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1.
温度和频率对鱼糜介电特性的影响 总被引：2，自引：0，他引：2
采用同轴探针方法分别测定了30～80℃，频率320～2960MHz内罗非鱼鱼糜和阿拉斯加狭鳕鱼糜的介电常数和介电损失率。频率一定时，两种鱼糜的介电常数随温度升高而降低；在相同的温度下，频率增加，鱼糜的介电常数反而减小。频率升高使两种鱼糜的介电损失率先减少后增加，分别在890MHz(罗非鱼鱼糜)和1350MHz(狭鳕鱼糜)出现拐点。温度与介电损失率的相关性与频率有关，拐点频率之前，温度与介电损失率成正相关性，而大于拐点频率时，则成负相关性。本研究提出了两种鱼糜的介电常数和介电损大率关于温度和频率的预测方程，预测值与实验值具有良好的一致性。两种鱼糜的穿透深度在915MHz随温度升高而减小，在2450MHz时则正好相反。鱼种的差异对鱼糜介电特性和穿透深度有较大影响。SPSS软件可以对鱼糜的介电特性进行有效预测。 相似文献
2.
915 MHz和2 450 MHz频率下温度和大豆分离蛋白对鲢鱼糜复合素材介电特性的影响 总被引：1，自引：0，他引：1
以鲢擂溃鱼浆及其添加不同比例的大豆分离蛋白乳化物的复合素材为对象,在10~80 ℃范围内,采用同轴探针方法分别测定了915 MHz和2 450 MHz频率下的介电常数和介电损失率。结果表明,鲢擂溃鱼浆及其复合素材的介电常数随温度的升高而减小,介电损失率随温度的升高而增大;温度一定时,介电常数和介电损失率均随频率的增加而减小;添加大豆分离蛋白乳化物添加量在6.5%~28%范围内时,介电常数和介电损失率随添加量的增加而增大。鲢擂溃鱼浆及其复合素材的穿透深度随温度的升高而减小,随大豆分离蛋白乳化物的添加量增加而减小。频率、温度和大豆分离蛋白乳化物对鲢擂溃鱼浆的介电特性和穿透深度有较大影响。利用SPSS软件进行回归分析得到预测方程,对介电常数、介电损失率和穿透深度能够进行有效预测。 相似文献
3.
温度对尼罗罗非鱼无乳链球菌毒力的影响 总被引：1，自引：3，他引：1
为了解温度对鱼源无乳链球菌毒力的影响机制,本实验研究了温度对无乳链球菌毒力相关参数(生长、粘附、入侵、毒力基因表达以及对罗非鱼致死率)的影响。结果发现,不同培养温度下(25~40 ℃)无乳链球菌的生长速度不同,37 ℃为其最适生长温度,25 ℃时生长速度最慢;25~34 ℃内无乳链球菌粘附在惰性基质上的菌体对应的吸光值(OD590nm)之间无显著差异(P>0.05),37 ℃时显著增加,40 ℃时又急剧下降;罗非鱼在人工感染无乳链球菌后各时间点(6、12、24和48 h),鱼体脑组织中菌量随注射菌体培养温度的增加呈先上升后下降的趋势,且与不同培养温度下的无乳链球菌对罗非鱼的致死率呈正相关;无乳链球菌毒力基因的表达也与培养温度相关,hly和cfb基因的表达量随菌体培养温度的升高先增加后降低,分别在34和37 ℃处达到峰值,不同培养温度下无乳链球菌sip基因表达的变化幅度较小,而scpB基因的表达则随培养温度增加而下降;无乳链球菌对罗非鱼的致死率随其培养温度的升高呈先升高后降低趋势,低温(25和28 ℃)培养条件下的菌体对罗非鱼致死率较低(<20%),37 ℃时致死率最高66.67%±6.67%。以上结果表明温度参与无乳链球菌生长、粘附、转移、入侵和部分毒力基因表达的调控,它们共同影响无乳链球菌对罗非鱼的毒力。 相似文献
4.
