Electrical Responses of the Olfactory Bulb of Pacific Salmon Oncorhynchus nerka and Oncorhynchus kisutch

1972 ◽  
Vol 29 (9) ◽  
pp. 1351-1355 ◽  
Author(s):  
Toshiaki J. Hara
Keyword(s):  
Rainbow Trout ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Threshold Concentration ◽  
Salmo Gairdneri ◽  
Olfactory Responses ◽  
Amino Acid Solutions ◽  
Normal Fish ◽  
Different Sources ◽  
Electrical Responses

Olfactory bulbar electrical responses elicited by nasal infusion of food extracts, hand rinse, and several amino acid solutions were studied in sockeye (Oncorhynchus nerka) and coho (O. kisutch) salmon from several different sources. Comparison was also made in rainbow trout (Salmo gairdneri). Significant variations in the olfactory bulbar responses were observed among different species and even among the same species from different sources. The estimated lowest threshold concentration for L-serine was between 10−6 and 10−7 M in salmon. Olfactory responses of rainbow trout were always several times larger than those of salmon.Pretreatment of nasal cavity with 10−4 M solutions of HgCl2 or CuSO4 (27 or 16 mg/liter, respectively) for 10 sec completely blocked the olfactory responses in all fish species studied. The effect was reversible; the responses returned to their original level by rinsing. Exposure of fish to 0.1 mg/liter HgCl2 for up to 3 days reduced the olfactory responses to 40–10% of those of normal fish. CuSO4 was the more toxic.

Apparent Digestibility in Rainbow Trout (Salmo Gairdneri): Influence of Hypoxia

1988 ◽  
Vol 45 (11) ◽  
pp. 2003-2009 ◽  
Author(s):  
T. Pouliot ◽  
J. de la Noüe
Keyword(s):  
Rainbow Trout ◽  
Feed Intake ◽  
Animal Protein ◽  
Control Fish ◽  
Salmo Gairdneri ◽  
Apparent Digestibility ◽  
Oxygen Saturation Level ◽  
Gross Energy ◽  
Isocaloric Diets ◽  
Different Sources

We assessed the influence of hypoxia, which is likely to reduce the productivity of fish culture, on the digestibility of nutrients in rainbow trout (Salmo gairdneri). Rainbow trout (seven to each diet) were kept for 8 d in water with an oxygen saturation level of 40.0 ± 4.0%, while control fish were kept in 89.4 ± 4.2% oxygen-saturated water. Three isonitrogenous and isocaloric diets composed of different sources of protein (animal, plant, and mixed) were used. The apparent digestibility coefficients (ADC) were calculated by the indirect method (chromic oxide) after the automatic collection of feces. The experimental hypoxia used did not change the ADC for protein (total nitrogen), gross energy, or dry matter. The amino acids only showed a tendency for better absorption: proline, glycine, alanine, and tryptophan had a significantly higher ADC (P < 0.05) in experimental fish than in control fish when the animal protein based diet was used. Finally, we noted that feed intake was diet dependent. In contrast with what we observed with the commercial (mixed protein sources) and plant protein based diets, the fish receiving the animal protein based diet maintained a normal (or returning to normal) feed intake when they were subjected to hypoxia.

Molybdenum Concentrations in Tissues of Rainbow Trout (Salmo gairdneri) and Kokanee Salmon (Oncorhynchus nerka) from Waters Differing Widely in Molybdenum Content

1973 ◽  
Vol 30 (6) ◽  
pp. 841-842 ◽  
Author(s):  
James V. Ward
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Nerka ◽  
Weight Basis ◽  
Molybdenum Content ◽  
Salmo Gairdneri ◽  
Kokanee Salmon ◽  
Water Fish ◽  
Wet Weight ◽  
Molybdenum Concentration

Concentrations of molybdenum in tissues of rainbow trout (Salmo gairdneri) from three waters increased only slightly with increase in molybdenum concentration of the water. Fish from high (300 ppb) molybdenum water had mean concentrations of 13–332 ppb on a wet-weight basis; those from low (6 ppb) molybdenum water, 10–146 ppb; and those from trace molybdenum water, 5–118 ppb. Rainbow trout exhibited generally higher molybdenum concentrations than did kokanee salmon (Oncorhynchus nerka) in high molybdenum water. A possible plateau mechanism concerning molybdenum accumulation by salmonids is discussed.

