驯化15 d后,分析盐度对西杂鲟幼鱼血清生化指标、抗氧化指标,鳃、肾、肠Na^(+)-K^(+)-ATP酶活性、激素水平及免疫、生长发育相关基因表达的影响。结果显示:(1)低盐驯化对西杂鲟幼鱼血糖、总蛋白、总胆固醇、甘油三酯、过氧化氢酶、还原型谷胱甘肽、总抗氧化能力、丙二醛、Na^(+)和肾、肠Na^(+)-K^(+)-ATP酶活均无显著影响,但低盐驯化对西杂鲟幼鱼鳃Na^(+)-K^(+)-ATP酶活和血清Cl-的影响呈“U”型变化,为先下降后升高的表达趋势;(2)利用ELISA法测定血清甲状腺激素(T 3、FT 3)和皮质醇水平后,随着盐度的升高,两者呈先升后降的趋势,但各组间无显著差异;(3)利用qRT-PCR测定免疫和生长发育相关基因的表达量,随着驯化盐度的升高,西杂鲟幼鱼hsp70、hsp90、igf-Ⅱ、fshr、erα表达水平呈先下降后升高趋势,tnf-α、igf-Ⅰ、vtg表达水平呈先升高后降低趋势,lysozyme、gst表达水平逐渐升高,fsh、lhr、erβ表达水平逐渐下降,但各组间均无显著差异,S 8处理组lh的表达水平显著低于对照组。综上所述,在适应低盐的过程中,西杂鲟幼鱼鳃Na^(+)-K^(+)-ATP酶被激活,参与渗透压平衡调节,表明15 d的低盐驯化可能提高了西杂鲟幼鱼的耐盐性,但未显著影响西杂鲟幼鱼的生长发育和免疫性能。

杂交鲟源温和气单胞菌的分离鉴定及生物学特性的研究

为探明引起彭水县某鲟养殖场杂交鲟(Acipenser baerii♀×A.schrencki♂)患病的病原,本研究从患病杂交鲟的腹水中分离出一株细菌(A20)。通过菌落形态观察、革兰氏染色、溶血性实验、生理生化特征、16S rDNA基因和gyrB基因序列分析对菌株A20进行鉴定,同时探究菌株A20的耐受性、毒力基因、半致死浓度和药物敏感性等生物学特性。结果显示:菌株A20鉴定为气单胞菌属(Aeromonas spp.)短杆状革兰氏阴性菌温和气单胞菌(A.sobria);菌株A20生长的最适pH为7,对温度和盐度的耐受力较强;该菌携带hlyA、ompA、alt、aer 4种毒力基因;人工回归感染实验结果表明菌株A20为导致杂交鲟患病的病原菌,LD 50为1.37×10^(7)CFU/mL;药敏结果表明,该菌对氟苯尼考、恩诺沙星等15种抗菌药物敏感。

MS-222对俄罗斯鲟幼鱼的麻醉效果

通过观测不同浓度下MS-222处理后俄罗斯鲟(Acipenser gueldenstaedtii)幼鱼的麻醉深度、入麻时间和复苏时间,初步确定了适宜麻醉浓度,并通过测定呼吸频率、耗氧率、排氨率和露空苏醒弹动时间等指标分析麻醉对鱼体造成的影响,综合评估了MS-222的适宜麻醉浓度范围。试验结果表明,随着MS-222浓度的增加,血液中药物浓度达到动态平衡时俄罗斯鲟幼鱼的麻醉程度逐渐加深,达到相同麻醉程度所需的时间逐渐缩短,且复苏时间出现上升趋势。麻醉剂浓度在200~300 mg/L时,试验鱼20 min内即可进入较为稳定的麻醉状态。MS-222对试验鱼的呼吸频率有极显著影响,也能有效降低鱼体的耗氧率和排氨率。根据试验结果,可认为最适于俄罗斯鲟幼鱼麻醉运输的MS-222浓度范围为50~60 mg/L,适于俄罗斯鲟幼鱼人工操作的MS-222浓度范围为150~200 mg/L。

