不同盐度下凡纳滨对虾生长和存活性状遗传评估

为揭示不同盐度环境对凡纳滨对虾家系体质量和存活性状的影响,本研究标记来自72个家系的4348尾对虾,在盐度30(HS组)和盐度15(LS组)条件下混养60 d,分析体质量和存活性状的遗传参数以及基因型与环境互作效应。结果显示,HS组的凡纳滨对虾平均体质量和存活率均高于LS组。估算体质量、存活性状遗传参数,结果显示HS和LS组体质量的遗传力估计值分别为0.51±0.08和0.30±0.07,属高遗传力;转换后存活性状遗传力估计值分别为0.22和0.39,也表现为中高遗传力水平。综合HS和LS组的数据,估算的体质量和转换后存活性状遗传力分别为0.45±0.07和0.31,均表现为高遗传力水平。然而由于收敛原因,在估计模型中未能包括共同环境效应,上述遗传参数估计值偏高。估算基因型与环境互作效应(G×E),结果显示两个盐度间体质量和存活性状均表现为高度遗传相关(0.81~0.90),G×E方差组分与加性遗传方差组分比值均小于0.5,G×E效应均不显著。研究表明,尽管凡纳滨对虾的生长和存活性状在两个盐度下存在一定差异,然而基因型与盐度的互作效应并不显著,由此认为在盐度15~30的范围内,不需要针对不同的盐度建立不同的选育系。     

限制投喂环境下中国对虾体重的间接遗传效应分析

为研究竞争性环境下中国对虾(Fenneropenaeus chinensis)体重性状的间接遗传效应,设计多家系多分组方案,对来源于中国对虾G11代育种群体的103个测试家系限制配合饲料投喂量(正常投喂量50%),利用经典动物模型和包含间接遗传效应的扩展动物模型估算收获体重的遗传参数。基于2种模型估计出的经典遗传力分别为0.581±0.071和0.616±0.074。似然比率检验表明,体重的间接遗传效应显著,对总遗传方差的贡献度高达75.03%。由于存在一个较大的负直接遗传效应与间接遗传效应协方差(-2.1982),导致总遗传方差与表型方差的比值仅为0.524±0.212,小于经典的遗传力估计值。基于协方差获得的直接遗传效应与间接遗传效应的遗传相关系数为-0.495±0.184,暗示测试个体间存在较强的竞争交互。本研究表明,在饲料投喂量受限制的竞争性环境下,对虾个体间较强的竞争交互行为,对中国对虾收获体重间接产生了可遗传的效应,减少了可利用的总遗传变异。今后在设计中国对虾育种方案时,应避免在资源受限的强竞争环境下开展性状测试和遗传评估。     

长牡蛎壳橙快速生长品系基因与环境(G×E)互作效应分析

为了分析长牡蛎(Crassostrea gigas)壳橙快速生长品系生长存活性状的基因型与环境(G×E)互作效应, 本研究构建 28 个全同胞家系并将每个家系均分成 3 组, 分别在乳山、荣成和黄岛海域进行养殖。利用双性状动物模型和 REML 法估计 12 月龄橙快长牡蛎生长和存活性状的遗传力及 G×E 效应, 采用 BLUP 育种值估计法将壳高、体重和存活性状 3 个指标的育种值综合加权, 以期筛选出普适性育种材料。结果显示, 乳山和黄岛海区的表型显著优于荣成海区, 更适合作为养殖海区。乳山、荣成和黄岛 3 个海区生长存活性状的遗传力分别为 0.09~0.75、0.02~0.94 和 0.03~0.75, 存在尺度效应, 但除了存活性状的遗传力外, 都属于中高遗传力, 具有良好的遗传潜力, 通过育种值估计法选育效果更佳; 存活性状则主要受环境因素影响, 可通过表型直接选育。以不同海区为固定效应, 综合 3 个环境计算出的生长和存活性状的遗传力为 0.02~0.44, 综合遗传力下降说明环境差异影响遗传力评估。此外, 选育的目标性状在两两海区间的遗传相关均小于 0.8, 存在显著的 G×E 效应, 在选育过程中应综合考虑环境因素。通过比较综合育种值发现存在明显的基因重排效应, 家系 G25 对乳山海区表现出特殊的适应性, 家系 G16 对荣成海区具有特适性, 而家系 G23 对乳山和黄岛表现出适应性, 且筛选出了对 3 个海区具有普适性的家系 G2。研究结果为橙快长牡蛎品系的良种选育提供了重要的参考资料。     

