加州鲈弹状病毒三水株全基因组序列测定及分析

【目的】对加州鲈弹状病毒弱毒三水株(MSRV-SS-7)及其母源株(MSRV-SS)进行全基因组克隆和测序分析。【方法】采用分段扩增方法对MSRV-SS-7及MSRV-SS基因组核心序列进行PCR扩增,第1轮根据鳜鱼弹状病毒(SCRV)基因序列(NC_008514.1)设计10对引物进行扩增并测序;在第1轮扩增产物测序、拼接基础上,设计8对引物进行第2轮扩增,拼接后获得基因组核心序列。同时用cDNA末端快速扩增法(RACE)获得3′和5′末端序列。采用Vector NTI 8.0对基因组核心序列和末端序列进行拼接,获得基因组全序列,使用Clone Manager 8.0对MSRV-SS-7和MSRV-SS进行序列比对分析;同时使用DNAMAN将基因组G基因序列转换为氨基酸序列,并通过MEGA 5.0与其他鱼类弹状病毒的G蛋白氨基酸序列进行进化树分析。【结果】MSRV-SS-7及其母源株MSRV-SS基因组全长均为11 548 bp,包含N、P、M、G、L等5个结构基因,基因组结构为3′Leader-N-P-M-G-L-Trailer 5′;MSRV-SS-7与MSRV-SS全基因组中共有10处核苷酸不同。G蛋白进化分析表明,MSRV-SS-7及母源株MSRV-SS与SCRV亲缘关系最近,且与鲈鱼弹状病毒属(Perhabdovirus)聚为一支。【结论】克隆分析了MSRV-SS-7的全基因组序列,可以用于后续活疫苗的开发。     

驯食配合饲料的大口黑鲈3个选育世代的遗传多样性分析

为了检测驯食配合饲料的大口黑鲈(Micropterus salmoides)3个选育世代群体遗传多样性水平变化,利用微卫星标记技术对驯食配合饲料大口黑鲈选育基础群体(Sp0)和第二、三和四代选育群体(Sp2、Sp3和Sp4)共240尾样品进行检测。结果显示,18个微卫星位点共获得44个等位基因。Sp0、Sp2、Sp3和Sp4的平均观测杂合度(H_o)分别为0.4895、0.4802、0.4579和0.4206,平均期望杂合度(H_e)分别为0.4615、0.4454、0.4621和0.3916,平均多态信息含量(PIC)分别为0.3791、0.3659、0.3764和0.3257。4个群体间的配对比较群体间遗传分化指数(F_(st))值在0.01612～0.16162之间、遗传距离(D_a)在0.0249～0.1434之间。遗传变异来源(AMOVA)分析显示,只有8.38%的变异来自于群体间,其余遗传变异均来自于个体间。研究表明,经连续多代选育之后,易驯食配合饲料的快长大口黑鲈选育群体具有中度遗传多样性,具备选育潜力,可继续进行选育。     

Turbidity‐induced changes in emergent effects of multiple predators with different foraging strategies

Abstract – In natural systems, prey frequently interact with multiple predators and the outcome often cannot be predicted by summing the effects of individual predator species. Multiple predator interactions can create emergent effects for prey, but how those change across environmental gradients is poorly understood. Turbidity is an environmental factor in aquatic systems that may influence multiple predator effects on prey. Interactions between a cruising predator (largemouth bass Micropterus salmoides) and an ambush predator (muskellunge Esox masquinongy) and their combination foraging on a shared prey (bluegill Lepomis macrochirus) were examined across a turbidity gradient. Turbidity modified multiple predator effects on prey. In clear water, combined predators consumed in total more prey than expected from individual predator treatments, suggesting risk enhancement for prey. In moderately turbid water, the predators consumed fewer prey together than expected, suggesting a risk reduction for prey. At high turbidity, there were no apparent emergent effects; however, the cruising predator consumed more prey than the ambush predator, suggesting an advantage for this predator. Understanding multiple predator traits across a gradient of turbidity increases our understanding of how complex natural systems function.     