不同脂肪源对西伯利亚鲟生长性能的影响

该试验以西伯利亚鲟(Acipenser baerii)为研究对象,探究饵料中不同脂肪源对其生长性能的影响,并筛选出比较适宜的脂肪源。试验选择体重约为80g、健康无病的西伯利亚鲟500尾,随机分成5组,每组100尾。各组西伯利亚鲟分别饲喂以鱼油、豆油、葵花籽油、亚麻籽油及玉米油作为脂肪源的试验饵料。试验周期为8周,预饲养期1周。试验结束,检测各组西伯利亚鲟的增重率、特定生长率、饵料系数、肝体比、脏体比等指标。结果表明,豆油组的试验末体重和增重率显著高于亚麻籽油组和玉米油组(P<0.05);豆油组的饵料系数显著低于玉米油组(P<0.05);不同脂肪源的试验饵料对脏体比和肝体比未产生显著性的影响,且各组的成活率均为100%,未出现死亡。结果表明,各组植物油中以豆油替代鱼油对西伯利亚鲟的生长性能效果最优,与鱼油组的生长性能最接近。

放养密度对杂交鲟生长性能的影响

为了研究杂交鲟放养密度对其生长性能的影响,该研究选用体重(0.090±0.025)g、体长(2.00±0.22)cm的达氏鳇♀(Huso dauricus)与施氏鲟♂(Acipenser schrencki)杂交的14日龄杂交鲟幼鱼43200尾。随机分为密度1组、密度2组、密度3组和密度4组,每一组分3个平行。密度1组、密度2组、密度3组和密度4组的杂交鲟放养密度分别为0.4万尾/m^(3)、0.6万尾/m^(3)、0.8万尾/m^(3)和1.0万尾/m^(3)。整个试验为期5周。试验过程记录杂交鲟的始末体重及饲料饲喂情况。结果显示,放养密度3组的杂交鲟终末体长、终末体重、日增重、特定生长率均极显著地高于密度1组和密度4组(P<0.01);密度2组的终末体长、日增重和特定生长率显著地高于密度1和密度4组(P<0.05),显著地低于密度3组(P<0.05)。饵料转化率密度1组、密度2组、密度3组和密度4组呈上升趋势。成活率密度1组、密度2组、密度3组在同一个水平,密度4组相比下降了10%左右。研究表明,0.8万尾/m^(3)的放养密度最适宜杂交鲟生长,且对其成活率不造成影响。

水流对杂交鲟幼鱼游泳行为的影响

在26℃水温下,使用特制的鱼类游泳行为测定装置研究了杂交鲟(Huso duricusGeorgi♂×Acipenser schrenc-kiBrandt♀)幼鱼在0 m/s、0.1 m/s、0.3 m/s、0.5 m/s 4种流速条件下的游泳行为。结果显示:杂交鲟幼鱼随着流速的增加趋流率增大,且在90min内趋流率达到100%所需的时间明显缩短。实过过程中0.3 m/s和0.5 m/s两组摆尾频率都高于0.1 m/s和静水组,但在各个时段内,摆尾频率与趋流率均没有显著的相关。杂交鲟幼鱼的游泳状态明显受到所处流速的影响:0.1 m/s流速下以逆流前进为主,约占时间比例56.3%;0.3 m/s流速下以逆流静止为主,约占时间比例58.1%;0.5 m/s流速下以逆流后退为主,约占时间比例80.7%。在逆流前进和逆流静止两种游泳状态下,杂交鲟幼鱼的游泳速度和摆尾频率呈线性相关。但在逆流后退和顺流而下两种状态下,两者之间却没有显著的相关,且此两种状态下其游泳速度和摆尾频率随流速增加的变化趋势也不一致。