大口黑鲈

从十月开始,大口黑鲈进入成鱼上市阶段,除以前介绍过的捕大留小,减少密度,促进尚未达到商品规格快速生长,以便在年底前绝大部分能够达到上市场规格。     

大口黑鲈

一、养殖和管理 经过几个月的精心养殖,池塘养殖的大口黑鲈已达到上市规格（0．4kg以上）,要及时注意鱼类的生长情况,采用捕大留小的方法,将部分达到上市规格的大口黑鲈上市。     

大口黑鲈MyoD基因结构和单核苷酸多态性位点的筛选

本研究采用PCR技术和基因组步移技术从大口黑鲈基因组DNA中扩增得到MyoD基因及其5’调控区序列。该基因序列全长3797bp,其中5’调控区长1077bp,MyoD基因转录区由3个外显子（分别为591bp、81bp和78bp）和2个内含子（分别为1077bp和486bp）组成。5’调控区含有与肌肉特异性基因转录密切相关的转录调控元件E box、肌细胞增强因子2（MEF2）、肌肉特异性金属硫蛋白结合位点（MTBF）及一些转录反应调控元件（TATA box 、OCAAT box、OCT1、PRE、AP4、Pit1）。运用PCR-SSCP技术和直接测序法进行大口黑鲈MyoD基因SNP位点筛选,结果表明MyoD基因序列中存在7个突变点,均位于内含子上。养殖群体中这7个突变点分析结果显示突变比例范围在0.042～0.353之间。本研究结果为SNPs位点与大口黑鲈生长性能关联分析奠定了基础。     

大口黑鲈选育效果的初步分析

通过选择培育获得大口黑鲈群体选育子三代,对其选育效果进行初步评价。实验数据分析表明,经过三代的选育,大口黑鲈2个选育组在体长、体高和体重上均大于对照组,且差异极显著（P〈0.01）,选育组1和2的日增重率分别比对照组提高了25.32%和23.42%,平均每代的选育效应分别为8.44%和7.81%,而体重变异系数分别是26.8%和20.2%,相比对照组分别降低了9.8%和21.1%。试验结果表明,大口黑鲈的选育效果明显,F3代的生长性能有了显著性的提高,个体之间的生长速度更加趋于一致,同时,F3代仍具有较大的选育潜力,可继续对其进行选育。该研究为进一步通过选择育种培育大口黑鲈优良品种（系）奠定了基础。     

大口黑鲈

培育塘经消毒、培育水质放入鱼种（五月份主要是培育大规格鱼种）,除投喂水蚯蚓（红虫）外、家鱼幼苗和下杂鱼浆等饲料。     

小型水库搭配大口黑鲈的初步试验

在水库原有养殖模式不变的情况下,进行了搭配大口黑鲈的初步试验。套养加州鲈可以将营养价值低的野杂鱼转化为高品质的鲈鱼,同时减轻了养殖鱼类的竞争压力。2005年套养加州鲈后比2004年净利润增加22 026元,增长22.4%。除增加购买加州鲈苗种的费用外基本上未增加其它经费开支,也不增加管理上的麻烦,更没有增加水库养殖的风险。     

大口黑鲈溃疡综合征病毒MCP基因序列分析及PCR快速检测方法的建立

为了早期快速诊断近年来流行于广东省养殖大口黑鲈(Micropterussalmoides)中的病毒性溃疡综合征,本研究用基因组步移的方法获得了大口黑鲈溃疡综合征病毒(Largemouthbassulcerativesyndromevirus,LBUSV)主要衣壳蛋白(MCP)基因,该基因编码区全长1392bp。通过序列比较分析,在MCP基因内确定了一段241bp的特异性较强的片段作为靶序列,设计并合成引物,经过优化PCR反应条件,建立了可以快速检测大口黑鲈溃疡综合征病毒的PCR方法。实验表明,在PCR进行到30个循环反应时可以检测到的质粒最小浓度是104拷贝数/μL,相当于104个病毒粒子。利用该方法,从天然感染LBUSV的大口黑鲈脾脏组织DNA可扩增出241bp的片段,而健康大口黑鲈和感染了传染性脾肾坏死病毒样病毒的大口黑鲈脾脏组织则没有扩增条带。本研究建立的PCR检测方法具有检测快速、成本低、准确性高的特点,适用于大范围早期病害诊断的推广应用。     

