鱼塘增氧设备的使用方法

鱼池若想达到立体增氧效果,需要合理搭配与使用涌浪机、水车式增氧机、纳米曝气盘等先进增氧设备,注意各种增氧机的使用方法,做到适时合理开机,实现互补作用,有效提高水体溶氧量,减少疾病发生,达到健康养殖、提高经济效益的目的。     

池塘正确使用增氧机的技术要点

一、增氧机的种类和功能 (一)叶轮式增氧机 具有增氧、搅水、爆气等综合作用,适用于水深1米以上的大面积池塘增氧,是目前最多采用的增氧机。 (二)水车式增氧机 具有良好的增氧及促进水体流动的效果,适用于淤泥较深,面积1.5～3.8亩的池塘使用。 (三)射流式增氧机 增氧动力效率超过水车式,充气、喷水等形式的增氧结构简单,能形成水流,搅拌水体。射     

江苏:推广高效养虾蟹设备

今年,江苏南通启东市东海镇推广"池塘虾蟹养殖立体式增氧技术",即每个池塘安装微孔曝气式增氧设备,还必须配备1～2台叶轮式或水车式增氧机,目前,已使2万多亩养殖区微孔增氧机和叶轮式或水车式增氧机同时安装面积达80%以上。据悉,在往年     

池塘养殖中微孔曝气增氧技术

本文通过对比微孔曝气增氧技术和水车式的增氧机在池塘养殖中的应用发现,微孔曝气增氧技术可以有效节约电量,快速增氧,且增氧效果良好;另外,微孔曝气增氧技术还可以改善池塘养殖的水体环境,缩短养殖周期。因此,池塘养殖应推广运用微孔曝气增氧技术,提升养殖效益。     

使用增氧机应注意的几个问题

一、根据水域情况选购增氧机。目前全国市场上有增氧机系列10个左右,品种近达几十种,主要有潜水喷泉式、叶轮式、水车式、移动式增氧机等,可根据水域大小、经济情况、使用习惯、电源等诸多因素选购合适的增氧机械。 二、负荷合理。常规一台3千瓦的增氧机可负荷水面4002m~2～4669m~2,最多不得超过6670m~2,购买时应根据塘面积大小选购使用。     

增氧机的配置及使用技术

水中溶氧量的高低直接影响鱼类的摄食、生长和饲料利用率,乃至影响鱼类的生存。因此,实行精养高产的集约化养鱼池塘,需要配置增氧机。 增氧机有叶轮式、水车式、喷水式和充气式等多种。要根据池塘水体条件、池鱼密度和产量等情况配置增氧机。一般水深在2米以上的池塘,可配置叶轮式或     

渔用增氧机节能措施

渔用增氧机具有增氧解救一浮头”、搅水提高港氧及提高饵料生物产量、改善水质．从而提高鱼类产过的功效。l．选择最佳开机时间（l）黎明前开机。此时气压较低．鱼类及各种动植物已经一夜耗氧．开机1～2小时即可使池水中溶氧量恢复到4毫克／升以上。（2）上午8时30分至10时30分开机。此时是全天光照最佳时间．开机l～2小时．除了能向水中补充氧气外．还能促进池水交换．并利用浮游植物的光合作用。增加池水的溶氧量。（3）下午15时至17时开机。此时气温较高．水温上升．池水溶氧量随水温增高而减少。而鱼类体内的新陈代谢旺盛．耗氧量随之增…     

渔业上应用的超声波增氧系统的研究进展

氧是鱼类赖以生存和生长发育的必备条件之一，水中含氧量主要与自然温度、湿度以及鱼体的密度有关。在炎热的夏天，溶氧量的减少会使鱼上浮水面吸氧，鱼体能消耗大，长期后还可能导致鱼的生病及死亡。因此，鱼类的人工养殖必须进行增氧。超声波增氧系统对鱼类养殖有着积极意义，     

冬管塘鱼防缺氧

<正>冬季光照时间短,水中浮游植物光合作用减弱,产氧量减少,会造成养殖水体溶氧量不足,因此,加强鱼池越冬期间缺氧测定与增氧管理,是提高鱼类养殖效益不可缺少的重要环节,有条件测定鱼池冬季缺氧的地方,应每隔10d进行一次溶氧量测定,测定分析鱼池水中的溶氧情况,当池水中溶氧量降为每升水3mg时,要及时预防结冰积雪。在冬季下大雪时,如果鱼池冰面上积雪过厚,就会影响水中浮游生物的代谢和光合作     

