The Distribution of 35S-Sulfadiazine and 14G-Trimethoprim in Rainbow Trout,Salmo Gairdneri

The distribution of 35S-labelled sulfadiazine and 14G-labelled trimethoprim was studied in rainbow trout by use of whole body autoradiography and liquid scintillation. As compared to mammals, gastrointestinal absorption and elimination were slow. Accumulation in the skin and the uveal tract of the eye was observed for both drugs tested. The results also indicated that the bile was an important route of excretion. Considerable radioactivity was still present in the skin at 144 hr. survival time.     

The occurrence of Aeromonas and Streptococcus in Rainbow Trout, Salmo gairdneri Richardson

Smears were taken from the eyes, spleen and blood from rainbow trout collected from a fish farm and classified as clinically sick, under treatment, recovered and apparently healthy. The smears were examined microscopically and the bacteria present identified as Aeromonads or Streptococci. The results indicated a high incidence of Aeromonads in the eye and the spleen but not the blood in all groups including those apparently healthy while streptococci were present in the blood as well as the eye and the spleen.     

皮质醇的周年变化与雌性虹鳟性腺成熟的关系

利用放射免疫分析法对饲养于恒定水温和自然光照下的雌性虹鳟血浆中皮质醇和性激素含量的周年变化进行了测定．结果表明：１）根据性腺结构指数和性激素分泌量判断,三龄时,雌性虹鳟达到性成熟;２）在血浆中不仅性激素而且皮质醇的变化水平与性腺结构指数的变化高度相关．排卵前性激素的水平都较高,伴随着排卵的进行性激素水平下降．而且在产卵季节虹鳟血浆中皮质醇水平也较高,三龄时皮质醇水平与性腺结构指数的相关系数为０．８６．这些结果提示,皮质醇在虹鳟的繁殖过程中可能发挥某种作用．     

Thermoresistance of Erythrocytes and Hemoglobin at Acclimation of the Rainbow Trout Salmo irideus

Changes of parameters of thermally induced hemolysis of erythrocytes and of thermal denaturation of hemoglobin were studied at acclimation of the rainbow trout Salmo irideus to seasonal changes of water temperature in the range of 0–20°C. A correlation was revealed between thermoresistance of erythrocytes, activation energy of thermal hemolysis, and water temperature variations, whereas thermostability of hemoglobin remained practically constant. The conclusion is made that seasonal changes of thermoresistance of erythrocytes are determined by rearrangements in membrane, which play adaptive role and are due to variations in lipid composition.     

Purification and Characterization of Glycoprotein from the Skin Mucus of the Rainbow Trout,Salmo gaivdneri

Mucus glycoprotein (RGP) was purified and characterized from the skin mucus of rainbow trout, Salmo gairdneri. RGP was found to contain 30.1% NeuAc, 26.0% GalNAc, 5.0% Gal, and 26.0% amino acids. The protein moiety of RGP is very rich in Thr (32.4 mol%). Neither NeuGc nor KDN (2-keto-3-deoxy-d-glycero-d-galacto-nononic acid) was found in RGP. Alkaline borohydride treatment of RGP yielded a major disaccharide alditol, NeuAcα2→6GalNAc-ol and more than 4 minor oligosaccharide alditols including NeuAc→(GalNAcα1→)GalNAc-ol. It was evident that an average RGP molecule has approximately 500 NeuAc-containing oligosaccharide chains, which are attached to the Thr and Ser residues of the protein moiety and spaced at an average of 3 amino acids apart.     

