Two Taiwanese researchers studying obesity have successfully developed a new subject for screening anti-obesity drugs: a zebrafish, Danio rerio, with an overactive growth gene that they have dubbed the “fat fish.”
The fish’s AKT1 gene, which regulates metabolism, cell survival and growth, can be manipulated to make the creature resemble a human with a metabolic disorder, making the transgenic fish a prime subject for testing different compounds to see which can cause the animal to lose weight, said Lin Dar-shong (林達雄), director of Pediatric Genetics at Mackay Memorial Hospital and one of the researchers involved in the study.
Out of the top 10 leading causes of death in Taiwan, eight are obesity-related afflictions such as cardiovascular diseases, high blood pressure and diabetes, a statistic which makes obesity studies crucial, Lin said.
Hsiao Chung-der (蕭崇德), an assistant professor of Bioscience Technology at Chung Yuan Christian University who also cooperated in the research, said zebrafish with an overactive AKT1 gene grow significantly larger than control fish that are fed the same amount of food.
The “fat fish” display a significantly reduced ability to adjust their blood sugar levels, have less energy and a lower survival rate than the control fish, all of which are symptoms similar to those of humans suffering from obesity, Hsiao said.
Because zebrafish, which grow from embryo to fish in only a few days, can be grown in large numbers quickly and are easy to manipulate genetically to display conditions that resemble human disorders, they are becoming prime subjects for drug-screening tests, the researchers said.
In addition, the zebrafish can yield an unexpected economic benefit through their production of oil, the researchers said.
Because the fish is rich in fat, aquaculturists can raise them and extract their oil to make dietary supplement products, avoiding the heavy metal contamination that is commonly found in oil from deep-sea fish, according to the researchers.
Their study, titled Introducing Fat Fish for Anti-Obesity Drug Screening, has been published in the Public Library of Science One Journal, as well as in the Disease Models & Mechanisms Journal.