三聚氰胺对吉富罗非鱼的急性毒性研究

采用接触、腹腔注射及口服3种致毒方式,对吉富罗非鱼(GIFT Oreochromis niloticus)进行三聚氰胺的急性毒性研究.口服急性毒性实验中,在饲料中添加不同浓度的三聚氰胺,进行21d的吉富罗非鱼摄食养殖实验,实验鱼初体重为(55.00±0.05)g.实验结果表明:三聚氰胺溶解度较低,在接触实验中其水溶液没有表现出毒性,96LC50>3500mg/L;而在腹腔注射致毒方式下,三聚氰胺对吉富罗非鱼的半致死剂量LD50=1311.90mg/kg;LD5095%可信限为1169.06～1472.21mg/kg;在21d口服急性毒性实验中,添加三聚氰胺后不同程度地降低了吉富罗非鱼的摄食率和特定生长率,但对存活率和饲料系数均无显著影响.三聚氰胺对吉富罗非鱼21d的最大未观察到有害作用剂量(no-observed-adverse-effect-level,NOAEL)为31.00mg/(kg*d).     

福寿鱼生长率与体重的关系

１９９８年４─１０月于汕头大学南澳海洋生物实验站对福寿鱼进行了四次生长实验,结果表明福寿鱼在海水或淡水中特定生长比数（ＳＧＲ）均随体重（Ｗ）增加明显下降,在海水中二者间回归方程为ｌｎＳＧＲ＝１．９５４—０．３２７ｌｎＷ,在淡水中为ｌｎＳＧＲ＝３．１６１—０．６５ｌｎＷ．淡水中福寿鱼ＳＧＲ与体重关系的斜率（ｂ值）明显低于鱼类常见ｂ值（－０．４）,其原因与实验后期水温下降和福寿鱼领域行为变化有关．实验显示福寿鱼在不同生长阶段ＳＧＲ与体重的关系并非完全恒定,因此应根据相同条件下得出的ＳＧＲ与体重关系来校正和评价福寿鱼体重对ＳＧＲ的影响．     

埃及品系尼罗罗非鱼三个世代耐寒性能的选育

采用闭锁群体继代选育法,以埃及品系尼罗罗非鱼的自然种群作为选育种群进行自繁,通过耐寒与生长性能评价及低温选育,获得埃及品系尼罗基础群和核心群各1个,基础群1 180尾,选留率30.50%;P0代核心群292尾,雌雄比例为1∶1,选留率16.48%;P1代核心群均由10个家系组成,每个家系选留80～100尾,选留率25%左右,核心群的个体在400尾左右。在核心群选育的基础上,应用巢式配对的方法配对P1代家系283个,产苗家系137个,配对成功率48.41%,产苗135 550尾;配对P2代家系91个,产苗家系42个,配对成功率46.13%,产苗30 400尾。选留的10个家系耐寒和生长性能结果表明,P1和P2代的平均半致死温度分别为8.07°C和7.75°C,比自然种群低7.88%和13.98%,平均相对存活率分别提高21.52%和26.35%,平均生长速度提高9.77%和18.90%;其中P1和P2代耐寒性能最好家系的半致死温度分别比自然种群降低9.13%和18.98%,平均相对存活率提高25.29%和30.34%,生长速度提高15.87%和33.00%。埃及品系尼罗罗非鱼耐寒选育P1、P2代的所有家系和核心群的耐寒和生长性能均高于自然种群。     

Inhibition of Microbial Growth by Nano-chitosan for Fresh Tilapia (Oreochromissp) Preservation

Nano-chitosan was tested as a novel preservation agent for fresh tilapia fish (Oreochromissp). The fish samples were immersed in 0.6% nano-chitosan for 30 minutes and were kept in storage at room temperature, low temperature (10-15^oC), and very low temperature (2-7^oC). In room temperature, nano-chitosan did not exhibit significant preservative effect to inhibit the growth of microbes to be compared to sample without nano-chitosan treatment and kept in room temperature (control). However at lower temperature, a significant difference was observed in term of decreasing fish deterioration rate for the nano-chitosan treated samples to be compared to control. The rate of deterioration was quantified using three parameter logistic model for objective comparison among treatments, based on measured parameters (total volatile base and total plate count).     

基于细胞色素b序列的罗非鱼选育群体遗传变异分析

对吉富品系尼罗罗非鱼(Oreochromis niloticus)不同世代选育群体细胞色素b序列进行测定和分析,45个样本经重排比较后获得1 064 bp的同源序列.共检测到161个变异位点,占分析位点数的15.13%.同源序列中多态位点比例随着选育世代数的累进,呈现出降低的趋势,F_0、F_6、F_7、F_8、F_9代分别为14.38%、13.47%、13.38%、10.24%、9.49%.核苷酸多样性指数也呈现出同样的降低趋势,F_0、F_6、F_7、F_8、F_9代分别为0.065 47、0.049 05、0.048 81、0.036 19、0.033 81.本研究结果表明,新吉富罗非鱼仍保持了一定程度的遗传变异水平,新吉富罗非鱼逐步趋于纯化.     

