Growth of juvenile tilapia, Oreochromis niloticus L. from Lakes Zwai, Langeno and Chamo (Ethiopian rift valley) based on otolith microincrement analysis     

D.Admassu  I.Ahlgren 《Ecology of Freshwater Fish》2000,9(3):127-137

Abstract – Age and growth of juvenile tilapia, Oreochromis niloticus , from Lakes Zwai, Langeno and Chamo (Ethiopia) were studied from microincrements in otoliths. Growth in length was best described by the Gompertz model. Average growth rate of the fish was most rapid in Lake Chamo (0.39 mm  ·  day⁻¹, 1.14%  ·  day⁻¹), intermediate in Lake Zwai (0.20 mm  ·  day⁻¹, 0.72%  ·  day⁻¹) and slowest in Lake Langeno (0.16 mm  ·  day⁻¹, 0.62%  ·  day⁻¹). Similarly, back-calculation from otolith increment widths gave growth rates of 0.28 to 0.43 mm  ·  day⁻¹, 0.15 to 0.32 mm  ·  day⁻¹ and 0.11 to 0.28 mm  ·  day⁻¹ for Chamo, Zwai and Langeno fish, respectively. In addition, Fulton's condition factor was largest for Chamo tilapia and smallest for Langeno tilapia; the difference between fish from Langeno and Zwai was small. Rapid growth of juvenile O. niloticus in Lake Chamo was attributed to warm temperature and better food quality. ^Note  相似文献   

Effect of different photoperiod cycles on metabolic rate and energy loss of fed and unfed adult tilapia Oreochromis niloticus: Part II     

Amal Kumar  BISWAS  Toshio  TAKEUCHI 《Fisheries Science》2002,68(3):543-553

ABSTRACT: To study the influence of different photoperiod cycles on the metabolic rate and energy loss of fed and unfed adult tilapia Oreochromis niloticus (bodyweight 102–107 g) at 28°C, four photoperiod cycles (i.e. 3L : 3D, 6L : 6D, 12L : 12D, and 24L : 24D) were applied. A computer-operated respirometer with a closed tank was used so as to prevent water from condensing from the air or evaporating into the air. A photoperiod-mediated metabolic cycle was demonstrated during the routine state in which the metabolic rate was higher during the light phase compared with during the dark phase for all photoperiods. The combined effects of photoperiod and feeding episodes acted as a strong Zeitgeber (cue or synchronizer) for synchronizing the daily rhythm in fed fish. Fish exposed to short photoperiod cycles showed a higher metabolic rate and energy loss compared with those exposed to longer photoperiod cycles. Mean oxygen consumption in the fed and unfed fish were 295.7 mg/kg per h and 149.8 mg/kg per h, respectively, during the 3L : 3D period; 286.5 mg/kg per h and 143.3 mg/kg per h during the 6L : 6D period; 262.2 mg/kg per h and 130.3 mg/kg per h during the 12L : 12D period; and 238.3 mg/kg per h and 120.4 mg/kg per h during the 24L : 24D period. The highest post-prandial increase in energy loss was recorded during the 3L : 3D period (56.2 kJ/kg per day), followed by 55.1 kJ/kg per day during the 6L : 6D period, 50.7 kJ/kg per day during the 12L : 12D period, and 45.4 kJ/kg per day during the 24L : 24D period. The study's results demonstrated that the fish conserve energy when raised under longer photoperiod cycles.  相似文献   

Sensitivity of Tilapia (Oreochromis mossambicus) to Clostridium botulinum toxins     

K V Lalitha  & K Gopakumar 《Aquaculture Research》2001,32(9):761-764

The sensitivity of Oreochromis mossambicus to Clostridium botulinum toxin types A–E was investigated. All five toxin types were toxic to O. mossambicus. In the case of toxin types A–D, O. mossambicus was considerably more resistant than mice and, in the case of type E toxin, fish were more sensitive. The minimum intraperitoneal (i.p.) dose of type E toxin for fish was half the minimum lethal dose for mice. The results of the study suggest that good hygiene should be maintained in fish/shrimp farms to keep contamination at a low level.  相似文献   

Impact of the timing of stocking on growth and allometric index in aquaculture-based fisheries     