大口黑鲈

经过十个月的养殖,渔农养殖的大口黑鲈绝大部分已经达到上市规格,可以随时上市。由于放养密度和生长期间体重的增长,养殖池塘中的大口黑鲈的存塘量已大大超过它的允养量。因此,饲料投喂量要适度控制,避免大口黑鲈已经达到一定肥满度后摄食减少而饲料投喂没有减少造成的资源浪费、因此摄食不完造成生态环境负面影响压力,注意水质的变化,尽管11月气温逐步降低,但有时气温、气压、水中溶氧等因子的变化也会对个体较大、肥满度高、密度较大的池塘中的大口黑鲈的生长带来各种不确定的因素,必须及时做好调节,根据市场需求,将部分成鱼上市,及时注入新水,在注水前先排出部分底层水,将注入新水,每次不超过20％。     

大口黑鲈肌肉营养成分分析及营养评价

对三种不同来源(人工配合饲料饲养、冰鲜下杂鱼饲养和野生捕捞)的大口黑鲈成鱼的含肉率、肌肉中的水分、蛋白质、脂肪、灰分含量和氨基酸组成进行了分析,对其营养价值进行了综合评价,并与完全摄食人工配合饲料的中国花鲈进行了比较。结果表明:三种来源的大口黑鲈蛋白质含量在17.97%~20.15%,脂肪含量在0.81%~6.41%,灰分含量1.24%~1.41%,水分含量72.12%~79.98%,肌肉中17种氨基酸总量为14.19%~16.47%,其中必需氨基酸占氨基酸总量的44%以上,表明大口黑鲈肌肉蛋白是一种优质蛋白源。使用人工配合饲料饲养的大口黑鲈与使用冰鲜下杂鱼饲料饲养的大口黑鲈其肌肉营养成分以及氨基酸组成相差不大,但含肉率存在很大差异,人工配合饲料饲养、冰鲜下杂鱼饲养和野生捕捞的大口黑鲈含肉率分别为74.27%、64.86%和62.71%。而全部摄食人工配合饲料的中国花鲈含肉率为72.53%,氨基酸总量和必需氨基酸含量都高于三种来源的大口黑鲈。     

大口黑鲈POU1F1启动子区域SNPs对生长的影响

采用基因组步移技术克隆了大口黑鲈垂体特异性转录因子POU1F1启动子序列,该序列全长1 629 bp,预测存在4个八聚体转录因子1(Oct-1)结合位点和TATA框等基本转录元件,1个Homeobox转录因子结合位点和2个cAMP反应元件结合蛋白(CREB)结合位点。采用直接测序法研究发现,大口黑鲈POU1F1启动子序列的-18和-183两个位点存在SNPs,该两个突变位点只检测到A、B两种单倍型。对养殖群体进行不同单倍型的基因频率和生长关联分析,结果表明,单倍型A的等位基因频率为0.246,单倍型B的等位基因频率为0.754;群体关联分析表明,基因型为AA型和AB型的个体在体质量、体长、全长、体高和体宽等方面明显高于BB型个体,但基因型为AB型和AA型的个体之间在体质量方面没有明显差异。该研究结果为下一步进行分子标记辅助选择提供了基础。     

患白云病加洲鲈的同工酶分析

采用垂直平板聚丙烯酰胺凝胶电泳技术,对感染致病菌后的加洲鲈5种组织中5种同工酶系统的酶谱表型及活性进行分析。证实在5种酶的4种组织中出现明显的紊乱现象,表明病鱼的病理机制与代谢异常有关,其特异性变化可以作为疾病早期诊断及病理分析的生化辅助指标。     

维生素C对大口黑鲈生长与非特异性免疫的影响

以不同维生素C水平(添加量分别为0、500、1000、2000和4000mg·kg-1)的5种饲料喂养初始体重为19g左右的大口黑鲈1个月,每个处理50尾鱼,各处理3个重复,研究维生素C对大口黑鲈生长及非特异性免疫的影响。结果显示:饲料中添加维生素C能显著促进大口黑鲈的生长和脾体指数(P<0·05),然而对大口黑鲈的成活率以及肝体指数等不产生影响(P>0·05);饲料中添加维生素C能显著促进大口黑鲈血清中超氧化物歧化酶活力和溶菌酶活力(P<0·05);随着饲料中维生素C添加水平的提高,大口黑鲈肝脏中维生素C的积累量显著升高(P<0·05)。实验证明,Vc作为免疫刺激剂能有效地提高大口黑鲈的生长与非特异性免疫能力。     

