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The behavior of larval zebrafish reveals stressor-mediated anorexia during early vertebrate development.

De Marco RJ, Groneberg AH, Yeh CM, Treviño M, Ryu S - Front Behav Neurosci (2014)

Bottom Line: Here we demonstrate that an encounter with a stressor can suppress food consumption in larval zebrafish.We also show that feeding reoccurs when basal levels of cortisol (stress hormone in humans and teleosts) are re-established.The results present evidence that the onset of stress can switch off the drive for feeding very early in vertebrate development, and add a novel endpoint for analyses of metabolic and behavioral disorders in an organism suitable for high-throughput genetics and non-invasive brain imaging.

View Article: PubMed Central - PubMed

Affiliation: Developmental Genetics of the Nervous System, Max Planck Institute for Medical Research Heidelberg, Germany.

ABSTRACT
The relationship between stress and food consumption has been well documented in adults but less so in developing vertebrates. Here we demonstrate that an encounter with a stressor can suppress food consumption in larval zebrafish. Furthermore, we provide indication that food intake suppression cannot be accounted for by changes in locomotion, oxygen consumption and visual responses, as they remain unaffected after exposure to a potent stressor. We also show that feeding reoccurs when basal levels of cortisol (stress hormone in humans and teleosts) are re-established. The results present evidence that the onset of stress can switch off the drive for feeding very early in vertebrate development, and add a novel endpoint for analyses of metabolic and behavioral disorders in an organism suitable for high-throughput genetics and non-invasive brain imaging.

No MeSH data available.


Related in: MedlinePlus

Mechanosensory stress suppresses feeding. (A) Distance (in % relative to maximum) every 40 ms between a single larva swimming in darkness at 28°C (±0.1°C) and the submerged tip of a silica capillary tube fixed to a computer-controled piezo bender actuator. The capillary’s tip (stimulus source) moves laterally upon voltage applied to the actuator, thereby causing fast hydrodynamic flows. The bender’s LDs (of known frequency and duration) can be triggered at any given time or only when the larva swims within pre-defined areas of the swimming chamber, such as the half of the chamber containing the stimulus source (ON, bottom). Larvae respond to the stimulus by increasing the distance to the source. Insert: x-y coordinates from an exemplary 300 s track illustrating how a single larva avoids the area surrounding the source (red dashed circle, scale bar, 10 mm). (B) Left: distance swam by representative larvae before, during (between dashed lines) and after stimulation of increasing stimulus strength (delivered at 1 Hz), as determined by the voltage applied to the bender (Vact), either 3 (top) or 3.5 V (bottom); right: average distance swam before, during and after stimulation. (C) Whole-body cortisol measured 10 min after stimulation as a function of stimulus strength (in % relative to maximum Vact); linear regression (p < 0.0001) designated by red line. (D) Cortisol level as a function of time after stimulation (stimulus strength: 60%). Asterisks designate statistical differences as compared to basal levels (*p < 0.05, ***p < 0.001). Non-linear regression (R-square = 0.77) designated by red line (C,D: different letters designate statistical differences determined by one-way ANOVAs followed by post-hoc comparisons; sample size in parentheses). (E,F) DSU in larvae pre-exposed to mechanosensory stress using stimulus strength levels of 30% (E) and 60% (F), defined as in (C) (asterisks designate results from one-sample t-tests against 0, **p < 0.01, ***p < 0.001). Top bars: each rectangle represents a 5 min time period; from left: mechanosensory stimulation (yellow), first 10 min period without prey (light gray), second 10 min period with prey (dark gray). Shown are DSU values measured either 5–25 min (left, early) or 30–50 min (right, late) after mechanosensory stimulation.
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Figure 4: Mechanosensory stress suppresses feeding. (A) Distance (in % relative to maximum) every 40 ms between a single larva swimming in darkness at 28°C (±0.1°C) and the submerged tip of a silica capillary tube fixed to a computer-controled piezo bender actuator. The capillary’s tip (stimulus source) moves laterally upon voltage applied to the actuator, thereby causing fast hydrodynamic flows. The bender’s LDs (of known frequency and duration) can be triggered at any given time or only when the larva swims within pre-defined areas of the swimming chamber, such as the half of the chamber containing the stimulus source (ON, bottom). Larvae respond to the stimulus by increasing the distance to the source. Insert: x-y coordinates from an exemplary 300 s track illustrating how a single larva avoids the area surrounding the source (red dashed circle, scale bar, 10 mm). (B) Left: distance swam by representative larvae before, during (between dashed lines) and after stimulation of increasing stimulus strength (delivered at 1 Hz), as determined by the voltage applied to the bender (Vact), either 3 (top) or 3.5 V (bottom); right: average distance swam before, during and after stimulation. (C) Whole-body cortisol measured 10 min after stimulation as a function of stimulus strength (in % relative to maximum Vact); linear regression (p < 0.0001) designated by red line. (D) Cortisol level as a function of time after stimulation (stimulus strength: 60%). Asterisks designate statistical differences as compared to basal levels (*p < 0.05, ***p < 0.001). Non-linear regression (R-square = 0.77) designated by red line (C,D: different letters designate statistical differences determined by one-way ANOVAs followed by post-hoc comparisons; sample size in parentheses). (E,F) DSU in larvae pre-exposed to mechanosensory stress using stimulus strength levels of 30% (E) and 60% (F), defined as in (C) (asterisks designate results from one-sample t-tests against 0, **p < 0.01, ***p < 0.001). Top bars: each rectangle represents a 5 min time period; from left: mechanosensory stimulation (yellow), first 10 min period without prey (light gray), second 10 min period with prey (dark gray). Shown are DSU values measured either 5–25 min (left, early) or 30–50 min (right, late) after mechanosensory stimulation.

