Changes in Serum Free Thyroxine, Prolactin, and Olfactory Activity during Induced Smoltification in Atlantic Salmon (Salmo salar)

1994 ◽  
Vol 51 (9) ◽  
pp. 1985-1992 ◽  
Author(s):  
Pierre-Philippe Morin ◽  
Øivind Andersen ◽  
Egil Haug ◽  
Kjell B. Døving
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Acute Phase ◽  
Serum Levels ◽  
Free Thyroxine ◽  
Sensitive Period ◽  
Atlantic Salmon Salmo Salar ◽  
Increasing Temperature ◽  
Olfactory Imprinting ◽  
Second Peak

Serum levels of free thyroxine (FT4) and prolactin (PRL) and olfactory activity were studied in juvenile Atlantic salmon (Salmo salar) induced to undergo premature smoltification by a regime of increasing temperature and photoperiod. The olfactory epithelium was stimulated with L-alanine or taurocholate (10−8–10−4 M) while electroencephalographic responses were recorded from the rostrolateral and rostromedial surfaces of the olfactory bulb. Two peaks of olfactory activity occurred during the 8-wk test period for three combinations of recording site and odorant, lateral–alanine, lateral–taurocholate, and medial–taurocholate, but not for the medial–alanine combination. The first peak occurred at the beginning of smoltification (the "acute phase") coinciding with the previously described sensitive period for olfactory imprinting. Whereas this peak of olfactory activity was not associated with a rise in serum FT4, the second peak, occurring after the acute phase of smoltification, coincided with a FT4 peak. PRL remained constant throughout the acute phase of smoltification but increased 1 wk after the second peak of olfactory activity. It is concluded that olfactory activity is at least partly related to thyroid activity during induced smoltification.

Cardiac Responses to a Natural Odorant as Evidence of a Sensitive Period for Olfactory Imprinting in Young Atlantic Salmon, Salmo salar

1989 ◽  
Vol 46 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Pierre-Philippe Morin ◽  
Julian J. Dodson ◽  
François Y. Doré
Keyword(s):  
Heart Rate ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Age Groups ◽  
Sensitive Period ◽  
Age Group ◽  
Olfactory Recognition ◽  
Atlantic Salmon Salmo Salar ◽  
Cardiac Responses ◽  
Olfactory Imprinting

Olfactory imprinting was assessed in young Atlantic salmon, Salmo salar, undergoing smoltification (parr–smolt transition) by measuring their cardiac responses to a natural odorant, L-cysteine. Condition factor and body coloration were used for characterizing the degree of smoltification. In Experiment 1, heart rate conditioning to L-cysteine was used to compare olfactory learning between fish from different age groups of smoltification. In Experiments 2 and 3, other fish from the same age groups of smoltification were exposed to L-cysteine and their long-term olfactory memory was assessed by measuring their unconditioned cardiac responses to L-cysteine after smoltification. In Experiment 2, the time from the end of odor exposure to testing for olfactory recognition was kept constant for ail age groups of smoltification whereas in Experiment 3, the age of fish tested for olfactory recognition was kept constant. Greater conditioning (heart rate reduction) to L-cysteine occurred in age-groups 3 (612–619 d since birth) and 6 (642–649 d) as compared with any other age group of smoltification. Fish tested for odor recognition exhibited a greater unconditioned response (cardiac deceleration) to L-cysteine if they belonged to age-group 3 than to any other age group of smoltification. Our results demonstrated the existence of a sensitive period for olfactory imprinting in Atlantic salmon that occurred between 21 and 28 d after the onset of smoltification induced in the laboratory.