日本囊对虾耐高氨氮与生长性状的遗传参数估计

研究估计了日本囊对虾基础群体的体长、腹长、体质量与耐高氨氮性状的遗传参数,为制定综合选择指数、选择方法与育种目标提供技术参考。试验引进日本囊对虾台湾群体亲本,以1尾亲虾构建1个家系,共建立63个全同胞家系,每个家系单独培育,密度调整后开展共同环境养殖测试。各家系养殖150d后,统计每个家系生长性状,并分别从家系中随机选取30尾个体,在氨氮质量浓度为68.5mg/L下进行耐高氨氮试验,48h后统计各个家系的存活率。利用一般线性动物混合模型与广义线性模型分析方法分别估计生长和耐高氨氮性状的方差组分和遗传参数。试验结果表明,日本囊对虾幼虾体长(估计值0.79±0.13)、腹长(0.74±0.24)与体质量(0.31±0.25)遗传力为中高等遗传力水平性状;耐高氨氮性状为低遗传力水平性状,估计值为0.13±0.06,48h后家系耐高氨氮性状平均值为(8.84±12.65)%,耐高氨氮性状的变异水平为143.10%。体长、腹长、体质量与耐高氨氮性状的表型相关与遗传相关系数分别为-0.082~0.08和-0.067~0.17,检验结果不显著。研究结果表明,采用复合育种技术对日本囊对虾生长性状与耐高氨氮性状同时进行改良,可以起到加快育种进程的作用。     

斑节对虾耐氨氮和淡水应激性状的遗传参数估计

该研究以高氨氮和淡水胁迫致死时间为衡量指标,估计了斑节对虾(Penaeus monodon)耐氨氮和淡水应激性状的遗传参数。以斑节对虾"南海1号"和非洲品系为亲本,建立了27个全同胞家系,含5个半同胞家系。利用单性状动物模型和ASReml软件估计斑节对虾幼体阶段的耐氨氮和淡水应激性状的方差组分和遗传参数。通过最佳线性无偏预测法估计所有个体和家系耐氨氮和淡水应激性状的育种值。斑节对虾耐氨氮和耐低盐的遗传力分别为0.11±0.04和0.29±0.08,且统计检验达到显著水平。斑节对虾耐氨氮和淡水应激性状的家系表型值相关系数为0.15,表现为低度线性正相关。斑节对虾耐氨氮和淡水应激性状的家系育种值相关系数为0.57,表现为中度线性正相关。因此在进行斑节对虾耐氨氮性状选育时,耐淡水应激性状也能得到一定的改良。     

罗氏沼虾开放和闭锁核心育种群生长和存活性能分析

开放核心育种体系可增加核心群体的选择强度,进而增加育种目标性状的遗传进展。本研究以罗氏沼虾(Macrobrachium rosenbergii)为研究对象,向闭锁核心群(closed nucleus population,NP)内引入扩繁群(multiplier population, MP)个体,构建两个杂交群体(正交群体NP/MP,反交群体MP/NP),并以闭锁核心群(NP/NP)为对照,应用线性混合效应模型(linear mixed effects model, LME)和广义线性混合模型(generalized linear mixed model, GLMM)对不同群体收获体重和存活率的估计边际均值进行比较,评估在虾类选择育种中构建开放核心育种体系的可行性。结果显示:(1) NP/NP、MP/NP和NP/MP群体的收获体重估计边际均值分别为45.83 g、49.57 g和46.62 g;与NP/NP群体相比, MP/NP和NP/MP群体分别提高了8.16%和1.72%。(2) NP/NP、MP/NP和NP/MP群体的存活率估计边际均值分别为72.92%、68.04%和66.55%;与NP/NP群体相比,MP/NP和NP/MP群体分别降低了6.69%和8.74%。综上所述,在罗氏沼虾核心群中引入扩繁群个体,构建开放核心育种群体,可以有效地增加收获体重的遗传进展;同时在制定选择指数时,应加大存活性状的权重,选择生长和存活性能均优良的家系生产扩繁群体,导入闭锁核心育种群,构建生长和存活性能均优良的开放核心育种群。     

