2011年罗非鱼出口量将超33万t

11月8～9日,第八届罗非鱼产业发展论坛在广西南宁举行,国内罗非鱼产业相关政府机构、企业、科研单位、业界同行等共100余人与会,对本年度罗非鱼产业现状及问题等,进行了探讨与公示。从会议了解到,经历了5～8月低迷的出口贸易期,9月份开始国内罗非鱼出口贸易开始逐步恢复。随着市场     

罗非鱼池塘网箱育苗技术

罗非鱼系热带性鱼类，原产非洲。近10年来，随着加工、出口贸易的发展，罗非鱼成了我国南方一个非常重要的咸淡水养殖品种，广大养殖企业与养殖户对种苗的质量也越来越重视。利用池塘网箱培育罗非鱼苗，操作方便，成活率高，经济效益好。可以提高放养密度，同一池塘可以放养不同批次与规格的水花，可提高池塘利用效率，并且培育的鱼苗规格整齐。现将池塘网箱育苗技术简述如下。     

罗非鱼养殖技术之四奥尼罗非鱼工厂化育苗技术

奥尼罗非鱼是尼罗罗非鱼(♀)和奥利亚罗非鱼(♂)的杂交子一代,是我国罗非鱼养殖的首选品种。目前,我国普遍存在罗非鱼亲本种质退化、繁殖力下降、工厂化生产程度不高、优质的奥尼罗非鱼养殖普及率低等问题,制约了罗非鱼产业化的发展。广西水产研究所从中国水产科学研究院淡水渔业研究中心引进了尼罗罗非鱼、奥利亚罗非鱼等2种亲本,进行了奥尼罗非鱼工厂化高产繁育技术研究与开发,经过4年实施,选育出了种质较好、生长速度快、遗传稳定、体型好的尼罗罗非鱼和奥利亚罗非鱼高纯度亲本,并利用40亩池塘每年生产杂交奥尼罗非鱼4000万尾~6000万尾,…     

罗非鱼选育方法研究进展

针对我国罗非鱼养殖业对优良品种(品系)的强烈需求,提出了目前罗非鱼养殖业中存在的问题,综述了罗非鱼选育方法的研究进展,旨在为生产实践中人工控制罗非鱼性别、培育全雄种群,解决罗非鱼良种繁育生产问题等提供参考.     

罗非鱼咸水养殖研究进展

本文结合国内外研究成果,从罗非鱼咸水养殖现状、罗非鱼咸水养殖生物学、罗非鱼咸水养殖驯化及养成模式三个方面对罗非鱼咸水养殖技术进行了论述,望为我国罗非鱼在咸水及盐碱水中养殖提供技术参考。     

发展罗非鱼产业正当时

罗非鱼是联合国粮农组织推广养殖的鱼类品种之一,目前全世界有85个国家和地区养殖罗非鱼,年产量约120万吨.2001年我国罗非鱼产量为69万吨,占世界总产量的58%.近年来,随着产量逐年增长,以及国际市场对罗非鱼需求量的不断扩大,我国罗非鱼出口量飞速增加,国内一些水产养殖专家认为,罗非鱼是我国最具国际竞争实力的品种之一,也是最具产业化发展条件的品种,我国台湾省把罗非鱼称之为"21世纪人民之鱼".目前,广东、海南、广西、福建、北京、山东等地都得到了迅速发展,并带动种苗、饲料、加工、贸易等相关产业的发展.     

