全雄罗非鱼池塘混养试验

选择璧山县青杠渔场１号池（面积９亩）和三角滩渔场５号池（面积１２亩）进行全雄罗非鱼池塘混养试验,亩净产成鱼５７３．０公斤和５３７．５公斤,其中全雄罗非鱼亩产７２公斤和５０公斤,每亩增加收入８００元。     

池塘养殖全雄罗非鱼技术

池塘养殖全雄罗非鱼技术曹文龙罗非鱼，又称非洲鲫鱼，属热带性鱼类，具有生长快、食性来源广、繁殖力强、养殖周期短、病害少，产量高等优良性伏，深受广大水产养殖户的欢迎。但是，由于罗非鱼繁殖力虽，在池塘养殖过程中，因其频繁繁殖，会造成池塘中子代过多，密度失控...     

全雄罗非鱼育苗试验

本文探讨了在江西省宁都县罗非鱼良种场利用种间杂交技术,采用尼罗罗非鱼母本(♀)与奥利亚罗非鱼父本(♂)杂交,获得全雄子代奥尼罗非鱼,捞苗共计136.5万尾,全雄率为95%。     

采用节粮型饲料网箱养殖全雄罗非鱼和红尼罗的试验

采用紫穗槐粉、啤酒糟粉、鸡粪代替20%左右粮食进行网箱饲喂全雄罗非鱼和红尼罗对比试验。结果：饲喂79天，全雄罗非鱼和红尼罗产量分别为61.56kg/m^2和49.16kg/m^2，全雄罗非鱼单产比红尼罗单产高25.22%。Ⅰ号配方的饵料系数为1.97，好于其他2个配方。1990年10月专家鉴定认为，用紫穗槐粉、鸡粪代替粮食能降低生产成本，提高经济效益，是较好的节粮型饲料配方。     

尼罗罗非鱼与奥利亚罗非鱼及其杂种一代的雄性率、生长对比的初步观察

为了谋求罗非鱼的高产优质，探索罗非鱼单性养殖的途径，巳成为当今举世瞩目的课题。我们于1985年在慈利县罗非鱼繁殖场进行了尼罗罗非鱼、奥利亚罗非鱼及其杂种(正反交)一代的雄性率、个体生长速度、群体生产力比较的初步观察。现将试验结果报告如下：     

单雄性罗非鱼与尼罗罗非鱼池塘养殖对比试验

在两口条件基本一致的池塘中，按80:20池塘主养模式进行主养单性奥尼罗非鱼和尼罗罗非鱼对比试验，亩产奥尼罗非鱼822公斤，亩纯收益3130元；亩产尼罗罗非鱼720公斤，亩纯收益316.62元。奥尼罗非鱼平均个体300克，尼罗罗非鱼平均个体168克。奥尼鱼较尼罗罗非鱼生长快42.6%。     

单雄性罗非鱼与尼罗罗非鱼池塘养殖对比试验

罗非鱼系鲈形目，鲡鱼科，罗非鱼属，属热带性鱼类，是世界上养殖最广泛的鱼类之一，因其具有肉质好，生长快，产量高，食性杂，繁殖力强，养殖周期短，疾病少等优良性状，联合国粮农组织把它作为一种优良的养殖对象向全世界推广。困扰罗非鱼养殖业发展的重要因素之一是罗非鱼性成熟早，雌鱼因繁殖、孵化而生长缓慢，过度繁殖的仔鱼又因个体太小，无商品价值，造成饲料与水体空间的浪费。因此，如何控制其繁殖一直为人们所关注。利用杂交技术生产的单雄性罗非鱼，是解决该问题的主要方法之一。为比较单雄性罗非鱼和普通尼罗罗非鱼的生产性能…     

尼罗罗非鱼的池塘养殖

<正> 尼罗罗非鱼1973年从以色列引进菲律宾,研究表明,它比莫桑比克罗非鱼生长快,因此养殖尼罗罗非鱼获利更多。池塘的准备放养鱼种之前,池塘要彻底排干,清除障碍物,水草和野鱼。塘底要干透,直到出现裂纹,然后用新鲜、干净的水灌满鱼塘。若施干的鸡粪之类的有机肥,应撒到水深为20～40厘米的塘底。鸡粪的施用量为每     

Comparative digestion efficiencies in conventional, genetically improved and genetically male Nile tilapia, Oreochromis niloticus (L.)