MC与MG对尼罗罗非鱼和大口黑鲈游泳行为的影响

尼罗罗非鱼(Tilapia nilotica)和大口黑鲈(Micropterus salmoide)是中国主要的淡水经济鱼类,其养殖过程中常遇到微囊藻毒素(Microcystin,MC)与孔雀石绿(Malachite green,MG)的危害。MC和MG通过食物链在人体中富集,给人类的健康造成了严重的威胁。研究测定了人工饲养的尼罗罗非鱼和大口黑鲈在含有MC和MG的水体中的行为反应。结果表明,尼罗罗非鱼和大口黑鲈在0.2和0.5μg/L MC-LR的水体中处理60min内,其游泳行为相对于对照组无显著性差异,然而,在0.5mg/L MG的水体中处理30min后,尼罗罗非鱼胸鳍摆动频显著上升,大口黑鲈胸鳍摆动频率也在25、30、45min等3个不连续的时间点出现显著的变化。说明尼罗罗非鱼和大口黑鲈对天然毒素MC具有较强的抵抗能力,而对人工毒素MG较为敏感;胸鳍摆动频率可作为尼罗罗非鱼和大口黑鲈一个较为敏感的反映环境变化的行为指标。     

同位素稀释液质联用法测定鱼体中氯丙嗪的残留

建立了高效液相色谱-串联质谱(HPLC/MS/MS)分析鱼体中氯丙嗪残留的方法.样品用乙腈提取,MCX固相萃取柱净化,氨化甲醇洗脱.在正离子模式下以电喷雾串联质谱仪进行测定,采用内标法定量,氘代氯丙嗪为内标物.以欧洲鳗鲡、鳜鱼和大口黑鲈为研究对象,在1.0、5.0、25.0μg/kg添加水平下,方法平均回收率为90.1...     

Physiological responses of largemouth bass to acute temperature and oxygen stressors

Abstract Temperature and oxygen gradients exist in nearly every water body, but anthropogenic activities can subject fish to rapid changes in these important environmental variables. These rapid changes in temperature and oxygen (generally referred to as temperature or oxygen shock) may have sub‐lethal consequences depending upon the magnitude and the fish species. This study quantified physiological changes in largemouth bass, Micropterus salmoides (Lacepède), exposed to two levels of heat and cold shocks and to two levels of hypoxic and hyperoxic shocks. Following a cold shock from 20 °C to 8 °C, plasma cortisol and glucose increased after 1 h and lactate dehydrogenase activity increased after 6 h. Plasma glucose and K⁺ concentrations increased 1 h after a heat shock from 20 °C to 32 °C but not after 6 h. Bass subjected to a hypoxic shock from 8 to 2 mg O₂ L^?1 showed decreased plasma K⁺ and increased plasma glucose and white muscle lactate. No changes in physiological parameters were observed in bass subjected up to 18 mg O₂ L^?1 hyperoxia. Results from this study suggest that largemouth bass can tolerate a wide range of temperature and oxygen shocks, but temperature decreases of 20 to 8 °C and hypoxia as low as 4 mg O₂ L^?1 should be avoided to minimise physiological perturbations.     

When and why do smallmouth bass abandon their broods? The effects of brood and parental characteristics

Abstract Variation in brood abandonment was explored by conducting partial brood removals from smallmouth bass, Micropterus dolomieu Lacepède, nests in two north temperate lakes. In both lakes, percent of the brood removed had no effect on nest failure rates. Nest failure prior to offspring swim‐up was more common, but unrelated to brood size after removal, in the lake with higher post‐spawning mortality and lower growth and fecundity. Brood size after removal was negatively related to nest failure in the lake with high survival, growth and fecundity. Nests guarded by young males failed more frequently than those of old males, and young broods failed more frequently than old broods. Dynamic programming and logistic regression models developed to predict nest fate worked better for the lake with selective pressures that theoretically favoured abandonment (e.g. high post‐spawning mortality). Both models identified male age and brood age as important factors in predicting nest fates. Because nest success is related to the age of the parent, this could have consequences for overall nest success for populations with different demographics.     