广东罗非鱼养殖 现状及发展前景

罗非鱼是联合国粮农组织推广养殖的种类之一,目前全世界有85个国家和地区养殖罗非鱼,年产量约120万吨。2001年我国罗非鱼产量为69万吨,占世界总产量的58%。近年来,随着产量逐年增长,以及国际市场对罗非鱼需求量的不断扩大,我国罗非鱼出口量飞速增加,国内一些水产养殖专家认为,罗非鱼是我国最具国际竞争实力的品种之一,也是最具产业化发展条件的品种,我国台湾省把罗非鱼称之为“21世纪人民之鱼”。目前,广东、海南、广西、福建、北京、山东等地都得到了迅速发展,并带动种苗、饲料、加工、贸易等相关产业的发展。广东具备养殖罗非鱼的得天独厚…     

罗非鱼的加工技术

2003年,我国罗非鱼年产量近80万吨,占世界总产量的58%以上。我国的罗非鱼产量已多年居世界第一,它是我国最具国际竞争实力的品种,也是最具产业化发展条件的品种。除了鲜食外,我国罗非鱼的加工业近年来也得到了较快的发展,罗非鱼产品出口迅速增长,1998年,罗非鱼产品输美量为471吨;而2000年为13492吨,产值2013万美元。但是,罗非鱼产品主要是冻鱼片和冻全鱼,一方面这些产品的加工水平较低,品种单一,附加值不高;另一方面在生产过程中产生了大量的下脚料,如鱼骨、鱼内脏等。因此,有必要提高罗非鱼的精深加工水平和综合利用能力,开发品种多样的罗…     

罗非鱼耐寒品种选育研究进展

罗非鱼目前已成为我国主要淡水养殖品种之一，2010年我国罗非鱼产量达到133．2万吨，占世界罗非鱼产量的一半。罗非鱼为暖水性鱼类，最适生长水温为22-35℃，因此广东、广西、福建、海南等华南地区为罗非鱼主产区。由于罗非鱼不耐低温，越冬时节必须搭建温棚，此举提高了罗非鱼的养殖成本。近年来，极端天气时有发生，简易温棚内养殖的罗非鱼时有冻死，选育出耐寒能力强的罗非鱼品种显得较为迫切。     

广东罗非鱼养殖生产现状

广东基本属亚热带湿润季风气候,具备养殖罗非鱼的得天独厚的优越条件,是我国养殖罗非鱼最早、养殖面积最多和产量最高的地区。1957年广东省引进莫桑比克罗非鱼(Orcochromis mossambicus),我国大陆开始了罗非鱼养殖业。据统计,2001年广东省罗非鱼上市量达27万t,占全国总产量的40.5%,占广东淡水鱼产量11.4%。     

Consumer preferences for farmed tilapia in Tanzania: A choice experiment analysis

ABSTRACT

This study used a choice experiment to analyze the preferences of consumers for the attributes of tilapia (price, mode of production, product form, and size), a major aquaculture product in Tanzania. The results showed that consumers were willing to pay a price 665.020 Tanzanian shillings (TZS) lower for farmed tilapia than for wild tilapia; a price TZS 833.210 and TZS 1799.110 higher for medium-size and large-size tilapia respectively than for small-size tilapia; and a price TZS 1214.090 higher for fresh tilapia than for smoked tilapia. Consumers’ willingness to pay less for farmed tilapia than for wild tilapia is mainly attributed to issues related to taste and availability. It was also found that consumers were heterogeneous in their preferences for all the tilapia attributes (mode of production, size, and form) considered in this study.     

Genetic variation inferred from RAPD fingerprinting in three species of tilapia

This study used random amplified polymorphic DNA (RAPD) fingerprinting for estimating genetic variation and species differentiation in three species of tilapia. A 16-mer random primer generated RAPD markers ranging from 250 to 2400 base pairs (bp). Genetic similarity estimates obtained by pairwise comparisons based on the method of Nei and Li (1979) indicated high genetic similarity (mean genetic similarity (± sd), 0.73 (± 0.15) for Nile tilapia; 0.78 (± 0.12) for Mozambique tilapia; and 0.87 (± 0.07) for Aureus tilapia) within each of the tilapia species. The average interspecies genetic similarities obtained among the three species were 0.59 (± 0.07) for Mozambique/Nile tilapia, 0.46 (± 0.09) for Aureus/Nile tilapia and 0.38 (± 0.07) for Aureus/Mozambique tilapia pair. DNA profiles generated in each species of tilapia were unique. A total of 13 RAPD markers differentiating the three species of tilapia were detected. Our study presented RAPD markers as a new class of useful genetic markers for assessment of genetic diversity and species differentiation in tilapia.     