适合中国对虾群体遗传多样性和系统进化分析的DNA分子标记技术

中国对虾（Fenneropenaeus chinensis）是我国海水养殖业中最具代表性的一项产业,优良种质和抗病力已成为对虾养殖业中迫切需要解决的问题。在遗传育种中若能筛选到与抗病、生长等数量性状紧密连锁的遗传标记,将为开展标记辅助育种工作和实现良种化奠定基础。对虾种质资源以及种群遗传学已成为研究热点,种群保护也已提到议事日程。这些研究工作的开展将为对虾良种选育提供理论依据,相信随着研究工作的继续深入,人们会更好、更有效地利用对虾资源。本文对目前已经在对虾遗传多样性和系统进化研究中进行应用的DNA标记技术方法进行分析总结,拟对今后其他物种开展相关工作提供借鉴。     

零换水工厂化养殖模式下凡纳滨对虾生长和存活性状遗传参数估计

针对凡纳滨对虾生长和存活性状,本实验估算了零换水养殖模式下的遗传参数,分析该模式与大换水量养殖模式的基因型与环境互作效应(genotype by environment interaction effect,G×E),为后续留种、配种方案制定等育种规划工作提供依据。通过人工授精技术,定向交尾建立了51个凡纳滨对虾全同胞家系。利用荧光标记识别家系,采用零换水养殖模式混养52 d后,测量并记录2个养殖池中的3822尾存活虾的体质量、体长及性别等信息。采用线性(广义线性)混合效应模型和REML算法,基于个体动物模型和父母本阈值模型估计生长和存活性状的方差组分和遗传力。结果显示,收获体质量和存活率具有较大变异系数。收获体质量和体长的遗传力分别为0.49±0.08和0.43±0.07,均属于中高遗传力(h2≥0.15);存活的遗传力为0.11±0.03,属于低遗传力(h20.15)。收获体质量与收获体长的遗传相关系数为0.98±0.01;收获体质量和体长与存活的遗传相关系数分别为0.31±0.15和0.34±0.15。对于体质量和存活性状,零换水和大换水量养殖模式间的遗传相关系数分别为0.62±0.11和0.65±0.11,G×E效应显著(K0.5)。综上所述,凡纳滨对虾在零换水养殖模式下存在较高的遗传变异,但是与大换水量常规养殖模式相比,家系间存在较大的重排序效应,因此针对该养殖模式应单独建立选育系进行新品种培育。     

应用重复力模型估计虹鳟生长性状的遗传力和育种值

采用单性状重复观测值动物模型（重复力模型）对中国水产科学研究院黑龙江水产研究所渤海冷水性鱼类试验站5个品系后代的4026尾虹鳟 (Onchorynchus mykiss) 的生长性状（体重、体长和肥满度）进行了遗传参数和育种值的估计,并对各个性状的表型和遗传趋势进行预测。在此模型中考虑了年份-季节固定效应、父本固定效应和母本固定效应;随机效应有个体的加性效应和个体永久环境效应。结果表明：该5个品系虹鳟及后代体重的遗传力为0.35,体长为0.10、肥满度为0.34。个体间的育种值差异较大,仅排名前20位相差近10倍;从不同评定方法的秩相关来看,用综合育种值法与单个性状方法之间存在极显著的相关,其相关度分别为0.998, 0.877, 0.85. -0.071, -0.064和-0.13。用综合育种值对虹鳟个体的选择价值的评定和名次排列, 以及与单个性状的评定名次有着一定程度上的差别。体重、体长和肥满度性状,其表型趋势与遗传趋势基本一致的品系,均可通过表型值进行选择。     

