斑点叉尾鮰人工孵化试验     

刘澧津张跃红  刘希泰张志杰 张荣 《河北渔业》1993,(5):20-21

斑点叉尾鮰(Ictalurus Pantatus)属鲶形目，卵枯黄色，受精后呈粘性，结成铁状卵块。目前，美欧等主要养殖国家，人工繁殖通常采用池塘自然产卵人工孵化，孵化使用多种类型的孵化器。我们在1992～1993课题试验期间，采用池塘放置产卵巢诱导亲鱼产卵，用水车式水动力孵化器孵化，获得了成功。  相似文献   

Development of furnished cages for laying hens     

Appleby MC  Walker AW  Nicol CJ  Lindberg AC  Freire R  Hughes BO  Elson HA 《British poultry science》2002,43(4):489-500

1. A 3-year trial was carried out of cages for laying hens, occupying a full laying house. The main cage designs used were 5000 cm2 in area, 50 cm high at the rear and furnished with nests and perches. F cages had a front rollaway nest at the side, lined with artificial turf. FD cages also had a dust bath containing sand over the nest. H cages had two nest hollows at the side, one in front of the other. They were compared with conventional cages 2500 cm2 in area and 38 cm high at the rear. 2. Cages were stocked with from 4 to 8 ISA Brown hens per cage, resulting in varied allowances of area, feeder and perch per bird. No birds were beak trimmed. In F and FD cages two further treatments were applied: nests and dust baths were sometimes fitted with gates to exclude birds from dust baths in the morning and from both at night; elevated food troughs, with a lip 33 cm above the cage floor, were compared with standard troughs. 3. Management of the house was generally highly successful, with temperature control achieved by ventilation. Egg production was above breeders' standards and not significantly affected by cage design. More eggs per bird were collected when there were fewer birds per cage but food consumption also then tended to be higher. 4. The number of downgraded eggs was variable, with some tendency for more in furnished cages. Eggs laid in dust baths were often downgraded. Those laid at the back of the cage were frequently dirty because of accumulation of droppings. H nests were unsuccessful, with less than 50% of eggs laid in the nest hollows. However, up to 93% of eggs were laid in front rollaways, and few of these were downgraded. 5. Feather and foot damage were generally less in furnished than in conventional cages, greater where there were more birds per cage. With an elevated food trough there was less feather damage but more overgrowth of claws. In year 2, mortality was greater in cages with more birds. 6. Pre-laying behaviour was mostly settled in front rollaway nests. Dust baths were used more for pecking and scratching than for dust bathing. Comfort behaviour was more frequent in furnished cages than conventional, although still not frequent. Locomotion was strongly affected by number of birds per cage or by space per bird, being reduced by crowding. Most birds perched at night except in one treatment providing only 10.7 cm perch per bird. 7. Behaviour was more unrestricted and varied, and physical condition was better, in furnished than in conventional cages. However, egg production will cost more in furnished cages, partly because more eggs are downgraded. Dust baths must be fitted with gates that the birds cannot open from outside, but gates for nest boxes were found unnecessary. If a low perch is fitted it must be far enough from the back of the cage for birds to walk there. 8. Where there was less space per bird (more birds per cage) than the requirements in the 1999 European Commission Directive on laying hens, there were: fewer eggs per hen, but still above the breeders' target; lower food consumption; more feather and foot damage, but less than in conventional cages; higher mortality in one trial out of three; less freedom of movement. However, the results were still very good even with 8 birds per cage, and support the principle that furnished cages provide an acceptable way of protecting the welfare of laying hens.  相似文献   

虹鳟鱼病     

米尔.  Л 刘澧津 《河北渔业》1990,(2):14-16

<正> 三、寄生虫病 1、口丝虫病病原体为口丝虫Ichthyobdo necator,属鞭毛虫纲,游动时呈豆形或椭园形,两根鞭毛,固着时近梨形。长5～20μm(平均约10μm),宽2.5～10μm(平均约4μm),鞭毛长9～18μm。是一种专性外寄生虫,寄生鱼体表面。分裂方式繁殖。离开鱼体成球形,0.5—1小时死亡。接触鱼体便寄生其上,尤其高密度养殖,这一寄生过程完成的很快。口丝虫经常引起大量死亡,尤其是网箱  相似文献   

AN UNDESCRIBED ALTERNARIA AFFECTING THE APPLE     

Longyear BO 《Science (New York, N.Y.)》1905,21(540):708-710

  相似文献   

虹鳟肝癌一例   总被引：2，自引：0，他引：2  

刘澧津 《河北渔业》1995,(6):3-4

本文报道了对虹鳟肝脏肿瘤进行的组织学检验情况,认定为恶性肿瘤。病因为饲料中含黄曲霉毒素及鱼体老龄化。  相似文献   

Changes in arterial PO₂, physiological blood parameters and intracellular antioxidants in free-swimming Atlantic cod (Gadus morhua) exposed to varying levels of hyperoxia     