虹鳟鱼雌性化及其鱼子酱加工的初步研究

虹鳟鱼的养殖量目前在我国虽然呈逐渐增加之势,但占产量５％～１０％的鱼卵大多数作为废弃物而未被利用。本项目道德在对虹鱼养殖生物学特性系统总结的基础上,进行虹鳟鱼雌性化例,把握虹鳟鱼发育的适合时机,提高虹鳟鱼卵数量、质量,采集并进行深加工,提高虹鳟鱼养上经济附加值。     

Adrenergic involvement in blood oxygen transport and acid-base balance during hypercapnic acidosis in the Rainbow Trout,Salmo gairdneri

Summary Rainbow trout (Salmo gairdneri) were subjected to 12 h of external hypercapnia (1% CO₂ in air) during - and/or -adrenoceptor blockade in order to assess the importance of adrenergic responses in modulating blood oxygen transport and acid-base balance during an acute acidotic stress. External hypercapnia caused an elevation of blood carbon dioxide tension and a reciprocal decrease in whole blood pH. A gradual elevation of blood bicarbonate levels caused whole blood pH to increase toward pre-hypercapnic values throughout the hypercapnic period. Pre-treatment of fish with propranolol (a -adrenoceptor antagonist) or phentolamine (an -adrenoceptor antagonist) did not affect their ability to regulate extracellular acid-base status during hypercapnia. On the other hand, adrenergic responses were essential in the maintenance of arterial blood oxygen content during hypercapnia despite the severe extracellular acidosis and a marked Root effect in trout blood, in vitro. Important adrenergic responses included pronounced increases in haematocrit (an -adrenergic effect) and arterial oxygen tension (- and -adrenergic effects) as well as partial regulation of red blood cell pH (a -adrenergic effect). Although pre-treatment of fish with either propranolol or phentolamine caused a reduction in blood oxygen content during hypercapnia, fish died only during complete adrenoceptor blockade, presumably due to severe hypoxemia.Symbols and abbreviations total concentration of oxygen or carbon dioxide, respectively - hct haemotocrit - rbc red blood cell     

亚致死浓度的铜对虹鳟生理指标的影响

外部环境决定着有机体的功能状态;当有机体与外部环境之间相互关系遭到破坏时,无论机体的生理系统,还是其调节机能都会发生变化。生理指标反映出物体内环境对外部作用作出的反应,以此可确定外部作用的强度,阐明作用机制,确定机体的适应能力,并预测其影响（Хайн...     

Increase of Metallothionein-immunopositive Chloride Cells in the Gills of Brown Trout and Rainbow Trout After Exposure to Sewage Treatment Plant Effluents

Metallothionein, a biomarker of exposure and toxicity of heavy metals, has been detected in the gills of brown trout (Salmo trutta fario L.) and rainbow trout (Oncorhynchus mykiss Richardson) by means of immunohistochemistry. A very prominent labelling of chloride cells was found after exposure to diluted sewage plant effluents. No significant increase was observed in either the number of labelled cells or their labelling intensity after exposure to water of a polluted river compared to fish kept in tap water. These results do not correlate with findings of a histopathological study, suggesting that the metal levels at the sewage treatment plant were too low to produce gross histopathology. A comparison between the species indicated that the rainbow trout showed a generally higher metallothionein expression than the brown trout.     

Identification of a Gene Regulating the Tissue Expression of a Phosphoglucomutase Locus in Rainbow Trout

Nine percent of the rainbow trout (Salmo gairdneri) from a hatchery source have a greater than 100-fold increase in expression of a phosphoglucomutase (PGM) locus, Pgm1, in the liver but have normal expression of this locus in other tissues. The results of genetic crosses are consistent with a single regulatory gene with additive inheritance being responsible for the differences in the amount of PGM activity in the liver.—The allele responsible for the expression of Pgm1 in the liver is apparently a recent mutation. This is supported by its restricted distribution in rainbow trout and the absence of liver Pgm1 expression in closely related species. This genetic system is valuable for future analysis of the control of gene expression and in determining the relative evolutionary importance of genetic variation at structural and regulatory genes.     

水温对虹鳟血清中血糖含量的影响

度下的动态变化对虹鳟南移温水驯化养殖具有参考价值.     

