Identification of core genes responsive to the complex stress caused by transportation in Largemouth bass

Live fish transportation elicits complex stress to the fish, such as fishing and emersion before and after transportation, increase of ammonia concentration, crowding, hypoxia and agitation during transportation. The fish are susceptible to pathogens in the recovery phase shortly after transportation. However, transcriptional responses to transportation and the genes that determine the outcome of exposure to the transportation-caused complex stress remain unknown. Largemouth bass is a widely cultured species and sensitive to environmental stressors. In this study, we exposed the fish to 4-hour transportation with high density, after arrival at the laboratory the fish were let to recover for 5 days in aquaria supplied with circulating water. During the recovery phase, except the dead ones, some fish got sick due to bacterial infection and physical damage caused by crash with the aquaria wall. Samples were collected before and at the end of transportation, after recovered for 1, 3, 4, 5 days, both normal and abnormal (sick) individuals were sampled. The liver and spleen tissues were collected and subjected to RNA sequencing to characterize gene expression and to identify the core genes responsive to the complex stress caused by transportation.