Mentions: We next examined the extent to which stressor identity accounted for the effect of NaCl exposure on food intake. We therefore measured prey-dependent DSU changes in larvae pre-exposed to a novel stress protocol based exclusively on mechanosensory stimuli. To evoke mechanosensory stress, we used fast water movements caused by the rapid LDs of an inflexible silica capillary (360 µm OD) submerged partially (2 mm) in the larvae’s surrounding medium. The capillary was fixed to a computer-controled piezo bender actuator and the voltage applied to the actuator (or stimulus strength, in % relative to maximum voltage) determined the speed of the capillary’s LDs (maximum displacement: ±1000 µm). To examine how larvae reacted to the capillary’s LDs, we placed them individually in a rectangular swimming chamber and LDs of known frequency and duration were triggered only when they swam within the half of the chamber containing the tip of the capillary (stimulus source). Larvae responded to LDs by increasing rapidly their distance to the centre point of the moving capillary (Figure 4A). In line with this, their overall locomotion during continuous stimulation (i.e., series of 10 2-ms LDs delivered at 1 Hz, irrespective of the larva’s position relative to the source) increased together with stimulus strength (Figure 4B). We thus assumed that LD-borne stimuli resembled, at least partially, motion and pressure waves (cues) encoding predation threat, such as those derived from the movements of larger fish and approaching predators. Notably, such a form of repeated mechanosensory stimulation increased whole-body cortisol in a stimulus strength-dependent manner (Figure 4C, Kruskal-Wallis test, H = 22.4, p < 0.0001, followed by Dunn’s multiple comparison tests and linear regression), and post-peak cortisol levels were undistinguishable from basal levels 30 min after stimulation (Figure 4D, Kruskal-Wallis test, H = 10.8, p = 0.0045, followed by Dunn’s multiple comparison tests and non-linear regression). An analysis of space use after mechanosensory stimulation showed that low (30%) and moderate (60%) stimulus strength levels abolished prey-dependent DSU changes 15–25 min after exposure to LDs (Figures 4E,F, left, Paired t-tests, 30%: t(23) = 0.48, p = 0.63, 60%: t(23) = 0.004, p = 0.99). Normal DSU changes were detectable 40–50 min later (Figures 4E,F, right, Paired t-tests, 30%: t(23) = 4.2, p = 0.0004, 60%: t(23) = 4.6, p = 0.0001). As before, across group comparisons of total a.u.c. values indicated that locomotion variability could not account for prey-dependent DSU changes (Two-Way Repeated-Measures ANOVA, Group factor: F(5,54) = 0.38, p = 0.86, Prey factor: F(1,54) = 0.40, p = 0.53, Group X Prey factor: F(5,54) = 0.20, p = 0.96).