DESCRIPTION OF A BACTERIUM ASSOCIATED WITH REDMOUTH DISEASE OF RAINBOW TROUT (SALMO GAIRDNERI)

1966 ◽  
Vol 12 (4) ◽  
pp. 763-770 ◽  
Author(s):  
A. J. Ross ◽  
R. R. Rucker ◽  
W. H. Ewing
Keyword(s):  
Rainbow Trout ◽  
Taxonomic Position ◽  
Salmo Gairdneri ◽  
Gram Negative ◽  
The Family ◽  
Normal Fish

A description was given of a gram-negative, peritrichously flagellated, fermentative bacterium that was isolated on numerous occasions from kidney tissues of rainbow trout (Salmo gairdneri) afflicted with redmouth disease. Although the bacteria apparently were members of the family Enterobacteriaceae, it was impossible to determine their taxonomic position within the family with certainty. Hence it was recommended that their taxonomic position remain sub judice for the present. As a temporary designation RM bacterium was used.Redmouth disease was transmitted from infected to normal fish through the medium of water.

Factors Affecting Rainbow Trout (Salmo gairdneri) Predation on Migrant Fry of Sockeye Salmon (Oncorhynchus nerka)

1976 ◽  
Vol 33 (1) ◽  
pp. 19-24 ◽  
Author(s):  
R. M. Ginetz ◽  
P. A. Larkin
Keyword(s):  
Rainbow Trout ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Development Stage ◽  
Salmo Gairdneri ◽  
Factors Affecting ◽  
Light Intensities ◽  
Salmon Fry ◽  
Lower Stream ◽  
Downstream Movement

Predation of rainbow trout (Salmo gairdneri) on migrant sockeye salmon (Oncorhynchus nerka) fry in experimental streams was higher on fry at an earlier development stage, in moonlight by contrast to cloudy night light intensities, at lesser turbidities, and at lower stream velocities. At dusk light intensities, from.05 to.30 ft-c, mortality from predation was inversely related to light intensity. The longer the period of exposure of fry to naturally declining light intensities prior to downstream movement, the lower was the loss to predators. Exposure of predators to high light intensities prior to the downstream movement of fry resulted in decreased fry mortality. Fry that had survived exposure to predators in an experimental stream 1 and 2 days previous were less vulnerable to predation than "naive" fry. Successive exposures further decreased the loss to predation. Fry enumerated at a counting fence suffered less predation than fry not enumerated. Experienced fry moved downstream more rapidly than naive fry.In laboratory aquaria, experienced fry formed compact schools prior to and in response to stimuli, while naive fry formed loose schools or did not school. Experienced fry were less active in responding to stimuli. Enumerated fry resembled experienced fry; nonenumerated fry resembled naive fry.Various techniques of enhancing sockeye salmon fry survival during downstream migration are suggested by these results.

Effects of Mercury and Copper on the Olfactory Response in Rainbow Trout, Salmo gairdneri

1976 ◽  
Vol 33 (7) ◽  
pp. 1568-1573 ◽  
Author(s):  
Toshiaki J. Hara ◽  
Y. M. C. Law ◽  
S. Macdonald
Keyword(s):  
Heavy Metals ◽  
Rainbow Trout ◽  
Exposure Time ◽  
Fish Species ◽  
Olfactory Response ◽  
Toxic Chemicals ◽  
Salmo Gairdneri ◽  
Metals Recovery ◽  
Olfactory Organs ◽  
Electrical Responses

The effects of mercury and copper on the olfactory response of rainbow trout (Salmo gairdneri) were studied by perfusing HgCl2 and CuSO4 solutions through the olfactory organs while recording the olfactory bulbar electrical responses to the standard stimulant, L-serine.The olfactory response was depressed during exposure to mercury and copper. The lowest concentrations of mercury and copper needed to cause appreciable effects within 2 h were estimated at 0.10 and 0.008 mg/liter, respectively. The depression increased with increase in the concentration and exposure time of the heavy metals. Recovery of the olfactory response was slower with higher concentrations and longer exposure.The method is rapid, accurate, and sensitive, and can be applied to other toxic chemicals and fish species.

