Inhibitory effect of anaesthesia with 2-phenoxyethanol as compared to MS222 on glucose release in isolated hepatocytes from rainbow trout (Salmo gairdneri)

1. Glucose production by freshly isolated hepatocytes from rainbow trout was studied after anaesthesia of the animals with 2-phenoxy ethanol (2PE) or tricaine methanesulphonate (MS222). 2. At the end of the procedure, hepatic contents of glycogen, glucose, lactate, ATP, ADP, AMP, were not significantly different between the two treatments. 3. Glucose production was considerably lower for 2PE than for MS222 anaesthetized trouts. This discrepancy results probably from an inhibition of glycogenolysis, suggesting that 2PE anaesthetized animals were less stressed than MS222 anaesthetized ones.     

Effects of sampling on blood parameters in the rainbow trout, Salmo gairdneri Richardson

The effects of sampling and short-term storage of blood samples on the blood parameters of rainbow trout were evaluated by comparing values obtained from resting fish sampled via cannulae and from fish sampled by cardiac puncture. Sampling stress causes an increase in haematocrit value and a decrease in mean cellular haemoglobin concentration, indicating red cell swelling. These changes are aggravated by consecutive storage of samples. Also, blood ionic balance is affected. The K⁺ concentration of plasma increases and plasma Cl⁻ concentration decreases owing to sampling. During storage the plasma K⁺ concentration decreases far below resting levels in samples taken by cardiac puncture, whereas plasma Cl⁻ level returns to pre-stress levels. Owing to the sampling- and storage-induced changes in blood parameters, care must be taken to ensure that similar sampling procedure is employed throughout to allow reliable comparisons between groups to be made.     

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.     

Effects of sampling conditions on selected blood variables of rainbow trout, Salmo gairdneri Richardson

The effects of two methods of specimen immobilization (MS 222 anaesthesia and stunning), two types of anticoagulant (EDTA and heparin), two storage temperature ranges (0–2°C and 22–25°C) and four sample storage periods (0, 1, 3, and 24 h) on the haemoglobin, haematocrit, plasma and packed cell sodium, potassium and chloride ion concentrations and packed cell ATP levels of rainbow trout were examined. Stored samples exhibited increases in cell volume, net transfer of sodium and chloride from plasma into cells, net loss of potassium to plasma and rapid depletion of ATP. Room temperature conditions and prolonged storage exacerbated these changes. Use of EDTA, particularly in combination with MS 222, frequently led to haemolysis. Least change in most variables was observed in samples drawn from stunned specimens, treated with heparin and refrigerated before use or preparation for deep cold storage.     

Effects of gossypol on rainbow trout Salmo guirdneri Richardson

Rainbow trout were fed gossypol acetate or cottonseed meals containing gossypol for 14 months. Toxic effects were indicated by growth depression, reduced hematocrit, hemo-globin, and total plasma protein. Histological changes were noted, particularly in the liver and kidney.     

Effects of partial hepatectomy on various blood and hepatic parameters in the rainbow trout (Salmo gairdnerii, Rich.)

After 36% of hepatic mass removal , rainbow trout recovered its initial liver weight in 20-30 days, i.e., with a regeneration rate clearly lower than in mammals. During early regeneration process hematocrit index and hemoglobin content were slightly decreased, but both parameters rapidly reached their normal values. The evolution of both glycaemia and hepatic glycogen content supported the idea of the existence of a late regeneration wave, which, in this case, could begin at about the 20th post-operative day.     

Some blood parameters of the rainbow trout (Salmo gairdneri Richardson)

Some of the blood constituents of male, female and immature rainbow trout of the Shasta variety, maintained in known environmental and dietetic conditions, were examined and the results statistically treated. The parameters for male and female trout were similar, only the erythrocyte count exhibiting a significant difference. Large but expected differences were evident between the parameters for mature and immature fish.     

Some blood parameters of the rainbow trout (Salmo gairdneri Richardson)

Fifty rainbow trout of the Kamloops strain were examined for 12 haematological parameters: erythrocyte sedimentation rate, haemoglobin, packed cell volume, erythrocyte count, erythrocyte diameters, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, leukocyte count, differential leukocyte count, plasma total protein and plasma glucose concentration. The fish had been held under known environmental and dietetic conditions, and at the time of sampling were 14 months old. The majority of results for erythrocyte sedimentation rate, haemoglobin, packed cell volume, erythrocyte count, erythrocyte diameters, total protein and differential leukocyte count fell within narrow ranges. The total leukocyte counts and glucose levels were more widely spread. The results are discussed and compared with those already published for Idaho and Shasta strains. It is impossible to say whether the differences that were observed between Kamloops and these other varieties were due to strain alone, since other variables were present. Some problems associated with establishing normal ranges for these parameters in fish are discussed.     