大口黑鲈对饲料中丁基羟基茴香醚的耐受性评价

本试验旨在通过生长性能、血浆生化指标、组织抗氧化指标及肝脏、肠道组织学变化,评价大口黑鲈对饲料中丁基羟基茴香醚(BHA)的耐受性。以初始体重为(6.20±0.01)g的大口黑鲈为靶动物,在基础饲料中依次添加0(D0组,作为对照组)、150(D150组)、300(D300组)和1 500 mg/kg(D1500组)的BHA,其中300和1 500 mg/kg分别是最高推荐剂量(150 mg/kg)的2和10倍,进行为期10周的饲喂试验。每组6个重复,每个重复30尾鱼。结果表明:4组中以D150组的生长性能最好,其余各组的终末均重、特定生长率、增重率和摄食量无显著差异(P0.05)。各组肥满度、脏体比和肝体比无显著差异(P0.05)。对照组血浆中总胆固醇、甘油三酯含量及碱性磷酸酶活性显著高于其余各组(P0.05)。D150和D300组血浆中高密度脂蛋白胆固醇/总胆固醇显著高于对照和D1500组(P0.05)。D1500组血浆中谷草转氨酶、谷丙转氨酶活性显著低于对照组(P0.05),与D150、D300组无显著差异(P0.05)。D150和D300组肝脏中超氧化物歧化酶活性显著低于对照组(P0.05),与D1500组无显著差异(P0.05)。饲料中添加1 500 mg/kg BHA可以显著提高肝脏中总抗氧化能力(P0.05);饲料中添加150、300、1 500 mg/kg BHA均显著降低了血浆、心脏和肝脏中丙二醛的含量(P0.05)。对照、D150和D1500组大口黑鲈的肝脏、肠道都有不同程度的损伤,但D150和D1500组的损伤相对较少。上述结果表明,饲料中添加150 mg/kg BHA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,安全系数为10倍。     

Diet of the largemouth bass, Micropterus salmoides (Lacepède), in Lake Naivasha, Kenya

Abstract The major food items of adult largemouth bass, Micropterus salmoides (Lacepède), in Lake Naivasha, Kenya are not markedly different from those in its native range. Although insects and their larvae are major components of the diet for both temperate and equatorial populations of juvenile bass, the equatorial population also eats Procambarus clarkii (Girard), juvenile fish and aquatic weeds. In temperate populations they also eat crustaceans, rotifers and oligochaetes. The frequency of occurrence of the major prey organisms in the stomachs of M. salmoides varies seasonally with population peaks in these organisms. Similar to North American populations, the Naivasha population feeds during the day between dawn and dusk. In contrast to temperate populations, the population of M. salmoides in this equatorial lake feeds throughout the year, with feeding intensity correlated with water temperature.     

Diel and seasonal utilization of home ranges in a small lake by smallmouth bass (Micropterus dolomieui)

Abstract– Diel and seasonal movements of 9 smallmouth bass were monitored by ultrasonic tracking for 1–1.5 years in a small gravel pit lake in northeastern Illinois. Each fish had several home ranges over the study period. Males established home ranges around a nesting site in May and June. During the summer months, smallmouth bass had diurnal, nocturnal, diurnal and nocturnal home ranges. The fish exhibited 2 types of behavior when they were within their home ranges. They were either motionless, which generally occurred on the nocturnal home ranges, or they swam slowly about their home ranges. Rapid directional swimming movements occurred when fish were swimming across the lake or moving between home ranges. The home ranges were transitory. The average size of the reproductive (male) home range was 0.07 hectare; 0.12 hectare for nocturnal home ranges; 0.18 hectare for diurnal home range; and 0.20 for diurnal-nocturnal home range. Generally, reproductive and nocturnal home ranges were smaller; other types could be as small as these but were often larger. However, there was no significant difference in home range sizes.