Modeling Fetal Alcohol Spectrum Disorders in Zebrafish to Characterize the Impact of an Adverse Embryonic Environment on Adult Social Behavior

Summary

The goal of the current protocol is to outline the steps necessary to establish and use a social preference assay for adult zebrafish and demonstrate that it can be used to characterize ethanol-induced social defects.

Abstract

Fetal alcohol spectrum disorders (FASD) describe all alcohol-induced birth defects. Birth defects such as growth deficiencies, craniofacial, behavioral, and cognitive abnormalities are associated with FASD. Social difficulties are common behavioral abnormalities associated with FASD and often result in serious health issues. Animal models are critical to understanding the mechanisms responsible for ethanol-induced social defects. Zebrafish are social vertebrates that produce externally fertilized transparent eggs; these characteristics provide researchers with a precise yet simple procedure for creating the FASD phenotype and an innate behavior that can be leveraged to model the social deficits associated with FASD. Thus, zebrafish are ideal for characterizing the social deficits of FASD. The goal of the current protocol is to provide the user with a simple behavioral assay that can be used to characterize the consequences of a negative environment early during development and the effects it can have on social behavior in adulthood. The protocol can be used to characterize the effect mutations or teratogens have on adult social behavior. The protocol outlined here demonstrates how to characterize the social behavior of individual fish during a 20-min social assay. Furthermore, the data obtained using the current protocol provides evidence that the protocol can be used to characterize the effects of embryonic ethanol-induced social defects in adult zebrafish.

Introduction

Prenatal alcohol exposure can lead to a variety of birth defects collectively known as fetal alcohol spectrum disorders (FASD)¹. Impaired behavior, such as social difficulties, are common birth defects associated with FASD^2,3. Unfortunately, social difficulties frequently result in serious mental health issues⁴, which can adversely affect the quality of life for individuals with FASD. Thus, understanding the mechanisms responsible for ethanol-induced social defects is paramount.

Zebrafish have biological and behav....

Protocol

All methods described here have been approved by the Institutional Animal Care and Use Committee (IACUC) of the University of South Dakota.

1. Zebrafish housing, care, and embryonic ethanol exposure

1. Raise and breed zebrafish as described¹⁶.
2. Ethanol exposure
   1. Choose the appropriate developmental stage at which to conduct the ethanol exposure. In this protocol embryos were exposed to ethanol at 24 hpf.
   2. Place egg.......

Discussion

Zebrafish have a number of biological and behavioral characteristics making them a highly attractive organism for research involving genes, the environment, and behavior^5,19. This protocol gives the end user a relatively simple guide to assay social behavior, multiple ways to quantity the social behavior, and has the potential to link the behavioral responses of individual fish with treatments such as embryonic ethanol exposure, genetic mutations, or other pharma.......

Materials

Name	Company	Catalog Number	Comments
1.4-l ZT140 Aquaneering tanks	Aquaneering	ZT140	Tanks for social stimulus
Aqueon 20" Deluxe Fluorescent Full Hood aquarium light	https://www.petco.com/shop/en/petcostore/product/aqueon-aquarium-black-24-fluorescent-deluxe-full-hood-215740		Light for the 37-I tank
Aqueon Standard Open-Glass Glass Aquarium Tank, 10 Gallon	https://www.petco.com/shop/en/petcostore/product/aga-10g-20x10x12bk-tank-170917		37-l tank for the social assay
Ethanol	Fisher Scienticfic	BP28184
Ethovision XT tracking system	https://www.noldus.com/ethovision-xt
R-Capable Color Basler GigE Camera	https://www.noldus.com/ethovision-xt
White corrugated plastic	https://www.homedepot.com/p/Coroplast-48-in-x-96-in-x-0-157-in-4mm-White-Corrugated-Twinwall-Plastic-Sheet-CP4896S/205351385		Plastic to line the back and the bottom of the 37-I tank and back of the tanks used for the social stimulus