Ameliorative effect of MS222 for high density land-sea relay transport in spotted knifejaw (Oplegnathus punctatus)

Fish transportation is a critical aspect of marine aquaculture operations. In the present study, we evaluated the effects of pre-treatment with anesthesia MS222 during high-density land-sea relay transport on hematological parameters (white blood cells [WBC], red blood cells [RBC]), hemoglobin [Hb], and hematocrit [Hct]),plasma cortisol and glucose, hepatic and muscle glycogen, glycolysis limited enzymes (hexokinase [HK], phosphofructokinase [PFK], pyruvate kinase [PK]), and hepatic antioxidant (aspartate-aminotransferase (AST) and alanine-aminotransferase (ALT) activities, superoxide dismutase [SOD], catalase [CAT] and glutathione peroxidase [GSH-Px]), malondialdehyde (MDA) content, histological alteration, apoptosis and stress-related gene expression (mr, gr1, gr2, hsp70, hsp90a, hsp90b) in spotted knifejaw. Results showed that high-density transportation significantly increased cortisol, glucose, Hb and Hct contents, WBC and RBC number, hepatic and plasma ALT and AST activities. Hepatic HK, PFK, PK, SOD, CAT, GSH-Px activities and MDA content manifested similar results to glucose under high density transportation. Hepatic glycogen significantly decreased, whereas muscular glycogen remained unchanged. The proportion of hepatocyte vacuolation and apoptosis rate increased significantly subject to high-density transportation. Hepatic mr, gr1, gr2, hsp70, hsp90a and hsp90b mRNA levels were significantly up-regulated under high-density transportation. However, the above parameters were recovered to normal after exposure to 80 mg/L MS222 prior to high-density transportation. These results suggest that MS222 could alleviate the physiological stress induced by high-density land-sea relay transport and help maintain homeostasis in spotted knifejaw.