中国对虾“黄海2号”新品种的培育

选取中国对虾“黄海1号”、“即抗98”2个养殖群体,朝鲜半岛南海群体、乳山湾群体、青岛沿岸群体及海州湾群体等4个自然群体,采用不平衡巢式交配方案设计,于2005年建立了中国对虾育种的基础群体。设计并建立了中国对虾的多性状复合育种技术,选育的目标性状为生长速度、白斑综合症病毒感染后的存活时间及养殖存活率。为最大限度消除环境差异对遗传方差的影响,在中国对虾家系构建过程中采用标准化程序培育苗种,经过对体长为3cm左右的幼虾进行荧光标记,每个家系标记后混合养殖测试。随机从每个家系中抽取同等数目的标记对虾分成2组,一组共同养殖在养殖池中,测试生长速度和养殖存活率,另一组在封闭的水泥池中进行WSSV感染实验,测试病毒感染后的存活时间长短。中国对虾遗传参数的估计结果表明,养殖170天收获体重的遗传力为0.22,抗WSSV存活时间的遗传力为0.14,存活率的遗传力为0.03。采用BLUP法估算个体育种值,通过百分比加权的形式,分别赋予生长速度、抗WSSV存活时间和存活率的加权值为：80%、15%和5%,并对性状育种值进行标准化,获得综合选择指数;按照每个家系及个体的综合选择指数大小进行家系间及家系内留种,并根据系谱信息,设计交配方案,将每代的近交系数控制在1%以内。选育4代后的统计结果表明,平均每代的遗传进展为：生长速度,13.56%;抗病力,6.76%;存活率,5.05%。三个性状中,收获体重的遗传力最高、加权最大,每代获得的遗传进展稳定在12%以上;抗WSSV存活时间与存活率遗传力较低,每代获得的遗传进展相对小且不稳定。实验培育的新品种“黄海2号”于2009年通过全国水产原良种委员会审定,可在适合中国对虾的养殖区进行推广养殖。为更快地培育抗病新品种,解决对虾养殖病害问题,进一步的研究需查明对虾抗病的遗传机制,提高抗病性状的选择强度,快速培育对虾抗病新品种。     

Heritability and genetic correlations for infectious hypodermal and hematopoietic necrosis virus load,body weight at harvest,and survival rate in Pacific white shrimp (Litopenaeus vannamei)

Heritability and genetic correlations for body weight at harvest size (BW), grow-out survival (SU), and log-transformed infectious hypodermal and hematopoietic necrosis virus (IHHNV) load (VL_ln) in Litopenaeus vannamei were estimated. Data were obtained in 2012 from a shrimp breeding population in Mexico using 12,440 shrimp for BW and 16,814 shrimp for SU, and quantitative polymerase chain reaction determinations from 160 full-sib families were obtained for VL_ln. DNA was extracted from pooled muscle samples of six shrimp per family for a total of 960 individuals. Heritability estimates for BW, SU, and VL_ln at the family mean and at individual levels were 0.24 ± 0.08, 0.02 ± 0.01, 0.42 ± 0.45, and 0.08 ± 0.11, respectively. Genetic correlation estimates of BW with SU, BW with VL_ln, and VL_ln with SU were 0.40, −0.04, and −0.57, respectively. Our results suggest that VL_ln has genetic variation and a favorable genetic association with BW and SU. No serious drawbacks were found from selection responses estimated using single-trait and multitrait indices to increase BW and SU and decrease VL_ln. Favorable correlated responses for IHHNV tolerance estimated as BW/VL_ln and SU/VL_ln were also found. This study offers new insights into the possibility of using IHHNV viral load as a possible selection criterion in L. vannamei breeding programs.     

Feed intake, growth and feed utilization of offspring from wild and selected Atlantic salmon (Salmo salar)

The aim was to assess whether selection for increased growth rate in Atlantic salmon (Salmo salar) is associated with increased feed intake and/or better feed utilization. Growth responses of offspring from selected and wild lines of Atlantic salmon (initial weight 814±14 g and 533±12 g, respectively) were tested in a 14-week experiment. Selected and wild salmon increased body weight by 79 and 39%, respectively, during the experiment. Relative feed intake (DFI), thermal growth coefficient (TGC) and feed efficiency ratio (FER) were significantly higher in the selected (DFI: 0.67% BW d⁻¹, TGC: 2.96×10⁻³ and FER: 1.16), than in the wild, line (DFI: 0.48% BW d⁻¹, TGC: 1.39×10⁻³ and FER: 0.93). FER was positively correlated with mean growth rate (r=0.90, n=6, P<0.05), and differences between the lines indicated a 4.6% increase in FER per generation of selection. Fish of the selected line had a significantly lower intake of protein and energy per kilogram gain, so the higher growth rate of the selected line was the result of both greater feed consumption and more efficient feed utilization for growth. This implies that selection for increased growth rate in Atlantic salmon may improve both of these traits.     

