Effects of green wavelength light on antioxidant and non-specific immune responses of the olive flounder Paralichthys olivaceus maintained at different stocking densities

In the present study, we investigated the effects of green light illumination on antioxidant systems and immunity in the olive flounder Paralichthys olivaceus. Fish at three different stocking densities (900, 1350, and 2250 fish per 8-ton tank) were compared. The effects of green light illumination were assessed by measuring survival rates, mRNA expression activity of antioxidant enzymes (superoxide dismutase and catalase), an oxidative stress-related parameter (hydrogen peroxide, H₂O₂), and immune-related parameters (lysozyme and melatonin). Overall, fish survival rates decreased over the 30-day period of the experiment, but survival rates were significantly higher among the groups of fish exposed to green light. In high stocking densities groups, mRNA levels and activities of antioxidant enzymes and H₂O₂ concentrations had increased at 30 days; however, in fish under green light conditions, significantly lower levels of antioxidant enzyme expression were observed. By contrast, parameters indicating immune responses decreased in high stocking densities groups, although in fish under green light treatment, significantly higher levels of immune response were observed. A comet assay revealed that a high stocking density increased the rate of nuclear DNA damage; however, treatment with green wavelength light reduced the frequency of damage. These results indicate that although high density induces oxidative stress and reduces immune system responses in olive flounder, green wavelength light prevents oxidative stress and boosts the immune system.     

软骨藻酸对海湾扇贝(Argopecten irradians)血淋巴免疫力和抗氧化力的影响研究

软骨藻酸是一种神经性贝类毒素，大多数研究只报道了对陆生动物神经系统的毒性和在贝类组织内累计的软骨藻酸的浓度，而对软骨藻酸对贝类自身的免疫及抗氧化系统的毒性作用相关的研究不足。扇贝作为无脊椎动物，缺乏适应性免疫，主要依靠先天免疫系统进行防御。因此，本研究以海湾扇贝（Argopecten irradian）为研究对象，在0、10 ng/mL、50 ng/mL和100 ng/mL软骨藻酸浸泡6 h、12 h和24 h后通过测定扇贝血淋巴中超氧化物歧化酶（SOD）、溶菌酶（LZM）活性和谷胱甘肽（GSH）含量以及免疫、抗氧化相关基因（Cu/ZnSOD、MnSOD、GST和ACP）相对表达量来研究其对扇贝免疫力及抗氧化系统的影响。结果发现，LZM活性在10 ng/mL和50 ng/mL软骨藻酸处理后显著提高；ACP基因表达量在6 h和12 h内表达量受到上调，而在24 h表达量显著下调；10 ng/mL、50 ng/mL和100 ng/mL软骨藻酸浸泡扇贝6~24 h后SOD活性受到抑制，并且Cu/ZnSOD和MnSOD基因表达受到调控；GSH含量显著提高，并且GST基因表达量显著上调。以上结果表明软骨藻酸处理虽然会抑制抗氧化酶SOD活性，并且高浓度长时间处理会造成免疫疲劳现象，但机体可通过提高血淋巴GSH水平和GST基因的表达量来抵抗软骨藻酸的毒性。因此，本研究初步揭示了软骨藻酸对扇贝等双壳类免疫力、抗氧化力和解毒力的影响。     

Effects of different stocking densities on the growth performance and antioxidant capacity of Chinese mitten crab (Eriocheir sinensis) in rice crab culture system

This study assessed the effects of stocking density (D02, 0.2 individuals/m²; D03. 0.3 individuals/m²; D04, 0.4 individuals/m²; D05, 0.5 individuals/m²; D06, 0.6 individuals/m²) on Chinese mitten crab (Eriocheir sinensis; 6.25?±?0.11 g) growth performance, tissue indices, antioxidant enzyme activity (total superoxide, catalase, glutathione peroxidase, total antioxidant capacity, and malondialdehyde), and mRNA expression of antioxidant-related genes (SOD, CAT, GPx) in rice crab culture systems. Our results demonstrated that increasing stocking densities decreased the final weight (FBW), weight gain rate (WGR), specific growth rate (SGR), feed conversion efficiency (FCR), and protein efficiency ratio (PER) of the crabs. The hepatosomatic index (HSI) of female crabs in D04 group was higher than that of other groups. The gonadosomatic index (GSI) of the male crabs in the D04 group was significantly higher than that of the other groups(P?<?0.05). The meat yield (MY), total edible yield (TEY), and condition factor (CF) of the female and male crabs in the D04 group were higher than those of the other groups. The antioxidant enzyme activity (T-SOD, CAT, GSH-Px, and T-AOC) of male and female crabs in the D04 group was significantly higher than that of the other groups, and the MDA content of the D04 group was significantly lower than that of the other groups (P?<?0.05). The stocking density of 0.4 individuals/m² effectively promoted the efficient mRNA expression of SOD, CAT, and GPx genes in the hepatopancreas of male and female crabs. In summary, the optimal stocking density of E. sinensis in the rice crab culture system is 0.4 individuals/m².