冰封期越冬池塘的生物增氧

北方地区冬季冰封期长(达 150d以上),水温低(约为1℃～3℃),越冬池塘的溶氧量成为鱼类安全越冬的重要因素。越冬池塘中的溶氧状况主要取决于耗氧和产氧两个方面。耗氧是指水中生物的呼吸和有机物的氧化等。产氧是指水生维管束植物(某些沉水植物)及浮游植物的光合作用。生物增氧就是根据具体情况,创造一切有利条件,促进冰下浮游植物的生长、繁殖并在光合作用中产生氧气。生物增氧可改善水质、满足鱼类呼吸的需要,有利于鱼类安全越冬。     

盐碱池塘主养鲤鱼高产试验

不使用增氧机和增氧剂,池塘不换水,采用自制配合颗粒饲料,训练投饲,两口池塘主养丰鲤,生长期105d,亩产分别为560.2kg和556.5kg,出塘规格750g/尾和650g/尾,增重倍数18.8和16.3,饲料报酬1.8和2.0,亩纯利润871.8元,亩成本利润率达40.9％.     

Simultaneous infusions of propofol and ketamine in ponies premedicated with detomidine: a pharmacokinetic study

The pharmacokinetics of propofol and ketamine administered together by infusion were investigated in four ponies. Blood propofol and plasma ketamine and norketamine concentrations were measured by high performance liquid chromatography. After premedication with detomidine (20 μg kg⁻¹) anaesthesia was induced with ketamine (2·2 mg kg ⁻¹ intravenously). The trachea was intubated and the ponies were allowed to breathe 100 per cent oxygen. A bolus dose of propofol (0·5 mg kg⁻¹) was then administered intravenously and propofol and ketamine were infused for 60 and 45 minutes, respectively. The average mean infusion rate of propofol was 0·136 mg kg⁻¹ min⁻¹, and the ketamine infusion rate was maintained at 50 μg kg⁻¹ min⁻¹. The mean (SD) elimination half-lives of propofol and ketamine were 69·0 (8·0) and 89·8 (26·7) minutes, the mean volumes of distribution at steady state were 0·894 (0·161) litre kg⁻¹ and 1·432 (0·324) litre kg⁻¹ the mean body clearances were 33·1 (4·5) and 23·9 (3·8) ml kg⁻¹ min⁻¹ and the mean residence times for the infusion were 87·1 (4·1) and 110·7 (8·2) minutes, respectively. Norketamine, the main metabolite of ketamine, was detected throughout the sampling period. The mean residence time for norketamine was 144 (16) minutes. All the ponies recovered quickly from the anaesthesia; the mean times to sternal recumbency and standing were 11·1 (5·3) and 30·0 (20·8) minutes, respectively, from the end of the infusion.     

Oxygen affinity and Bohr effect responses to 2,3-diphosphoglycerate in equine and human blood

The dependence of blood oxygen affinity and the Bohr effect on the concentration of 2,3-diphosphoglycerate (DPG) in erythrocytes was investigated in 24 trotter horses and 24 healthy men. The oxygen tension at half saturation and standard conditions (P₅₀st at pH 7·4 PCO₂40 mniHg and 37°C) and the carbon dioxide or fixed-acid-induced Bohr effect (dlogP₅₀/dpH) were determined. Samples of fresh blood and blood depleted of or enriched with DPG were studied. In the absence of measurable DPG, the equine and human blood had similar mean (SD) values of P₅₀st (16·6 [0·6] and 16·2 [0·7] mmHg, respectively). In both species these values increased with increasing DPG, but the response of equine blood was significantly lower, at least up to physiological values (P₅₀st =24·6 [0·6] and 26·2 [0·7]) mmHg; DPG=14([1·8] and 12·8 [1·2] μmol gHb⁻¹, respectively, in fresh blood). concentrations above 20 to 25 μmol gHb⁻¹ of DPG the difference between the values of P₅₀st in the two species tended to de crease because the response in human blood reached a plateau. The interactions between the Bohr effect and the concentration of DPG showed that in the horses, as in the men, the level of DPG played an important role in governing the relative magnitude of carbon dioxide and fixed acid factors. The difference between them, which is associated with the oxylabile carbamino binding, was greatest in DPG-depleted blood, but whereas in the men the difference was suppressed by an above normal DPG concentration, in the horses it was still measurable.     

Blood flow measurement to the duodenum,jejunum, ileum and caecum of conscious goats

Blood flow rates in ml/100 g tissue/minute to the duodenum, jejunum, ileum and caecum of conscious goats have been measured using radioactive microspheres (15±5 m diameter). The blood flow rates to these various sections of the intestine were significantly higher (P<0·001) under normal conditions than during epinephrine or norepinephrine infusions. Blood flow to the jejunum was also higher than that to the duodenum, ileum or caecum under normal conditions. The differences were found to be significant for duodenum and ileum (P<0·001), while non-significant for caecum (P>0·10).     

