如何正确投喂?——如果想做人工繁殖或者加工鱼子酱

亲爱的中国读者朋友、鲟鱼养殖生产者:l我是托马斯,匈牙利的独立鲟鱼专家,很多国家的人们称呼我“鲟鱼博士”。l我从事鲟鱼养殖、繁殖研究已经27年了。l我第一次成功人工繁殖小体鲟是在1979年。l我来中国传授鲟鱼繁殖技术也已经7年了。l我结识了许多中国的鲟鱼养殖生产者。l他们几乎都梦想着鲟鱼人工繁殖和加工鱼子酱,但许多技术问题在困扰着他们。l我的多年合作伙伴李融先生建议我借这个栏目,与中国朋友们分享我27年的经验。l今天,我们就来谈谈——李融:目前中国的鱼类养殖十分兴旺,也有许多类型的人工配合饲料供应。对于这些饲料在鲟鱼生…     

Excess polyspermy reduces the ability of porcine oocytes to promote male pronuclear formation after in vitro fertilization

Male pronucleus (MPN) formation is a very important physiological event during fertilization, which affects in vitro production of transferrable embryos. The aim of this study was to find out the correlation between the number of penetrated sperm and the occurrence of failure of MPN formation in porcine oocytes. In vitro matured porcine oocytes were fertilized in vitro with frozen epididymal sperm. Two different frozen sperm lots were tested in this study, which were different in terms of polyspermy rates. The numbers and the status of penetrated sperm in oocytes were evaluated 10 h after insemination. Under high polyspermy condition, the polyspermy rate was 83.5% with an average mean of 3.5 sperms per penetrated oocyte, whereas the percentage of polyspermy was 65.5% with an average mean of 2.4 sperms per penetrated oocyte under moderate polyspermic condition. Correlation analysis revealed a negative correlation between the number of penetrated sperm and their MPN formation percentage both in the sperm lot of high polyspermy (R = −0.560, p < 0.05) and in the sperm lot of moderate polyspermy (R = −0.405, p < 0.05) which suggests that penetration of excessive spermatozoa disables the oocyte cytoplasm to promote MPN formation.     

鲟鱼养殖中的几个常见问题

亲爱的中国读者朋友、鲟鱼养殖生产者:l我是托马斯,匈牙利的独立鲟鱼专家,很多国家的人们称呼我“鲟鱼博士”。l我从事鲟鱼养殖、繁殖研究已经27年了。l我第一次成功人工繁殖小体鲟是在1979年。l我来中国传授鲟鱼繁殖技术也已经7年了。l我结识了许多中国的鲟鱼养殖生产者。l他们几乎都梦想着鲟鱼人工繁殖和加工鱼子酱,但许多技术问题在困扰着他们。l我的多年合作伙伴李融先生建议我借这个栏目,与中国朋友们分享我27年的经验。l今天,我们就来谈谈——李融:你在中国从事鲟鱼养殖技术咨询已经7年了,在此期间你是否发现中国鲟鱼养殖存在很多的错…     

Effect of alfaxalone infusion on the electroencephalogram of dogs anaesthetized with halothane

ObjectiveTo describe the effects of alfaxalone on the canine electroencephalogram (EEG).Study designExperimental study.AnimalsEight healthy adult Huntaway dogs.MethodsAnaesthesia was induced with propofol and maintained with halothane (0.85-0.95 end-tidal volume %) in oxygen. Animals were ventilated to maintain stable end-tidal CO₂ and halothane concentrations. Following a 30 minute stabilisation period, alfaxalone (0.5 mg kg^?1) was infused intravenously over a 5 minute period. The electroencephalogram was recorded from the beginning of the stabilisation period until 60 minutes following the start of alfaxalone treatment. Data were subjected to fast Fourier transformation, and median frequency, 95% spectral edge frequency and total EEG power were calculated. Two-factorial repeated measures anova (time and EEG channels were factors) was used for statistical analysis (p<0.05).ResultsA shift in the dominant frequency band from beta to delta after alfaxalone treatment and occasional burst suppression were observed. Median frequency decreased significantly below baseline (9.2 ± 1.4 Hz) (mean ± SD) during alfaxalone infusion. The lowest value (4.8 ± 1.2 Hz) was recorded 5 minutes after the start of infusion. Spectral edge frequency also decreased below baseline (26.2 ± 1.5 Hz) and the lowest value (22.6 ± 1.5 Hz) also was detected at 5 minutes after the start of infusion. Total EEG power did not change significantly. In some frequencies EEG power increased soon after the start of alfaxalone infusion, then decreased below baseline later (biphasic pattern).Conclusions and clinical relevanceAlfaxalone induced biphasic changes on EEG and decreased F₅₀ and F₉₅ in halothane anaesthetized dogs.     

