Diurnal variation in somatotrop activity and correlated changes in plasma free fatty adds and tissue lipid levels in rainbow trout<i>Salmo Gairdneri</i>

Leatherland, J. F.; Nuti, R

doi:10.1080/09291018209359780

Cited by 6 publications

(6 citation statements)

References 30 publications

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“…9) (as measured by means of a sensitive homologous ELISA based on monoclonal antibodies), are in general agreement with earlier reports of higher somatotropic cell activity in rainbow trout and tilapia (Sarotherodon mossambicus), based on histological criteria (Leatherland and Nuti 1982;Carrillo et al 1980), and higher plasma GH concentrations, measured using a heterologous RIA, in kokanee salmon during the early scotophase (Leatherland et al 1974).…”

Section: Parameters In Phase With Periods Of Hypophagiasupporting

confidence: 79%

“…4). A similar pattern was found for rainbow trout held under a 12L:12D, but not in trout held under an 08L:16D photoperiod regime (Leatherland and Nuti 1982); however, in this earlier study, the fish were given only one meal per day at 14:00h. In a similar study with kokanee salmon (Oncorhynchus nerka) that were fed twice daily at 09:00h and 16:00h and held under a 12L:12D photoperiod regime, peak plasma NEFA levels occurred between 09:00h and 12:00h, i.e., shortly after the first meal of the day (Leatherland et al 1974).…”

Section: Parameters In Phase With Periods Of Hypophagiamentioning

confidence: 63%

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Circadian pattern of hepatosomatic index, liver glycogen and lipid content, plasma non-esterified fatty acid, glucose, T3, T4, growth hormone and cortisol concentrations in Oncorhynchus mykiss held under different photoperiod regimes and fed using demand-feeders

Boujard

Leatherland

1992

Fish Physiol Biochem

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The circadian patterns of several tissue and plasma metabolites, and several plasma hormone concentrations are described in rainbow trout (Oncorhynchus mykiss) that were held in groups under three different photoperiod regimes, and given free access to a demand-feeder. Regardless of photoperiod regime, all the measured parameters showed significant diel rhythms that appeared to be synchronized by dawn; dawn was represented by the concomitant onset of both light and feeding. The diel increases in hepatic glycogen content, and plasma T4 and cortisol concentrations were in phase with the main period of feeding activity, whereas the peaks in plasma T3 and glucose concentrations that may also be triggered by feeding activity, were delayed by several hours. The peaks in hepatosomatic index, plasma non-esterified fatty acids and plasma growth hormone concentrations were 180° out of phase with the main period of feeding activity, and associated with periods of hypophagia and low activity.

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Section: Parameters In Phase With Periods Of Hypophagiasupporting

confidence: 79%

Section: Parameters In Phase With Periods Of Hypophagiamentioning

confidence: 63%

Circadian pattern of hepatosomatic index, liver glycogen and lipid content, plasma non-esterified fatty acid, glucose, T3, T4, growth hormone and cortisol concentrations in Oncorhynchus mykiss held under different photoperiod regimes and fed using demand-feeders

Boujard

Leatherland

1992

Fish Physiol Biochem

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“…In most studies, there were different patterns of rhythmicity of the studied parameters depending on age, ontogenetic interval or reproduction sequence (Hontella & Peter 1978 gender (Garcia & Meier 1973), photoperiod or season (Spieler et al 1976, Spieler 1979, Leatherland & Nuti 1982, Lamba et al 1983, Noeske & Spieler 1983, Knight & Sage 1987, Laidley & Leatherland 1988, and temperature (Spieler et al 1978, Fivizzani et al 1984.…”

Section: Die1 Rhythm Of Feedingmentioning

confidence: 99%

“…Most studies of rhythms of pituitary hormones such as prolactin and growth hormone were based on heterologous radioimmunoassays (Leatherland & McKeown 1973, Leatherland et al 1974, McKeown & Peter 1976, Spieler et al 1976, Delahunty et al 1978a), or histological studies (Leatherland & Nuti 1982). Because of this, the data must be interpreted with considerable caution, and additional studies, using homologous assay systems are required before rhythms in the plasma levels of these protein hormones can be validated.…”

Section: Die1 Rhythm Of Feedingmentioning

confidence: 99%

Circadian rhythms and feeding time in fishes

1992

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SynopsisAlthough several studies have described effects of meal frequency and timing of meals on growth performance and body composition of different species of fishes, the mechanisms by which such variables influence the energy partitioning processes is not known. They may interact with the natural feeding rhythm of the fish, or with various behavioural and physiological parameters that exhibit 'circadian-like' patterns; however, in most cases, the endogenous character of such rhythms is not clear. The time of feeding, perse, can act as a Zeitgeber and override the effect of the light/dark alternation. Fish that are fed always at the same time of day show typical pre-feeding activity. Blood levels of some nutrients and hormones also show peaks or troughs at the time of feeding, but whether these are pre-feeding or post-prandial events is not clear. These results from fish are compared with similar studies with mammals. The existence and location of an endogenous multi-oscillator system is also discussed.

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“…In most fish species a diel fluctuation in plasma glucose is found (see review by Boujard and Leatherland, 1992a). Only a few studies report on the presence of diel fluctuations in free fatty acids (FFA) concentration in fish, mainly salmonids (Leatherland et al, 1974;Leatherland and Nuti, 1982;Boujard and Leatherland, 1992b;Boujard et al, 1993). In sea bass (Dicentrarchus labrax), a diel fluctuation in glycerol levels was found but its presence depended heavily on the type of diet and the moment of feeding (Carillo et al, 1982;Perez et al, 1988).…”

Section: Introductionmentioning

confidence: 96%

Diel fluctuations in blood metabolites in cannulated African catfish (Clarias gariepinus, Burchell 1822)

Heeswijk¹,

Vianen²,

Thillart³

2005

Animal Biol

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African catfish were cannulated in the dorsal aorta to study diurnal changes in blood metabolites. Cannulation of the branchial artery was tested but proved to be less successful. A clear diel fluctuation in the two major blood metabolites, free fatty acids (FFA) and glucose, was observed. Compared to the initial value at 8.30 a.m., the plasma FFA levels dropped by ca. 50% within 2 hours, after which the FFA concentration stayed relatively constant. Minimum values of 0.26±0.04 mM were reached at 12.30. The FFA concentration recovered to the initial value within the following 3 hours. The fluctuation in plasma glucose levels showed a comparable course but there was a phase-shift by 2 hours. The most astonishing finding of our study was the almost complete absence of glucose in the plasma of African catfish (0.05 ± 0.03 mM), a never reported phenomenon for any fish species. This study demonstrates the relatively low level of control of plasma glucose levels as compared to plasma FFA levels in African catfish.

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Diurnal variation in somatotrop activity and correlated changes in plasma free fatty adds and tissue lipid levels in rainbow troutSalmo Gairdneri

Cited by 6 publications

References 30 publications

Circadian pattern of hepatosomatic index, liver glycogen and lipid content, plasma non-esterified fatty acid, glucose, T3, T4, growth hormone and cortisol concentrations in Oncorhynchus mykiss held under different photoperiod regimes and fed using demand-feeders

Circadian pattern of hepatosomatic index, liver glycogen and lipid content, plasma non-esterified fatty acid, glucose, T3, T4, growth hormone and cortisol concentrations in Oncorhynchus mykiss held under different photoperiod regimes and fed using demand-feeders

Circadian rhythms and feeding time in fishes

Diel fluctuations in blood metabolites in cannulated African catfish (Clarias gariepinus, Burchell 1822)

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