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1.
随着对虾养殖业的持续发展，目前已发现对虾病害多达几十种，而在细菌性疾病中尤以弧菌病最难治愈，其治愈难度与病毒性疾病相差无几。弧菌病也是对虾养殖中危害最大、最普遍的一种虾病，其病原副溶血弧菌、溶藻弧菌平时广泛潜伏于海水或虾体内，是一种条件致病菌，当养殖环境恶化、虾抵抗力下降时，就会大量繁殖蔓延，引发对虾发生弧菌病，导致对虾的大规模死亡。 一、典型病症 患病的对虾往往会有游泳无方向性，活动力减弱，多数沉于水底不动，食欲不振，摄食量大减等症状，故检查其胃部，仅有少量食物或空胃。随着对虾养殖业的发展，养殖…  相似文献   

2.
用1000ml小水体进行斑节对虾和凡纳对虾各期幼体对卤虫无节幼体摄食量的比较实验，结果表明，二种对虾的卤虫摄食量与卤虫密度有关，在相同密度下，糠虾期凡纳对虾卤虫日摄食量明显高于斑节对虾，而卤虫密度对摄食量的影响凡纳对虾略低于斑节对虾，仔虾期卤虫摄食量差异日渐减小，P5-P6已很接近。  相似文献   

3.
对虾幼苗质量的优劣关系到成虾养殖的成败,育苗和养殖户都十分关心幼体的健康状态。以往一些外观特征如色泽、活动力、虾体洁净度、胃含物和肌肉发育程度都曾用来估计对虾幼体的健康状况。虽然这些方法起到一定的作用,但很难定量,不能准确反映对虾幼苗的质量。现国外正应用一种简单的抗逆力测试法来估计对虾幼体的生理状态和幼苗的质量。这就是将对虾幼体投入较低盐度的水体中,1个小时后计算幼体的存活率。具体方法为将5期幼体投入到14‰海水中,10期投入到7‰海水中,15期投入到淡水中。这一方法也被用来估计育苗期间幼体的摄食情况。  相似文献   

4.
鲈与中国对虾混养试验   总被引：1，自引：0，他引：1  
１９９５、１９９６年进行鲈与中国对虾混养试验，利用鲈摄食病虾及小型糠虾类，阻断病毒传播，推迟了对虾发病，试验池产量，效益成活率均高于对照池。  相似文献   

5.
养虾池的水质是影响对虾产量的主要因素之一。有经验的养殖人员都讲“养虾就是养水”水对对虾的重要性,尤如空气对人,在不良水质中,对虾摄食量下降,甚至停止摄食,其生长受到严重影响;水质严重恶化时,直接造成大批甚至全池对虾的窒息死亡,而导致养虾的失败。不良的水质又可助长各种寄生  相似文献   

6.
饵料系数又称饲料系数，是指被摄食的饵料量与对虾净增肉重量的比值，生产上饲料系数常常是指投饵系数，即指在养殖过程中投饵总量与虾产量的比值。由于饲料成本在养虾的总成本中所占的比例达50％以上。投饵系数的高低，对养虾效益影响极大。特别在当前对虾饲料价格居高不下、对虾销售价格偏低、养虾效益普遍下降的情况下，如何降低饵料系数成为减少养虾成本的一项主要技术措施和提高养殖经济效益的一条重要途径。  相似文献   

7.
水质，是对虾养殖中影响其生长和产量的重要因素。良好的水质是对虾养殖的必需条件。不良的水质将使对虾摄食量下降，甚至停止摄食，并胁长细菌繁殖和有毒物质的积累，导致对虾发病。水质严重恶化时还能造成对虾窒息死亡，使养虾失败。因此，水质的控制，是对虾养成期间的重要管理工作。  相似文献   