本研究以耳石为年龄鉴定材料, 结合生物学测量数据, 利用函数拟合求得生长方程, 并解剖观察性腺发育情况, 对采自西藏哲古措的 1616 尾异尾高原鳅(Triplophysa stewarti)开展了年龄、生长及繁殖特性研究。结果发现, 所采集的异尾高原鳅年龄分布为 1~6 龄, 高龄个体较少。体长为 3.47~14.30 cm, 体重为 0.40~28.70 g, 生长特性符合 von Bertalanffy 生长方程: Lt=13.891[1?e?0.168(t+2.895)](R2 =0.940); Wt=28.179[1?e?0.168(t+2.895)] 3.0115(R2 =0.991)。拐点年龄为 3.65, 对应的体长和体重分别为 9.26 cm、8.31 g。异尾高原鳅雌雄性比为 1∶3.01, χ2 检验结果显示雌雄差异极显著(P＜0.01)。Fulton 肥满度雄体平均为 1.07, 雌体平均为 1.03; Clark 肥满度雄体平均为 0.88, 雌体平均为 0.76。 异尾高原鳅 1 冬龄达到性成熟。雄性群体成熟系数为 1.57%, 雌性群体为 2.37%。绝对繁殖力为 1040~10176 粒/尾, 平均为 4397 粒/尾。研究结果, 哲古措异尾高原鳅年龄结构简单且低龄化, 生长缓慢, 肥满度低, 雌性个体性腺成熟系数低, 可能是受哲古措特殊的地理位置和生态环境等因素影响。本研究可为高原鳅属鱼类积累基础生物学资料, 并为藏南内流湖泊生态环境及渔业资源保护提供理论依据。 相似文献
5.
对高水分鱼蛋白的挤压组织化进行研究, 以双轴挤压设备操作参数中的进料水分、腔体温度、螺杆转速、进料速率和电机转速为影响参数, 挤压模拟产物的纤维化程度、硬度、弹性、咀嚼性和色泽为响应因素, 通过中心组合设计及响应面分析法, 探讨了高水分挤压重组技术对鱼蛋白模拟肉类产物特性的影响。结果表明: 首先, 高水分组织化模拟产物具有明显的天然肉类的纤维结构、方向性、弹性和口感。其次, 进料水分对产物的纤维化度、硬度和咀嚼性影响相当显著(P<0.01), 对模拟物色泽中的L*和a*影响显著(P<0.05), 进料水分的增加使产物的纤维化度、硬度、咀嚼性和a*降低, 但提升产物 L*; 腔体温度对产物的咀嚼性和a*影响特别显著(P<0.01), 对硬度影响显著(P<0.05), 升高腔体温度会增加的产物咀嚼性和a*, 硬度则先上升后下降; 进料速率对产物的纤维化度影响极其显著(P<0.01)。 相似文献
6.
在2 450 MHz频率的微波处理条件下,为了考察添加鲢鱼糜对小麦粉面团糊化的影响,将小麦粉、鲢鱼糜、NaCl和去离子水按比例混合制成鲢鱼糜面团,面团中鲢鱼糜含量分别为0%,10%,20%和30%(w/w,质量百分比),对样品面团中淀粉的介电特性和糊化特性进行研究。结果表明,对于相同尺寸的面团样品,添加鲢鱼糜可改善面团样品在电磁场中的加热均匀性。随着温度的升高,面团的介电常数和介电损失率分别在20~23和9~12内波动并呈下降趋势,微波的穿透深度因淀粉的糊化略有上升。淀粉的糊化速率随温度的升高而下降。降低样品中淀粉的含量,会使面团糊化活化能由113.54 kJ/mol下降至59.96 kJ/mol。 相似文献
7.
