大口黑鲈原代肝细胞的培养及其应用于CYP450活性的诱导

体外培养大口黑鲈(Micropterus salmoides)原代肝细胞,观察其在培养过程中的形态变化,同时检测培养上清液中的乳酸脱氢酶(LDH)、白蛋白(ALb)含量,从而判定肝细胞的增殖和代谢能力,进而应用于CYP450的诱导研究。结果表明:培养5 d后,肝细胞连接成片,分裂增多;培养至7 d,细胞渐至单层;14 d后,细胞停止生长,出现老化迹象。培养至第3~4天的细胞上清液中LDH的渗出量呈上升趋势,在第4天时达到峰值,随着培养时间的延长,肝细胞的酶渗出量逐渐减少。ALb的分泌量在第3~5天呈上升的趋势,第4~8天维持在较高水平,在第5天达到最高,此后随着培养时间的延长,ALb的分泌量呈下降趋势,故选择培养至第5天的大口黑鲈肝细胞应用于CYP450酶系中的氨基比林-N-脱甲基酶(ANDM)的诱导研究。40μM利福平诱导24 h后,ANDM活性最高。ANDM的诱导研究为鱼类细胞药物代谢酶体外诱导奠定基础。     

宠物级鸡肉粉替代鱼粉的饲料中补充苏氨酸对大口黑鲈生长性能、糖脂代谢和免疫的影响

为研究饲料中不同苏氨酸水平对大口黑鲈生长性能、糖脂代谢、免疫及宠物级鸡肉粉利用率的影响,实验采用初始体质量为(4.16±0.06) g的大口黑鲈作为研究对象,设计3种等氮等脂的饲料:苏氨酸对照组(TC,65.0%鱼粉),低水平苏氨酸组(LT,65.0%宠物级鸡肉粉添加除苏氨酸以外的必需氨基酸含量至TC水平组)和苏氨酸添加组(TS,LT组添加苏氨酸含量至TC水平组),养殖实验开展8周。结果显示,与对照组相比,LT处理组饲料显著降低了大口黑鲈的生长性能、饲料效率和鱼体营养物质组成,饲料中添加苏氨酸可在一定程度上改善宠物级鸡肉粉完全替代鱼粉后导致的生长性能受限、饲料效率低下和鱼体营养物质组成降低等问题。宠物级鸡肉粉完全替代鱼粉还显著降低了血浆中营养成分和多种游离氨基酸的含量,饲料中添加晶体苏氨酸能够显著提高血浆中游离氨基酸的水平,使之与对照组间无显著性差异。mRNA水平上,饲料中添加苏氨酸可显著改善鸡肉粉完全替代鱼粉引起的肝脏中糖脂合成代谢抑制和分解代谢加剧的现象,同时添加苏氨酸也可显著降低细胞炎症因子的mRNA的表达水平。研究表明,饲料中适量苏氨酸的添加可在一定程度上提高大口黑鲈的生长性能...     

Diet of introduced largemouth bass in Korean rivers and potential interactions with native fishes

Abstract –  A dietary analysis of largemouth bass ( Micropterus salmoides ), an exotic, piscivorous species, was conducted in large South Korean river systems (>third order streams, 31 sites). Micropterus salmoides larger than 100 mm exhibited intense piscivory on native Korean juvenile fishes, with levels of piscivory amongst the highest recorded globally, for native and introduced populations. Largemouth bass exhibited an ontogenetic shift in diet, showing a progressive increase in piscivory with size, typical of this species within its native range but unlike several studies on introduced largemouth bass in Europe and Africa. Sampling of fish communities at the same sites used for diet studies showed that native piscivores and the main food fish species of largemouth bass were significantly less abundant ( P  = 0.049 and 0.045, respectively) at sites where bass were present than at sites where no bass were recorded. Largemouth bass may pose a threat to the structure of fish assemblages in Korean river systems and further study of their population interactions and how to minimise their spread is needed.     