摄食对大口黑鲈消化器官蛋白酶和淀粉酶活力的影响

试验从摄食方面研究食物对大口黑鲈主要消化器官蛋白酶和淀粉酶分泌的影响,对摄食后主要消化器官蛋白酶和淀粉酶活力进行了研究。结果表明,摄食对蛋白酶活力影响:摄食后1h胃蛋白酶降低,至摄食后4 h升高到平稳水平(P>0.05);幽门盲囊蛋白酶活力摄食后开始降低,而从摄食后4 h开始升高(P<0.05);肠道蛋白酶活力摄食后1 h出现升高,摄食后4 h降到最低,10 h又升高到较大活力。摄食对淀粉酶活力影响:胃淀粉酶活力摄食后开始降低,摄食后4h又升高到最大(P<0.05);肠道淀粉酶活力摄食后开始升高,至摄食后4 h达到稳定(P>0.05);幽门盲囊淀粉酶活力在摄食后开始降低,到摄食后4h升高到较高活力,并保持到摄食后10 h;摄食后1 h肝脏淀粉酶活力便保持在较高水平(P>0.05)。     

饥饿对大口黑鲈消化器官、蛋白酶和淀粉酶活力的影响

对饥饿和饥饿后投喂的大口黑鲈(Micropterus salmoides)蛋白酶和淀粉酶活力及消化组织的变化进行了研究,饥饿周期为30d。饥饿对大口黑鲈消化道指数的影响为肝体比从试验的第3天开始明显下降(P<0.05),第20天开始保持稳定水平(P>0.05);幽门盲囊重与体重比先上升后下降;胃重与体重比始终呈上升趋势(P<0.05);肠重与体重比在第10天开始保持稳定水平(P>0.05);肠长与体长比呈上升趋势(P<0.05)。饥饿对蛋白酶活力影响为从开始到第3天胃蛋白酶活力上升,第10天开始下降;幽门盲囊蛋白酶活力在第10天之后持续下降(P<0.05);肠道蛋白酶活力一直呈下降趋势。饥饿对淀粉酶活力影响为肝脏淀粉酶活力、胃淀粉酶活力和幽门盲囊淀粉酶活力均呈下降趋势(P<0.05);肠道淀粉酶活力第10天之后即稳定在低水平(P>0.05)。饥饿后摄食对蛋白酶活力和淀粉酶活力的影响为饥饿后摄食蛋白酶活力和淀粉酶活力均呈上升趋势,上升的速度在不同组织有差异,在恢复摄食后的第10天基本达到正常水平。     

Digestibility of nutrients and amino acids of different protein sources in practical diets by largemouth bass Micropterus salmoides (Lacepéde, 1802)

This study evaluated the apparent digestibility coefficients (ADCs) of dry matter, protein, lipid, energy, calcium, phosphorus, and essential and non‐essential amino acid availability of animal and plant protein sources in practical diets for the carnivorous fish, largemouth bass Micropterus salmoides (8.0±0.5 g; 10.0±0.3 cm). Fish were conditioned to accept artificial feed and those stocked in plastic cages were fed pelleted test diets. Diets contained 30% of the ingredient tested mixed with 70% of a reference ration (RD) containing 40 g 100 g^?1 of crude protein, 19.85 kJ g^?1 crude energy, and 0.5% of chromic oxide. Cages were then transferred to cylindrical, conical‐bottomed aquaria (200 L) where the faeces were collected by sedimentation in a refrigerated container. All the tested ingredients had high ADCs for protein and lipid; ADCs of amino acids of varying protein sources showed significant differences (P<0.01). Plant protein sources did not significantly influence the ADCs of diets. The results allow the inference that the availability of amino acids in plant and animal protein sources varies considerably.     