Sodium Efflux and Potential Differences across the Irrigated Gill of Sea Water-Adapted Rainbow Trout (Salmo gairdneri)

Sodium extrusion (J_out^Na) was measured across the gills of rainbow trout, Salmo gairdneri, adapted to sea water (SW) using a gill-irrigation system of small volume. The potential difference (TEP) was also measured under similar conditions. J_out^Na was usually between 100–250 µeq (100 g)^–1 h^–1, about an order of magnitude faster than in fresh water (FW)-adapted trout, but slower than has been reported for any other marine teleost. The TEP was between 10–11 mV, body fluids positive to SW. When the external medium was changed from SW to FW J_out^Na was reduced to about 25 % of the initial value, and the TEP was reduced by 40–50 mV (i.e. body fluids negative by 30–40 mV). Addition of either Na⁺ or K⁺ in SW concentrations reversed the changes; J_out^Na increased and the gill repolarized. The electrical behavior and sodium efflux in irrigated trout gill is qualitatively the same as has been reported for unanaesthetized, free-swimming fish of other species. Thus, the irrigated gill provides an adequate model for studying the mechanism of sodium extrusion in marine teleosts.     

Improvement of Sperm Motility of Sex-Reversed Male Rainbow Trout, Oncorhynchus mykiss, by Incubation in High-pH Artificial Seminal Plasma

Changes in the motility time of spermatozoa collected from the testes and the sperm duct of normal and sex-reversed male (XX) rainbow trout in physiological balanced salt solution were examined after incubation in artificial seminal plasmas of various pHs. Although untreated spermatozoa from the sperm duct retained motility for 60–90 s in the balanced salt solution, the spermatozoa collected from the testes were immotile. During the incubation in artificial seminal plasma of pH 7.0, the spermatozoa from the sperm duct hardly moved, similar to the testicular spermatozoa in the balanced salt solution. By suspending and incubating the testicular spermatozoa in artificial seminal plasma of pH 9.9 for 2 h at 4°C, the percentage of motile spermatozoa increased from 0–5% to 80%. The spermatozoa remained motile for at least 2 min after long-term incubation (12 h). When the full-sib eggs were inseminated with untreated testicular spermatozoa or testicular sperm treated for 2 h at high pH, the percentage survival increased from 5.5% to 53.8% at the eyed stage due to the high-pH treatment. The incubation of the spermatozoa in high-pH artificial seminal plasma improved the motility of the spermatozoa from the testes of the sex-reversed male that had lost its sperm duct. By this treatment, it is possible to markedly increase the mass production efficiency of all-female or all-female triploid sterile progenies.     

An Ultrastructural and Fluorescence Histochemical Study of the Myenteric Plexus of the Stomach of the Rainbow Trout Salmo gairdneri

The myenteric plexus of the rainbow trout Salmo gairdneri is enclosed within an incomplete Schwann-like sheath which allows bundles of unmyelinated axons to pass into the adjacent smooth muscle layers. Neuronal and non-neuronal constituents of the myenteric plexus are divided into smaller units by endoneurial collagen which in places condenses to form a perineurial covering. The myenteric plexus is avascular but arterioles and fenestrated capillaries are present close to the plexus in the intermuscular space. Small groups of neurones constitute the ganglia of the plexus but as yet few ultrastructural indications of differing neurone types have been observed. Within the neuropil of the ganglia five types of axon profile, characterised by their vesicle content, have been identified. One of these types was only recognisable following the administration of 5-hydroxydopamine. Axo-somatic and axo-dendritic synaptic contacts were only made by Type 1 axons but these were uncommon. The presence of an adrenergic component of the myenteric plexus was confirmed ultrastructually following 6-hydroxydopamine-induced degeneration and also by Falck-Hillarp fluorescence histochemistry which revealed an extensive distribution of adrenergic nerves in the plexus. The structural organisation of the plexus, the comparatively few ultrastructurally recognisable axon and neurone types and the sparsity of synaptic contacts all indicate that the teleost myenteric plexus is less complex than its mammalian counterpart.     