A. L. Ibáñez 《Fisheries Management and Ecology》2004,11(2):81-87

The impact of tilapia stocking on fisheries production in Lake Metztitlán was determined through progression analysis of modes obtained from (Gaussian) kernel density estimators (KDEs) of size frequency distributions of juvenile tilapia stocked after a period of total desiccation. The relationship between the allometric index of four cohorts and water temperature and variation in the volume of the basin was analysed. The use of KDEs was found to be a useful technique for the recognition and progression analysis of modes. The reasons for the low yields from the tilapia fishery of Lake Metztitlán are poor growth rate, low water temperature, which is manifest in low allometric indices, and the use of small mesh size nets. Yields can be sustained by improving fishery management; otherwise it is necessary to continue stocking.  相似文献   

添加海带废渣饲料养殖尼罗罗非鱼种的试验     

李建生  王寿昆  林树根  彭时尧  甘纯玑  施木田 《福建农林大学学报(自然科学版)》1996,(4)

试验设计了海带废渣添加量分别为０％、５％、１０％、２０％和３０％等５种水平，粒度小于０．３ｍｍ的５种饲料，饲料中鱼粉添加量均为５％，实测粗蛋白含量平均为２３．１％．结果表明，５％海带废渣饲料组的尼罗罗非鱼种（Ｏｒｅｏｃｈｒｏｍｉｓｎｉｌｏｔｉｃｕｓ）增重效果分别显著高于对照组（Ｐ＜０．０５）和３０％海带废渣饲料组（Ｐ＜０．０１），１０％和２０％海带废渣饲料组亦分别显著高于３０％海带废渣饲料组（Ｐ＜０．０５），而５％－２０％海带废渣饲料组间的增重效果无显著差异．５％海带废渣饲料组的饲料系数最低，为２．１０．氨基酸蓄积率和蛋白质效率（ＰＥＲ）亦以５％海带废渣饲料组为最高．饲料的必需氨基酸（ＥＡＡ）含量与鱼体肌肉组织的必需氨基酸含量呈微弱正相关，而与鱼体肌肉组织的氨基酸蓄积率呈显著负相关  相似文献   

YY型莫桑比克罗非鱼雌性转化后测交筛选的研究   总被引：6，自引：0，他引：6  

万松良  杨永铨 《水产科技情报》1994,21(5):195-199

采用与ＹＹ型雄鱼测交的方法，从１９７尾转化雌鱼中初步选出１５尾ＹＹ型雄鱼，其中３尾鱼的Ｆ１雄性率为１００％，１０尾鱼的Ｆ１雄性率为９０．６％－９８．４％。对３尾初选ＹＹ型雄鱼进行重复验证，其中２尾鱼的Ｆ１中，ＹＹ型雄性比率分别是４５．８％和４８．１％，Ｘ＾２检验符合５０％ＹＹ型雄鱼的理论比值；另１尾ＹＹ型雌鱼又与ＹＹ型雄鱼交配，Ｆ１中ＹＹ型雄鱼为１００％。３尾母本均再次被证实为ＹＹ型雌鱼。雌性转化  相似文献   

红罗非鱼稚鱼与雌雄亲鱼肌肉脂肪酸组成分析     

陈涛  徐高骁  黄凯 《广西农业科学》2013,(5):850-853

【目的】测定红罗非鱼（Oreochromissp．）稚鱼、雌雄亲鱼的肌肉脂肪酸组成,为红罗非鱼的生物学研究及科学养殖提供基础资料。【方法】采用常规的化学分析方法及气相色谱技术检测红罗非鱼稚鱼与雌雄亲鱼肌肉脂肪酸的组成及含量变化。【结果】从红罗非鱼稚鱼肌肉中检测出10种脂肪酸,雌雄亲鱼肌肉中检测出16种脂肪酸,以C16：0、C16：1、C18：0、C18：In．9、C18：2n．6的含量较高,占总脂肪酸含量的84％以上。红罗非鱼肌肉脂肪酸含量因生长期和性别不同而异,C20：5n．3（EPA）和C22：6n．3（DHA）在稚鱼肌肉中未能检出,雌亲鱼肌肉中含有少量（0．47％h和0．65％）,雄亲鱼肌肉含量丰富（1．39％和2．33％）;红罗非鱼稚鱼和雄性亲鱼肌肉中,脂肪酸含量次序为：饱和脂肪酸含量（ESFA）〉单不饱和脂肪酸含量（∑MUFA）〉多不饱和脂肪酸含量（~,PUFA）,雌性亲鱼肌肉中：∑MlIFA〉∑SFA〉∑PU-FA。【结论】红罗非鱼稚鱼阶段主要依靠∑sFA提供能量以满足其生长所需,雌雄亲鱼则依靠∑MuFA和∑PuFA来提高其繁殖性能。  相似文献   

Physicochemical and Antioxidant Properties of Gelatin and Gelatin Hydrolysates Obtained from Extrusion-Pretreated Fish (Oreochromis sp.) Scales     