8.
黑鳃病在对虾养殖中是一种常见的疾病,其危害程度可大可小,如处理不当,可引起对虾大量死亡。一、对虾黑鳃病的病原、症状及解剖变化1.病原:取病虾鳃丝磨片直接镜检及实验室检验,确定黑鳃病的病原主要为细菌,但池塘底质与水质不良会促使该病的发生。2.症状:病虾在水面慢游,尤其在傍晚及早晨日出之前多见;病虾不摄食,肠道空虚,外观其鳃部发黑;增氧机周围的池底有死虾。3.解剖变化:解剖病虾,可见鳃部发黑,胃、肠空虚;镜检鳃片,可见鳃丝发黑、肿胀及溃烂。病虾往往因鳃部呼吸功能受损、机体严重缺氧而死亡。二、对虾黑鳃病的病因经过大量的病例…  相似文献   

9.
中国明对虾、凡纳滨对虾仔虾的行为观察   总被引：7，自引：1，他引：6  
张沛东  张秀梅  李健 《水产学报》2008,32(2):223-228
在(22±1)℃及高密度养殖环境条件下,观察中国明对虾、凡纳滨对虾仔虾的摄食、自残、运动、间隔及攻击和防御行为,并探讨充气对两种仔虾行为的影响.结果表明,两种仔虾都偏好卤虫幼体.中国明对虾仔虾自残行为高发,运动活跃,间隔行为明显,攻击频率高;凡纳滨对虾仔虾自残现象少,好静,可忍受身体的相互接触,攻击频率低.充气对两种仔虾的行为均有显著影响.  相似文献   

10.
张良尧 《内陆水产》2006,31(1):25-25
饵料系数又称饲料系数,是指摄食的饵料量与对虾净增肉重量的比值,生产上饲料系数常常是指饵料系数。由于饲料成本在养虾的总成本中所占比例达50%￣60%以上,投饵系数的高低,对养虾效益影响极大。特别在当前对虾饲料价格居高不下、对虾销售价格偏低、养虾效益普遍下降的情况下,如  相似文献   

11.
该研究通过对17β-雌二醇(E2)的投喂方式和投喂时间进行比较,探索了XY全雄黄颡鱼(Pelteobagrus fulvidraco)的雌性化方法,进而建立3个家系(XY♀×XY♂),结合性别分子标记对黄颡鱼雌性化诱导的成活率和性逆转率进行了对比研究。结果显示,卤虫(Artemia sp.)组从开口第1天进行诱导的性逆转率为75.20%,而从开口第5天进行诱导得不到发育好的雌性;从开口第1天投喂激素,饲料组的成活率与卤虫组无显著差异(P>0.05),而性逆转率显著高于卤虫组(P<0.05);分子标记Y1和Y2相结合能够准确鉴定黄颡鱼的遗传性别;对照组中3个家系的成活率和各个基因型性别比例均无显著差异(P>0.05),成活率为51.00%~56.67%,XX雌性占比为90.91%~97.44%,XY雄性占比为94.56%~95.96%,而YY则为雄性;诱导组中3个家系的成活率和性逆转率均无显著差异(P>0.05)。结果表明,采用含50 mg·kg-1 E2的微颗粒饲料从开口第1天开始诱导30 d,并运用遗传性别与表型性别鉴定相结合的方法能够有效筛选获得发育良好的XY/YY雌性黄颡鱼。  相似文献   

12.
A feeding trial was conducted to evaluate the effect of inclusion of Sesbania leaf meal in the diet of Cyprinus carpio as a replacer of de‐oiled rice bran (DORB). Bacillus subtilis was used to ferment the Sesbania leaf meal (SLM) to produce FSLM (fermented sesbania leaf meal). Fishes were fed with five isonitrogenous (30% CP) and isocaloric diets for 60 days and treatments were viz., C (30% DORB, 0% SLM), R15 (15% DORB, 15% SLM), R30 (0% DORB, 30% SLM), F15 (15% DORB, 15%FSLM) and F30 (0% DORB, 30% FSLM) by replacing DORB with SLM. A similar growth performance with control was observed in 15% FSLM group while there was a growth reduction in all the raw leaf meal fed groups. Similarly, the expression of insulin‐like growth factor‐1 (IGF‐1) was significantly (p < .05) higher in control and 15% FSLM fed groups. Growth and metabolic enzymes such as protease, amylase, ALT and AST activities were significantly higher in the fermented leaf meal fed groups compared to their non‐fermented counterparts. Antioxidant enzymes, serum transaminase enzymes (SGOT, SGPT) and total bilirubin (TBR) were found to be increased by enhanced level of RSLM, however, reduced by inclusion of FSLM. However, 30% inclusion level of FSLM even after fermentation showed detrimental effect on growth and metabolic response at cellular and molecular level. Thus, the results concluded that fermented Sesbania leaf meal (FSLM) using B. subtilis could replace 50% DORB (15% FSLM group) in the diet of C. carpio without affecting the growth and other physiological responses.  相似文献   