Performance of genetically improved Nile tilapia compared with red hybrid tilapia fed diets containing two protein levels

A 10‐week feeding trial was conducted to investigate the interaction between tilapia genotype and dietary protein level on the growth, feed utilization efficiency and body composition of Nile tilapia [Oreochromis niloticus L., F₉ generation of genetically improved farmed tilapia (GIFT) strain] and red hybrid tilapia (Oreochromis sp.). Two isoenergetic diets (15.5 kJ g⁻¹ diet) containing 25% or 35% crude protein were formulated and fed to triplicate groups of tilapia (12.8±0.2 g) at a fixed daily ration of 4% of their body weight. The growth performance of the GIFT tilapia fed 25% or 35% dietary protein was significantly higher (P<0.05) compared with red tilapia at either protein level. Increasing the dietary protein level by 10% led to a further 10% increase in the final weight of GIFT tilapia but no further increase was observed in the weight gain of red tilapia. Growth was influenced by the interaction between diet and tilapia genotype. Feed conversion ratios were 14% and 33% better in GIFT tilapia compared with red tilapia fed the 25% or 35% protein diet respectively. Protein efficiency ratio and net protein utilization were influenced by both diet and tilapia genotype, but not the interaction between the two. The apparent digestibility coefficients of dry matter and protein did not differ significantly between the two diets and tilapia genotypes but lipid digestibility was 1.2–4.7% higher for the GIFT tilapia. Tilapia whole‐body protein content was significantly influenced by both diet and tilapia genotype. The higher growth potential, better feed utilization efficiency and higher body protein content of GIFT tilapia compared with red tilapia should have a positive impact on tilapia farming in terms of production costs.     

低温驯化下4种不同品系罗非鱼血清皮质醇与免疫相关指标的变化

选取4种不同品系罗非鱼, 分别为吉富罗非鱼(Oreochromis niloticus)、奥尼罗非鱼(O. niloticus×O. aureus)、红罗非鱼(O. nilotica♂× O. mossambica♀)和奥利亚罗非鱼(O. aureaus)。在26℃水温下饲养3周后, 选取规格基本一致的罗非鱼(体质量50.73 g±4.23 g)进行低温驯化实验。水温以3℃/d的速度从26℃降至8℃, 分别于水温为26℃、20℃、14℃和8℃时进行采样, 比较不同驯化阶段4种不同品系罗非鱼血清皮质醇和免疫相关指标的变化规律。结果表明, 与26℃时的免疫指标相比, 水温降至8℃时, 吉富与红罗非鱼血清皮质醇水平显著升高; 然而血清C3、C4、IgM以及头肾C型溶菌酶mRNA水平显著下降(P<0.05), 血清中高皮质醇水平对鱼体的免疫产生了抑制作用。水温为8℃时, 奥尼罗非鱼血清皮质醇、IgM和补体C3以及头肾抗菌肽mRNA水平显著升高; 奥利亚血清皮质醇、C4和IgM以及头肾C型溶菌酶mRNA水平与26℃时相比无显著差异, 然而血清溶菌酶与C3水平降低。驯化实验结束后, 比较了4种不同品系罗非鱼在8℃水温下48 h内的累积死亡率。吉富与红罗非鱼组累积死亡率较高, 分别达到43.3%和40.0%; 奥尼罗非鱼其次, 为23.3%; 奥利亚罗非鱼最低, 为20.0%。较高的血清IgM和头肾溶菌酶和抗菌肽mRNA水平可能有助于提高奥尼和奥利亚罗非鱼的抗低温应激能力, 增加低温时的成活率。本研究通过分析4种品系罗非鱼不同驯化阶段血清皮质醇和免疫相关指标, 探讨不同品系罗非鱼在低温驯化过程中的免疫保护机制, 旨在为下一步抗低温新品系罗非鱼的选育提供理论依据。

     

