The effects of an obesogenic diet on behaviour and cognition in zebrafish (Danio rerio): traits average, variability, repeatability, and behavioural syndromes

Abstract

The obesity epidemic, largely driven by the accessibility of ultra-processed high-energy foods, is one of the most pressing public health challenges of the 21st century. Consequently, there is increasing concern about the impacts of diet-induced obesity on behaviour and cognition. While research on this matter continues, to date, no study has explicitly investigated the effect of obesogenic diet on variance and covariance (correlation) in behavioural traits. Here, we examined how an obesogenic versus control diet impacts means and (co-)variances of traits associated with body condition, behaviour, and cognition in a laboratory population of ~160 adult zebrafish (Danio rerio). Overall, an obesogenic diet increased variation in several zebrafish traits. Zebrafish on an obesogenic diet were significantly heavier and displayed higher body weight variability; fasting blood glucose levels were similar between control and treatment zebrafish. During behavioural assays, zebrafish on the obesogenic diet displayed more exploratory behaviour and were less reactive to video stimuli with conspecifics during a personality test, but these significant differences were sex-specific. Zebrafish on an obesogenic diet also displayed repeatable responses in aversive learning tests whereas control zebrafish did not, suggesting an obesogenic diet resulted in more consistent, yet impaired, behavioural responses. Where behavioural syndromes existed (inter-class correlations between personality traits), they did not differ between obesogenic and control zebrafish groups. By integrating a multifaceted, holistic approach that incorporates components of (co-)variances, future studies will greatly benefit by quantifying neglected dimensions of obesogenic diets on behavioural changes.

Intergenerational effects of overfeeding on aversive learning in zebrafish (Danio rerio)

“…Our study in the F0 parental generation revealed that zebrafish on an obesogenic diet displayed tendencies consistent with poor cognition. That is, some individuals in the obesogenic diet group performed consistently worse in aversive learning tests than control fish, which seemed to have led to higher repeatability estimates (Anwer, O'Dea, et al, 2022 ). Recently, two other studies examined cognitive function in zebrafish following a HFD treatment (Meguro et al, 2019 ; Picolo et al, 2021 ).…”

“…Overall, male and female zebrafish from the F0 (parental) obesogenic treatment group (see our paper (Anwer, O'Dea, et al, 2022) for more details on the F0 cohort) were significantly heavier than their control counterparts after 22 weeks of diet exposure (treatment female -control female est = 0.13, df = 171, t = 9.28, p < .0001; treatment male -control male est = 0.06, df = 171, t = 4.32, p = .0002).…”

“…Here, we address the question of how obesogenic diets in the parental generation (F0) can impact offspring cognition intergenerationally (F1) in zebrafish ( Danio rerio ). We conducted a multifactorial experiment by breeding four F1 groups from F0 fish from our previous work (Anwer, O'Dea, et al, 2022 ) with and without exposure to an obesogenic diet (i.e., treatment mothers × treatment fathers, or F1T; treatment mothers × control fathers, or F1M; treatment fathers × control mothers, or F1P; control mothers × control fathers, F1C). In our previous study (Anwer, O'Dea, et al, 2022 ), we examined effects of an obesogenic diet on the immediate generation (F0).…”

“…We conducted a multifactorial experiment by breeding four F1 groups from F0 fish from our previous work (Anwer, O'Dea, et al, 2022 ) with and without exposure to an obesogenic diet (i.e., treatment mothers × treatment fathers, or F1T; treatment mothers × control fathers, or F1M; treatment fathers × control mothers, or F1P; control mothers × control fathers, F1C). In our previous study (Anwer, O'Dea, et al, 2022 ), we examined effects of an obesogenic diet on the immediate generation (F0). In this study, offspring groups of the F0 generation (F1) are subjected to aversive learning assays to answer our main question—“What is the effect of an obesogenic parental diet on offspring cognition in terms of its magnitudes and variability?” (i.e., changes in means and variances between groups).…”

Intergenerational effects of overfeeding on aversive learning in zebrafish (Danio rerio)

“…Here, we address the question of how obesogenic diets in the parental generation (F0) can impact offspring cognition intergenerationally (F1) in zebrafish (Danio rerio). We conducted a multifactorial experiment by breeding four F1 groups from F0 fish from our previous work (Anwer, O'Dea, et al, 2022) with and without exposure to an obesogenic diet (i.e., treatment mothers × treatment fathers, or F1T; treatment mothers × control fathers, or F1M; treatment fathers × control mothers, or F1P; control mothers × control fathers, F1C). In our previous study (Anwer, O'Dea, et al, 2022), we examined effects of an obesogenic diet on the immediate generation (F0).…”