The impacts of increasing temperature and moderate hypoxia on the production characteristics, cardiac morphology and haematology of Atlantic Salmon (Salmo salar)

Aquaculture ◽  
2020 ◽  
Vol 519 ◽  
pp. 734874 ◽  
Author(s):  
Anthony K. Gamperl ◽  
Olufemi O. Ajiboye ◽  
Fábio S. Zanuzzo ◽  
Rebeccah M. Sandrelli ◽  
Ellen de Fátima C. Peroni ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Moderate Hypoxia ◽  
Cardiac Morphology ◽  
Atlantic Salmon Salmo Salar ◽  
Increasing Temperature ◽  
Production Characteristics

Changes in the Olfactory Function of Atlantic Salmon, Salmo salar, in the Course of Smoltification

1992 ◽  
Vol 49 (8) ◽  
pp. 1704-1713 ◽  
Author(s):  
Pierre-Philippe Morin ◽  
Kjell B. Døving
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Response Threshold ◽  
Sensitive Period ◽  
Electrophysiological Response ◽  
Atlantic Salmon Salmo Salar ◽  
Odor Memory ◽  
Odor Learning ◽  
The Right ◽  
Two Peaks

Electrophysiological responses were recorded from the surface of the rostromedial and rostrolateral regions of the right olfactory bulb of Atlantic salmon, Salmo salar, during stimulation of the olfactory epithelium with different concentrations of L-alanine and taurocholate. Fish exposed to taurocholate prior to testing were compared with nonexposed fish. The results revealed significant week-to-week differences in olfactory activity in nonexposed fish, with two peaks in activity of similar magnitude. The first peak occurred at the beginning of smoltification, when olfactory sensitivity reached its maximum (low response threshold). The second peak occurred after smoltification, when sensitivity was roughly 10 times lower (higher response threshold) than during the first peak. Fish exposed to taurocholate prior to testing did not exhibit these peaks in olfactory activity. Marked changes in the spatial distribution of the electrophysiological response to L-alanine and taurocholate occurred throughout the smoltification process in nonexposed fish. The two peaks in olfactory activity that we identified coincide with two peaks in odor learning (Morin et al. 1989. Can. J. Fish. Aquat. Sci. 46: 122–130, 131–136); the first coincides with a unique capacity for odor memory and is apparently a neural manifestation of a sensitive period for olfactory imprinting in Atlantic salmon.

Microstructure and texture of fresh and smoked Atlantic salmon, Salmo salar L., fillets from fish reared and slaughtered under different conditions

2001 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sjofn Sigurgisladottir ◽  
Margret S. Sigurdardottir ◽  
Helga Ingvarsdottir ◽  
Ole J. Torrissen ◽  
Hannes Hafsteinsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar

Persistence of Orally Administered Salmonella enterica Serovars Agona and Montevideo in Atlantic Salmon (Salmo salar L.)

2005 ◽  
Vol 68 (7) ◽  
pp. 1336-1339 ◽  
Author(s):  
L. L. NESSE ◽  
T. LØVOLD ◽  
B. BERGSJØ ◽  
K. NORDBY ◽  
C. WALLACE ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Salmonella Enterica ◽  
Most Probable Number ◽  
Fish Feed ◽  
Internal Organs ◽  
Probable Number ◽  
Atlantic Salmon Salmo Salar ◽  
Gastric Intubation

The objective of our experiments was to study the persistence and dissemination of orally administered Salmonella in smoltified Atlantic salmon. In experiment 1, salmon kept at 15°C were fed for 1 week with feed contaminated with 96 most-probable-number units of Salmonella Agona per 100 g of feed and then starved for 2 weeks. Samples were taken from the gastrointestinal tract and examined for Salmonella 1, 2, 8, 9, 15, and 16 days after the feeding ended. In experiment 2, Salmonella Agona and Montevideo were separately mixed with feed and administered by gastric intubation. Each fish received 1.0 × 108, 1.0 × 106, or 1.0 × 104 CFU. The different groups were kept in parallel at 5 and 15°C and observed for 4 weeks. Every week, three fish in each group were sacrificed, and samples were taken from the skin, the pooled internal organs, the muscle, and the gastrointestinal tract and examined for the presence of Salmonella. The results from the two experiments showed that the persistence of Salmonella in the fish was highly dependent on the dose administered. Salmonella was not recovered from any of the fish that were fed for 1 week with the lowest concentration of Salmonella. In the fish given the highest dose of Salmonella, bacteria persisted for at least 4 weeks in the gastrointestinal tract as well as, to some extent, the internal organs. The present study shows that under practical conditions in Norway, the risk of Salmonella in fish feed being passed on to the consumer of the fish is negligible.

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