Directional and color preference in adult zebrafish: Implications in behavioral and learning assays in neurotoxicology studies

Abstract

The zebrafish (Danio rerio) is a useful vertebrate model organism for neurological studies. While a number of behavior and learning assays are recently reported in the literature for zebrafish, many of these assays are still being refined. The initial purpose of this study was to apply a published T-maze assay for adult zebrafish that measures how quickly an organism can discriminate between different color stimuli after receiving reinforcement to measure learning in a study investigating the later life impacts of developmental Pb exposure. The original results were inconclusive as the control group showed a directional and color preference. To assess directional preference further, a three-chambered testing apparatus was constructed and rotated in several directions. The directional preference observed in males was alleviated by rotating the arms pointing west and east. In addition, color preference was investigated using all combinations of five different colors (orange, yellow, green, blue and purple). With directional preference alleviated results showed that both male and female zebrafish preferred colors of shorter wavelengths. An additional experiment tested changes in color preference due to developmental exposure to Pb in adult male zebrafish. Results revealed that Pb-exposed males gained and lost certain color preferences compared to control males and the preference for short wavelengths was decreased. Overall, these results show that consideration and pretesting should be completed before applying behavioral and learning assays involving adult zebrafish to avoid innate preferences and confounding changes in neurotoxicology studies and that developmental Pb exposure alters color preferences in adult male zebrafish.

Color Preference in Danio rerio: Effects of Age and Anxiolytic Treatments

“…Although the Avdesh group 4,9 used colors on the bottom, all other investigators used colors on the walls. [10][11][12][13] The clearest discriminations are observed when yellow zones are compared with blue zones. Almost all animals immediately swim into the blue zone.…”

“…Some authors report a clear blue aversion, 4,9 whereas others report a blue preference. [10][11][12][13] Again the location of the color is of critical importance. Although the Avdesh group 4,9 used colors on the bottom, all other investigators used colors on the walls.…”

“…Some authors report a clear aversion for the color blue, 2,4,9 whereas others show a strong preference for this color. [10][11][12][13] It is also not known whether the color preference of zebrafish larvae and adults is identical or develops over time. Color preference can furthermore be induced by a preference for one color or an aversion for the alternative.…”

A colour preference technique to evaluate acrylamide-induced toxicity in zebrafish

“…Similarly, BarbaEscobedo and Gould (2012) found that zebrafish were more likely to enter a blue rather than orange box (as assessed by initial preference) while Bault et al (2015) found that zebrafish preferred colours of shorter wavelength. These and the current results differ from the findings reported by Avdesh et al (2012) who used both a place preference procedure similar to that used in the current study and a T-maze procedure.…”

“…4 introduced assays of zebrafish learning and behaviour that have been used in testing the neurotoxicity of drugs (Avdesh et al, 2012;Bault et al 2015;Emran et al, 2008;Li et al, 2014;Parng et al, 2007;Schloss, 2015). Natural colour preference is a major factor by which learning, memory, decision-making and functionality of the zebrafish visual system can be assayed.…”