为了解亚硝酸盐氮长期胁迫下尼罗罗非鱼（Oreochromis niloticus）生理功能变化,实验设置不同浓度亚硝酸盐氮（空白对照、0.03 mmol/L、0.06 mmol/L、0.12 mmol/L、0.23 mmol/L）,研究亚硝酸盐氮21 d胁迫对尼罗罗非鱼幼鱼血液和肝脏组织的生理生化、代谢功能和非特异性免疫的影响。结果表明,随着亚硝酸盐氮的浓度的提高,尼罗罗非鱼幼鱼血液中白细胞数呈现略微上升的趋势,而红细胞数和血红蛋白浓度均呈现显著下降的趋势（P<0.05）;幼鱼血清中,葡萄糖、谷丙转氨酶、谷草转氨酶和K+随着亚硝酸盐氮的增加浓度显著提高（P<0.05）,与此同时甘油三酯、总胆固醇、总蛋白、Na+和Cl-浓度、超氧化物歧化酶、碱性磷酸酶、溶菌酶和免疫球蛋白浓度以及亚硝酸盐氮浓度表现出负相关的下降趋势（P<0.05）;肝脏组织中非特异性免疫因子HSP70、IL-1β、IL6和TNF-α随着亚硝酸盐氮的浓度增加表达量显著上升（P<0.05）,而LYS因子表达量则与之相反。研究表明,0.06~0.23 mmol/L亚硝酸盐氮长期胁迫下可导致罗非鱼幼鱼血液生理、代谢和免疫产生功能障碍,并影响肝组织的非特异性免疫基因表达。本研究结果有助于进一步了解亚硝酸根离子在罗非鱼体内的毒性机制,为建立罗非鱼养殖水质亚硝酸盐氮因子的安全阈值提供参考。 相似文献
8.
试验以硫酸锌为锌源，评价不同锌水平对奥尼罗非鱼幼鱼（Oreochromis aureus♂×Oreochromis niloticus♀）生长和抗氧化能力的影响。体质量为(4.13±0.32)g罗非鱼随机分配在18个水族箱中，每箱20尾，每3个箱为1个处理组，分别以添加锌为0、20、40、80、160和320 mg•kg-1的6种饲料投喂，日投喂率为鱼体重5%～9%。8周的试验结果表明：20mg•kg-1锌饲料组的增重率和鱼体蛋白含量显著高于其它各组(P＜0.05)，蛋白质效率、饲料转化率也明显高于其它各组；全鱼脂肪含量随着饲料锌水平的升高而升高，但320mg•kg-1锌饲料组降低；20mg•kg-1锌饲料组，脊椎骨中锌离子浓度达到最大值且显著高于0mg•kg-1锌饲料组(P＜0.05)；20mg•kg-1与40mg•kg-1锌饲料组的血液中红细胞数量显著高于其它各添加组(P＜0.05)，20mg•kg-1锌饲料组的血液中血比容显著高于0mg•kg-1组(P＜0.05)，与其它各组没有显著差异；肌肉中，硫代巴比妥酸反应产物(TBARS)(Thiobarbituricacid reactive substances)的量，锌为0mg•kg-1饲料组显著高于其它各组(P＜0.05)。综上所述，饲料中锌添加量为20mg•kg-1饲料促进了罗非鱼生长，使鱼体抗氧化功能增强。 相似文献
9.
环境因子对鼠尾藻幼苗叶绿素荧光参数的影响 总被引：1，自引：0，他引：1
为了揭示鼠尾藻幼苗的生态适应性,研究了温度(5~34 ℃)、盐度(10~50)和营养盐等环境因子对鼠尾藻幼苗叶绿素荧光参数的影响。结果表明,(1) 氮浓度高于8 mg/L或磷浓度高于1.2 mg/L,或温度高于28 ℃,对鼠尾藻幼苗的光合作用均有显著影响(P<0.05);(2) 短时间的5~15 ℃的低温胁迫或10~50盐度胁迫6 h对鼠尾藻幼苗的Fv/Fm值影响不明显;(3) 氮、磷浓度分别为2~4 mg/L和0.2~0.8 mg/L,且NH+4-N∶NO-3-N的比值为1~3时,较利于鼠尾藻幼苗光合作用的进行。 相似文献
10.