Karlsson A  Heier LS  Rosseland BO  Salbu B  Kiessling A 《Fish physiology and biochemistry》2011,37(1):249-258

Free-swimming Atlantic cod (Gadus morhua) were exposed to water oxygen pressures (P _wO₂) ranging from 18.1 to 41.5 kPa and sampled for blood using an indwelling caudal artery cannula. Arterial blood oxygen pressure (P _aO₂) increased with increasing P _wO₂, from 12.0 kPa in normoxia (18.1 kPa) to 34.2 kPa in the highest hyperoxic level tested (41.5 kPa). Blood CO₂ pressure and plasma bicarbonate concentration increased with P _wO₂, indicating reduced ventilation with increased P _wO₂. Plasma glucose, sodium and potassium were not affected by water oxygen level. Blood oxidative stress biomarkers, reduced glutathione, oxidized glutathione and the oxidative stress index (ratio between oxidized and total glutathione) differed intermittently between normoxia and hyperoxia. The oxidative stress index was higher in the blood of exposed compared to unexposed control cod. Together with elevated P _aO₂, these findings suggest increased production of reactive oxygen species and increased oxidative stress in Atlantic cod exposed to hyperoxia.  相似文献   

鲑科鱼类疾病的预防     

刘澧津 《河北渔业》2002,(6):30-32

<正> 养殖过程中的鱼病防治,必须坚持‘防’重于‘治’,这是养鱼者的共识。但实际生产上,人们似乎并未真正认识到预防的重要性。平时整天忙的是检查鱼病,抓紧治疗,而对发病前的预防,想得少,做得更少。  相似文献   

Application of time-frequency distribution correlating and matching method in signal extraction     

LIU Xiao feng  LI Hui  BO Lin  PENG Yong jin 《保鲜与加工》2011,(11):31-36

The time-frequency coupling relation between useful non-stationary components and noises bring great difficulties to the realization of de-noising for non-stationary signals,which can not be solved by classic de-noising method in time or frequency domain. The principles of short time Fourier transform(STFT),Wigner-Ville transform,Chirplet adaptive decomposition are analyzed,and then a novel de-noising method for non-stationary based on joint time-frequency distribution is proposed. In this method,the analyzed signal WVD is seen as the combination of auto-WVD and cross-term WVD. Firstly,STFT energy spectrum of the analyzed signal is used as template to cross-correlate with its corresponding WVD in order to obtain the satisfactory time-frequency distribution with high time-frequency resolution and without cross-term interferences. Secondly,the useful components are decomposed as Chirplet function using the two-dimension least square fitting method,and then are extracted out to reconstruct for noise suppression. Finally,the computer simulation results verify the effectiveness of this proposed method. Its application in gearbox fault diagnosis indicates that with the method the extracted cycle of the gearbox vibration impulses has a good consistency with the corresponding fault frequency.  相似文献   

CIBA Tissue Transplantation Symposium     

Rogers BO 《Science (New York, N.Y.)》1953,117(3046):3

  相似文献   

Anionic constitution of 1-atmosphere silicate melts: implications for the structure of igneous melts     

Virgo D  Mysen BO  Kushiro I 《Science (New York, N.Y.)》1980,208(4450):1371-1373

A structural model is proposed for the polymeric units in silicate melts quenched at 1 atmosphere. The anionic units that have been identified by the use of Raman spectroscopy are SiO(4)(4-) monomers, Si(2)O(7)(6-) dimers, SiO(3)(2-) chains or rings, Si(2)O(5)(2-) sheets, and SiO(2) three-dimensional units. The coexisting anionic species are related to specific ranges of the ratio of nonbridging oxygens to tetrahedrally coordinated cations (NBO/Si). In melts with 2.0 < NBO/Si < approximately 4.0, the equilibrium is of the type [See equation in the PDF file]. In melts with NBO/Si approximately 1.0 to 2.0, the equilibrium anionic species are given by [See equation in the PDF file]. In alkali-silicate melts with NBO/Si <~ 1.3 and in aluminosilicate melts with NBO/T < 1.0, where T is (Si + Al), the anionic species in equilibrium are given by [See equation in the PDF file]. In multicomponent melts with compositions corresponding to those of the major igneous rocks, the anionic species are TO(2), T(2)O(5), T(2)O(6), and TO(4), and the coexisting polymeric units are determined by the second and third of these disproportionation reactions.  相似文献