A review of production frontier analysis for aquaculture management

Abstract

This paper examines recent advances in production economics with special reference to efficiency measurement using production frontiers and its implications for aquaculture management. Compared with agriculture and other industries, the use of production frontiers in aquaculture is still very limited. However, in recent years several frontier applications in aquaculture have appeared in the literature, suggesting potential applications of these techniques in aquaculture. A synopsis of stochastic frontier production function model and data envelopment analysis (DEA), the two most popular approaches to efficiency measurement, is presented, followed by a review of recent frontier studies in shrimp, carp and tilapia production. The paper concludes with a brief discussion of future development and prospects of frontier applications for aquaculture management.     

Rainbow trout (Oncorhynchus mykiss,Walbaum ) develop a more robust body shape under organic rearing

Prolonged exposure to captive conditions has led to the development of a rainbow trout ‘farmed’ phenotype, which is different from that of wild trout. Selection for desirable productive traits in hatcheries has resulted in the development of some morphological traits that are maladaptive in nature. The recent development of organic aquaculture, guided by the well‐being of the fish, could potentially produce a new farmed phenotype that would be more adaptive in nature. In this study, rainbow trout reared in intensive and organic farms were compared by means of shape analysis, to detect patterns of shape variation associated with rearing environment. The results of this study highlight a significant effect of the rearing method on rainbow trout shape: organically reared trout showed a higher body profile, in particular in the head and trunk regions, shorter median fins and a deeper caudal peduncle. A combined effect of density and habitat complexity could have contributed to the observed shape differences: in organic rearing systems, lower densities and steady water could increase territoriality and aggressive interactions, promoting body designs more functional in rapid attacks and escapes.     

池蝶蚌组织蛋白酶L1-like基因的克隆及表达特征分析

为了解淡水贝类是否存在组织蛋白酶L的亚型及其亚型的免疫相关作用,本实验利用已构建的池蝶蚌血细胞全长c DNA文库,筛选获得与之同源的EST序列,结合RACE技术进一步克隆了池蝶蚌一个新的组织蛋白酶L基因的c DNA全长,命名为Hs Cts L1-like基因(Gen Bank登录号为KF015273)。该序列全长为1280 bp,5′-非翻译区(5′UTR)为31 bp,3′-非翻译区(3′UTR)为256 bp,开放阅读框区(ORF)为993 bp,编码330个氨基酸,预测蛋白相对分子量为36.86 ku,理论等电点为6.23。序列分析结果显示,Hs Cts L1-like与其他软体动物相对应序列具有共同结构特征,包含信号肽、前肽抑制域和成熟肽三部分,在其他物种中已鉴定的Cts L签名序列标签(ERF/WNIN、GNFD、GCXGG和QCHN等)在Hs Cts L1-like中均可找到。其氨基酸序列同缢蛏Cts L1(AGL33704.1)同源性最高,达67%;与报道的三角帆蚌Cts L(ADV03094)和池蝶蚌中另一个Cts L(AEX88474)仅均为52.91%;系统进化分析表明,Hs Cts L1-like与缢蛏、长牡蛎和合浦珠母贝的Cts L1聚为一分支,推测Hs Cts L1-like属于Cts L家族中的亚型1。实时荧光定量PCR(q RT-PCR)检测显示,Hs Cts L1-like m RNA在肝脏中表达量最高,其次是卵巢和精巢。注射鳗弧菌后,血细胞和肝脏Hs Cts L1-like m RNA转录水平显著升高,暗示其是一个免疫有关的基因,参与了池蝶蚌的先天免疫应答反应。     