真空包装青石斑鱼片在0 ℃贮藏时的品质变化特性 总被引：2，自引：0，他引：2
以感官特性、细菌总数、理化参数(基本营养组成、质构、色差、pH、TBA、TMA-N、TVB-N、K值、Ca2+-ATPase活性、SDS-PAGE)为指标,考察了真空包装的青石斑鱼片在0 ℃贮藏过程中的品质变化情况。结果表明,青石斑鱼片是一类高蛋白低脂肪的食品;气味和口感与贮藏时间均有显著正相关性(r=0.94和0.98),且口感评分比气味评分增加得快,但未达到阈值3分;细菌总数随贮藏时间呈显著递增(r=0.97),在第12天仍没有超过4 Log CFU/g,保持着一级鲜度,在第15天达到4.34 Log CFU/g,处于二级鲜度;硬度(r=-0.89)、胶黏性(r=-0.73)、咀嚼性(r=-0.87)与时间显著负相关;随着肌肉的老化,L*值和Cab值随贮藏时间显著下降(r=-0.91和-0.95),而b*值与贮藏时间呈显著正相关性(r=0.99),肌肉逐渐呈灰色调、变暗、彩度明显下降;pH、TBA值在贮藏期变化不大,与贮藏时间弱相关,因此,不适合用于作为反映青石斑鱼片品质变化的指标;在贮藏期末,TVB-N与TMA-N与贮藏时间呈显著线性相关(r=0.86和0.99),其含量分别达到12.94 mg N/100 g和0.75 mg N/100 g,均低于腐败水平阈值;SDS-PAGE显示肌动蛋白球重链和肌动蛋白呈连续性的水解;Ca2+-ATPase活性下降速度较快,且与贮藏时间显著相关(r=-0.96);K值随贮藏时间延长而显著增加(r=0.98),贮藏末期达到54.91%,呈中等新鲜水平。因此,0 ℃真空包装下,其细菌总数增长缓慢,保持较好的感官品质及延缓TVB-N等理化指标的变化及和蛋白质的水解。感官指标、细菌总数、质构(硬度、粘附性和咀嚼性)、色度(L*、b*和Cab值)、TVB-N、TMA-N、Ca2+-ATPase活性和K值在贮藏期内变化显著,且与贮藏时间显著相关,可考虑作为反映青石斑鱼片腐败的合适指标,但货架期的评定,需综合上述参数而定。 相似文献
11.
Shun Watanabe Jun Aoyama Seishi Hagihara Bunpei Ai Rhodora V. Azanza Katsumi Tsukamoto 《Fisheries Science》2013,79(3):375-383
Anguilla luzonensis and A. huangi were each described in 2009 using eels obtained from northern Luzon Island. We examined the taxonomic status of these two groups of eels using morphological and molecular genetic characters. There were no significant differences in two vertebrae counts between eels of A. luzonensis and A. huangi. Mitochondrial 16S ribosomal RNA and cytochrome b genes sequences were obtained and compared among 28 specimens of A. luzonensis, the holotypes of A. luzonensis and A. huangi, and one specimen of the other 15 anguillid species. The specimens of A. luzonensis exhibited almost identical sequences, including the holotype, with only a few site differences, and the genetic difference between the holotypes of A. luzonensis and A. huangi was within the range of differences of specimens of A. luzonensis. The other anguillid species were genetically very different from A. luzonensis and A. huangi, although A. interioris is a closely related species. It is clear that A. luzonensis and A. huangi are the same species, and according to the principle of priority in zoological nomenclature, A. luzonensis Watanabe, Aoyama, and Tsukamoto, 2009 is the valid species name, and A. huangi Teng, Lin, and Tzeng, 2009 is a junior synonym of A. luzonensis. 相似文献
12.