     

Different effects of low- and high-dose waterborne zinc on Zn accumulation,ROS levels,oxidative damage and antioxidant responses in the liver of large yellow croaker <Emphasis Type="Italic">Pseudosciaena crocea</Emphasis>

The aim of the present study was to assess survival rate, Zn accumulation, reactive oxygen species (ROS) levels, oxidative damage and antioxidant responses after Zn exposure (2 and 8 mg L^?1 Zn) at different exposure times (6, 12, 24, 48 and 96 h) in the liver of large yellow croaker. Survival rate was reduced at 96 h, and hepatic Zn content increased during 24–96 by 8 mg L^?1 Zn. In the 2 mg L^?1 Zn group, no fish died and the increase in Zn content merely occurred at 96 h. Exposure to 8 mg L^?1 Zn induced accumulation of ROS, lipid peroxidation and protein carbonylation during the late stage of exposure. In contrast, exposure to 2 mg L^?1 Zn did not result in oxidative damage, which may result from the up-regulation of antioxidant defenses. Although exposure to 8 mg L^?1 Zn increased activities and mRNA levels of antioxidant enzymes during the early stage of exposure, including Cu/Zn–SOD, Mn–SOD, CAT, GPx and GR, the activities of these enzymes except Cu/Zn–SOD were inhibited at 96 h. Furthermore, a sharp increase in Nrf2 expression was observed in fish exposed to 8 mg L^?1 at 6 and 12 h, and 2 mg L^?1 at 12 h and 24 h, suggesting that Nrf2 was required for the protracted induction of these genes. The late increase in Keap1 expression may support its role in switching off the Nrf2 response. In conclusion, the present study demonstrated different effects of low- and high-dose waterborne Zn on antioxidant responses, which could contribute to the understanding of antioxidant and toxic roles of zinc on a molecular level.     

Curcumin analogue inhibits lipid peroxidation in a freshwater teleost, <Emphasis Type="Italic">Anabas testudineus</Emphasis> (Bloch)—an in vitro and in vivo study

The effect of a synthetic curcumin analogue (salicylcurcumin) on fish lipid peroxidation was investigated in both in vitro and in vivo conditions using a teleost model Anabas testudineus (Bloch). Curcumin analogue inhibited the formation of lipid peroxidation products and thiobarbituric acid reactive substances (TBARS) content at the three concentrations (10⁻² M, 10⁻³ M and 10⁻⁴ M) in vitro. TBARS content was reduced by 80% in the liver and 68% in brain by the higher concentration of salicylcurcumin. For in vivo study, salicylcurcumin (0.5%) was supplemented along with the basal feed for a period of 60 days. It produced a 60% reduction in liver TBARS content. The antioxidant enzyme superoxide dismutase (SOD) was stimulated, whereas catalase (CAT) and glutathione peroxidase (GPx) were inhibited. Glutathione (GSH) was reduced and glutathione reductase (GR) unchanged. Even though there was an increase in SOD activity, the CAT and GPx did not increase accordingly, maybe due to the direct scavenging of H₂O₂ by salicylcurcumin. The protein content also increased in the curcumin-fed animals, indicating a positive growth-promoting effect. Therefore, it would be beneficial to supplement salicylcurcumin along with the aquaculture feed in order to help the fish to cope with adverse conditions in the environment. This would increase the survival rate, disease resistance and ultimately the growth rate.     

Biomarkers of oxidative stress and antioxidant defences as indicators of different disinfectants exposure in the heart of rainbow trout (Oncorhynchus Mykiss Walbaum)

The aim of this study was to evaluate the impacts of different disinfectants' treatment using in aquaculture on the oxidative stress biomarkers such as thiobarbituric acid reactive substrates (TBARS) and carbonyl derivatives of protein oxidative modification, as well as antioxidant defences [superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPx) activity] and total antioxidant capacity (TAC) in the heart tissue of rainbow trout (Oncorhynchus mykiss). In the disinfectants exposure, fish were treated to chloramine‐T (final concentration 10 g m^?3), chloride dioxide (5 g m^?3), formalin (200 mL m^?3) and CIP disinfectant based on peracetic acid and hydrogen peroxide (16 mL m^?3) for 20 min and repeated three times every 3 days. Both chlorine dioxide and formalin treatment was indicated by a significant increase in the level of heart TBARS levels and carbonyl derivatives content and decreased SOD activity. Tissue oxidative stress biomarkers were unchanged upon chloramine‐T or CIP disinfectant exposure. Increased oxidative stress could modify antioxidant defences, principally causing increased CAT activity in the heart tissue of formalin‐ or ClO₂^?‐exposed fish. The correlation between oxidative stress biomarkers and GPx activity indicates that enzymes related to glutathione metabolism were responsible to formalin or ClO₂^?‐induced oxidative stress. Hence, TBARS, carbonyl derivatives and antioxidant defences could be used as biomarkers in evaluating the toxicity of formalin and chlorine dioxide using as disinfectants to trout.     

