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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

Salt stress suppresses feeding. (A) Exemplary tracks from larvae swimming in darkness at constant temperature (scale bar: 10 mm). Traces from single larvae appear biasedly distributed when 5 µl of NaCl50mM (left), but not of E2 (right), are added (dashed red circle) to the 3 ml E2 medium in the chamber, revealing active avoidance of sharp salinity variations. (B) NaCl exposure increases whole-body cortisol in a dose-dependent manner; linear regression (p < 0.0001) designated by red line. (C) Maximum cortisol levels are detected 10–20 min after NaCl exposure; as exposure length increases, cortisol drops after reaching a peak; non-linear regression (R-square = 0.78) designated by red line. (D) Stress-induced cortisol reach basal levels 30 min after NaCl exposure (dashed line denotes average basal levels); non-linear regression (R-square = 0.78) designated by red line. (B–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-incubated with either NaCl50mM(E) or NaCl100mM(F). Top bars: each rectangle represents a 5 min time period; from left: NaCl exposure (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 NaCl exposure. Asterisks designate results from a one-sample t-test against 0, p < 0.01.
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Figure 2: Salt stress suppresses feeding. (A) Exemplary tracks from larvae swimming in darkness at constant temperature (scale bar: 10 mm). Traces from single larvae appear biasedly distributed when 5 µl of NaCl50mM (left), but not of E2 (right), are added (dashed red circle) to the 3 ml E2 medium in the chamber, revealing active avoidance of sharp salinity variations. (B) NaCl exposure increases whole-body cortisol in a dose-dependent manner; linear regression (p < 0.0001) designated by red line. (C) Maximum cortisol levels are detected 10–20 min after NaCl exposure; as exposure length increases, cortisol drops after reaching a peak; non-linear regression (R-square = 0.78) designated by red line. (D) Stress-induced cortisol reach basal levels 30 min after NaCl exposure (dashed line denotes average basal levels); non-linear regression (R-square = 0.78) designated by red line. (B–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-incubated with either NaCl50mM(E) or NaCl100mM(F). Top bars: each rectangle represents a 5 min time period; from left: NaCl exposure (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 NaCl exposure. Asterisks designate results from a one-sample t-test against 0, p < 0.01.

Mentions: Salt exposure is a well-established stressor in teleosts and has been shown to increase whole-body cortisol in larval zebrafish (Yeh et al., 2013). We observed that freely swimming larvae avoided a sudden increase of salt concentration, as they rapidly moved away from a spot where 5 µl of 50 mM NaCl solution was added to their medium and continued to avoid the vicinity of the addition spot over a 180 s video-recording period; such a series of avoidance reactions did not occur when 5 µl of E2 were added to the medium (Figure 2A). In separate experiments, we next measured whole-body cortisol as a function of (1) NaCl concentration in a steady-state hyperosmotic medium, (2) NaCl exposure duration; and (3) time after exposure (Figures 2B–D). The results showed that NaCl exposure increased cortisol in a concentration-dependent manner (Figure 2B, Kruskal-Wallis test, H = 48.6, p < 0.0001, followed by Dunn’s multiple comparison tests and linear regression), that maximum cortisol levels were detectable 5–10 min after NaCl exposure (Figure 2C, One-Way ANOVA, F(4,29) = 22.8, p < 0.0001, followed by Bonferroni post-tests for pair comparisons and non-linear regression), and that basal levels were re-established 30 min later (Figure 2D, One-Way ANOVA, F(3,23) = 25.4, p < 0.0001, followed by Bonferroni post-tests for pair comparisons and non-linear regression).


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)

Salt stress suppresses feeding. (A) Exemplary tracks from larvae swimming in darkness at constant temperature (scale bar: 10 mm). Traces from single larvae appear biasedly distributed when 5 µl of NaCl50mM (left), but not of E2 (right), are added (dashed red circle) to the 3 ml E2 medium in the chamber, revealing active avoidance of sharp salinity variations. (B) NaCl exposure increases whole-body cortisol in a dose-dependent manner; linear regression (p < 0.0001) designated by red line. (C) Maximum cortisol levels are detected 10–20 min after NaCl exposure; as exposure length increases, cortisol drops after reaching a peak; non-linear regression (R-square = 0.78) designated by red line. (D) Stress-induced cortisol reach basal levels 30 min after NaCl exposure (dashed line denotes average basal levels); non-linear regression (R-square = 0.78) designated by red line. (B–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-incubated with either NaCl50mM(E) or NaCl100mM(F). Top bars: each rectangle represents a 5 min time period; from left: NaCl exposure (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 NaCl exposure. Asterisks designate results from a one-sample t-test against 0, p < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 2: Salt stress suppresses feeding. (A) Exemplary tracks from larvae swimming in darkness at constant temperature (scale bar: 10 mm). Traces from single larvae appear biasedly distributed when 5 µl of NaCl50mM (left), but not of E2 (right), are added (dashed red circle) to the 3 ml E2 medium in the chamber, revealing active avoidance of sharp salinity variations. (B) NaCl exposure increases whole-body cortisol in a dose-dependent manner; linear regression (p < 0.0001) designated by red line. (C) Maximum cortisol levels are detected 10–20 min after NaCl exposure; as exposure length increases, cortisol drops after reaching a peak; non-linear regression (R-square = 0.78) designated by red line. (D) Stress-induced cortisol reach basal levels 30 min after NaCl exposure (dashed line denotes average basal levels); non-linear regression (R-square = 0.78) designated by red line. (B–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-incubated with either NaCl50mM(E) or NaCl100mM(F). Top bars: each rectangle represents a 5 min time period; from left: NaCl exposure (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 NaCl exposure. Asterisks designate results from a one-sample t-test against 0, p < 0.01.
Mentions: Salt exposure is a well-established stressor in teleosts and has been shown to increase whole-body cortisol in larval zebrafish (Yeh et al., 2013). We observed that freely swimming larvae avoided a sudden increase of salt concentration, as they rapidly moved away from a spot where 5 µl of 50 mM NaCl solution was added to their medium and continued to avoid the vicinity of the addition spot over a 180 s video-recording period; such a series of avoidance reactions did not occur when 5 µl of E2 were added to the medium (Figure 2A). In separate experiments, we next measured whole-body cortisol as a function of (1) NaCl concentration in a steady-state hyperosmotic medium, (2) NaCl exposure duration; and (3) time after exposure (Figures 2B–D). The results showed that NaCl exposure increased cortisol in a concentration-dependent manner (Figure 2B, Kruskal-Wallis test, H = 48.6, p < 0.0001, followed by Dunn’s multiple comparison tests and linear regression), that maximum cortisol levels were detectable 5–10 min after NaCl exposure (Figure 2C, One-Way ANOVA, F(4,29) = 22.8, p < 0.0001, followed by Bonferroni post-tests for pair comparisons and non-linear regression), and that basal levels were re-established 30 min later (Figure 2D, One-Way ANOVA, F(3,23) = 25.4, p < 0.0001, followed by Bonferroni post-tests for pair comparisons and non-linear regression).

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