工厂化水产养殖中的悬浮物处理技术

在循环水工厂化水产养殖中,鱼类的排泄物、残饵、生物团等产生的悬浮物和固体物,增加了水体的浑浊度,堵塞了生物滤器,影响系统的性能和鱼类健康生长。本文根据我国现代渔业发展的趋势,结合国内外有关水产养殖水处理技术的研究成果与发展趋势,论述和分析了目前工厂化水产养殖中悬浮与固体物的物理、化学和生物处理技术及发展趋势,为研发新型水处理设备奠定基础。     

沿海滩涂异育银鲫养殖池塘真核浮游生物群落DNA指纹结构与理化因子的关系

为研究沿海滩涂异育银鲫养殖池塘浮游生物群落周年变化及其与理化因子的关系,2011年每月采集养殖池塘水样,测定相关理化因子。采用18s rDNA PCR-DGGE技术对真核浮游生物群落多样性进行了分析。运用CCA方法分析了真核浮游生物与理化因子的关系。结果表明:TP含量为0.17~1.12 mg/L,7月出现峰值。PO4-P含量为0.04~0.30 mg/L,7月和8月较高。NO2-N含量为0.02~0.57 mg/L,12月最高。NH+4-N含量为0.20~2.37 mg/L,5月出现峰值。NO3-N含量为0.04~10.47 mg/L,11月出现峰值。DGGE结果显示,1—12月共有73条谱带,平均每月谱带数为24.67。5月、6月、8月和9月份多样性指数较高。谱带匹配后聚类分析表明:除3月、7月和11月份外,真核浮游生物变化具有季节性,其中8月、9月和10月聚为一支,4月、5月和6月聚为一支,1月、2月和12月聚为一支。CCA分析表明,温度、TP和NH+4-N与真核浮游生物群落结构组成显著相关,为养殖生态调控和养殖模式优化提供理论依据。     

循环水养殖条件下水温对大菱鲆氨氮排泄、转氨酶及免疫因子的影响

在高密度工业化封闭循环海水养殖条件下（养殖密度为14?2±0?48 kg／m2）,选取大菱鲆（371?68±43?15 g）360尾,随机均分4组,设置4个水温梯度14℃、16℃、18℃和21℃,旨在探寻水温对大菱鲆氨氮排泄、转氨酶及血清免疫因子的影响,试验期为56 d。结果表明：（1）养殖水体总氨氮浓度随水温升高呈先升后降,18℃时总氨氮浓度极显著高于14℃、21℃时;大菱鲆氨氮排泄率随水温升高而升高,且二者呈指数关系。（2）大菱鲆肝脏GPT、GOT活力随水温升高呈先升后降,均在18℃达最大值;而血清两种指标变化趋势与之相反,均在21℃达最大值。（3）血清LZM、SOD活力及皮质醇含量均随水温升高呈先升后降,均在18℃达最大值;血氨含量则逐渐下降,14℃时极显著高于18℃、21℃时;鳃丝Na＋?K＋?ATPase活力随水温升高而升高,但组间差异不显著。综上,封闭循环水养殖大菱鲆的适宜水温为16～18℃。     

Modulation of neuronal activity and hepatic metabolism by ploidy and l‐carnitine supplement in rainbow trout (Oncorhynchus mykiss)

l ‐carnitine, a multiphysiological, bioactive and pollution‐free additive, is known to act as a growth‐enhancer and appears to act as an antioxidant compound. However, high dosages may cause detrimental physiological effects to fish. Considering such, a feeding trial was carried out to evaluate the effects of dietary l ‐carnitine content on neuronal activity (acetylcholinesterasic activity), hepatic metabolism (catalase activity) and liver histological markers in both diploid and triploid trout (Oncorhynchus mykiss) juveniles. Fish were hand‐fed for 56 days on three nutritionally identical diets, varying in l ‐carnitine content; unsupplemented diet (15 mg kg^?1) and supplemented (200 or 530 mg kg^?1) diets. Moderate to severe glycogen/lipid depletion was the major liver histopathological disorder observed in all dietary groups. This cause–effect relationship appeared to be dose and time‐dependent, suggesting an important role of l ‐carnitine in the liver metabolism. Moreover, the hepatocite size and nuclear diameter appeared to be larger in l ‐carnitine supplemented groups than in control group. l ‐carnitine caused significant induction of catalase activity and inhibition of AChE. Diploid and triploid trouts showed marked differences in enzymatic activities, reflected by consistently higher values of AChE activities for triploid animals.     

