Lysosomal damage under nitrite intoxication in rainbow trout (Salmo gairdneri Rich.)

1. In Salmo gairdneri specimens exposed to 450 micrograms/l NO2-N (nearly 36 hr LC50) for various exposure times (12-72 hr) some parameters of liver lysosomal function were examined. 2. In vivo both total proteolytic activity and single protease activities were inhibited, the inhibition increasing with the lengthening of exposure time. In vitro no analogous effect was observed. 3. Lysosomal membranes showed an increased fragility correlated with the physiological conditions of treated animals. 4. Data were considered as the results of a nitrite mediated effect on functional and structural proteins.     

The development of catecholamines in embryos and larvae of the rainbow trout (Salmo gairdneri Rich.)

Catecholamines are present in the late embryonal and early larval developmental stages (alevin) of the rainbow trout. Changes in the alevin behaviour can be related to the catecholamine concentrations.     

Nutritional regulation of glycolysis in rainbow trout (Salmo gairdneri R.)

1. Some physico-chemical constants and the nutritional regulation of pyruvate kinase (PK), phosphofructokinase (PFK) and hexokinase (HK) from rainbow trout liver was investigated. 2. The maximum activity pH for the three enzymes appears to be in a physiological range. 3. The PK-enzyme shows sigmoid kinetic with respect to PEP with a Hill-coefficient of 3.1; the other two enzymes show michaelian kinetic for their substrates. 4. The nutritional treatments show that HK-enzyme increases its level with high carbohydrate diet and decreases with high protein diet and starvation. 5. PFK-enzyme decreases with high protein diet and starvation. 6. PK-enzyme only shows a decrease in level with starvation conditions.     

Spermiogenesis in the rainbow trout (Salmo gairdneri)

In an ultrastructural study on the spermiogenesis of the rainbow trout (Salmo gairdneri R.) four spermatogenetic stages were identified. In young round spermatids, the nuclear chromatin was first heterogeneous (euchromatin and heterochromatin). Subsequently, it became more homogeneous and started to condense in the form of coarse granules and fibers and then into fibrils associated in ribbon-like elements which eventually partly fused together. During early spermiogenesis, a juxtanuclear vacuole appeared in the area where the nuclear envelope was specialized due to condensation of material between the two envelopes and a slight accumulation of nuclear material. This area was finally located in the anterior part of spermatids and spermatozoa; it probably plays a role during fertilization. A flagellar rootlet appeared early in spermiogenesis; it may play a role in the attachment of the flagellum to the nucleus since it persisted until the centriolar complex was definitively fixed in the implantation fossa. The flagellum did not display a plasma membrane and was first located in the cytoplasm, but when it was later extruded from the cell, it acquired a membrane. The cytoplasm was rich in ribosomes (free or in small groups) but poor in membranous organelles. The few mitochondria polarized around the centriolar complex were finally organized into an annular mid-piece. The spermatids remained connected by intercellular bridges until the end of spermiogenesis. The complexity of trout spermiogenesis is intermediate between that in poecilids and that in carp and pike, which have very simple spermatozoa. The role of the material from the nucleus and the cytoplasm reaching the Sertoli cell in the control of spermatogenesis has been discussed.     

Apomorphine-induced vomiting in rainbow trout (Salmo gairdneri)

1. The LD50 for a 7-day period following intraperitoneal injection of apomorphine-HCl was calculated to be 158 mg/kg in rainbow trout. 2. Intraperitoneal injection of apomorphine at doses of 60 mg/kg or greater caused vomiting of plastic balls which had been placed in the stomachs of rainbow trout. 3. Apomorphine-induced effects included vomiting, vomiting behavior, toxicity, increased respiration, impaired motor control and equilibrium, and increased aggression. 4. The vomiting control mechanism of trout may be similar to that described in mammals.     

Absorption and fate of labelled canthaxanthin 15, 15'-3H2 in rainbow trout (Salmo gairdneri Rich.)

1. Using one force fed meal, absorption of labelled canthaxanthin 15,15'-3H2 was studied by collecting blood via caudal punction at regular intervals and measuring radioactivity in various tissues and organs of rainbow trout. 2. Canthaxanthin absorption showed a large variability between individuals irrespective of their sex. A rapid increase in the radioactivity linked to canthaxanthin 15,15'-3H2 is observed in the blood followed by a slow decrease. 3. Twenty-four and 72 hours after ingestion of labelled canthaxanthin by rainbow trout, the radioactivity was widely distributed. From the total radioactivity given, most was found 24 hours after the meal in the pyloric caeca, ovary and skin. Seventy-two hours after diet, the radioactivity increased in the muscle, liver and kidney. On the other hand, the percentage of radioactivity of intestine and caeca declined. 4. Data from absorption curve indicates that 0.86% of radioactivity ingested is present in the blood, suggesting that canthaxanthin is not readily transferred from the digestive tract. 5. The metabolic clearance of canthaxanthin (lambda = 0.0246/hr +/- 0.005) which would correspond to a half-life of 28 hours gives a preliminary idea of the digestive and metabolic utilization of canthaxanthin by the rainbow trout.     