Testing options for the commercialization of abalone selective breeding using bioeconomic simulation modelling

The genetic response and economic benefit from alternative breeding programme designs for blacklip and greenlip abalone (Haliotis rubra and Haliotis laevigata, respectively) were evaluated using a computer simulation model. Two selection criteria were investigated, one used family breeding values for liability to disease challenge test infection and the other used a direct selection of the best performing individuals across families for growth rate. Five scales of breeding programme were tested and the model predicted that if growth rate is the only selection criterion, breeding programmes of a scale using 150 families of each species each generation would result in 12–13% genetic improvement in initial generations and have the greatest beneficial economic impact on the Australian abalone industry of the options tested. The model predicts an average discounted benefit–cost ratio of 48:1, total added discounted benefit of AU$4.90 for each kilogram of abalone produced and nominal economic effect on operating income of over AU$16 million per year after 10 years. If disease resistance is the only selective breeding criterion, 100 families of each species would result in the highest benefit–cost ratio of the options tested, although some genetic gain would need to be sacrificed to reduce inbreeding to acceptable levels in this scenario. A strategy for a stand‐alone abalone selective breeding cooperative was also modelled. For a farm of current tank area yielding 100 t year^?1, participation is expected to yield over AUThe genetic response and economic benefit from alternative breeding programme designs for blacklip and greenlip abalone (Haliotis rubra and Haliotis laevigata, respectively) were evaluated using a computer simulation model. Two selection criteria were investigated, one used family breeding values for liability to disease challenge test infection and the other used a direct selection of the best performing individuals across families for growth rate. Five scales of breeding programme were tested and the model predicted that if growth rate is the only selection criterion, breeding programmes of a scale using 150 families of each species each generation would result in 12–13% genetic improvement in initial generations and have the greatest beneficial economic impact on the Australian abalone industry of the options tested. The model predicts an average discounted benefit–cost ratio of 48:1, total added discounted benefit of AU$4.90 for each kilogram of abalone produced and nominal economic effect on operating income of over AU$16 million per year after 10 years. If disease resistance is the only selective breeding criterion, 100 families of each species would result in the highest benefit–cost ratio of the options tested, although some genetic gain would need to be sacrificed to reduce inbreeding to acceptable levels in this scenario. A strategy for a stand‐alone abalone selective breeding cooperative was also modelled. For a farm of current tank area yielding 100 t year^?1, participation is expected to yield over AU$0.7 million in discounted total added production value and annual discounted returns of over AU$0.4 million per annum by year 10.     

日本囊对虾早期生长性状遗传参数估计

基于68个日本囊对虾(Marsupenaeus japonicus)全同胞家系,采用混合线性模型和约束极大似然法对日本囊对虾生长性状进行遗传参数的估计。结果表明:1)45日龄、75日龄体长性状的遗传力估计值分别为0.1545±0.0505、0.1933±0.0475,腹节长性状的遗传力估计值分别为0.1672±0.0473、0.1937±0.0468,体重性状的遗传力估计值分别为0.1934±0.0439、0.1992±0.037,均为中等遗传力;2)不同日龄下日本囊对虾生长性状间的表型相关与遗传相关均为高度正相关,45日龄体长–腹节长、体长–体重、腹节长–体重的表型相关为0.7121±0.0188、0.5147±0.0277、0.5052±0.0280,遗传相关为0.9896±0.00340、0.9304±0.0321、0.9429±0.0301,75日龄体长–腹节长、体长–体重、腹节长–体重的表型相关为0.6710±0.0236、0.6555±0.0181、0.6534±0.0160,遗传相关为0.7637±0.0161,0.7479±0.0148,0.7177±0.0131。本研究表明对日本囊对虾生长性状进行选择是有效的,以体长、腹节长、体重任一性状作为指标进行选育均可达到生长改良的目的,本研究结果可为日本囊对虾的早期选择育种和多性状选择提供数据参考。     

草鱼生长性状的遗传参数和育种值估计

利用草鱼(Ctenopharyngodon idellus)生长性状选育核心群亲本,采用人工授精方式构建21个全同胞家系,并选用动物模型对16月龄草鱼生长性状进行遗传参数和育种值估计。结果显示,草鱼选育种群的生长性状存在丰富变异。采用约束极大似然法估计方差组分,发现草鱼体重、体长和体高性状的遗传力分别为0.39,0.47,0.21,属于中高遗传力;肥满度性状遗传力为0.11,属于低遗传力;4个性状的共同环境效应值相近且较小,范围为0.07~0.17。采用两性状动物模型分析相关性,发现体重、体长和体高性状间表型和遗传相关系数均达到高度正相关(r=0.88~0.97),而肥满度性状与三者间相关系数接近零,只与体高性状存在一定遗传正相关(r=0.43)。结合各性状遗传变异系数和相对遗传进度,分析表明,以体重为目标性状可便捷有效地改良草鱼生长性能。采用最佳线性无偏估计法预测个体育种值,发现4个性状育种值与表型值的相关系数范围为0.77~0.93。基于单性状育种值和表型值分别进行个体选择,按10%留种率,各性状选留个体相同率为68.75%~81.82%,秩相关系数范围为0.19~0.81,两种选择方式显示出较大差异,且差异大小与性状遗传力成反比例。本研究为草鱼生长性状选择育种提供了理论依据和技术支撑。     