Wei-Cheng Shiao  Tien-Chiu Wu  Chia-Hung Kuo  Yung-Hsiang Tsai  Mei-Ling Tsai  Yong-Han Hong  Chun-Yung Huang 《Marine drugs》2021,19(5)

Fish gelatin and its hydrolysates exhibit a variety of biological characteristics, which include antihypertensive and antioxidant properties. In this study, fish gelatins were extracted from extrusion-pretreated tilapia scales, and then subjected to analyses to determine the physicochemical properties and antioxidant activity of the extracted gelatins. Our findings indicate that TSG2 (preconditioned with 1.26% citric acid) possessed the greatest extraction yield, as well as higher antioxidant activities compared with the other extracted gelatins. Hence, TSG2 was subjected to further hydrolyzation using different proteases and ultrafiltration conditions, which yielded four gelatin hydrolysates: TSGH1, TSGH2, TSGH3, and TSGH4. The results showed that TSGH4 (Pepsin + Pancreatin and ultrafiltration < 3000 Da) had a higher yield and greater antioxidant activity in comparison with the other gelatin hydrolysates. As such, TSGH4 was subjected to further fractionation using a Superdex peptide column and two-stage reverse-phase column HPLC chromatography, yielding a subfraction TSGH4-6-2-b, which possessed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity compared with the other fractions. Further LC-ESI/MS/MS analysis of TSGH4-6-2-b suggested two novel peptides (GYDEY and EPGKSGEQGAPGEAGAP), which could have potential as naturally-occurring peptides with antioxidant properties. These promising results suggest that these antioxidant peptides could have applications in food products, nutraceuticals, and cosmetics.  相似文献   

慢性盐度胁迫对吉丽罗非鱼(尼罗罗非鱼♀×萨罗罗非鱼♂)及其两亲本耐盐性的影响     

李学军  郭瑄  聂国兴  孔祥会  乔志刚 《水产学报》2013,37(2):256-262

为深入研究养殖新品种吉丽罗非鱼[尼罗罗非鱼(♀)×萨罗罗非鱼(♂)]的耐盐性能,对吉丽罗非鱼及其两个亲本尼罗罗非鱼和萨罗罗非鱼进行了慢性盐度胁迫实验,分析了3种罗非鱼耐盐性能的差异,建立了盐度胁迫过程中死亡率与致死盐度及时间的回归模型,结果显示:(1)3种罗非鱼的耐盐能力差异显著,吉丽罗非鱼的耐盐性能接近于萨罗罗非鱼,远高于尼罗罗非鱼,耐盐胁迫时3种罗非鱼的平均致死盐度分别为57.9、66.7和18.5.(2)盐度胁迫实验中尼罗罗非鱼个体间死亡时间差异最大,萨罗罗非鱼个体之间差异最小,吉丽罗非鱼介于其间;吉丽罗非鱼和萨罗罗非鱼死亡时间都有极显著的正态负偏移,离群值和极值较多,尼罗罗非鱼有较显著正态正偏移,只有离群值,没有极值.(3)3种罗非鱼盐度胁迫实验中死亡率与死亡时间及盐度之间的回归关系更适合一元回归,吉丽罗非鱼盐度胁迫实验中死亡率(y)与死亡时间(t)的回归模型为增长模型Y=e (-7.694+0.031t)(R2=0.979),死亡率(Y)与盐度(s)的回归模型为二次模型Y =0.542-0.037s +0.001s2(R2=0.950).  相似文献   

Impact of Sump Tank Size on Growth,Survival, and Production of Marron,Cherax tenuimanus,in an Intensive System     

《Journal Of Applied Aquaculture》2013,25(3):23-31

Juvenile marron, Cherax tenuimanus were cultured in an intensive crayfish culture system for a period of six months to study the effects of sump tank size on crayfish growth, survival, and production. Water volume in the large sump system was 2750 L and in the small sump tank system was 500 L. Crayfish were held in individual compartments (surface area 320 cm², depth 10 cm) and fed with commercial pellets (30% protein; 3-5% body weight per week). Specific growth rate (SGR) was 0.75%/day in the large sump system and 0.68%/day in the small sump system; survival was 83% in the large sump system and 71% in the small sump system; and biomass roduction (B) was 239 g/m² in the large sump system and 158 g/m² in the small sump system. These values were all higher (P < 0.05) in the large sump system. The results suggest that crayfish production could be improved by using large sump tanks in recirculating intensive crayfish culture systems.  相似文献