大口黑鲈弹状病毒的分离与鉴定

为探明广东省韶关市某大口黑鲈（Micropterus salmoides）养殖场的大口黑鲈幼鱼大量死亡的原因,对患病鱼进行临床观察,并从细菌学、寄生虫学、病毒学三方面进行检测,排除细菌和寄生虫感染的可能性后,通过RT-PCR检测、细胞分离培养、人工感染、组织病理切片苏木精-伊红（H&E）染色、超薄切片透射电镜观察、系统发育树分析,初步确定分离得到1株大口黑鲈弹状病毒（micropterus salmoides rhabdovirus,MSRV）,命名为大口黑鲈弹状病毒韶关株（MSRV-SG01）。人工感染试验结果显示,试验鱼2 d内出现死亡,并伴随出血、烂尾、拖便等临床症状,7 d内死亡率达100%,通过组织病理学切片观察到病鱼的肝脏、脾脏均呈现大面积坏死,与自然患病鱼症状相符。根据G蛋白氨基酸序列,将分离到的MSRV-SG01毒株与GenBank中已报道的其他的弹状病毒进行系统发育树分析比对,结果显示, MSRV-SG01毒株与MSRV-FJ985、MSRV-YH01、SCRV聚为一类,且与已报道的MSRV-FJ985毒株、MSRV-YH01毒株同源性高达97%以上。通过以上的试验分析,确定幼鱼大量死亡的原因为MSRV感染。     

加州鲈人工繁殖技术

采用平均体重为0.5kg的加州鲈（Micropterus salmoides)亲鱼雌雄各221尾（221对），人工催产3d后开始产卵，经40d共产卵988批，889.2万粒，出苗711.4万尾，孵化率80%，经20-30d的培育共获2-5cm的幼鱼370万尾，居活率52%，结果表明：加州鲈具有极强的繁殖力；其卵母细胞具有分批成熟，分批产卵的习性；加州鲈亲鱼的产卵量与卵母细胞成熟度有关，与温度无关。     

加州鲈肌肉生长抑制素(MSTN)cDNA的克隆和序列分析

肌肉生长抑制素是抑制肌肉生长和发育的生长调控因子。对运用RT-PCR和RACE技术从加州鲈成鱼肌肉总RNA中扩增得到的MSTN cDNA全序列进行了序列分析。结果表明,加州鲈MSTN cDNA全长为1626bp,其开放阅读框为1 134bp,共编码377个氨基酸,前面的22个氨基酸为信号肽,中间有四个氨基酸(RARR)为蛋白水解加工位点;该基因总共有13个半胱氨酸残基,后面9个在蛋白水解加工位点之后的C端生物活性区,与其它脊椎动物比较,它们的位置完全一致,对该基因的结构和功能非常重要。与GenBank中已知的条纹狼鲈、金鲷、斑马鱼、虹鳟、斑点叉尾鮰、人、猪、鸡、鸽MSTN的ORF相比较,核苷酸序列同源性为63%~94.4%,氨基酸同源性为61.4%~96%,特别是在C端生物活性区氨基酸同源性为88.1%~100%,高度的保守性反映了该基因受到了高度的进化限制以及功能的重要性。加州鲈MSTN基因的克隆为研究该基因打靶和鱼类肌肉发育调控机理奠定了基础。     

Otoliths versus scales: evaluating the most suitable structure for ageing largemouth bass,Micropterus salmoides,in South Africa

The suitability of scales for ageing Micropterus salmoides was determined by comparing the precision of growth zone counts on scales with those obtained from sectioned sagittal otoliths from a sample of 496 fish collected from Wriggleswade and Mankazana Impoundments in the Eastern Cape, South Africa. Otoliths (1.4% rejected) were more readable than scales (41.7% and 7.5% rejected) for Wriggleswade and Mankazana Impoundments respectively. Otolith readings were more precise (average percentage error (APE) = 13.6%; coefficient of variation (CV) = 15.8%) than scales (APE = 18.0%; CV = 21.9%) for the total sample. Growth zone counts between structures were not symmetrically distributed around the agreed ages (otolith age = scale age) of the fish from Wriggleswade Impoundment (Bowker’s test H²: χ² = 136, d.f. = 27, P < 0.05) and graphical comparison showed that scales tended to underestimate age, particularly for fish older than five years. Scales are therefore not suitable structures for ageing South African M. salmoides which may attain ages of up to 13 years.     

