Physiological and morphological changes in Turbot (Psetta maxima) gill tissue during waterless storage

Waterless transportation is a novel method used to keep turbot alive during transportation. In the present study, the effect of atmospheric air or pure oxygen at low temperature on the morphology and several biochemical parameters of living turbot (Psetta maxima) subjected to water-free storage conditions were evaluated. The results of hematoxylin-eosin (HE) staining and scanning electron micrographs indicated that treatment of turbot with pure oxygen for 6 h had no effect on gill silk morphology, and slight shrinkage of the fish gill silks and deformation of the gill filaments were observed 12 h later, relative to the controls (living in the water). In contrast, the atmospheric air treatment induced dramatic alterations in gill structure with a wrinkled surface and narrowed space between gill filaments of the turbot. Furthermore, other biochemical indicators, including of ATP levels, blood glucose levels, cortisol levels and blood urea nitrogen levels, were similarly non-affected by the oxygen treatment, over the course of a 12 h treatment. The data of this study is helpful in understanding fish survival and in providing the theoretical base for improving the live transportation of turbot.