Apparent digestibility of dry matter, protein, lipid and energy of a fishmeal‐based feed (41% crude protein, 9% crude lipid and 19 kJ g⁻¹ gross energy) was compared in genetically improved farmed tilapia (GIFT), genetically male Nile tilapia (GMNT) and conventional Nile tilapia (CNT) (Oreochromis niloticus). The experimental fish were reared individually under standardized conditions in a recirculation system at 27±0.1°C for 10 weeks. Titanium dioxide (TiO₂) was used as a marker. Faeces of individual fish were collected daily by siphoning and stored at −18°C before analysis. No significant differences (P<0.05) were observed in the digestibility coefficients of feed dry matter (78.2±3.4%, 77.7±4.4% and 76.4±3.7%), protein (87.9±3.0%, 88.4±2.8% and 88.0±3.3%), lipid (90.0±2.5%, 91.0±2.1% and 89.4±3.0%) and energy (90.4±1.9%, 90.7±2.0% and 89.4±2.3%) in GIFT, GMNT and CNT respectively. At the end of the experiment, there were no significant differences (P<0.05) in average percentage growth (82.2±7.2, 87.3±7.7 and 74.7±4.1 respectively for GIFT, GMNT and CNT), growth rates or feed utilization efficiencies between the three tilapia groups. We conclude that the higher growth claimed for improved GIFT and GMNT as compared with CNT, if ever existing, cannot be attributed to higher nutrients or energy digestibility.     

Growth performance of mixed sex, hormonally sex reversed and progeny of YY male tilapia of the GIFT strain, Oreochromis niloticus

The growth performance of three experimental groups consisting of mixed sex fish (control), hormone-treated fish and progeny of YY male tilapia, all originated from the genetically improved farmed tilapia (GIFT) strain was evaluated. Masculinization of sexually undifferentiated fry was achieved by providing a supplement of 5 mg of 17-α-methyltestosterone per kg of feed over a period of 21 days (after sac absorption). Both mixed sex and progeny of YY male groups were fed a standard commercial ration. Mixed sex fish did not deviate significantly ( P >0.05) from the 1:1 male to female ratio. Percentages of male averaged 75% in hormone-treated fish and 95% in YY male group over the sampling periods and at final harvest. The effect of sex on weight and length was statistically significant ( P <0.001). The model used to analyse weight and length included experimental group and sex in each culture period as the fixed effects, and replicate cages as the random effect. Over the culture period of 141 days, there were no statistical differences ( P >0.05) in body weight and length between mixed sex, hormonally treated and progeny of YY males. There were also no significant differences in level of variability in harvest weight between three groups of fish when the data were classified into five categories (=<100, 100 to <150, 150 to <200, 200 to <250 and ≥250 g). It is concluded that monosex culture of all male tilapia would be of no advantage over mixed sex culture for the GIFT strain under conditions of cages suspended in earthen ponds.     

Genetic differences between sexes for morphometric traits of GIFT tilapia

The study was carried out to verify the genetic differences in the morphometric traits between male and female tilapia GIFT under the selection for weight gain. The data set used contained information of 6650 animals of the third (2198), fourth (1720) and fifth (2732) generations of GIFT in Brazil, in addition to the 8590 animals, of the first five generations, included in the relationship matrix. The morphometric traits used were standard length (SL: 19.8 ± 1.7), body depth (BD: 7.6 ± 0.76), body width (BW: 3.5 ± 0.54), body area (BA: 151.3 ± 27.6) and body volume (BV: 536.7 ± 143.5). Bicharacter analyses were performed considering the same morphometric measure evaluated for each sex as different traits to estimate the (co)variance components. The heritability and environmental common effects of the larval and fry phases for each trait of each sex were estimated. Genetic correlations between males and females for the same body trait were estimated. The larval effect was higher for females (SL = 0.1; BD = 0.07; BW = 0.05; BA = 0.09; BV = 0.09) than for males (SL = 0.04; BD = 0.03, BW = 0.01, BA = 0.04; BV = 0.03), while the fry effect was similar between the sexes. The heritability of males (SL = 0.25; BD = 0.3; BW = 0.33; BA = 0.31; BV = 0.35) was, in general, higher than those present in females (SL = 0.19; BD = 0.2, BW = 0.18, BA = 0.2; BV = 0.2), and the genetic correlations between males and females were below 0.5 (SL = 0.5; BD = 0.39, BW = 0.42, BA = 0.45; BV = 0.43). Thus, it can be seen that the males respond differently to the females in terms of body shape, of the selection for weight gain.     

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.     