13.
The effects of six formulated diets containing different protein and lipid levels on growth performance and body composition of juvenile southern flounder were evaluated. Test diets were prepared with a combination of three crude protein (CP) levels (45, 50 and 55%) and two crude lipid (CL) levels (10 and 15%). Diets (CP/CL) were as follows: 45/10, 45/15, 50/10, 50/15, 55/10, 55/15 and a commercial diet (50/15). Southern flounder (1.10 g) were fed the respective diets for 42 d in triplicate recirculating tanks (20 fish/tank). Percent body weight gain (BWG) for fish fed diet 45/10 (413%) and the commercial diet (426%) were significantly (P < 0.05) lower than fish fed other diets (823–837%). Increasing protein level from 45 to 50% produced a significant increase in BWG for the 10% lipid diet (823%) but further increasing protein did not produce a significant effect on BWG irrespective of dietary lipid levels. Specific growth rate (SGR), feed intake, feed conversion efficiency (FCE), protein efficiency ratio (PER), and total lipid content in the whole body were significantly affected by different dietary protein and lipid levels. Results indicated that a combination of 50% protein and 10% lipid was optimal for the growth performance of southern flounder juveniles.  相似文献   

14.
Optimum dietary protein and lipid levels for juvenile rockfish were determined. Eight hundred and ten juvenile fish averaging 3.22 g were randomly chosen and distributed into 27 flow‐through tanks of 50 L (30 fish per tank). Nine experimental diets were prepared according to a 3 × 3 factorial experimental design: three crude protein levels (45%, 50% and 55%) × three crude lipid levels (11%, 15% and 19%). Crude protein and crude lipid levels increased at the expense of dextrin and cellulose in the experimental diets. Survival of fish was not affected by either dietary protein or lipid level. Weight gain of fish was affected by dietary protein level, but not by dietary lipid level. Weight gain of fish fed the 50P‐15L (50% protein and 15% lipid) diet was higher than that of fish fed the 45% protein diets regardless of lipid level, but not different from that of fish fed the 50P‐11L (50% protein and 11% lipid), 50P‐19L (50% protein and 19% lipid), 55P‐11L (55% protein and 11% lipid), 55P‐15L (55% protein and 15% lipid) and 55P‐19L (55% protein and 19% lipid) diets. Feed consumption of fish was affected by dietary protein level, but not by dietary lipid levels. Feed efficiency ratio (FER) of fish was affected by dietary protein level, but not by dietary lipid level. Protein efficiency ratio (PER) of fish was affected by dietary protein level, but not by dietary lipid level. Nitrogen retention efficiency (NRE) of fish fed the 45P‐19L diet was higher than that of fish fed the 45P‐11L, 50P‐11L, 50P‐15L, 50P‐19L, 55P‐11L, 55P‐15L and 55P‐19L diets, but not different from that of fish fed the 45P‐15L diet. Moisture, crude protein and crude lipid contents of fish was affected by dietary protein and/or lipid level. Plasma triglyceride of fish was affected by dietary lipid level, but not by dietary protein level. In conclusion, optimum protein and lipid levels for growth and feed utilization (PER and NRE) for juvenile rockfish were 50% and 15%, and 45% and 19%, respectively, and the optimum dietary protein‐to‐energy ratio of 27.4 and 23.9 mg protein kJ?1.  相似文献   