Lakeshore residential development and growth of largemouth bass (Micropterus salmoides): a cross‐lakes comparison

Gaeta JW, Guarascio MJ, Sass GG, Carpenter SR. Lakeshore residential development and growth of largemouth bass (Micropterus salmoides): a cross‐lakes comparison.
Ecology of Freshwater Fish 2011: 20: 92–101. © 2010 John Wiley & Sons A/S Abstract – Lakeshore residential development is associated with changes in littoral habitat, riparian habitat, and ecosystem function with potential impacts ramifying through aquatic food webs. Effects of these changes on economically important game fishes may vary with fish size. We investigated largemouth bass (Micropterus salmoides) size‐specific growth rates across 16 lakes spanning the range of lakeshore residential development in Wisconsin’s Northern Highland Lake District using a longitudinal multilevel model. Growth rates of small fish had a strong positive relationship with lakeshore residential development. The strength of the relationship decreased with length and became increasingly negative for fish longer than 210 mm. This pattern may be driven by a release from density‐dependent growth, shifts in available prey sources, reduced macrophyte cover, or angling‐induced selection pressures. Regardless of the mechanism, our results indicate, relative to undeveloped lakes, largemouth bass in highly developed lakes take 1.5 growing seasons longer to enter the fishery (356 mm).     

Comparison of the amino acid contents of roe, whole body and muscle tissue and their A/E ratios for largemouth bass Micropterus salmoides (Lacepéde, 1802)

Nutritional amino acid requirements of varying size classes of largemouth bass were estimated using A/E ratios. Nutrient and amino acid contents of roe and carcass of the different size classes were determined and compared to results of selected, classic works related to the concept of ideal protein and relationship between the contents of individual, essential amino acids and the total contents of essential amino acids – A/E ratios. Protein content in the roes of the largemouth bass were higher in comparison to the carcass, but the content of lipids of the roes and of the carcass didn’t present significant difference (P<0.05). Largemouth bass showed higher muscle protein content in comparison to other species. Although some authors report variation in the contents of some amino acids in the carcass of selected species, differences observed in this study regarding carcass amino acid contents of tilapia, speckled catfish and largemouth bass were not significant (P<0.05), values of the ratio A/E followed the same trend. Results, herein presented, indicate that the amino acid profile of largemouth bass could be used as complementary tool for balancing amino acids in formulated feed for the species, and in the validation of amino acid requirements determined in performance studies.     

Diet of the largemouth bass, Micropterus salmoides (Lacepède), in Lake Naivasha, Kenya

Abstract The major food items of adult largemouth bass, Micropterus salmoides (Lacepède), in Lake Naivasha, Kenya are not markedly different from those in its native range. Although insects and their larvae are major components of the diet for both temperate and equatorial populations of juvenile bass, the equatorial population also eats Procambarus clarkii (Girard), juvenile fish and aquatic weeds. In temperate populations they also eat crustaceans, rotifers and oligochaetes. The frequency of occurrence of the major prey organisms in the stomachs of M. salmoides varies seasonally with population peaks in these organisms. Similar to North American populations, the Naivasha population feeds during the day between dawn and dusk. In contrast to temperate populations, the population of M. salmoides in this equatorial lake feeds throughout the year, with feeding intensity correlated with water temperature.     

Apparent digestibilities of common feedstuffs for bluegill Lepomis macrochirus and largemouth bass Micropterus salmoides using individual test ingredients

Apparent digestibility of dry matter and energy, and availability of amino acids from blood meal (BM), fish meal (FM), meat and bone meal (MBM), poultry by-product meal (PBM), soybean meal (SBM), corn, wheat and yellow grease (YG) were determined for bluegill Lepomis macrochirus (mean weight, 57 g), and likewise, but not for BM or wheat, for largemouth bass Micropterus salmoides (mean weight, 30 g). To avoid nutrient interaction from a reference diet, diets containing 98.5% (985 g kg⁻¹) of test ingredients were used, except for semi-solid, YG which was mixed with corn to permit pelletization. Faeces were collected by a siphoning method. Apparent dry matter digestibility values ranged from 50% (corn) to 87% (BM) for bluegill and from 53% (MBM) to 76% (PBM) for largemouth bass. Apparent energy digestibility values ranged from 53% (corn) to 92% (BM) for bluegill and from 63% (MBM) to 93% (YG) for largemouth bass. Apparent digestibility of most amino acids exceeded 90% for evaluated protein sources, except for MBM which showed slightly lower values (80–90%) for both fishes. Isoleucine digestibility from BM was relatively low (82%) for bluegill. High digestibility values for SBM, PBM and BM, indicate good potential for replacing FM in diets for both fishes.