海豚链球菌感染对不同品系罗非鱼血液生化指标和肝脏HSP70 mRNA表达的影响

以吉富罗非鱼、新吉富罗非鱼、埃及尼罗罗非鱼和红罗非鱼为研究对象,饲养100d后,进行海豚链球菌(2.95×108CFU/mL)感染试验,分析攻毒前后各品系罗非鱼的血液生化指标和肝脏HSP70 mRNA表达量的变化规律。另从各桶中取20尾鱼进行同样的攻毒试验,统计攻毒后各时间点的累积死亡率。结果表明,感染海豚链球菌96h后,吉富罗非鱼和新吉富罗非鱼对病原较为敏感,累积死亡率分别达到36.67%和38.33%;埃及尼罗罗非鱼对病原敏感性较差,试验期间未见死亡。吉富罗非鱼、新吉富罗非鱼和红罗非鱼血清皮质醇和葡萄糖水平以及肝脏HSP70 mRNA的表达量在攻毒后明显提高,血清谷丙转氨酶、谷草转氨酶与溶菌酶活力也呈上升趋势,碱性磷酸酶活力与甘油三酯和胆固醇水平低于攻毒前。埃及尼罗罗非鱼可以利用糖原和脂类产生的能量,提高了HSPS与一些特定免疫蛋白(溶菌酶、球蛋白等)的合成,增强了鱼体的非特异性免疫力。罗非鱼选育过程中,需要将抗病力与生长性能进行有效的结合,在注重生长速度的同时也要增强其抗应激能力,从而为罗非鱼产业的可持续发展提供保证。     

3种品系尼罗罗非鱼生长及高密度胁迫后生理响应变化的比较

以‘吉富’、‘新吉富’、‘埃及尼罗’3种不同品系尼罗罗非鱼(Oreochromis niloticus)为研究对象, 通过不同品系之间生长与高密度胁迫反应的比较, 探讨3种尼罗罗非鱼的生长特点与应激后生理响应的变化规律。将初始规格基本一致的3种品系尼罗罗非鱼饲养100 d后, 吉富罗非鱼特定生长率最高, 新吉富其次, 两者间无显著差异(P>0.05), 埃及尼罗罗非鱼特定生长率显著低于吉富罗非鱼(P<0.05)。吉富与新吉富罗非鱼的内脏比显著高于埃及尼罗(P<0.05); 3种尼罗罗非鱼的肥满度之间无显著差异(P>0.05)。养殖实验结束后, 进行48 h的急性高密度(100 g/L)应激实验。应激48 h内, 吉富与新吉富罗非鱼血清总蛋白、葡萄糖、谷草转氨酶、胆固醇与溶菌酶活力/水平以及肝HSP70mRNA水平呈先上升后下降的变化。应激48 h后, 埃及尼罗罗非鱼血清皮质醇水平与应激前相比无显著差异(P>0.05), 吉富与新吉富罗非鱼的皮质醇水平显著高于应激前(P<0.05); 埃及尼罗罗非鱼血清溶菌酶活力与肝HSP70 mRNA水平在应激后48 h内始终高于应激前(P<0.05)。研究结果表明, 短期高密度胁迫可提高3种尼罗罗非鱼血清葡萄糖与甘油三酯的利用, 并诱发肝损伤。埃及尼罗罗非鱼的抗高密度应激能力高于吉富和新吉富罗非鱼。

     

Changes in purine content of tilapia surimi products during processing

ABSTRACT:   Changes in purine-related compounds of tilapia surimi product during processing were investigated. The washing step could result in about 60% decrease of total purine content in tilapia mince during processing. The main released purine substance was inosine monophosphate. The major reducing effect was conducted in the first 10 min during washing. No significant changes were observed after washing for 20 and 30 min. The lowest total purine content of tilapia surimi product was obtained with repeating the washing step twice. Thus, this procedure could reduce the purine content of tilapia mince from a high purine content level to a middle level. The gel strength of tilapia surimi product increased with increasing washing duration within 30 min. However, tilapia surimi product with a middle purine content and acceptable gel strength might be produced by washing twice in 10 min during processing.     

