Alterations of protein expression in response to crowding in the Chinese shrimp (Fenneropenaeus chinensis)

Crowding, as a result of high stocking densities in aquaculture, can affect the physiological state and flesh quality of aquatic animals. To better understand the mechanism of response to crowding stress in Chinese shrimp (Fenneropenaeus chinensis), two-dimensional gel electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) mass spectrometry (MS) identification were used to analyze differentially expressed muscle proteins between shrimp under crowded and non-crowded conditions. Spots corresponding to 34 differentially expressed proteins were found. Further MALDI-TOF/TOF analysis indicated that three of the enhanced proteins, 14-3-3-like protein, actin T2 and pyruvate kinase 3, were involved in myogenic signaling, muscle cytoskeleton and carbohydrate catabolism, respectively. Moreover, quantitative RT-PCR showed that mRNA levels of 14-3-3-like protein and pyruvate kinase 3 were up-regulated after a 2-h crowding stress, whereas actin T2 showed down-regulation. The alterations of protein expression observed in the muscle may cause flesh quality decline of shrimp after crowding stress.