鲟鱼的杂交育种——兼谈杂交后代的能育与不能育

亲爱的中国读者朋友、鲟鱼养殖生产者：我是托马斯,匈牙利的独立鲟鱼专家,很多国家的人们称呼我“鲟鱼博士”。我从事鲟鱼养殖、繁殖研究已经27年了。我第一次成功人工繁殖小体鲟是在1979年。我来中国传授鲟鱼繁殖技术也已经7年了。我结识了许多中国的鲟鱼养殖生产者。他们几乎部梦想着鲟鱼人工繁殖和加工鱼子酱,但许多技术问题在困扰着他们。我的多年合作伙伴李融先生建议我借这个栏目,与中国朋友们分享我27年的经验。今天,我们就来谈谈——     

如何鉴定鲟鱼的性别?

亲爱的中国读者朋友、鲟鱼养殖生产者:我是托马斯,匈牙利的独立鲟鱼专家,很多国家的人们称呼我“鲟鱼博士”。我从事鲟鱼养殖、繁殖研究已经27年了。我第一次成功人工繁殖小体鲟是在1979年。我来中国传授鲟鱼繁殖技术也已经7年了。我结识了许多中国的鲟鱼养殖生产者。他们几乎都梦想着鲟鱼人工繁殖和加工鱼子酱,但许多技术问题在困扰着他们。我的多年合作伙伴李融先生建议我借这个栏目,与中国朋友们分享我27年的经验。今天,我们就来谈谈——     

Comparison of an infrared anaesthetic agent analyser (Datex‐Ohmeda) with refractometry for measurement of isoflurane,sevoflurane and desflurane concentrations

ObjectiveTo assess agreement between infrared (IR) analysers and a refractometer for measurements of isoflurane, sevoflurane and desflurane concentrations and to demonstrate the effect of customized calibration of IR analysers.Study designIn vitro experiment.SubjectsSix IR anaesthetic monitors (Datex-Ohmeda) and a single portable refractometer (Riken).MethodsBoth devices were calibrated following the manufacturer’s recommendations. Gas samples were collected at common gas outlets of anaesthesia machines. A range of agent concentrations was produced by stepwise changes in dial settings: isoflurane (0–5% in 0.5% increments), sevoflurane (0–8% in 1% increments), or desflurane (0–18% in 2% increments). Oxygen flow was 2 L minute^?1. The orders of testing IR analysers, agents and dial settings were randomized. Duplicate measurements were performed at each setting. The entire procedure was repeated 24 hours later. Bland–Altman analysis was performed. Measurements on day-1 were used to yield calibration equations (IR measurements as dependent and refractometry measurements as independent variables), which were used to modify the IR measurements on day-2.ResultsBias ± limits of agreement for isoflurane, sevoflurane and desflurane were 0.2 ± 0.3, 0.1 ± 0.4 and 0.7 ± 0.9 volume%, respectively. There were significant linear relationships between differences and means for all agents. The IR analysers became less accurate at higher gas concentrations. After customized calibration, the bias became almost zero and the limits of agreement became narrower.Conclusions and clinical relevanceIf similar IR analysers are used in research studies, they need to be calibrated against a reference method using the agent in question at multiple calibration points overlapping the range of interest.     

A novel flow partition device for spirometry during large animal anaesthesia

ObjectiveWe describe and test a novel device for large animal anaesthesia monitoring that uses standard human medicine spirometry sensors.Study designIn-vitro study.MethodsThe device consists of two adapters that enable the flow to be split evenly into four tubes in parallel, each tube containing a D-lite sensor. The performance of this flow partitioning device (FPD) over a range of flows from 100 to 700 L minute^?1 was determined and the pressure versus flow relation, resistance and dead space was compared with a Horse-lite (Moens 2010).ResultsEquipped with four D-lite sensors, and a flow of 700 L minute^?1 the pressure drop of the FPD was 13.5 cmH₂O, resistance 1.17 cmH₂O second L^?1 and volume (potential dead space) 182 mL, compared to 2.8 cmH₂O, 0.24 cmH₂O second L^?1 and 54 mL respectively for the Horse-lite. The predicted value of the flow partition of ¼ could be confirmed. Limits of agreement were found to be 4.2% in inspiratory direction and 7.1% in expiratory direction.Conclusions and clinical relevanceThe FPD is an affordable device that extends the specification of any commercially available human spirometry sensors to large animal applications. However, an increase in total resistance and dead space has to be taken into account. Therefore, the new device could be useful during equine anaesthesia.