Feed preference and growth response of juvenile Litopenaeus vannamei to supplementation of marine chemoattractants in a fishmeal‐challenged diet

This study compared the feed preference and growth response of Litopenaeus vannamei to chemoattractants. A diet with 3% fishmeal was supplemented with either 3% salmon meal (POS), 3% soy protein concentrate (NEG), 3% krill meal (KRM), 3% squid meal (SQM), 3% shrimp head meal (SHM), 3% shrimp meal (SM), 3% squid liver meal (SLM), or 5% liquid sardine hydrolysate (SAH). Shrimp with a body weight (BW) of 0.99 ± 0.08 g were stocked at 100 animals/m² in 56 tanks of 1 m³ and fed 10 times daily for 74 days. Feed preference was evaluated by feeding shrimp of 10.87 ± 1.82 g in excess twice a day for 10 days in two separate feeding trays allocated in 50 tanks of 0.5 m³. Survival reached 93.3 ± 5.80% and was unaffected by supplementation. Final BW was the highest for shrimp fed the KRM‐supplemented diet (11.97 ± 0.93 g), followed by POS (11.11 ± 0.77 g) and SQM (11.01 ± 1.17 g). Diets SHM, SM, SLM, and NEG showed a lower shrimp BW than POS, but were not statistically different among them. Shrimp fed the SAH diet achieved the lowest BW (10.06 ± 1.02 g). The highest gained yield was obtained with diets KRM and POS. No statistical difference was observed in shrimp yield among other diets. The lowest feed conversion ratio (FCR) was achieved with shrimp fed KRM (1.31 ± 0.05) when compared to diets SHM (1.47 ± 0.05), SAH (1.47 ± 0.07), and SLM (1.45 ± 0.17). Two‐by‐two comparisons indicated that shrimp preferred SHM and KRM, except when these were compared to SQM and SLM. No difference in feed preference was found between diets with SQM and SLM. SAH was the least preferred raw material in all comparisons. Results indicated that KRM acts as a powerful feeding effector and growth enhancer in fishmeal‐challenged diets for whiteleg shrimp. A dietary supplementation with 3% KRM is more effective than the same dose of any other chemoattractant evaluated.     

家蝇蛆粉替代鱼粉对凡纳滨对虾生长、抗氧化和免疫指标的影响

设计6种等氮等能的试验饲料,以评价不同比例的家蝇蛆粉替代鱼粉对凡纳滨对虾幼虾生长性能、抗氧化以及非特异性免疫指标的影响。选用960尾体质量为(0.56±0.03)g的凡纳滨对虾随机分为6组,分别投喂用家蝇蛆粉替代鱼粉的6种饲料,替代比例(等蛋白替代)分别为0、20%、40%、60%、80%和100%,记为G0、G20、G40、G60、G80和G100。45 d的养殖试验结果显示,G20~G60组凡纳滨对虾的增重率(WGR)与对照组相比差异不显著(P>0.05),G80、G100组WGR显著降低(P<0.05)。除G40组外,各替代组凡纳滨对虾的特定生长率(SGR)均显著低于对照组(P<0.05)。G100组摄食量(FI)显著低于其它各组(P<0.05)。当替代水平不超过60%时,家蝇蛆粉对凡纳滨对虾的饲料系数(FCR)、蛋白质效率(PER)、蛋白质沉积率(PPV)和肝胰指数(HSI)影响不显著(P>0.05);随替代水平的继续增加,FCR和HSI显著升高,PER和PPV显著降低(P<0.05)。替代组对虾肥满度(CF)和存活率(SR)均不同程度的高于对照组,但差异不显著(P>0.05)。随家蝇蛆粉替代水平的增加,全虾粗蛋白、钙(Ca)和总磷(P)含量显著升高(P<0.05),粗脂肪含量显著降低(P<0.05),干物质和灰分含量差异不显著(P>0.05)。各替代组对虾血清和肝胰腺超氧化物歧化酶(SOD)活性、血清丙二醛(MDA)含量与对照组相比差异不显著(P>0.05),G80和G100组肝胰腺MDA含量显著高于对照组(P<0.05)。血清酚氧化酶(PO)活性随家蝇蛆粉替代量的增加而显著降低,其中G20组显著高于其它各组(P<0.05)。肝胰腺碱性磷酸酶(AKP)活性随添加量的增加而显著降低(P<0.05)。家蝇蛆粉替代鱼粉对凡纳滨对虾的血细胞总数(THC)、血清一氧化氮(NO)含量、AKP活性和肝胰腺PO活性、NO含量影响不显著(P>0.05)。     