The Effect of Ration on Acclimation to Environmental Acidity in Rainbow Trout

Freshwater salmonids exposed to low environmental pH typically suffer a net loss of ions, primarily Na⁺ and Cl^–, across the gills, resulting in reduced plasma and tissue ion concentrations. However, in recent experiments in our laboratory, juvenile rainbow trout, Oncorhynchus mykiss, fed a ration of 1% body weight d^–1 or greater showed no ionoregulatory disturbance during chronic, sublethal acidification. This raised the possibility that these fish had acclimated to low pH in that they would be better able to withstand further, more severe acidification than fish that had no prior experience of acid conditions: previous studies had concluded that such acclimation does not occur. This hypothesis was tested by measuring unidirectional ion fluxes during a 24h acute acid challenge (pH 4.2) in juvenile rainbow trout that had previously been exposed to either ambient pH 6.2 (naive fish) or sublethal low pH 5.2 (acid pre-exposed fish) for 90 days, and fed a ration of either 1.0 or 0.25% d^–1 (wet basis). No mortalities were observed during the acute acid challenge in the fish fed the higher ration and no differences between the two groups in the response of Na⁺ fluxes were observed. Sodium influx in both groups was significantly inhibited throughout the challenge and Na⁺ net flux was significantly stimulated over the first 6h. Prior to the acute acid challenge, the fish fed the lower ration that had previously been exposed to pH 5.2 had significantly lower plasma ion concentrations than those fish previously exposed to pH 6.2. Both groups suffered mortalities; those of the naive fish (22% by 24h) being markedly lower than those of the acid pre-exposed fish (68% by 24h). However, there were no significant differences in either Na⁺ or Cl^– fluxes between the two groups of fish during the acid challenge: both showed significant inhibition of ion influxes and significantly greater net ion losses, resulting in reduced plasma ion concentrations. These results indicate that rainbow trout are unable to acclimate to environmental acidification irrespective of the availability of dietary salts.     

Histidine Absorption across Apical Surfaces of Freshwater Rainbow Trout Intestine: Mechanistic Characterization and the Influence of Copper

The essential amino acid histidine performs critical roles in health and disease. These functions are generally attributed to the amino acid itself, but could also be mediated by a positive effect on trace element bioavailability. Mechanistic information regarding the absorption of histidine across the gastrointestinal tract is essential for understanding the interplay between amino acid and mineral nutrients and the implications of these interactions for nutrition and toxicology. Using intestinal brush-border membrane vesicles obtained from freshwater rainbow trout, absorption of histidine over the range 0.78–780 μm was found to be saturable, with a maximal transport rate (J _max) of 9.1 ± 0.8 nmol mg protein⁻¹ min⁻¹ and a K _m (histidine concentration required to reach 50% of this level) of 339 ± 68 μm. Histidine uptake was highly specific as 10-fold elevated levels of a variety of amino acids with putative shared transporters failed to significantly inhibit uptake. Elevated levels of d-histidine, however, impaired uptake of the natural l-isomer. The presence of “luminal” copper (8.3 μm) significantly increased both the J _max and K _m of histidine transport. This suggests that chelated copper–histidine species cross the brush-border epithelium through transport pathways distinct from those used by histidine alone.     

Consistency in Context-specific Measures of Shyness and Boldness in Rainbow Trout, Oncorhynchus mykiss

Shyness and boldness has been considered a fundamental axis of human behavioural variation. At the extreme ends of this behavioural continuum subjects vary from being bold and assertive to shy and timid. Analogous patterns of individual variation have been noted in a number of species including fish. There has been debate on the nature of this continuum as to whether it depends on context. That is, whether it is domain‐general (as in humans), or context‐specific. The purpose of our study was to test if shyness and boldness depends on context in rainbow trout, Oncorhynchus mykiss and to this end we estimated boldness in five different situations. Our data provide evidence of a shy–bold behavioural syndrome in rainbow trout. Bold trout tended to be bold in four situations when the context was similar (when the context concerned foraging). However, in a different context, exploring a swim flume, the ranking was entirely different. We suggest that shyness and boldness depends on context in rainbow trout.