Glutathione Injection Alleviates the Fluctuation of Metabolic Response under Thermal Stress in Olive Flounder, Paralichthys olivaceus.

Seonghye Kim,Seohee Ma,Suhkmann Kim,Do-Hyung Kim,Sujin Lee,Wonho Lee,Ahran Kim,Dahye Yoon

doi:10.3390/metabo10010003

Seonghye Kim, Seohee Ma + Show 6 more

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https://doi.org/10.3390/metabo10010003

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Abstract

Continuous increases in water temperature disturb homeostasis and increase oxidative stress in fish. Glutathione (GSH) is an intracellular antioxidant that helps to relieve stress in animals. In this study, we observed the effect of GSH on olive flounder exposed to high temperature using serum parameters and NMR-based metabolomics. Based on the results from the first experiment, 20 mg of GSH was chosen as an effective dose with lower infection rates and mortality. Then, fish were divided into Control, Temp (PS injection), and GSH (glutathione injection) groups, and fish in Temp and GSH groups were exposed to temperature fluctuations (20 °C→24 °C→27 °C). In OPLS-DA score plots, Temp group was clearly distinguished from the other groups in the kidney. In the liver, the metabolic patterns of GSH group were close to the Temp group on day 4 and became similar to Control group from day 7. Serum parameters did not change significantly, but the deviation in Temp group was greater than that in GSH group. Metabolite levels that were significantly altered included GSH, lactate, O-phosphocholine, and betaine in the kidney and taurine, glucose, and several amino acids in the liver, which were related to antioxidant activity and energy system. Therefore, GSH supplements could relieve thermal stress influencing metabolic mechanisms in fish.

Highlights

Environmental stressors are detrimental to fish when they are present at concentrations above the normal range
According to the Ministry of Oceans and Fisheries, the average water temperature of Korea’s coast has risen by 2.89 ◦ C over the past decade, and the coastal water temperature in July 2018 reached over 28.5 ◦ C on Jeju Island, which has a lot of aquaculture farms of olive flounder
Natural infection by Edwardsiella piscicida was observed from the first week and over a 40% infection rate was observed until the third week in the Control and 10 mg GSH groups

Summary

Introduction

Environmental stressors are detrimental to fish when they are present at concentrations above the normal range. Fish are poikilothermic (ectothermic) animals and cannot avoid alternations, such as changes in salinity and temperature and exposure to pollution, in their surrounding environment [2]. Water temperature is important to the well-being and survival of fish [3]. According to the Ministry of Oceans and Fisheries, the average water temperature of Korea’s coast has risen by 2.89 ◦ C over the past decade, and the coastal water temperature in July 2018 reached over 28.5 ◦ C on Jeju Island, which has a lot of aquaculture farms of olive flounder. Olive flounder (Paralichthys olivaceus), one of the major fish species in the aquaculture industry of South Korea, is a stenothermal fish that survives at an Metabolites 2020, 10, 3; doi:10.3390/metabo10010003 www.mdpi.com/journal/metabolites

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