A literature review of the blood chemistry of rainbow trout, Salmo gairdneri Rich.

The literature on the blood chemistry of rainbow trout, Salmo gairdneri Rich., is reviewed from the aspects of experimental methods, electrophoresis, normal values, environmental and endogenous factors including toxic substances and diseases.     

Crystallization of the rainbow trout (Salmo gairdneri) haemoglobin IV

Crystals of rainbow trout (Salmo gairdneri) haemoglobin IV were grown in mini batches from a solution of ammonium sulphate. Large single crystals grew over five days and were up to 2 mm in length. X-ray diffraction experiments indicated a space group of C222(1) with unit cell dimensions of a = 85.3 A, b = 94.6 A and c = 105.7 A. The crystals diffract to better than 2.5 A but exhibit some mosaicity along the c axis.     

Hepatectomy in rainbow trout (Salmo gairdneri). A preliminary study

1. Partial hepatectomy (25% of liver mass removed) has been performed on rainbow trout using a procedure allowing a high level of survival. 2. The liver regeneration was complete from the point of view of liver weight, at the 30th post-operative day. 3. During the first weeks after surgery, the NH-excretion rate in both hepatectomized and shamoperated trout was higher than in intact controls. Likewise, the food intake was lower in the operated animals. 4. Both facts can be attribute to the stress situation caused by the surgical manipulations rather than the removal of the liver.     

Chromosome polymorphism in the rainbow trout (Salmo gairdneri Richardson)

Chromosome preparations from lymphocyte cultures of 50 rainbow trout were studied. Diploid chromosome numbers of 59, 60, 61, 62 and 63 were found in different individuals in which the arm number (NF) was 104. Intraindividual polymorphism was found at a low level in 25 of the fish. The results suggest that numerous chromosome polymorphisms exist in rainbow trout.     

Oxygen uptake by rainbow trout blood, Salmo gairdneri

Oxygen uptake rate by rainbow trout red cells was measured in the temperature range 5° to 40° C. Between 5° and 20° C there was a steady increase in rate and at 20° C a maximum rate of 2.5 μl O₂/min/ml red cells occurred, followed by a decline in the rate as the temperature increased. A morphological investigation of the red cell was conducted and possible functions of the nucleus in fish red blood cells are discussed.     

The saccus dorsalis of the rainbow trout,Salmo gairdneri Richardson

The saccus dorsalis of the brain of the rainbow trout, Salmo gairdneri Richardson, has been investigated by means of histological, cytochemical, enzyme-cytochemical, electron microscopical autoradiographical techniques. The saccus dorsalis is a rostro-dorsal evagination of the diencephalic roof, and consists of a partly folded epithelial wall separating the cerebrospinal fluid from the meningeal matrix fluid. The well-developed vascular system around the epithelial wall, consisting of capillaries with different diameters, seems to be part of the pineal vascular system. No structures were found that may be involved in a possible mechanical or nervous blood flow control. The single-layered epithelium consists of highly specialized cells of one specific type. These cells are mainly characterized by infolded basal membranes, long microvilli of a peculiar shape, non-folded lateral membranes bordering intercellular spaces, apical concentrations of elongate and cup-shaped macromitochondria, a basally located rough endoplasmic reticulum, an apically situated smooth endoplasmic reticulum and apical concentrations of micropinocytotic vesicles. Morphological evidence is presented of a multiple function of these cells: (1) fluid secretion, (2) extrusion of low molecular weight organic substances into the ventricular system, (3) uptake of high molecular weight substances, and (4) uptake of low molecular weight organic substances (aminergic neurotransmitters [GABA]) from the cerebrospinal fluid. The significance of light and dark cells is discussed. Indications of a possible innervation of the saccus dorsalis epithelial cells were not observed. The functional significance of the saccus dorsalis (possible analogue of the choroid plexus?) is discussed.     

Plasma oestrogen levels in rainbow trout Salmo gairdneri Richardson

Levels of oestrogens in plasma of mature fall-spawning rainbow trout Salmo gairdneri were determined using a radio-immunoassay. No significant difference was found in oestrogen concentration between the sexes (male =2.5 ng/ml; female =4.4 ng/ml); between individual variability was great. Four blood samplings over a 24-h period via cardiac puncture of males revealed no diel variation or change in estrogen levels due to the stress of bleedings. Although no gonado-somatic index-estrogen relationship could be demonstrated for either sex, there was correlation between oestrogen and androgen levels in the female.     

Ultrastructure of the physostomatous swimbladder of rainbow trout (Salmo gairdneri)

Summary Rainbow trout swimbladder epithelium consists of non-ciliated and ciliated cells in the ratio of greater than 21. Non-ciliated cells contain vesicles filled with a mucus-like material and similar material is found lining the surface of the swimbladder lumen. Morphological evidence for discharge of the vesicle contents was obtained. In addition, nonciliated cells contain osmiophilic lamellar bodies which resemble the cytosomes of lung alveolar cells of air-breathing vertebrates. The non-ciliated cells do not appear to be involved in a process of active gas secretion.Supported by a research grant from the American Cancer Society, Oregon Division, Inc.