Transcriptome assembly and candidate genes involved in nutritional programming in Xiphophorus multilineatus

Nutritional programming takes place in early development. Variation in the quality and/or quantity of nutrients in early development can influence long-term health and viability. However, little is known about the mechanism of nutritional programming. The live-bearing fish Xiphophorus multilineatus, has the potential to be a new model for understanding these mechanisms, given evidence of both genetic and nutritional programming influences on juvenile growth rate. To study the molecular signatures of nutritional programming, we assembled a de novo transcriptome for X. multilineatus, and used RNA-Seq to profile gene expression in the brains of males reared in low and high quality juvenile environments. We found131 genes were differentially expressed, including metabolism and appetite master regulator agrp gene. Overall design: Xiphophorus multilineatus were read in High Quality Juvenile Environment (HQJE:fish were housed individually after 14 days of age, and were fed Tetramin and brine shrimp, ad libitum) or Low Quality Juvenile Enviroment (LQJE; densities > 6 fish per liter, N = 23. Fish in this group were fed Tetramin once a day) . 2 biological replicates for each treatment were performed.