The Effects of Quercetin on Physiological Characteristics and Oxidative Stress Resistance in Olive Flounder, Paralichthys olivaceus

Abstract

We investigated the effect of quercetin on growth and plasma cholesterol level and the effects of quercetin pretreatment (Diet 1, 0%; Diet 2, 0.25%; and Diet 3, 0.5% quercetin) for 30 and 60 days on oxidative stress induced by hypo-osmotic conditions (17.5, 8.75, and 4 psu) in olive flounder. The weights of flounder were higher with Diet 3 than with Diet 1 and 2, which indicated that a high concentration (Diet 3) of quercetin was very effective in growth. Total cholesterol levels were lower with Diets 2 and 3 than with Diet 1, leading us to hypothesize that quercetin removed low-density lipoproteins from circulation and thereby reduced total cholesterol. To understand the antioxidant role of quercetin, we measured the mRNA expression and activities of superoxide dismutase (SOD) and catalase (CAT) and the H 2 O 2 concentration in quercetin-treated flounder exposed to osmotic stress. The H 2 O 2 concentration and the SOD and CAT expression and activity levels were lower in flounder fed with Diets 2 and 3 than with Diet 1, suggesting that quercetin directly scavenges reactive oxygen species to reduce oxidative stress. Furthermore, the plasma lysozyme activity and osmolality were higher with Diets 2 and 3 than with Diet 1, indicating that quercetin increases immune function and helps to maintain physiological homeostasis. Plasma cortisol was lower with Diets 2 and 3 than with Diet 1, suggesting the quercetin protects against stress. These results indicate that quercetin has hypocholesterolemic and antioxidant effects, increases immune function, and acts to maintain physiological homeostasis.

Effect of hypoosmotic and thermal stress on gene expression and the activity of antioxidant enzymes in the cinnamon clownfish,Amphiprion melanopus

“…Generally, marine organisms, including fish, experience oxidative stress due to changes in water salinity (Halliwell and Gutteridge 1989;Liu et al 2007). The results of the present study were in particular agreement with those of recent studies in which the expression and activation of antioxidant enzyme genes increased in olive flounder (Choi et al 2008;Shin et al 2010b), black porgy , and crab (Paital and Chainy 2010) exposed to hypoosmotic environments. Our results indicate that the expression and activation of antioxidant enzymes in the cinnamon clownfish increased to reduce the oxidative stress induced by osmotic stress.…”

“…When the external environment changes rapidly, the stress occurring in the body suppresses immune function, which activates lysozyme (Wang et al 2008). The current results are in agreement with those of Cheng et al (2009) and Shin et al (2010b), who found that lysozyme activity decreased in olive flounder and orange-spotted grouper, Epinephelus coioides, exposed to hypoosmotic and low-temperature conditions, respectively. Thus, one can speculate that a sudden change in environment induces intracorporeal stress, resulting in a decrease in immune function.…”

Effects of Dietary Quercetin on Growth Performance, Serum Lipids Level and Body Composition of Tilapia (Oreochromis Niloticus)

“…This observation was consistent with the quercetin study on flounder conducted by Shin et al (2010aShin et al ( , 2010b, who observed that the weight gain of flounder fed diet containing 0.25% or 0.50% quercetin, for 30 and 60 days was significantly higher than that of flounder fed diet which did not contain quercetin. It also indicated that high concentration of quercetin is more effective than low concentration in growth.…”

“…Recent researches in aquatic animals have been conducted to investigate the effect of quercetin on the reproductive system of female medaka (Oryzias latipes) (Weber et al, 2002), physiological characteristics and oxidative stress resistance in olive flounder (Paralichthys olivaceus) (Shin et al, 2010a(Shin et al, , 2010b and concentrations change of quercetin in tilapia (Oreochromis niloticus) plasma, liver and whole body homogenate (Park et al, 2009). The quercetin is absorbed quickly in tilapia and this flavonoid is deposited mainly in aglycone form in the body after absorption (Park et al, 2009).…”

Expression of phospholipase C β1 in olive flounder (Paralichthys olivaceus) following external stress stimulation

“…In particular, salinity and temperature changes affect growth, reproduction, metabolism, osmoregulation, and immune function (Ackerman et al 2000). Stress induced by changes in salinity has been associated with increased formation of ROS, which may considerably influence immune function and lead to oxidative stress (Paital and Chainy 2010;Shin et al 2010). Furthermore, rapid changes in water temperature have been shown to enhance oxidative stress by increasing the amount of ROS generation in fish (Halliwell and Gutteridge 1999;Liu et al 2007).…”