CdSe/ZnS量子点对雄性尼罗罗非鱼红细胞微核率及核异常率的影响

[目的]探究CdSe/ZnS量子点对尼罗罗非鱼(Oreochromis niloticus)的遗传毒性。[方法]分别设空白对照组、NaCl对照组和Cd2+对照组以及浓度分别为20、200、2 000和4 000 nmol/L 4个量子点处理组,以腹腔注射方式对雄性尼罗罗非鱼体进行暴露,暴露后1、4、7、14及28 d进行静脉取血制作血涂片,通过微核率、核异常率及总核异常率检测其遗传毒性。[结果]各NaCl对照组与空白对照组均无显著差异。暴露1 d后各量子点处理组产生的微核率达到峰值后总体呈下降趋势。Cd2+对照组的微核率在整个试验期间均与NaCl对照组有显著差异,其微核率14 d达到峰值。核质外凸和核质内凹是核异常的主要类型,核固缩及不均等缢裂细胞类型在前期易被诱导。[结论]量子点外壳及表面修饰基团的综合作用对鱼体有诱导微核率及核异常率增加的效应,但随着时间的推移,罗非鱼能逐步解除该负面效应,由此推测鱼体最终能解除由QDs诱导的遗传毒性。     

RAPD和AFLP在分析尼罗罗非鱼遗传多样性研究中的应用比较

比较了RAPD和AFLP标记技术在尼罗罗非鱼遗传多样性研究中的应用。共筛选20个RAPD引物和7个AFLP引物组合,检测到AFLP标记的有效等位基因数和平均多态信息量稍低于RAPD标记,但AFLP标记的多态性检测效率显著高于RAPD标记。两种分子标记所得遗传相似系数接近。结果表明:AFLP和RAPD适宜于基因组DNA检测,但AFLP优于RAPD。     

尼罗罗非鱼AFLP技术体系的优化

对AFLP技术从限制性内切酶水解、扩增条件、检测方法3个方面作了一些改进,建立了一套稳定的且简便易行的实验条件,同时用这种改进的AFLP技术体系对尼罗罗非鱼基因组DNA的多态性进行了初步研究,得到了良好的DNA的多态性检测效果,不仅分辨力较高,而且带型稳定。     

铜、锰诱导吉富罗非鱼血细胞凋亡及铁、锌的干预作用(英文)

为了研究重金属铜与锰对吉富罗非鱼血细胞凋亡的影响以及铁、锌的拮抗作用,采用原子吸收分光光度法检测血液及饲料中重金属的含量,采用流式细胞术检测实验鱼血细胞凋亡情况。360尾吉富罗非鱼幼鱼随机分为12组,每组30尾,分别以硫酸铜(0、2 000mg/kg)、硫酸锰(0、120 mg/kg)为攻毒组重金属源,以硫酸锌(20、320 mg/kg)、硫酸铁(150、350mg/kg)为拮抗组金属源,通过饲料投喂的方式进行血细胞凋亡的研究,养殖周期为20周。细胞凋亡分析结果表明,染铜组、染锰组实验鱼血细胞凋亡率显著高于对照组;补充铁和锌后,随着饲料添加铁、锌水平的增加,实验鱼血细胞凋亡率明显下降,但铁、锌干预组血细胞凋亡率显著高于对照组。试验表明,过量铜、锰可诱发实验罗非鱼血细胞凋亡;较高水平的铁、锌对铜、锰的毒性作用具有拮抗作用。     

印度菜粕替代国产菜粕对奥尼罗非鱼生长、体组成及健康状况的影响

【目的】研究印度菜粕替代国产菜粕对奥尼罗非鱼生长性能、免疫力及肝脏结构的影响。【方法】选取120尾初始体质量约为17.3 g的奥尼罗非鱼,随机分为4组;设计4种等氮等能的实用饲料G0、G50、G75和G100,其中,G0为对照组(国产菜粕用量35%),G50、G75和G100为分别用印度菜粕替代G0饲料中50%、75%和100%的国产菜粕并添加质量分数为0.1%的二甲基-β-丙酸噻亭(DMPT)为诱食剂,饲养周期为43 d。【结果】印度菜粕替代水平升高可导致罗非鱼的末均质量、增质量率、特定生长率降低,饲料系数升高,其中,G100组差异显著(P0.05)。全鱼体成分和血清常规生化指标差异不显著(P0.05),血清丙二醛(MDA)、NO含量和超氧化物歧化酶(SOD)、碱性磷酸酶(AKP)活性差异也不显著(P0.05),但G100组总抗氧化能力(T-AOC)和溶菌酶(LZM)含量比G0显著升高(P0.05)。随着印度菜粕替代水平的升高,奥尼罗非鱼肝细胞结构的损伤程度逐渐加大。【结论】生长阶段在17~70 g的奥尼罗非鱼,饲料中印度菜粕替代国产菜粕的水平不宜超过75%。     