The effects of exposing the eggs of Pacific threadfin and amberjack eggs (AEs) to different concentrations of hydrogen peroxide for 5 min on hatch rate and survival were assessed in a series of experiments using a petri dish model rearing system. Despite significant inter‐batch variation in hatch rate, it was shown that eggs of both species could be safely exposed to up to 11 340 mg L−1 H2O2 for 5 min. Exposure to 34 230 mg L−1 H2O2 for 5 min was shown to be lethal to AEs at a late stage of development. In two further experiments, it was demonstrated that Pacific threadfin eggs were resistant to all tested concentrations of a range of polyvinylpyrrolidone iodine (PVP‐I) concentrations and contact times (up to 1000 mg L−1 PVP‐I for 10 min). The level of bacteria adhering to the eggs of both species was highly variable. Where eggs were heavily colonized (>104 cfu egg−1), hydrogen peroxide concentrations of at least 11 340 mg L−1, or PVP‐I concentrations higher than 500 mg L−1 for 10 min, were required for effective sterilization. In less colonized batches, rinsing in sterile seawater or exposure to lower (550 mg L−1) concentrations of H2O2 was sufficient to result in high apparent levels of surface sterility (<1 cfu egg−1). 相似文献
13.
Nuhman Usman Bambang Irawan Agoes Soegianto 《Journal of the World Aquaculture Society》2013,44(4):547-556
The purpose of this study was to evaluate the acute toxicity of lead for different life stages of shrimp, Litopenaeus vannamei, and to determine the effect of its sublethal concentrations on osmoregulatory capacity (OC) as well as the possible histological alteration in the gills of juvenile shrimp. The 24‐, 48‐, and 96‐h LC50 values for lead to L. vannamei increased progressively with increasing life stage, from nauplii < zoeae < mysis < postlarvae < juvenile. After 15‐d exposure to 3.25, 6.50, and 9.75 mg Pb/L, the OC values of exposed shrimp were reduced by 39, 73, and 157%, respectively compared to control animals. Compared to controls, the lead concentrations in gill tissues increased significantly by 127,500, 137,500, and 141,000% in shrimps exposed to 3.25, 6.50, and 9.75 mg Pb/L, respectively. After lead exposure, hemocytic congestion in efferent vessels and multiple hyperplasia were observed in gill filaments, resulting in narrowed hemolymphatic lacuna. The histopathological effects increased with increasing Pb concentration. 相似文献
14.
对驼背鲈(Chromileptes altivelis)的胚胎发育及仔、稚、幼鱼的形态特征进行了详细的观察与研究,描述了从受精卵到仔、稚、幼鱼各发育期的时间和形态特征变化。结果表明,在水温25-26℃、盐度30的海水中,受精卵历时27 h 25 min完成整个胚胎发育过程,经历从卵裂、囊胚、原肠、神经胚到肌节形成、各器官的逐渐形成、变化、完善等一系列的胚胎发育和变化过程;根据其卵黄囊消长情况、鳞片的覆盖状态、体色发生的不同变化以及第二背鳍和腹鳍的消长,将胚后发育分为仔、稚、幼鱼3个阶段。在水温22-26℃、盐度29-31、DO≥5 mg/L的条件下,2-3 d仔鱼卵黄囊消失,开口摄食;生长发育至31 d,仔鱼已变态进入稚鱼期;培育至57 d,稚鱼完成变态,成为幼鱼。第二背鳍棘和腹鳍棘的生长与收缩等石斑鱼类早期发育的共性生长特征及其体表特性体色变化特征为驼背鲈胚后发育过程中最明显的特征。 相似文献
15.