The behavior of larval zebrafish reveals stressor-mediated anorexia during early vertebrate development.

De Marco RJ, Groneberg AH, Yeh CM, Treviño M, Ryu S - Front Behav Neurosci (2014)

Mechanosensory stress suppresses feeding. (A) Distance (in % relative to maximum) every 40 ms between a single larva swimming in darkness at 28°C (±0.1°C) and the submerged tip of a silica capillary tube fixed to a computer-controled piezo bender actuator. The capillary’s tip (stimulus source) moves laterally upon voltage applied to the actuator, thereby causing fast hydrodynamic flows. The bender’s LDs (of known frequency and duration) can be triggered at any given time or only when the larva swims within pre-defined areas of the swimming chamber, such as the half of the chamber containing the stimulus source (ON, bottom). Larvae respond to the stimulus by increasing the distance to the source. Insert: x-y coordinates from an exemplary 300 s track illustrating how a single larva avoids the area surrounding the source (red dashed circle, scale bar, 10 mm). (B) Left: distance swam by representative larvae before, during (between dashed lines) and after stimulation of increasing stimulus strength (delivered at 1 Hz), as determined by the voltage applied to the bender (Vact), either 3 (top) or 3.5 V (bottom); right: average distance swam before, during and after stimulation. (C) Whole-body cortisol measured 10 min after stimulation as a function of stimulus strength (in % relative to maximum Vact); linear regression (p < 0.0001) designated by red line. (D) Cortisol level as a function of time after stimulation (stimulus strength: 60%). Asterisks designate statistical differences as compared to basal levels (*p < 0.05, ***p < 0.001). Non-linear regression (R-square = 0.77) designated by red line (C,D: different letters designate statistical differences determined by one-way ANOVAs followed by post-hoc comparisons; sample size in parentheses). (E,F) DSU in larvae pre-exposed to mechanosensory stress using stimulus strength levels of 30% (E) and 60% (F), defined as in (C) (asterisks designate results from one-sample t-tests against 0, **p < 0.01, ***p < 0.001). Top bars: each rectangle represents a 5 min time period; from left: mechanosensory stimulation (yellow), first 10 min period without prey (light gray), second 10 min period with prey (dark gray). Shown are DSU values measured either 5–25 min (left, early) or 30–50 min (right, late) after mechanosensory stimulation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
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Figure 4: Mechanosensory stress suppresses feeding. (A) Distance (in % relative to maximum) every 40 ms between a single larva swimming in darkness at 28°C (±0.1°C) and the submerged tip of a silica capillary tube fixed to a computer-controled piezo bender actuator. The capillary’s tip (stimulus source) moves laterally upon voltage applied to the actuator, thereby causing fast hydrodynamic flows. The bender’s LDs (of known frequency and duration) can be triggered at any given time or only when the larva swims within pre-defined areas of the swimming chamber, such as the half of the chamber containing the stimulus source (ON, bottom). Larvae respond to the stimulus by increasing the distance to the source. Insert: x-y coordinates from an exemplary 300 s track illustrating how a single larva avoids the area surrounding the source (red dashed circle, scale bar, 10 mm). (B) Left: distance swam by representative larvae before, during (between dashed lines) and after stimulation of increasing stimulus strength (delivered at 1 Hz), as determined by the voltage applied to the bender (Vact), either 3 (top) or 3.5 V (bottom); right: average distance swam before, during and after stimulation. (C) Whole-body cortisol measured 10 min after stimulation as a function of stimulus strength (in % relative to maximum Vact); linear regression (p < 0.0001) designated by red line. (D) Cortisol level as a function of time after stimulation (stimulus strength: 60%). Asterisks designate statistical differences as compared to basal levels (*p < 0.05, ***p < 0.001). Non-linear regression (R-square = 0.77) designated by red line (C,D: different letters designate statistical differences determined by one-way ANOVAs followed by post-hoc comparisons; sample size in parentheses). (E,F) DSU in larvae pre-exposed to mechanosensory stress using stimulus strength levels of 30% (E) and 60% (F), defined as in (C) (asterisks designate results from one-sample t-tests against 0, **p < 0.01, ***p < 0.001). Top bars: each rectangle represents a 5 min time period; from left: mechanosensory stimulation (yellow), first 10 min period without prey (light gray), second 10 min period with prey (dark gray). Shown are DSU values measured either 5–25 min (left, early) or 30–50 min (right, late) after mechanosensory stimulation.
Mentions: We next examined the extent to which stressor identity accounted for the effect of NaCl exposure on food intake. We therefore measured prey-dependent DSU changes in larvae pre-exposed to a novel stress protocol based exclusively on mechanosensory stimuli. To evoke mechanosensory stress, we used fast water movements caused by the rapid LDs of an inflexible silica capillary (360 µm OD) submerged partially (2 mm) in the larvae’s surrounding medium. The capillary was fixed to a computer-controled piezo bender actuator and the voltage applied to the actuator (or stimulus strength, in % relative to maximum voltage) determined the speed of the capillary’s LDs (maximum displacement: ±1000 µm). To examine how larvae reacted to the capillary’s LDs, we placed them individually in a rectangular swimming chamber and LDs of known frequency and duration were triggered only when they swam within the half of the chamber containing the tip of the capillary (stimulus source). Larvae responded to LDs by increasing rapidly their distance to the centre point of the moving capillary (Figure 4A). In line with this, their overall locomotion during continuous stimulation (i.e., series of 10 2-ms LDs delivered at 1 Hz, irrespective of the larva’s position relative to the source) increased together with stimulus strength (Figure 4B). We thus assumed that LD-borne stimuli resembled, at least partially, motion and pressure waves (cues) encoding predation threat, such as those derived from the movements of larger fish and approaching predators. Notably, such a form of repeated mechanosensory stimulation increased whole-body cortisol in a stimulus strength-dependent manner (Figure 4C, Kruskal-Wallis test, H = 22.4, p < 0.0001, followed by Dunn’s multiple comparison tests and linear regression), and post-peak cortisol levels were undistinguishable from basal levels 30 min after stimulation (Figure 4D, Kruskal-Wallis test, H = 10.8, p = 0.0045, followed by Dunn’s multiple comparison tests and non-linear regression). An analysis of space use after mechanosensory stimulation showed that low (30%) and moderate (60%) stimulus strength levels abolished prey-dependent DSU changes 15–25 min after exposure to LDs (Figures 4E,F, left, Paired t-tests, 30%: t(23) = 0.48, p = 0.63, 60%: t(23) = 0.004, p = 0.99). Normal DSU changes were detectable 40–50 min later (Figures 4E,F, right, Paired t-tests, 30%: t(23) = 4.2, p = 0.0004, 60%: t(23) = 4.6, p = 0.0001). As before, across group comparisons of total a.u.c. values indicated that locomotion variability could not account for prey-dependent DSU changes (Two-Way Repeated-Measures ANOVA, Group factor: F(5,54) = 0.38, p = 0.86, Prey factor: F(1,54) = 0.40, p = 0.53, Group X Prey factor: F(5,54) = 0.20, p = 0.96).