低温胁迫对罗非鱼血液生理生化指标的影响

选取平均体质量(150±2)g的埃及尼罗、美国尼罗和美国奥利亚罗非鱼各90尾,随机分为25、15和12℃共3个试验组,每组设3个重复组,每重复10尾,应用人工室内降温,研究不同低温胁迫对罗非鱼血液生理生化指标的影响。结果表明,在15℃ 0、5、10、16d昏迷和12℃ 0、36、72h时,与对照组(25℃)相比,3种罗非鱼血液红细胞数量(RBC)的差异均不显著(P>0.05),血红蛋白(HGB)、平均红细胞血红蛋白量(MCH)和红细胞压积(HCT)降低(P>0.05),平均红细胞体积(MCV)显著降低(P<0.05),平均红细胞血红蛋白浓度(MCHC)显著提高(P<0.05);血清总蛋白(TP)浓度显著提高(P<0.05),白蛋白(ALB)浓度降低(P>0.05);谷丙转氨酶(ALT)和谷草转氨酶(AST)活性显著升高(P<0.05);超氧化物歧化酶(SOD)活性在15℃ 0、5、10d和昏迷时升高(P>0.05),在12℃ 0、36、72h时降低(P>0.05)。     

Characterization of Collagen from Three Genetic Lines (Gray,Red and F1) of Oreochromis niloticus (Tilapia) Skin in Young and Old Adults

From tilapia (Oreochromis niloticus) farming, the by-products have been identified as a source of collagen that could be used for the development of dermocosmetics or pharmaceutical products. However, the characteristics of collagen related to a specific strain or culture must be well defined prior to its application. Collagen was extracted from the skin of three strains of tilapia: red YY males (YY: two Y-type sex chromosomes), XX gray females, and the F1: offspring of crossing red YY males with XX gray females; at different ages in the adult phase, using acetic acid and pepsin enzyme. The characteristics of acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were shown by SDS-PAGE band profiles to be similar to bovine collagen type I (SIGMA), the PSC of gray tilapia being more fragile to temperature changes, consistent with the results of fractional viscosity. The characteristics of the F1 progeny were prioritized for being a commercially productive and sustainable source for the extraction of collagen, and the ASC form, being the one with the greatest stability and advantage over PSC, of importance to our investigations, leads to a controlled digestion as in the case of peptide induction, and also in the development of natural products in the pharmaceutical and/or dermocosmetic industry. Evaluations of the triple helix structure by FT-IR, X-ray diffraction and UV–visible spectroscopy give similar results between the strains: red, gray, and F1, and between ages in the adult form F1 (15, 24, and 36 months of age). Consequently, the skin of tilapia in adult form is recommended sustainably for up to 24 months of age where the collagen is obtained with the use of acetic acid without enzymatic treatment.     

固相萃取/高效液相色谱-串联质谱法测定罗非鱼中9种邻苯二甲酸酯

建立了罗非鱼中邻苯二甲酸二(2-甲氧基)乙酯(DMEP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二甲酸二(2-丁氧基)乙酯(DBEP)、邻苯二甲酸二戊酯(DPP)、邻苯二甲酸二(4-甲基-2-戊基)酯(BMPP)、邻苯二甲酸二己酯(DHXP)、邻苯二甲酸二(2-乙基)己酯(DEHP)、邻苯二甲酸二正辛酯(DNOP)共9种邻苯二甲酸酯(PAEs)的高效液相色谱-串联质谱测定方法。样品经乙酸乙酯提取后,经LC-Si固相萃取柱净化,以甲醇和甲酸-乙酸铵缓冲溶液为流动相,梯度洗脱,采用HPLC-MS/MS电喷雾正离子(ESI+)电离,多反应监测(MRM)模式检测,基质匹配外标法定量。9种PAEs在1.0～200.0μg.L-1范围内均具有良好的线性关系,相关系数不低于0.991 8,平均加标回收率为75%～107%,批内、批间相对标准偏差分别在1.9%～11.8%和3.6%～13.1%之间。该方法具有简单、快速、灵敏度高和定性准确等优点,满足残留分析的要求。     

不同低温条件下吉富罗非鱼的耐受性研究

应用室内人工降温,以0.5 ℃/2 h的降温方法研究吉富罗非鱼的低温耐受能力,分析比较不同低温条件下吉富罗非鱼的昏迷情况和死亡情况,评价其低温耐受性.结果表明:在8、9、10和11 ℃持续低温胁迫下,吉富罗非鱼的昏迷温度在8.9～10.5℃,半数昏迷温度为9.6℃左右;从开始出现昏迷到全部死亡的经历时间分别为14.5、18.5、24.5和28.5 h;昏迷维持时间与累计死亡率呈显著的线性相关,分别为:y=-0.0489x2+1.4330x-9.5078(R2=0.9999)、y=-0.0136x2+0.5024x-3.6385(R2=0.9649)、y=0.0038x2-0.0461x-0.1344(R2=0.9843)和y=-0.0034x2+0.2443x-3.2131(R2=0.9945).吉富罗非鱼的耐受性与时间和温度密切相关,其中8℃组耐受时间最短,11℃组最长.     

核电站液态排放中放射性核素从海水转移到海洋生物的数值模拟

采用潮流污染扩散的数值模拟,得到了大鹏澳和西大亚湾部分海域的流场、浓度场分布。在此基础上,建立了放射性核素在罗非鱼体内转移的数学模型,并根据Fick定律以及物质守恒的原理建立了相应的微分方程组,对罗非鱼从摄取放射性核素110mAg,直到排泄该核素的整个过程进行数值模拟。模拟结果与有关实验基本一致,说明本模型的建立以及参数的选取是可靠的。这为预测核电站废水排放中放射性核素对海洋生物的影响提供了科学依据。