The efficacy of ingredients included in shrimp feeds to stimulate intake

The inclusion in feed formulations of ingredients that act as attractants and feeding incitants or stimulants has been proposed as a means of increasing feed consumption, and hence growth, of farmed shrimp. Squid, crustacean and krill meals, fish and krill hydrolysates and a betaine product (Finnstim) were examined to assess their relative effectiveness in increasing the feed intake of black tiger shrimp Penaeus monodon. These presumed feeding effectors were added to a base feed at between 5 and 50 g kg^?1. Given a choice between the base feed and one containing one of the test ingredients, P. monodon showed a significantly greater preference for the feeds containing crustacean or krill meal. Four of the presumed feeding effectors were further evaluated in a growth response experiment. There was no significant difference in the amount the shrimp consumed of any of the feeds. However, the growth rate of the shrimp was about 20% faster on the feeds containing crustacean meal or krill meal. Although ingredients such as crustacean meal or krill meal can improve feed intake, in practical feed formulations that contain significant amounts of terrestrial protein but relatively low levels of marine ingredients, there does not appear to be need for additional feeding effectors. However, crustacean meal and krill meal do provide a significant nutritional benefit, as seen by the improved growth rates in this study.     

On‐farm evaluation of formulated feeds on the breeding performance of Catla catla reared in rural ponds

Female Catla catla brood fish were reared in 12 ponds (0.03–0.05 ha) and fed daily once in the morning at 30 g kg^?1 body weight for 150 days with formulated feeds (six treatment feeds each with two replicates of pond) to study the breeding performances. The feed ingredients were rice polish (RP) and groundnut oil cake (GNOC) (1 : 1) for T1 (control); RP, GNOC and fish meal (FM) (3 : 4 : 3) for T2; RP, GNOC, FM and soybean meal (SM) (3 : 4 : 2 : 1) for T3; RP, GNOC, FM and SM (3 : 4 : 1: 2) for T4; RP, GNOC, FM and SM (3 : 4 : 1 : 2) with added vitamin–mineral (VM) premix for T5; RP, GNOC, FM and SM (3 : 4 : 1 : 2) with added VM and vegetable oil for T6. Results indicated that except the feed T6, all other feed (T2–T5) with 338–344 g crude protein (CP) kg^?1 feed enhanced the breeding performances of the fish compared with control (262 g CP kg^?1). The feed T3 showed the best performances in terms of matured female (%), fully bred female (%), relative fecundity, spawn production and profit. This suggests that a combination of RP, GNOC, FM and SM at definite proportion could supply the essential nutrients needed for higher breeding response.     

Modeling of available size selectivity of the SURF-BRD for shrimp beam trawl

The System of Unwants Ramp-way Filtered-Bycatch Reduction Device (SURF-BRD) was developed to reduce shrimp bycatch in a shrimp beam trawl. It consists of a pair of rectangular net panels, namely, the front panel (FP) and rear panel (RP), and two fish escape vents. In this study, numerical models for expressing available selection by the SURF-BRD were proposed and assessed in several fishing experiments conducted using two types of the BRD: a prototype and an improved type with the BRD attached at a higher point on the side-nets . Contact probability and selectivity parameters of the FP and the RP for four major species were estimated for each BRD type. The improved type with the higher BRD showed a larger contact probability for the FP. Size selectivity of the FP and RP for two species (cinnamon flounder and spotted swimming crab) was almost equivalent to the mesh selectivity of the net panel, but that for lizard fish seemed to depend not on mesh size of the FP but on the swimming behavior of the fish. These results suggest that the smaller mesh size of the RP would be helpful for releasing more fish of smaller size and to exclude more spotted swimming crab, which hinder on-deck sorting by fishermen.