Assessment of orocaecal transit time in cats by the breath hydrogen method: the effects of sedation and a comparison of definitions

Oro-caecal transit times (OCTTs) were assessed in 10 healthy adult cats by the lactulose breath hydrogen method with either no sedation (group A), or after the intramuscular administration of three sedative regimens: a combination of acetylpromazine at 0·1 mg kg⁻¹ with buprenorphine at 10 μg kg⁻¹ (group B), ketamine at 5 mg kg⁻¹ with midazolam at 0·1 mg kg⁻¹ (group C), or medetomidine at 50 μg kg⁻¹ (group D). For each test, the OCTT was defined by four methods: a visual assessment, the first maintained 4 ppm increase in hydrogen production, and the first maintained 0·5 ml hr⁻¹ increase in hydrogen production assessed by two cumulative sum methods. Depending on the definition, the median OCTTs of the cats were between 113 and 131·5 minutes in group A, 86·5 and 97·5 minutes in group B, 218 and 235·5 minutes in group C and 86·5 and 97·5 minutes in group D. By two of the definitions, the median OCTTs in group C were significantly longer than in group A (P≤0·037) and approached significance by the other two definitions. The use of sedatives significantly increased the inter-individual variability of the OCTTs, particularly in groups C and D. There were significant differences between the median OCTTs defined by the four different methods, but all the methods were very highly and significantly correlated (r_s≤0·9503, P<0·0001).     

The effect of temperature and salinity on oxygen consumption in the brachyuran crab Cyclograpsus punctatus (Crustacea: Decapoda: Grapsidae)

The aquatic oxygen consumption of the estuarine brachyuran crab, Cyclograpsus punctatus, was investigated after a 24-hour acclimation period at different temperature (12.5, 20, 30°C) and salinity (9, 17.5, 35, and 44°) combinations . Salinity had no significant effect on oxygen consumption at 12.5 and 20°C in both large and small crabs. At 30°C and 44°, however, the rate of oxygen consumption declined in large crabs (from 0.233 to 0.176 mg O₂ g wwt/h) and increased in small crabs (0.300 to 0.469 mg O₂ g wwt/h). There was also a significant increase in the oxygen consumption (0.300 to 0.536 mg O₂ g wwt/h) of small crabs at the high temperature/low salinity combination. Temperature had a significant effect on the rate of oxygen consumption at all salinities, with Q₁₀ values ranging from 1.16 to 2.85. In all cases the mass-specific oxygen consumption rate of small crabs was higher than that of large crabs. The results suggest that the confinement of this species to the lower reaches of estuaries may, in part, be due to physiological constraints on juveniles and small individuals.     

Cardiopulmonary effects of a two hour medetomidine infusion and its antagonism by atipamezole in horses and ponies

The cardiopulmonary effects of an intravenous (iv) medetomidine injection (5 μg/kg) followed 5 min later by its infusion at 3.5 μg/kg/h for 115 rnin were studied in 9 horses and ponies. Five minutes after the end of infusion 60 μg/kg atipamezole were given. Physiological data during infusion were compared with pre-sedation values. Stroke volume was reduced significantly 5 min after initial medetomidine injection. Cardiac index was reduced significantly and systemic vascular resistance increased significantly for the first 20 min, but returned towards pre-sedation values after this time. Arterial blood pressures were reduced significantly from 30 min until the end of the procedure (minimum MAP was 102.4 ± 9.61 mmHg). Mixed venous oxygen tension was reduced significantly during the infusion. Respiratory rate fell and PaCO₂- rose significantly from 40 min onward. Other variables showed no significant changes. The horses recovered rapidly after atipamezole was injected. Arterial blood pressures remained significantly lowered, but other cardiovascular variables returned towards pre-sedation values. It is concluded that the infusion of medetomidine at 3.5 μg/kg/h causes minimum cardiopulmonary depression once the effects of an initial 5 μg/kg injection have waned, and so could prove suitable as part of an anaesthetic technique in equidae.     