Effects of magnetic field exposure on fertilization success in rainbow trout,Salmo gairdneri

The sensitivity of trout ova and sperm to 1-T magnetic fields was investigated. It was determined that (1) overall test results combining seven independent Z-statistics demonstrated a significant (α < 0.0001) enhancement of fertilization when ova alone were exposed to the magnetic field prior to fertilization; (2) similarly, overall test results combining Z-statistics from eight independent experiments indicated a significant (α < 0.0004) enhancement when sperm alone were exposed; and (3) statistical analysis of nine independent experiments confirmed enhanced fertilization (α < 0.0001) when both ova and sperm were exposed to the magnetic field prior to fertilization. Although these data indicated that both ova and sperm were sensitive to magnetic fields, simultaneous exposure of both gametes did not have a greater total effect on fertilization rate than the sum of their individual effects.     

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.     

The development of gill arches and gill blood vessels of the rainbow trout,Salmo gairdneri

Gill development begins on the sixth day of incubation at 10^°C and is complete by 31 days (hatching). Gill arches are formed by fusion and perforation of ectoderm and endoderm across the pharyngeal wall. A primary branchial artery forms within each arch and a second branchial artery forms as a branch from its ventral end. A series of filament loop vessels forms connecting the two arteries and when several are patent a unidirectional blood flow is established via afferent (second) branchial artery, filament loop vessels to efferent (primary) branchial artery. Part of the efferent branchial artery just above its junction with the afferent branchial artery constricts and occludes. It is suggested that this change in the pattern of blood flow is dependent on differences in resistance of the two branchial arteries. A later extension of the gill ventrally is thought not to be homologous with similar regions in elasmobranchs and Acipenser.     

Effects of low pH on the chorion of rainbow trout, Oncorhynchus mykiss, and brown trout, Salmo trutta f. fario

Morphological studies on the effect of low pH on egg shells (chorion) of rainbow trout, Oncorhynrhus mykiss Walbaum (formerly Salmo gairdneri ), and brown trout, Salmo trutta f. fario L., showed that the plugs of the outer layer of the chorion, which block the channels of the underlying layer, developed distinctive vacuolization at low pH exposure. This may lead to loss of chorional semi-permeability. Chorions were incompletely degraded at low pH inducing hatching problems. Partially hatched alevins showed only a small local zone of dissolution of the chorion around the head of the embryo preventing the larvae from being freed.     

Temperature-dependence of cardiac output and regional blood flow in rainbow trout, Salmo gairdneri Richardson

Cardiac output, blood flow distribution and regional perfusion were determined in free-swimming rainbow trout acclimated to 6, 12 and 18°C, using the indicator dilution and microsphere methods. Cardiac output (ml min⁻¹ kg⁻¹) increased linearly with increasing temperature, while circulation time decreased. Blood flow distribution (% of cardiac output) to the spleen, liver, kidney, gall bladder and gastro-intestinal tract was significantly reduced at 18°C relative to 6°C-acclimated fish. White muscle received the largest fraction of cardiac output, and blood flow distribution to white muscle increased significantly with increasing acclimation temperature. Blood perfusion (ml h⁻¹ g⁻¹) of various organs and red muscle was not influenced by acclimation temperature, while white muscle perfusion increased with increasing temperature. These results demonstrate physiological adaptation of the cardiovascular system of rainbow trout to changes in acclimation temperature.     

Observations of rainbow trout, Salmo gairdneri Richardson, infected with Cryptobia salmostica

Rainbow trout, Salmo gairdneri , were experimentally infected with Cryptobia salmositica . The parasitaemia was associated with increases in the size of the spleen, liver and heart (% body weight). The splenomegaly was pronounced and was often 600-fold larger. The amounts of blood lactic acid and lactic dehydrogenase in the infected and control fish were similar. However, glycogen levels of the liver, heart and epaxial muscle declined. Liver glycogen levels were most affected and decreased to values which represented 20% of the control values. The pattern of the glycogen levels of the liver, heart and epaxial muscle declined to rise to normal values by day 56 post-inoculation. Thus, the glycogen levels both paralleled the acute parasitaemia and the subsequent partial recovery of the infected fish as they tolerated a low chronic parasitaemia.