Effect of Temperature on Growth,Energy Budget,and Physiological Performance of Green,White, and Purple Color Morphs of Sea Cucumber,Apostichopus japonicus 
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下载免费PDF全文 Yucen Bai Yan Chen Yang Pan Libin Zhang Shilin Liu Xiaoshang Ru Lili Xing Tao Zhang Hongsheng Yang Jing Li 《Journal of the World Aquaculture Society》2018,49(3):625-637
As an intertidal species, Apostichopus japonicus is subject to diel and seasonal temperature fluctuations. Color variation is a distinct characteristic of A. japonicus, and a new color morph, purple A. japonicus, was recently found on the coast of Rushan, Weihai City. This study was conducted to compare the performance of green, white, and purple color morphs of A. japonicus at different water temperatures to help improving aquaculture technology and management. In this study, green, white, and purple color morphs of juvenile A. japonicus (1.5 ± 0.1 g) were cultured at 10, 14, 18, 22, and 26 C for 60 d, according to the suitable temperature range for sea cucumber growth. Temperature was shown to have a significant effect on growth, energy budget, and physiology of sea cucumbers (P < 0.05). Specific growth rates, feed conversion efficiencies, and the proportion of energy allocated to growth of all three color morphs were optimal at 18 C. Activities of the enzymes related with oxidative stress, immune response, and digestion were determined. Superoxide dismutase (SOD) and trypsin activities generally reached a maximum in all three color morphs at 18 C. The purple color morph of A. japonicus was higher in growth rate, food conversion efficiency, and proportion of energy allocated to growth than green and white color morphs at 18 and 22 C, consistent with its higher trypsin and SOD activity, indicating the mutual effect of growth and physiology. At 18, 22, and 26 C, the green color morph had the highest level of lysozyme activity and purple color morph had the lowest, indicating possible infection by external pathogens of green color morph, which might be caused by high temperature. These results suggested that the optimum temperature for culture of the three color morphs was approximately 18 C, the purple had a better adaption to high temperature, and the green and white color morphs may be more susceptible to thermal stress than the purple color morph. 相似文献
16.
Mulloway (Argyrosomus japonicus) occur in estuarine and coastal waters surrounding Australia, Africa, India, Pakistan, China, Korea and Japan, where they are important in fisheries. This study identified that mulloway in south-eastern Australia had similar growth rates, but matured at smaller lengths and younger ages, to those in South Africa and Western Australia. Growth of both sexes was similar to about 5 years, after which females grew faster and attained a greater maximum length than males. Female mulloway matured at 4–5 years of age with a L50 of 68 cm, whereas males matured at 2–3 years of age with a L50 of 51 cm. The commercial fishery in New South Wales was characterised by declining catches and a reduction in the proportion of mulloway of mature lengths in landings. During 2002–2005 commercial landings were dominated (83%) by fish within 15 cm of the current minimum legal total length of 45 cm and aged 2 and 3 years (>80%), even though mulloway can attain lengths of 200 cm and live >30 years. Estimates of the rates of instantaneous total mortality ranged between 0.34 and 0.45, whilst the rate of instantaneous natural mortality (M) was estimated to be approximately 0.12. Yield-per-recruit analyses indicated that mulloway in New South Wales are being growth overfished and substantial increases in yield could be achieved by increasing the length at first harvest. Values of the spawning potential ratio were below 0.2 under a range of mortality estimates, suggesting that mulloway are at risk of recruitment overfishing. These results suggest that the spawning stock of mulloway in south-eastern Australia has been depleted and that remedial management action is required to protect this iconic species. 相似文献
17.
Charles C. Mischke Matt J. Griffin Terrence E. Greenway David Wise 《Journal of the World Aquaculture Society》2013,44(2):288-292
Mosquitofish, Gambusia sp., have been spread throughout the world to biologically control mosquitoes. However, the fish has gained a reputation as an invasive species and has been implicated in displacing native aquatic species. Gambusia affinis are native to the southeastern United States and commonly occur in commercial channel catfish, Ictalurus punctatus, production ponds. We investigated effects of mosquitofish presence on zooplankton populations, water quality, disease occurrence, and fish production in experimental ponds. There were no differences between ponds with or without mosquitofish in numbers of calanoid copepods, cyclopoid copepods, total copepods, Bosmina sp., Ceriodaphnia sp., Moina sp., Daphnia sp., or total cladocerans. There were also no differences in copepod and cladoceran sizes. Copepod nauplii were more numerous during the summer months in ponds with mosquitofish. There were no differences in water quality variables (soluble reactive phosphorus, nitrate, nitrite, ammonia, total nitrogen, total phosphorus, pH) or phytoplankton density between ponds stocked with and without mosquitofish. Catfish production and disease occurrence were also similar between ponds with and without mosquitofish. Although mosquitofish may cause problems when stocked outside their native range, there does not appear to be any adverse effects of mosquitofish presence in catfish production ponds. 相似文献
18.