种植虎杖对吉富罗非鱼养殖水质和底质的影响

[目的]研究浮床栽培虎杖对吉富罗非鱼养殖池塘的水质、底质的净化作用。[方法]2016年5—10月测定了水体TOC、COD、Chl、TN、NH_4~+-N、NO_2~--N、NO_3~--N、TP、PO_4~(3-)-P和底泥TOC、TN、TP,研究种植虎杖对吉富罗非鱼养殖水质和底质的影响。[结果]2016年5月,虎杖塘浮床区和敞水区TOC、COD、Chl、TP显著下降;6月浮床区和敞水区TOC、COD、Chl、TP显著下降,浮床区NH_4~+-N、PO_4~(3-)-P显著下降;7月,浮床区和敞水区COD显著下降,且浮床区TOC、Chl显著下降;8月,浮床区和敞水区COD、TN显著下降,浮床区TOC和敞水区NH+4-N显著下降;9月,浮床区和敞水区TOC、COD、Chl、TN显著下降;10月,浮床区和敞水区COD、Chl、TN显著下降,浮床区TOC和敞水区NH_4~+-N显著下降。6—8月虎杖种植塘底泥TOC显著增加,6月底泥TN显著增加,7—10月底泥TN显著降低,6、8—10月底泥TP显著降低。[结论]虎杖种植能降低水体中TOC、COD和Chl,降低底泥TP和TN,种植前、后期能分别降低水体中TP和TN,且能显著提高其总产量和成活率,降低其饵料系数和相应的生物学指标。     

罗非鱼质量安全风险研究

目前中国针对罗非鱼(Oreochroms mossambcus)出口产品的质量安全监测系统尚不完善,建立罗非鱼质量安全评价标准、评估影响罗非鱼食品安全的因素,对于建立罗非鱼安全防控模式具有重要意义.本研究以罗非鱼的质量安全作为研究目标,通过对苗种培育、养殖环境及水产品流通等环节可能产生的风险事件的识别,建立罗非鱼质量风...     

Effect of dietary betaine levels on growth performance and hepatic intermediary metabolism of GIFT strain of Nile tilapia Oreochromis niloticus reared in freshwater

An 8‐week feeding experiment was conducted to determine the effect of dietary betaine levels on the growth performance and hepatic intermediary metabolism of genetically improved farmed tilapia (GIFT) strain of Nile tilapia Oreochromis niloticus (mean initial body weight: 78.3 ± 1.3 g, means ± SD). Six practical diets were formulated with the incorporation of betaine at the levels of 0 (control), 5, 10, 15, 20 and 25 g kg⁻¹. Survival showed no significant differences among the treatments (P > 0.05). The highest and lowest weight gain (WG) and specific growth rate (SGR) were observed for fish fed the diets containing 5 and 0 g kg⁻¹ (control) betaine, respectively. Feed intake showed similar trend with WG and SGR. In contrast, feed conversion ratio was the lowest when dietary betaine level was 5 g kg⁻¹. In general, dietary betaine supplementation showed no significant effect on hepatic composition of tilapia. Condition factor and viscerosomatic index tended to increase with increasing dietary betaine levels from 0 to 5 g kg⁻¹ and then decline when dietary betaine levels further increased from 5 to 25 g kg⁻¹. In contrast, hepatosomatic index declined with increasing dietary betaine levels (P < 0.05). Dietary betaine levels significantly influenced several hepatic enzymatic activities, including succinate dehydrogenase, lactate dehydrogenase, malic dehydrogenase, lipoprotein lipase and hepatic lipase, suggesting that dietary betaine addition had significant effects on nutrient metabolism in the liver. Based on the second‐order polynomial regression analysis of WG, 12.5 g kg⁻¹ of dietary betaine level seemed optimal for genetically improved farmed tilapia strain of O. niloticus.     

Effects of Oxygen Supplementation on Lake Trout Brood Stock

This study was conducted to determine the effects of oxygen supplementation and nitrogen supersaturation on the fecundity and performance of Lewis Lake strain lake trout, Salvelinus namaycush, brood stock. Performance of brood fish held in water supersaturated with oxygen was compared to that of controls raised at or below 100% saturation for 334 days. Incoming water averaged 78.4% saturation in the morning; the addition of oxygen increased saturation to 104.6%. As a result, average morning nitrogen saturation was reduced from 105.7% to 100.9%. In oxygen-supplemented water, peak daily oxygen saturation averged 129.0% in the afternoon. At this saturation level, average nitrogen gas was reduced to 98.4% saturation. Total gas pressure never exceeded 109.1% with oxygen supplementation; however, nitrogen supersaturation reached 110% in raceways with no oxygen supplementation. Weight gain, feed conversion, egg survival, egg size, and number of eggs per female were not affected by increasing oxygen saturation.     

Effects of sex ratio, stocking density and age of hybrid tilapia on seed production in concrete tanks in Saudi Arabia

The influence of sex ratio, stocking density and age of hybrid tilapia (Oreochromis niloticus X O. aureus) brood fish on seed production in concrete tanks were evaluated in 1992 and 1993. A sex ratio of 1:2 and 1:3 (male: female) and a density of 2 fish m-2 gave the best result with respect to number of seed female-1 day-1 and number of seed kg-1-1 female day-1. Maximum seed production female-1 day-1 was recorded for 3-year-old females and the minimum for 1-year-olds, but in terms of seed kg-1 female day-1 and seed m-2 day-1, 1-year-olds produced the maximum number of seed followed by 2-, 3- and 4-year-old females. Seasonal pattern in seed production was apparently influenced by season and temperature. From the first harvest on 21 April 1993 the production increased gradually, reaching a peak during the third harvest and a second peak during the sixth harvest. Thereafter seed production gradually decreased, reaching a minimum during the tenth harvest on 27 October 1993. No seed were found during the last harvest of 18 November 1993. Maximum production coincided with the highest water temperature of around 28°C.