Identification of environmental chemicals that induce yolk malabsorption in zebrafish using automated image segmentation

• An automatic method to segment and quantify yolk areas in zebrafish larvae was developed.
• The effect of nine chemicals on yolk absorption was investigated.
• Prochloraz exposure from 2 to 5 days post fertilization decreased yolk absorption.
• Butralin, tetrabromobisphenol A, tetrachlorobisphenol A and tributyltin exposures increased yolk absorption.

Environmental factors affecting nutrient availability during development can cause predisposition to diseases later in life. To identify chemicals in the environment capable of altering nutrient mobilization, we analyzed yolk malabsorption in the zebrafish embryo, which relies on maternally-derived yolk for nutrition during its first week of life. Embryos of the transgenic zebrafish line HGn50D, which fluoresce in the yolk syncytial layer, were exposed from two to five days post fertilization to different chemicals. We developed a software package to automatically and accurately segment and quantify the area of the fluorescing yolk in images captured at the end of the treatment period. Based on this quantification, we found that prochloraz decreased yolk absorption, while butralin, tetrabromobisphenol A, tetrachlorobisphenol A and tributyltin increased yolk absorption. Given the number and variety of industrial chemicals in commerce today, development of automated image processing to perform high-speed quantitative analysis of biological effects is an important step for enabling high throughput screening to identify chemicals altering nutrient absorption.