15.
Maca tuber meal is used in fish diet formulations in Andean trout culture and knowledge of its effects on fish growth is paramount to healthy human food production. In the first experiment with rainbow trout alevins (0.096±0.002 g), starter diets were offered from first feeding until 15 weeks. We formulated high protein content (～60%) semi‐purified starter diets supplemented with 0%, 5%, 10%, or 15% maca tuber meal (control, M‐5, M‐10, and M‐15 respectively). The second feeding trial was conducted with juveniles (1.56±0.02 g) fed one of three diets (control, M‐15, and commercial) for 8 weeks. In the first experiment, fish fed M‐10 and M‐15 diets exhibited significantly higher growth rates than the other dietary groups. Survival was significantly improved in the groups fed diets supplemented with maca tuber meal (60.0–69.2%) in comparison with the group fed a control diet (21.7%). The second experiment showed a higher growth rate in the M‐15 group compared with the control and a commercial diet fed group. Leucocyte numbers were increased by dietary supplementation of maca tuber meal. The findings of the present study suggest that a maca tuber meal inclusion at least 5% improves growth rate, feed utilization, immunity by increased leucocyte number, and survival of rainbow trout alevins and juveniles.  相似文献   

16.
Growth performance of kuria labeo, Labeo gonius as a component species in the major carp polyculture system was evaluated at two incorporation levels against a control without the species through a year‐round grow‐out study in nine earthen ponds (0.08 ha). Three species ratio of catla, silver carp, rohu, mrigal and kuria labeo at 15:15:40:30:0 (T‐1: control), 15:15:40:20:10 (T‐2) and 15:15:40:10:20 (T‐3) were evaluated as three treatments. The carps were stocked at a combined density of 7500 fingerlings ha?1. Silver carp demonstrated the highest survival (75–81%) followed by rohu (70–76%), catla (69–76%), kuria labeo (69–71%) and mrigal (67–69%). Species‐wise yield attributes such as survival, harvest weight, SGR and biomass yield of silver carp, catla and rohu were similar in their respective treatments. Kuria labeo at 10% inclusion demonstrated 12% higher harvest weight than its 20% inclusion. However, such higher weight gain could not affect the total biomass yields of carps which remained similar among the treatments. Furthermore, harvest weight of kuria labeo at 10% inclusion was comparable to that of mrigal when the latter incorporated at 20–30% level. Therefore, the study suggested 10% to be a suitable incorporation level for kuria labeo in the commercial grow‐out carp polyculture system.  相似文献   

17.
Two 21 day experiments were conducted to determine whether microparticulate diets could be used to substitute for diatoms for raising (Experiment 1) as well as settling and on‐growing (Experiment 2) Haliotis diversicolor supertexta postlarvae. The experiments were conducted in 10 L flow‐through tanks and each diet had three replicate tanks. In experiment 1, three experimental microparticulate diets supplied by a commercial feed company, labelled SF‐15, SF‐15 (T) and JFY‐13–1, were used, and in experiment 2, SF‐15 and SF‐15 (T). Artificial diets were compared to diatoms in terms of supporting growth and survival. The survival rate for experiment 1 was lowest for JFY‐13–1 (0%) and highest for diatoms (12.9±0.8%). The final size of postlarvae fed SF‐15 and SF‐15 (T) was significantly greater than that of postlarvae fed diatoms, 973±193 μm and 996±220 μm compared to 786±141 μm. In experiment 2, a total number of 501 larvae settled onto plates covered with SF‐15, 254 on SF‐15 (T) and 1085 on diatoms. The highest survival rate was 33.1±6.9% for SF‐15 and the lowest was 17.3±5.0% for diatoms. However, the final length of postlarvae fed diatoms was significantly greater than SF‐15 and SF‐15 (T); 1018±379 μm compared to 728±89 μm and 717±90 μm. The artificial micro diets used in this study were comparable to diatoms in terms of grow and survival of postlarval H. diversicolor supertexta.  相似文献   