Arterial blood gases and acid-base balance in geriatric dogs

To compare arterial blood gas pressures and acid-base balance in geriatric and young adult dogs, 23 clinically healthy aged dogs (>10 years old) and 16 young adult dogs (two to four years old) were studied. Blood gases (PaO₂ and PaCO₂), pH, Na, K, Ca and Cl were measured in arterial blood samples using selective electrodes. Haemoglobin was quantified with a co-oximeter. Total proteins and phosphorus were measured by spectrophotometry in plasma. The alveolar to arterial PO₂ gradient (P(A-a)O₂), bicarbonate, anion gap and the base excess of blood were calculated. Quantitative analysis of acid-base balance was carried out by calculating unidentified anions. Old dogs had significantly higher P(A-a)O₂ than young dogs (2·5±0·3 versus 1·4±0·3 KPa). Although the differences were not significant, aged dogs also had a lower PaO₂. No differences were detected in PaCO₂, pH, Na, K, Ca, Cl, haemoglobin, phosphorus, bicarbonate and base excess of blood. Plasma proteins were higher in old dogs than in young dogs (7·1±0·2 versus 6·5±0·2 g dl⁻¹). Anion gap was increased in aged dogs; however, no changes were found in unidentified anions. In conclusion, an increase in P(A-a)O₂ has been identified in a group of geriatric dogs. No major changes have been found in the acid-base balance of aged dogs.     

Effects of 2 different infusion rates of medetomidine on sedation score,cardiopulmonary parameters,and serum levels of medetomidine in healthy dogs

The effects of 2 different continuous rate infusions (CRIs) of medetomidine over an 8-hour period on sedation score, selected cardiopulmonary parameters, and serum levels of medetomidine were evaluated in 6 healthy, conscious dogs using a crossover study design. The treatment groups were: CONTROL = saline bolus followed by saline CRI; MED1 = 2 μg/kg body weight (BW) medetomidine loading dose followed by 1 μg/kg BW per hour CRI; and MED2 = 4 μg/kg BW medetomidine loading dose followed by 2 μg/kg BW per hour CRI. Sedation score (SS), heart rate (HR), respiratory rate (RR), temperature (TEMP), systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP), arterial and mixed venous blood gas analyses, lactate, and plasma levels of medetomidine were evaluated at baseline, at various intervals during the infusion, and 2 h after terminating the infusion. Statistical analysis involved a repeated measures linear model. Both infusion rates of medetomidine-induced dose-dependent increases in SS and dose-dependent decreases in HR, SAP, MAP, and DAP were measured. Respiratory rate (RR), TEMP, central venous pH, central venous oxygen tension, and oxygen extraction ratio also decreased significantly in the MED2 group at certain time points. Arterial oxygen and carbon dioxide tensions were not significantly affected by either infusion rate. In healthy dogs, both infusion rates of medetomidine-induced clinically relevant sedative effects, accompanied by typical alpha₂ agonist-induced hemodynamic effects, which plateaued during the infusion and subsequently returned to baseline. While additional studies in unhealthy animals are required, the results presented here suggest that medetomidine infusions at the doses studied may be useful in canine patients requiring sedation for extended periods.     

Pharmacokinetics of propofol infusions, either alone or with ketamine, in sheep premedicated with acepromazine and papaveretum

The pharmacokinetics of propofol were investigated in two groups of five Scottish blackface sheep undergoing surgery for the implantation of subcutaneous tissue pouches. After premedication with acepromazine and papaveretum, anaesthesia was induced with either propofol at 4 mg kg⁻¹ intravenously (group 1) or with a mixture of propofol at 3 mg kg⁻¹ and ketamine at 1 mg kg ⁻¹ intravenously (group 2). Anaesthesia was maintained with a variable infusion rate of either propofol alone (group 1) or propofol and ketamine (group 2). Both regimens produced satisfactory conditions for superficial surgery of the body surface. The mean (SD) duration of anaesthesia was 64·8 (3·1) minutes for group 1 and 60 (0) minutes for group 2; the mean total dose of propofol given to the sheep in group 1 was 801 (84) mg, and the sheep in group 2 received 470 (46) mg of propofol and 267 (30) mg of ketamine. The mean elimination half-life of propofol was 56·6 (13·1) minutes in group 1 and 50·3 (21·4) minutes in group 2; the mean volume of distribution at steady state was 1037 (0480) litre kg⁻¹ in group 1 and 1·515 (0939) litre kg⁻¹ in group 2; the mean body clearance was 85·4 (28·0) ml kg⁻¹ min⁻¹ in group 1 and 1280 (35·0) ml kg⁻¹ min⁻¹ in group 2; the mean residence time corrected for a bolus injection was 12·1 (4·2) minutes in group 1 and 11·9 (6·6) minutes in group 2; for the infusion, the mean residence time was 72·1 (4·2) minutes in group 1 and 69·9 (7·9) minutes in group 2. There were wide variations in the blood propofol concentrations reached in individual sheep by using this standard dosing regimen. All the sheep recovered quickly from anaesthesia; the mean times to extubation, sternal recumbency and standing for the animals in group 1 were 2·8 (0·4) 6·3 (1·2) and 10·9 (1·6) minutes from the end of the infusion, and the times for group 2 were 5·3 (0·9), 11·2 (1·7) and 15·1 (2·2) minutes.