吉富罗非鱼家系构建及抗病力检测

文章以吉富罗非鱼（GIFTstrainOreochromisniloticus）为研究对象,按照1雄配1雌原则进行家系配对,待家系鱼生长至50～60g·尾“时人工感染无乳链球菌（Streptococcusagalactiae）（菌株GD001）。通过对GD001菌株半数致死浓度测定及各家系感染死亡率的统计,研究了GD001无乳链球菌感染对各家系吉富罗非鱼抗病力的影响。结果表明,1）配对成功家系67个,经繁殖性能筛选后留种53个,家系留种率为79．1％;2）GD001菌株的半数致死浓度为4×108cfu·mL－1,感染后2～6d为死亡高峰期;3）GD001菌感染53个家系后有11个家系的成活率在90％以上,15个家系的成活率在70％～89％,19个家系的成活率在30％～69％,8个家系的成活率低于30％,表明不同家系对GD001菌株的抗病力存在着显著的差异（P〈0．05）。     

Dietary phosphorus requirement of GIFT strain of Nile tilapia Oreochromis niloticus reared in freshwater

A study was conducted to estimate the optimum requirement of dietary available phosphorus for GIFT strain of Nile tilapia Oreochromis niloticus. Six purified diets were formulated to contain graded levels (0 (control diet), 2.9, 4.8, 7.6, 9.1 and 10.9 g kg^?1 diet) of available phosphorus. Each diet was fed to triplicate groups of 12 fish with initial average weight (46.03 ± 2.14) g for 8 weeks. The results showed that fish fed the three lowest phosphorus diets (0, 2.9 and 4.8 g kg^?1) had significantly lower weight gain rate, specific growth rate (SGR) and feed efficiency than those fed the other diets (P < 0.05). The survival rate of fish fed the control diet was significantly lower than that of the fish fed the other diets (P < 0.05). Whole body viscerosomatic index and crude lipid content decreased significantly with increasing dietary available phosphorus levels (P < 0.05), while the contents of crude ash, calcium, phosphorus in the whole body and vertebrae showed the opposite trend (P < 0.05). The blood chemistry analysis showed that dietary available phosphorus had significant effects on serum phosphorus concentration, enzyme activities of alkaline phosphatase and parathyroid hormone level. Quadratic curve analysis based on SGR indicated that the minimum dietary requirement of available phosphorus for maintaining optimal growth of tilapia was 8.6 g kg^?1.     

吉富品系尼罗罗非鱼选育过程中遗传变异的微卫星分析

采用微卫星标记技术对选育新品种新吉富罗非鱼（F8－9）群体、基础群体（F0）、以及选育中群体（F6－7）在选育过程中出现的遗传变异进行观察与分析。19个微卫星位点扩增后的等位基因数为3～11个,随引物不同而异,合计得到115个等位基因,大小在70～270 bp之间。五群体平均基因多样性指数分别为,F0：(0.3083±0.1834)、F6：(0.2982±0.1889)、F7：(0.2923±0.1898)、F8：(0.2572±0.1923)、F9：(0.2743±0.1597),表明随着选育的进展,群体呈现出纯化趋势。AMOVA分析表明,在总遗传变异中,93.24%来自选育群体内,仅6.67%来自选育群体间。群体间的校正偏差后相似性系数在 F0与F6、F7之间分别为0.943 5和0.942 2,相对较高;而在F0与F8、F9之间分别为0.933 2和0.930 3, 相对较低。遗传距离在F0与F6、F7之间分别为0.058 1和0.059 5,相对较小;而在F0与F8、F9之间分别为0.069 1和0.072 2,相对较大。配对比较Fst值在F0与F6、F7之间分别为0.037 68和0.064 37,平均 值为0.051 03;而在F0与F8、F9之间分别为0.060 93和0.075 87,平均值为0.068 40,有所提高。这些指标的分析结果表明,经9年9代选育,已在罗非鱼世代间造成程度虽小但却可监测到的遗传分化;同选育群体F6－7相比,\"新吉富罗非鱼\"（F8－9）在遗传上更为稳定。图1表4     

Haematological response and growth performance of Nile tilapia (Oreochromis niloticus L.) fed diets containing folic acid

Haematological response and growth performance over 150 days, and resistance to a low-temperature stress of Nile tilapia fed diets with increasing folic acid (FA) levels were evaluated. The experiment was conducted in a completely randomized design with eight FA levels (0.0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 mg kg⁻¹ feed) supplemented in purified diets (32.0% CP and 13 398 kj DE kg⁻¹). One hundred and ninety-two fingerlings were randomly assigned to 32 net cages distributed in eight 1000 L aquaria with a physical and biological filter and a temperature control system (26.0 ± 1.0 °C). For cold-induced stress, fish were transferred to 24 30 L-aquaria with individual biofilters and aeration. The water temperature was gradually reduced until it reached 13 °C. Haematological parameters evaluated before and after cold stress were total erythrocytes and leucocytes count, differential leucocyte, haemoglobin, haematocrit, total plasmatic protein and haematometric indices. Growth performance parameters were mean weight gain, feed conversion ratio and survival. Dietary FA supplementation did not influence erythropoiesis under normal temperature conditions; cold stress impaired erythropoiesis, causing hypochromic microcytic anaemia and leucopoiesis, and also neutrophilia. Growth performance is influenced by folate and supplementation between 0.5 and 1.0 mg FA kg⁻¹ diet, which makes up for nutritional demands, guaranteeing production and health under appropriate temperature conditions.