Physiological, proteomic, and gene expression analysis of turbot (Scophthalmus maximus) in response to cold acclimation

Cold acclimation has a tremendous impact on the survivability and the freshness of turbot when presented to consumers for sale. In the present study, to better understand the response of turbot to cold acclimation, physiological parameters determination, two-dimensional-based proteomic analysis and the expression of target genes by quantitative real-time PCR were analyzed. The results of physiological parameters indicated that the levels of glucose, ATP and cortisol, and the activities of lysozyme, catalase (CAT) and superoxide dismutase (SOD) were elevated. Moreover, the liver damage may be determined due to the increase of glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in serum. Furthermore, a total of sixteen differentially accumulated proteins were identified, which are mainly involved in carbohydrate and energy metabolism. Based on these data, we concluded that turbot accelerate the glycogen hydrolysis in liver and muscle to increase the glucose level in serum and promote the energy metabolism, enhance innate immune and heighten the antioxidant capacity to respond to cold acclimation. Meanwhile, the cold acclimation can also cause adverse effect to the innate immune system and liver of turbot. These results are helpful in understanding the response of turbot to cold acclimation and in providing the theoretical base for applying fish cold acclimation in transport.