Preliminary Investigations into the Socio-Economic Feasibility of Saltwater Cage Culture of Florida Red Tilapia in Haiti

The primary objective of this study was to investigate the socio-economic feasibility of saltwater cage culture of Florida red tilapia as a new production activity in Haiti. Market outlets and potential prices for saltwater-reared red tilapia in Haiti were examined. Availability and prices of inputs to production were considered. Although this information was collected in the context of Haiti, it is relevant to other developing countries when assessing the potential for a mariculture industry.
Two types of market outlets for saltwater-reared red tilapia were found to exist in Haiti. The predominant rural market sector treated red tilapia as a low-value species and paid an average price ($0.90/kg roundweight) similar to that for freshwater black tilapia. Urban specialty markets treated red tilapia as a premium quality fish and paid an average price ($2.20/kg cleaned) equal to that for snapper and grouper.
Comparison of production costs to potential market prices indicates that saltwater cage culture of tilapia is not economically feasible on an artisanal scale and is a high financial risk on a commercial scale. Break-even prices are higher than prices in the large rural market sector. No data exists to indicate sufficient demand in the smaller urban specialty market sector or export markets.     

罗非鱼3个养殖群体的遗传多样性及特异性AFLP标记研究

对不同来源的养殖群体进行种质鉴定，探索在种苗阶段即区分新吉富罗非鱼（New GIFT strain Oreochromis niloticus）、吉诺玛罗非鱼（GenoMar strain O．niloticus）和奥杂罗非鱼（0．niloticus♀×O．aureus♂）3个养殖群体具有重要的意义。笔者选取了5对AFLP（amplified fragment length polymorphism）引物组合对3个罗非鱼养殖群体共60尾个体进行比较分析，引物组合E—ACA／M—CAT表现出较好的区分能力，有7条标记的分布在群体间表现出“有和无”的差别，引物组合E—ACA／M—CAG的扩增图谱中有2条带表现出“有和无”的差别。遗传多样性方面，平均基因多样性在新吉富罗非鱼和吉诺玛罗非鱼分别为0．1605和0．1595，而在奥尼罗非鱼为0．2214，多态位点百分数和Shannnon多样性指数也表现出相近的变化趋势。分析表明新吉富罗非鱼群体在遗传上已较为稳定，吉诺玛罗非鱼遗传多样性偏低。     

Effect of body colour of Oreochromis mossambicus (Peters) on predation by largemouth bass, Micropterus salmoides (Lacepède)

Abstract. Fifty each of F₂-generation gold ( gg ), bronze ( Gg ), and black ( GG ) Oreochromis mossambicus (Peters) and either zero, four or eight largemouth bass, Micropterus salmoides , (Lacepède) were stocked in 20-m² concrete tanks. After 7 days, water in all tanks was drained, and fish in each tank were censused. Largemouth bass ate 18% of the tilapia in the four-bass treatment (1 tilapia/bass/day) and 60% of the tilapia in the eight-bass treatment (1·6 tilapia/bass/day); the difference was significant (P=0–05). In the four-bass treatment there was a greater observed mean predation rate on gold than that on black or on bronze tilapia, but the difference was not significant: largemouth bass ate 25% of the gold tilapia, 16% of the bronze tilapia, and 13% of the black tilapia. In the eight-bass treatment, predation on the gold tilapia was significantly greater than that on both bronze (P=0·05) and on black (P=0·06) tilapia; predation on bronze and black tilapia was similar: largemouth bass ate 80% of the gold tilapia, 48% of the bronze tilapia, and 51% of the black tilapia. Overall average total predation (both treatments combined) on gold tilapia was significantly (P=0·06) greater than that on both bronze and on black tilapia, which did not differ: largemouth bass ate 52% of the gold tilapia, 32% of the bronze tilapia, and 32% of the black tilapia. The increased vulnerability of gold tilapia to predation was a negative pleiotropic effect of the gg genotype.