线粒体COI基因条形码在鲿科鱼类物种鉴定中的应用

为了探讨线粒体COI基因作为DNA条形码在中国鲿科(Bagridae)鱼类物种鉴定中的有效性,以及系统发育中的适用性,本研究对4属11种鲿科鱼类进行PCR扩增,获得48条线粒体COI基因序列,同时从Gen Bank筛选获得8种鲿科鱼类的12条COI基因序列进行分析。19种鲿科鱼类的COI基因序列特征显示:长度为674 bp的COI序列片段平均碱基组成为24.82%A,30.44%T,27.10%C和17.64%G,碱基组成呈现明显的AT偏倚性(55.26%),具有硬骨鱼类的线粒体COI基因的碱基组成的典型特征。核苷酸位点中有变异位点226个,简约信息位点195个,单一信息位点31个,转换颠换比为3.35。19种鲿科鱼类的种内、种间和属间平均遗传距离分别为0.0041、0.1136和0.1268,种间遗传距离平均为种内遗传距离的27.7倍。在本研究中,鲿科鱼类所有的物种均形成单系,在物种鉴别上与形态学分类结果基本一致,然而鲿科的4个属中只有鱯属形成单系,黄颡鱼属、属和拟鲿属均未形成单系,其进化地位需要进一步研究。线粒体COI基因作为条形码可有效对鲿科鱼类进行物种鉴定,也为鲿科的系统发育提供了参考。     

连环湖他拉红泡水质监测与分析

报道了2007年5～9月连环湖他拉红泡(卡拉白鱼放养场)的水质季节变化动态.结果表明:该水域水质基本处于良好壮况.其透明度22～35cm,pH值为8.00～8.84cm,硬度为1.269～3.359mmolL-1以及碱度为6.856～9.618mmolL-1.水呈碱性,水型属碳酸盐类,镁组Ⅰ型(CImg)和软水.水中COD含量为8.56～11.36 mgL-1.主要营养元素--总氮略低于黑龙江湖泊总氮含量,其总氮为0.490～0.824 mgL-1,磷酸盐量适中,总磷含量为0.369～0.498 mgL-1,属于中富-富营养型湖泊.湖水中多数理化组分在季节分布上差异不明显,个别测定值在5月(枯水期)较高,9月(平水期)出现回落.本文对湖泡的水质理化特征及营养状况进行了讨论和评价,为盐碱水域的渔业资源开发和利用提供了科学依据.     

尼罗罗非鱼Foxp1a/b的cDNA克隆及表达模式研究

为探讨低等脊椎动物Foxp1与免疫细胞活化及机体雌激素水平的相关性,本研究首次分离克隆了尼罗罗非鱼 (Oreochromis niloticus) Foxp1的开放阅读框序列,并通过real-time PCR对其mRNA表达水平进行检测。结果显示,尼罗罗非鱼具有两种不同基因编码的Foxp1分子,分别命名为OnFoxp1a与OnFoxp1b;OnFoxp1a为1710 bp,由15个外显子编码569个氨基酸,OnFoxp1b为2040 bp,由16个外显子编码679个氨基酸;OnFoxp1a/b均含有Foxp亚家族的特征性结构,即锌指结构、亮氨酸拉链样结构和叉状螺旋结构;与OnFoxp1a相比,OnFoxp1b与高等脊椎动物Foxp1具有更近的亲缘关系。Real-time PCR检测结果显示,OnFoxp1a/b几乎在所有组织中均有表达,OnFoxp1a在精巢中有高水平表达, OnFoxp1b在心脏中有高水平表达,同时OnFoxp1b在免疫相关组织如鳃、脾脏、肾脏、肠等均有中等水平表达;淋巴细胞多克隆刺激剂PHA、PMA、LPS刺激尼罗罗非鱼外周血单个核细胞（PBMC）,结果显示,50 μg/mL PHA和50 ng/mL PMA分别刺激6、12、24 h均显著增强OnFoxp1b的表达 (p＜0.05),20 μg/mL LPS刺激后,OnFoxp1b的表达出现先降低后升高的趋势 (p＜0.05);而OnFoxp1a的表达除50 μg/mL PHA 刺激24 h后有所升高,其余均无显著变化;雌激素处理6月龄雄性尼罗罗非鱼48 h,OnFoxp1a/b在肠、肾脏中的表达显著上调 (p＜0.05),而脾脏中无显著变化 (p>0.05)。综上所述,低等脊椎动物硬骨鱼类两种不同基因编码的Foxp1a/b均为哺乳动物Foxp1的同源分子,但其序列、结构特征、表达模式迥异,提示其功能发生歧化;同时两者的表达与淋巴细胞活化及机体雌激素水平密切相关。     

