Abstract: In the present study, we attempted to narrow the oxygen concentration range in the packaging atmosphere during waterless live fish transportation and hence reduce the packaging cost. Lateolabrax maculates were packaging with various oxygen concentrations (60%, 80% and 98%) and cooled before waterless live transportation for up to 8 h. The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in serum, the activity of body surface mucus lysozyme (LZM) and the morphology of the gill were determined during the transportation period. Results indicated that at each transportation time, the lowest serum MDA level occurred in the 60% O2 group. Serum SOD activity in the 80% O2 group remained stable during the 8 h transportation period, and LZM activity was always at the lowest level in the 98% O2 group. The gill filaments were swollen at 0 h, and the gill lamellas were fused and adhered together at 8 h; circular microridges (CM), star point rod-shaped (SPRS) structures and microvilli (MIC) were observed on the surface of gill lamellar epithelial cells under microscopy. At 8 h, in all three groups, the surface of gill lamellas was wrinkled and rough due to lack of water, the number of CM and SPRS declined and MIC almost disappeared. Moreover, free mitochondria inside the gill filaments increased and moved to the epidermis, mucous cells decreased, and CM at the edge of the epidermis became thicker or were exfoliated. In the 80% O2 group, the gill morphology was intact, more similar to that of the control group. Therefore, packaging with oxygen concentration of 60%–80% could be recommended for waterless live transportation of Lateolabrax maculatus.

Key words: Lateolabrax maculatus, packaging oxygen concentration, fish gill, waterless live transportation, lysozyme