Morphology and expression of genes related to growth and muscle atrophy during starvation and refeeding

Abstract

The growth rate of farmed fish is one of the most important factors for the success of aquaculture. Thus, the understanding of cellular events that occur in skeletal muscle when fish undergo periods of starvation and refeeding, can support the proposition of alternative strategies to benefit muscle growth of fish, while promoting lower production cost. The aim of this study is to investigate the morphological characteristics, and the expression of genes involved in muscle atrophy (MuRF-1 and MAFbx) and in the control of muscle growth (MyoD, Myogenin, Myostatin and IGF-1) in two species commercially important (Nile tilapia and pacu) submitted to starvation, followed by refeeding. The project comprises two experiments, the first one conducted with Nile tilapia and the second with pacu. The experiments will be conducted in a completely randomized design, in which different periods of fasting and refeeding will be used in accordance to previous studies carried with both species, as well as positive controls (feeding to apparent satiation during the trial periods). Sampling for growth evaluation and muscle tissue will be taken periodically during the experiment (n=30 fish per treatment). Performance parameters, and morphology and morphometry of muscle fibers during the different periods of starvation and refeeding will be measured. At the end of the experiment the survival rates of fish in all treatments will be determined. Expression of genes related to muscle growth and atrophy will be performed by real-time PCR after reverse transcription (RT-qPCR). (AU)