共轭亚油酸的性质及其生理功能

共轭亚油酸(CLA)是亚油酸同分异构体的混合物,是主要来源于反刍动物食品的天然营养成分。它具有抗癌、抗氧化、降低血清胆固醇、减少脂肪沉积、促进生长以及调节免疫等作用,是一种新型保健功能脂质,因此在药物和食品等研究领域中有很广阔的应用前景。在查阅大量文献的基础上,综述了CLA的来源、合成以及各种生理功能,以期为其应用及开发研究提供较为详细的信息资料。     

Automated image analysis as a tool to quantify the colour and composition of rainbow trout (Oncorhynchus mykiss W.) cutlets

The goal of this paper is to propose and evaluate automated image analysis methods for describing muscle cutlets in rainbow trout. The proposed automated image analysis methods were tested on a total of 983 scanned images of trout cutlets, and included quality traits such as fat percentage, flesh colour and the size of morphologically distinguishable subparts of the cutlet. A sub-sample of 50 images was randomly selected for manual segmentation of the cutlet, the dorsal fat depot and the red muscle and regions. The identification of these regions by manual and automatic image analysis correlated strongly (r = 0.97, r = 0.95 and r = 0.91, respectively). The estimated fat percentage obtained from image analysis, based on the area of visible fat and the colour of the cutlet flesh, correlated well with chemical fat percentage measured by mid-infrared transmission spectroscopy (MIT) (r = 0.78). The automated image analysis methods are therefore a reliable means of predicting the fat percentage of trout cutlets. Principal component analysis (PCA) loading plots were used to identify subsets of variables from the image analysis of special significance for further studies; cutlet area, dorsal fat depot area, red muscle area, back height, cutlet width, and width of left and right abdomen wall were among the variables selected. PCA loading plots of different colour variables indicated that simple statistical coefficients such as percentiles and mean values can be used to quantify different aspects of flesh colour. In conclusion, the methods presented here provide a powerful toolbox for describing important morphological structures and quality traits of trout cutlets.     

三沙湾海域化学需氧量（COD）分布特征及相关性分析

2012年5月和11月对三沙湾海域水质化学需氧量( COD)进行大面积调查研究,结果表明,2012年三沙湾海域COD含量变化范围为0．52~2．13 mg/L,平均含量为0．94 mg/L;水平分布特征呈西北侧向东南水域逐渐递减的趋势,白马港海域COD含量最高;秋季高于春季;平均COD含量能达到一类海水水质标准要求;化学需氧量与活性硅酸盐、无机氮、总氮及悬浮物呈极显著正相关;与pH值、盐度呈极显著负相关。     

厚壳贻贝5-羟色胺2A受体(5-HT2AR)基因克隆和时空表达

为探究5-羟色胺2A受体（5-HT 2A receptor, 5-HT2AR）基因在海水贝类生长发育中的作用,本研究通过RACE技术和实时荧光定量PCR（qRT-PCR）克隆了厚壳贻贝5-HT2AR 基因的cDNA全长,并分析该基因的时空表达。结果显示,5-HT2AR基因全长2 636 bp,开放阅读框（ORF）2 124 bp,共编码707个氨基酸。序列分析结果显示该序列与人、小鼠、斑马鱼、长牡蛎和虾夷扇贝等物种分别具有45%、45%、48%、49%和67%的同源性。厚壳贻贝雌雄成体各组织和器官中均有5-HT2AR基因表达,雄性中的鳃表达量最高,而在雌性鳃、外套膜和性腺中的表达稍高于其他组织和器官;推测该基因可能与厚壳贻贝的摄食、对外界环境的感知及促进卵母细胞成熟有关。5-HT2AR基因在厚壳贻贝各发育阶段均有表达,且稚贝的表达量为眼点幼虫的1.4倍,推测5-HT2AR基因可能参与了调控厚壳贻贝幼虫的生长发育过程。本研究为进一步了解5-HT基因家族在双壳贝类中的功能奠定了基础。