Dietary effects on egg production,egg‐hatching rate and female life span of the tropical calanoid copepod Acartia bilobata

Copepods are crucial source of live feeds in the aquaculture industry. In particular, several species of the genus Acartia are considered optimal prey for fish larvae. The species Acartia bilobata has excellent potential for marine larvae culture, as it is easy for mass culture. This study investigated the effects of various algal diets on the egg production and egg‐hatching rate of A. bilobata. The results indicated that the single‐species diet Isochrysis galbana was the most supportive diet for A. bilobata egg production and female life span in all treatments (egg production: 23.85 ± 0.70 eggs female^?1 day^?1 and female life span: 18.00 ± 1.45 days). Nannochloropsis oculata and Tetraselmis chui treatments gave markedly lower egg production and female life span as both single‐species and multiple‐species diets. For the egg hatching‐rate experiment, except for the T. chui treatment, which yielded a considerably lower hatching rate than the other diets, the hatching rate was only slightly affected by the algal diets. These results confirm that A. bilobata, a tropical brackish‐water copepod species, develops rapidly at 28°C and can produce a large number of eggs; therefore, it has considerable potential for larvae culture.     

现代生物技术在水产养殖中的应用

综述了生物技术在水产生物优良品种选育、水生生物种质资源保存、水产养殖生物病害防治与快速诊断、新型饲料蛋白源和促生长饲料添加剂的研制与开发等方面所发挥的巨大作用。     

水产养殖自身污染及其防治的探讨

结合水产动物的能量生态学、食物链及营养级等原理分析了目前水产养殖自身污染的现状以及存在的诸多问题。在总结了国内外研究最新动态的基础上,联系我国水产养殖实际,寻求有效的应对措施,并探讨了我国水产养殖自身污染防治的前景及其展望。     

循环流水池塘养殖系统浮游植物群落结构与特征

研究了循环流水池塘养殖系统和静态池塘养殖系统中浮游植物的种类组成、数量和生物量、多样性特征及群落相似性等,结果表明:养殖初期(6月),循环流水系统中池塘(循环塘)和静态养殖系统中池塘(对照塘)浮游植物的种类组成和数量没有明显差异,均以盘星藻、直链藻占优势,种类相似性水平较高,Jaccard指数在71.2%～83.3%之间变化,生物量在35.3～51.4 mg/L之间变动.但在养殖中后期(7～10月),两者差异明显:(1)优势藻类不同,循环塘以小环藻、衣藻、隐藻和裸藻等占优势,而对照塘则以微囊藻、席藻等占优势,种类相似性水平较低,Jaccard指数在40.3%～62.1%之间变化;(2)两者浮游植物数量也存在差异,对照塘波动变化大,循环塘相对较小;(3)循环塘浮游植物的Shannon-Wiener指数、Pielou指数均大于对照塘.聚类分析表明对照塘和循环塘群落相似性水平较低.表明该系统能够改变藻类组成,抑制微囊藻水华暴发,并能调控藻类数量,防止其过度繁殖,保持浮游植物多样性,使池塘生态系统更趋稳定,有利于水产养殖.     

工厂化水产养殖中水体增氧气泡最佳尺寸的计算

应用流体力学、热力学和物理化学的有关定理方程和物理、化学试验数据,通过数值计算的方法建立了增氧气泡在水中的运动、溶解和受力方程;并通过对氧气气泡在水中上升过程中的运动、尺寸、溶解和扩散变化的数值计算和结果分析,优选出在不同条件下可完全溶解的氧气气泡半径范围,获得在水深≤2m、气泡半径为0．1～0．5mm时的氧气气泡尺寸变化、上升距离和溶解速度之间的关系曲线图,分析了氧气气泡在水中的尺寸、质量和运动的变化规律,确定了计算结果的应用方法,为设计不同水深和溶解氧条件下的最佳溶解气泡的尺寸提供依据。