18.
Turbot Scophthalmus maximus, larvae were start‐fed with formulated feeds containing marine phospholipids (MP) or soya phospholipids (SP). The experiment was performed with six experimental groups, four groups were given formulated feeds, one group was given live feed and one group was starved. Phospholipid (PL) contents of the formulated feeds were respectively 5% MP, 15% MP, 5% SP and 15% SP. Larvae were offered feed from day 3 post‐hatch. There was no significant size difference on day 5 between the group fed 15% MP and the group given rotifers. Electron microscopical examination of enterocytes was performed on larval intestine on day 5. Larvae fed 5% and 15% MP and larvae fed rotifers had normal looking enterocytes with numerous normal looking mitochondria. In the enterocytes of larvae fed 5% SP and 15% SP the mitochondria appeared swollen with a translucent matrix and fragmented cristae. Thus, MP and not SP seemed suitable as a lipid and PL source for start‐feeding turbot larvae.  相似文献   

19.
This study was conducted to determine the effects of increasing dietary lipid concentrations on fillet characteristics of post-juvenile rainbow trout. A feeding trial was conducted with fish meal based diets containing 10, 15, 20, 25, or 30% lipid for 24 wk. Menhaden oil was the lipid ingredient. Weight gain was significantly greater in fish fed the 30% lipid diet than in fish fed either 10%, 15% or 20% lipid diets. There were no significant differences in visceral somatic index. Fillet lipid concentration of fish fed the 30% lipid diet (9.2-g lipid/ 100-g fillet) was significantly higher (P < 0.05) than fish fed either the 10% or 15% lipid diets (5.8- and 6.9-g lipid/100-g fillet, respectively). In samples stored for 3 d at 5 C or S wk at -20 C, sensory panelists reported that the cooked fillets from fish fed the 30% lipid diet were "more fishy" than fish fed the 15% lipid diet, and preferred the cooked fillets from the 15% lipid treatment over the 30% lipid treatment. Triangle tests and fillet colorimetry showed no significant differences between fillets from fish fed the 15% and 30% lipid diets at any sampling time point. No significant differences in fillet concentrations of thiobarbituric reactive substances were observed among dietary treatments stored at either 5 C or -20 C. These results suggest that two main effects of feeding a 30% lipid diet (with fish oil as the lipid source) are a higher lipid concentration in the fillet and a "fishier" aroma compared to fillets from fish fed a 15% lipid diet.  相似文献   

20.
Frozen beef liver fed at dietary levels of 5, 10, 15, 20, and 25% (dry weight) to postlarval Mucrobruchium rosenbergii was evaluated as a supplement to Mna Trout Chow No. 2. Final mean wet weights and yields of prawns fed 15, 20, and 25% beef liver were significantly higher than those of prawns that received 5 and 10% levels. Survival rates and food conversion ratios of dry matter fed to wet biomass produced were not significantly different among treatments. The suitability of 47 fresh and frozen fruits and vegetables as dietary supplements was tested. Fourteen fruits and vegetables sank and were readily consumed by prawns, and seven (fresh orange and sweet potato, and frozen banana, carrot tops, butternut squash, yellow squash, and turnip greens) were tested as supplements (10% dry weight of the total ration) to trout chow and 15% beef liver. There were no significant differences ( P < 0.05) in final mean weight, survival, yield, or food conversion ratio. Pigmentation of prams fed carrot tops or turnip greens was enhanced. No significant differences in final mean weight, yield, or survival were found when frozen banana was evaluated at levels of 0, 5,10,15, and 20% as a supplement to trout chow and 15% beef liver. Food conversion ratios for prawns fed 15 and 20% levels of banana were not different from those fed 10%, but were significantly higher than for prawns fed the 0 and 5% levels. Thus, a diet of Purina Trout Chow No. 2 plus 15% beef liver gives good results with postlarval M. rosenbergii in aquaria. Largescale testing and an economic analysis are needed to determine if this diet is practical for commercial prawn nurseries.  相似文献   

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