Bottom Line: Here we demonstrate that an encounter with a stressor can suppress food consumption in larval zebrafish.We also show that feeding reoccurs when basal levels of cortisol (stress hormone in humans and teleosts) are re-established.The results present evidence that the onset of stress can switch off the drive for feeding very early in vertebrate development, and add a novel endpoint for analyses of metabolic and behavioral disorders in an organism suitable for high-throughput genetics and non-invasive brain imaging.

View Article: PubMed Central - PubMed

Affiliation: Developmental Genetics of the Nervous System, Max Planck Institute for Medical Research Heidelberg, Germany.

ABSTRACT
The relationship between stress and food consumption has been well documented in adults but less so in developing vertebrates. Here we demonstrate that an encounter with a stressor can suppress food consumption in larval zebrafish. Furthermore, we provide indication that food intake suppression cannot be accounted for by changes in locomotion, oxygen consumption and visual responses, as they remain unaffected after exposure to a potent stressor. We also show that feeding reoccurs when basal levels of cortisol (stress hormone in humans and teleosts) are re-established. The results present evidence that the onset of stress can switch off the drive for feeding very early in vertebrate development, and add a novel endpoint for analyses of metabolic and behavioral disorders in an organism suitable for high-throughput genetics and non-invasive brain imaging.

No MeSH data available.


Related in: MedlinePlus