Kudoa thyrsites (Gilchrist, 1924) (Myxozoa) in the cardiac muscle of Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri)

1989 ◽  
Vol 67 (2) ◽  
pp. 341-342 ◽  
Author(s):  
Z. Kabata ◽  
D. J. Whitaker
Keyword(s):  
British Columbia ◽  
Cardiac Muscle ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Steelhead Trout ◽  
Myxozoan Parasite ◽  
Kudoa Thyrsites ◽  
Pacific Salmonids

An examination of the cardiac muscle of returning adults of all species of British Columbia Pacific salmonids, including steelhead trout (Salmo gairdneri), for infection by the myxozoan parasite Kudoa thyrsites showed that all species but chum (Oncorhynchus keta) and sockeye (Oncorhynchus nerka) are susceptible to infection. The prevalence of observed infection was low. Its intensity was not determined, but the small numbers of spores observed suggest that it was low. The possible causes of these observations are discussed.

Effect of Metopirone on Pituitary–Interrenal Function in Two Teleosts, Sockeye Salmon (Oncorhynchus nerka) and Rainbow Trout (Salmo gairdneri)

1968 ◽  
Vol 25 (7) ◽  
pp. 1465-1474 ◽  
Author(s):  
Ulf H. M. Fagerlund ◽  
J. R. McBride ◽  
Edward M. Donaldson
Keyword(s):  
Rainbow Trout ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Inhibitory Effect ◽  
Salmo Gairdneri ◽  
Pars Distalis ◽  
Marked Inhibitory Effect ◽  
Interrenal Cells ◽  
Rostral Region ◽  
Low Dosage

Metopirone (SU 4885), an inhibitor of 11β-hydroxylation of adrenocorticosteroids, was administered intramuscularly to adult castrated sockeye salmon (Oncorhynchus nerka) and intact rainbow trout (Salmo gairdneri). Marked hypertrophy of interrenal cells pointed to an increase in the activity of the interrenal tissue of both species. Increased cortisol concentrations in trout at low dosage levels of metopirone suggested that the drug was stressful. However, decreased concentrations at higher dosage levels in trout, and decreased cortisol concentrations in all salmon indicated that the drug was also exerting a marked inhibitory effect on 11β-hydroxylation. In salmon, a repository ACTH preparation (acthar) brought about interrenal hypertrophy similar to that produced by metopirone. Metopirone also induced degranulation and hyperplasia of the cells of the palisade-like layer in the rostral region of the pars distalis in both species of fish. These cells were the only cell type of the pars distalis that were stained with lead-haematoxylin. The evidence indicates that they are the corticotrops.

Age and Vision as Factors in Bottom Colour Selection by Rainbow Trout, Salmo gairdneri

1969 ◽  
Vol 26 (3) ◽  
pp. 687-693 ◽  
Author(s):  
Wen-hwa Kwain ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Light Intensity ◽  
Visible Light ◽  
Total Darkness ◽  
Salmo Gairdneri ◽  
Colour Discrimination ◽  
Significant Preference ◽  
Light Intensities ◽  
Behavioural Patterns ◽  
Normal Fish

Rainbow trout exposed in a circular tank to a choice of black or white bottom at a light intensity of 10−2 lux were randomly distributed until the age of 14 months at which time a significant preference for black began and became more pronounced with increasing age.Groups of fish (18–24 months of age) with normal eyes, without eye lenses, and lacking eyes, were held in total darkness and at 10−2, 10, and 200 lux. In total darkness all groups were randomly distributed and quiescent. Fish without eye lenses selected black at all visible light intensities and acted similarly to normal fish at 10−2 lux. Fish lacking eyes were randomly distributed and more-or-less inactive at all intensities.The eye is essential for bottom colour discrimination and behavioural patterns occurring in normal trout exposed to different light intensities.

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