不同剂量电子束辐照对鲈鱼半成品灭菌及

为探讨电子束灭菌技术应用于鱼类加工半成品的最佳剂量,采用0~8.56 kGy辐照剂量对鲈鱼半成品进行灭菌,分析不同剂量电子束辐照对鲈鱼半成品菌落总数、pH、持水性、色度值、剪切力和挥发性成分的影响。结果表明,随辐照剂量的增加,杀菌效果增强;辐照剂量为3.70~4.41 kGy时菌落总数即可降至≤10 CFU·g-1;辐照剂量在2.45~7.24 kGy范围内能控制鲈鱼半成品pH的下降;辐照剂量高于8.56 kGy时,辐照对鱼肉持水力和剪切力无显著影响;辐照剂量低于6.64 kGy时,对鲈鱼半成品色泽的影响较小;与6.64 kGy相比,低剂量（3.33 kGy）辐照处理有利于减少烷类、烯类挥发性成分的产生。综上所述,电子束辐照剂量在4.00 kGy左右时,可达到灭菌目的,并有效控制鱼肉色度、pH和持水性,最大限度地保持产品原有风味和品质。     

大口黑鲈对饲料中酵母硒的耐受性研究

本试验旨在通过研究酵母硒对大口黑鲈生长性能、血浆生化指标、组织抗氧化指标及肝脏组织结构的影响,评价大口黑鲈对饲料中酵母硒的耐受性。在基础饲料中分别添加0(Y0)、0.5(Y0.5)、2.5(Y2.5)、5.0 mg/kg(Y5.0)(以硒计)酵母硒,其中0.5 mg/kg是硒的最高推荐剂量,2.5和5.0 mg/kg分别是最高推荐剂量(0.5 mg/kg)的5和10倍。基础饲料本底硒含量为0.76 mg/kg。选用初始体重为(12.99±0.01)g大口黑鲈,随机分为4组,每组6个重复,每个重复20尾,试验期为10周。结果表明:Y0组增重率和摄食率最低,同时其饲料系数也最低,均显著低于其余各组(P0.05)。Y0组血浆中碱性磷酸酶活性显著高于其余各组(P0.05)。Y0.5组血浆中高密度脂蛋白胆固醇含量显著高于其余各组(P0.05)。Y2.5组血浆中尿素氮含量显著高于其余各组(P0.05)。Y2.5组、Y5.0组血浆中免疫球蛋白M含量显著高于Y0组、Y0.5组(P0.05)。与Y0组相比,酵母硒的添加显著降低了血浆中丙二醛的含量(P0.05),且显著提高了血浆中谷胱甘肽过氧化物酶的活性(P0.05)。Y5.0组肝脏硒含量显著高于Y0组、Y 0.5组(P0.05),与Y2.5组无显著差异(P0.05)。硒日摄入量和肝脏硒含量呈显著线性相关(P0.05),肝脏硒含量随硒日摄入量的提高呈线性增加。各组大口黑鲈的肝脏都有不同程度的损伤,但添加0.5 mg/kg酵母硒对肝脏损伤有缓减作用。由上述结果可知,饲料中添加0.5 mg/kg酵母硒(总硒含量为1.29 mg/kg)对大口黑鲈具有一定的脂肪代谢促进作用和抗氧化保护功能,且对大口黑鲈是安全的。本试验条件下,综合生长性能、血浆生化指标、组织抗氧化指标及肝脏组织结构,饲料本底硒含量为0.76 mg/kg时,大口黑鲈对饲料中酵母硒的耐受剂量为0.5 mg/kg(以硒计),即为硒的最高推荐剂量,安全系数为1。鱼粉、磷虾粉等动物蛋白质源中含有较高水平的硒元素,因此在高鱼粉水产动物饲料中补充硒要慎重。     

Evaluation of ageing accuracy with complementary non‐lethal methods for slow‐growing,northern populations of shoal bass

In the upper Chattahoochee River basin, where some populations of shoal bass, Micropterus cataractae Williams & Burgess, are imperilled, age and growth data are lacking. Age and growth of shoal bass in this basin were assessed with non‐lethal means using scales and mark–recapture. Mark–recapture data allowed for estimation of accuracy and determination of effects of any scale‐based inaccuracies on growth models. Scale‐based age estimates were accurate for 57% of the samples, and errors of 1 to 3 years included equal numbers of over‐ and underestimates of age. von Bertalanffy growth models based on scale ages were similar to those based on mark–recapture ages for ages 3–8 but noticeably divergent for younger and older fish. Scales provided estimates of longevity up to 12 years of age, and growth models produced from mark–recapture suggest scale ages underestimated age, especially for older fish. These populations of shoal bass live longer and grow slower than other populations, suggesting regional management strategies may be needed.