Recruitment strategy of swimming crab, Portunus trituberculatus, in Hiuchi-Nada, Japan 总被引：2，自引：0，他引：2
The recruitment strategy of swimming crabs, Portunus trituberculatus, was investigated by field observations and numerical experiments in Hiuchi-Nada, Japan. Calculated dispersal patterns of zoeal and megalopal stages in a three-dimensional numerical model reproduce observed patterns accurately. The temporal change of vertical migration patterns between the 1st and 2nd zoeas and the 3rd and 4th zoeas plays an important role in the process of recruitment of P. trituberculatus from spawning ground to nursery ground. 相似文献
19.
This study aimed to find out if dietary carotenoid (CD) supplement could make differences in survival, growth, pigmentation, and antioxidant capacity of characins Hyphessobrycon callistus, an ornamental fish. Two types of CD and its combination (AX — astaxanthin, BC — β-carotene, MX — 1:1 combination of AX and BC) at three concentrations (10, 20, and 40 mg/kg) were used resulting in nine pigmented diets. A diet without CD supplement served as control. No differences in growth and survival of the fish among treatments were found after 8 weeks rearing. Disregarding the types of dietary CD, AX dominated (> 98%) the body CD, indicating that this fish converted most dietary BC into body AX for storage. Body AX and BC content increased with increasing dietary CD concentration. Body AX in BC-fed fish was lower than that in both AX- and MX-fed fish. No difference in body AX was found between AX- and MX-fed fish, and in body BC in all pigmented fish. Serum total antioxidant status [TAS], serum antioxidant enzymes (superoxide dismutase [SOD], glutathione peroxidases [GPx]) and serum transaminases (alanine aminotransferase [ALT], aspartate aminotransferase [AST]) were chosen as indices of fish antioxidant capacity. Antioxidant activities changed with dietary CD type and concentration. Pigmented fish had lower SOD, GPx and ALT than control fish; dietary CD types only affected SOD and ALT in fish. AX-fed fish had the lowest SOD. Dietary AX had more numbers of negative correlations with antioxidant parameters in fish than BC. 相似文献
20.
《Journal Of Applied Aquaculture》2013,25(4):89-93
Abstract Effects of salinity on embryonic development and growth of African catfish, Clarias gariepinus, eggs and larvae were studied. Eggs were incubated at 27-29°C in 2,4,6,8, and 10 ppt sodium chloride. Rate of embryonic development was delayed in all salt solutions by 15, 15,28 and 30 minutes, in 2,4,6, and 8 ppt sodium chloride, respectively, when compared with the control group (0% salt); total mortality occurred at 12 hours after gastrula stage in the 10 ppt concentration. Percentage hatching was 45.1,47.7, 59.5,49.2, and 26.6% while percentage deformity was 10.4, 16.1, 52.0, 28.6, and 71.6% in 0, 2, 4, 6, 8, and 10 ppt salt treatments, respectively. There were significant differences (P <0.05) in the hatching percentage and in deformity percentage between 4, 6, and 8 ppt. Rate of yolk absorption was significantly faster in the control and 2 ppt salt treatments, but slower in 4, 6, and 8 ppt. Rate of increase in length was slower with increasing salinity. The optimum salinity for African catfish eggs and was between 0-2 ppt and acceptable up to 6 ppt. The results suggest that increasing salinity delayed hatching and development of African catfish eggs and larvae, respectively, as well as increased the deformity of the larvae. 相似文献