The Effects of Lemon Balm (Melissa officinalis L.) Essential Oil on the Stress Response, Anti-Oxidative Ability, and Kidney Metabolism of Sea Bass during Live Transport.

Qi Wang,Jun Mei,Jing Xie

doi:10.3390/ani12030339

Abstract

Simple SummaryThe greatest challenge of long-distance live transport of fish is high mortality caused by stress and oxidative damages. In this study, the effects of lemon balm (Melissa officinalis L., MO) on the stress response of sea bass were evaluated. Sea bass were treated with different concentrations of MO (10, 20, 40 mg/L, respectively) and were transported for 72 h in transport boxes. The results of this study indicated that the level of cortisol, glucose, lactic acid, heat shock proteins, catalase, myeloperoxidase, glutathione peroxidase, uric acid, and urea nitrogen of samples treated with MO were lower than the control. The sample treated with 40 mg/L MO showed higher antioxidant capacity. In conclusion, the effect of MO on alleviating stress responses was similar to MS-222 and eugenol.This study was conducted to enhance the viability and alleviate the oxidative stress response using MO for sea bass during live transport. Six experimental groups were designed, and the effects of the physiological responses of MO were evaluated in comparison with MS-222 and eugenol. The physiological stress levels, proprotein convertase subtilisin/kexin type 9 (PCSK-9), antioxidant enzyme activities, and kidney parameters of blood serum were determined. It was found that cortisol level, glucose (Glu), lactic acid (LD), heat shock proteins (HSPs), catalase (CAT), myeloperoxidase (MPO), glutathione peroxidase (GSH-Px), uric acid (UA), and urea nitrogen (BUN) in the MO-treated samples were lower than that of the control (133.72 ng/L); however, the total antioxidant capacity (T-AOC) was higher after 72 h of the simulated live transport. The ability to resist oxidative stress increased along with the increase in the MO concentration in the water during live transport, which was similar to the results of MS-222 and eugenol treatment. In conclusion, MO, acting as a kind of novel sedative and anesthetic, can be used to improve the oxidative system and survival rate during live transport. The results of this study provide a reference for enhancing animal welfare and anti-oxidative stress ability, reducing mortality and the stress response during live fish transport.

Highlights

Introduction conditions of the Creative CommonsLive fish transport is becoming increasingly important in aquatic product trade and fish are put in bags or containers and transported alive [1]
The survival rates of the fish treated with MO or anesthetics were higher than that of the control (50%) after 12 h of recovery
The results suggested that a decrease in the proprotein convertase subtilisin/kexin type 9 (PCSK-9) activity indicated alleviation of the stress response for sea bass after 12 h of recovery; the stress response was not completely eliminated

Summary

Introduction

Introduction conditions of the Creative CommonsLive fish transport is becoming increasingly important in aquatic product trade and fish are put in bags or containers and transported alive [1]. The toughest challenge during live fish transportation is minimizing the stress response and sensitivity induced by environmental changes to obtain a high survival rate. The stress response is a complex regulatory mechanism that occurs during live fish transport, which can be divided into three levels [12]. The first stress response is a neuroendocrine reaction, in which the hormones of fish are released along with an increase in cortisol, adrenaline, and other hormones. Nestor et al [13] found that capture, transport, and high stocking density caused high cortisol levels during live fish transport

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