Effect of acute crowding stress on rainbow trout (Oncorhynchus mykiss): A proteomics study

Proteomics has been used to analyze the global alterations in fish protein abundance in response to various kinds of stressors, but proteomics surveys concerning the post-stress recovery have not been performed. As liver is the main organ in the homeostatic adjustments to stress, we used a proteomics approach to address molecular response in this tissue during post-stress recovery in rainbow trout. The stressor consisted of a crowding (200 kg fish m−3, 45 min) by decreasing water volume in tanks. Blood samples were obtained prior to and 0, 2, 4, 8 and 24 h after stress. The acute stress response and recovery was confirmed by the transient changes in serum metabolites, which returned to pre-stress levels over a 24 h period. The liver tissues were also collected prior to (control group) and 24 h after stress (recovery group) for proteomics study. A total of 20 spots, which relative amount changed at least 2-fold under the applied conditions, were successfully identified by MALDI-TOF/TOF MS. The spots found to increase in the recovery group were identified as follow: adenosylhomocysteinase, glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase, 2-peptidylprolyl isomerase, fatty acid-binding protein, and serum albumin. Nine proteins including malate dehydrogenase, serum albumin, nucleoside diphosphate kinase, 2-peptidylprolyl isomerase, hydroxyprostaglandin dehydrogenase, peroxiredoxin, ATP synthase subunit d, glycine-rich RNA-binding protein, and transketolase-like protein were found to decrease in the recovery group. Our results suggest that the recovery after stress cause a switch from aerobic energy production toward anaerobic energy production in the liver cells of recovering fish.