L‐carnitine exerts a cytoprotective effect against H2O2‐induced oxidative stress in the fathead minnow muscle cell line

This study was conducted to investigate the protective effect of L‐carnitine (LC) against H₂O₂‐induced oxidative stress in the fathead minnow muscle cell line (FHM). The FHM cells were stimulated with 1 mM H₂O₂ for 1 h after LC pre‐treatment, and the cell viability and the activity and mRNA relative expression of antioxidant enzyme were measured to assess the antioxidant properties of LC. The results showed that the toxic effect of H₂O₂ on the viability of FHM cells was both dose‐ and time‐dependent. Furthermore, the viability of the 0.01–1 LC mM groups was significantly higher than those of the 1 mM H₂O₂ group. L‐carnitine protected the cells from H₂O₂‐induced oxidative damage, which was demonstrated by a significant reduction in the malondialdehyde and reactive oxygen species levels and increases in the intracellular total glutathione levels and the activities of total superoxide dismutase, catalase, glutathione peroxidase (GPx) and gamma‐glutamyl‐cysteine synthetase (γ‐GCS) in FHM cells pre‐treated with LC for 6 h compared with the 1 mM H₂O₂ group. In addition, the mRNA relative expression levels of the γ‐GCS catalytic subunit and nuclear factor nuclear factor erythroid 2‐related factor 2 were significantly higher than those of the 1 mM H₂O₂ group. It could be concluded that LC exerts a beneficial antioxidant effect against oxidative stress induced by H₂O₂ in FHM cells and that the appropriate treatment is 0.1–1 mM for 6 h in this study.     

Effects of azithromycin on tilapia (Oreochromis niloticus): health status evaluation using biochemical,physiological and morphological biomarkers

Bacterial diseases cause tilapia's high‐mortality outbreak. This study investigated the toxicity of azithromycin (AZT), a macrolide antibiotic that has been considered a possible therapeutic drug for tilapia aquacultural use. The 48‐h acute toxicity (50% lethal concentration, LC50; 48 h) of AZT was determined for Oreochromis niloticus. Thereafter, fish were exposed to 0, 1, 50 and 100 mg L^?1 AZT during 14 days (chronic exposure) and measured the haematological variables, the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione‐S‐transferase (GST) and the concentration of glutathione (GSH), protein carbonyl and lipid peroxidation in the liver; histopathology was analysed the liver, gills and kidneys. The LC50; 48 h was >100 mg L^?1. No fish died during chronic exposure. Haematocrit and haemoglobin concentration increased in fish exposed to 50 and 100 mg L^?1, and the total number of leucocyte and thrombocyte increased after exposure to 100 mg L^?1 AZT, suggesting a stimulation of defence cell production. In the liver, the antioxidant enzyme activities did not change, but GST activity and the GSH level increased in fish exposed to 100 mg L^?1 AZT. Oxidative stress did not occur. Histopathological index (HI_L) indicates moderate liver damage; minor histological changes in the gill and no change in the kidneys. AZT was considered non‐toxic for O. niloticus after acute exposure and, although it causes moderated histopathology in the liver after chronic exposure, this antibiotic may be an alternative against bacterial infections, depending on its efficacy to control bacterial disease in fish.     

Effects of diet on spontaneous locomotor activity and oxygen consumption in Adriatic sturgeon (Acipenser naccarii)

Adriatic sturgeon (Acipenser naccarii) were maintained on a commercial diet enriched either in long chain polyunsaturated fatty acids of the 3 series (3 LCPUFA) or in saturated fatty acids (SFA). The effects of dietary fatty acid composition on spontaneous locomotor activity in normoxia and hypoxia (O₂ tension = 10.5 ± 0.8 kPa), and on oxygen consumption (M^O ₂) in normoxia, in hypoxia (O₂ tension = 6.6 ± 0.8 kPa) and during recovery were then investigated. The effects of adding supplementary vitamin E to the fat-enriched diets were also studied.Dietary fatty acid composition had effects on spontaneous locomotor activity and M^O ₂ in normoxia. Activity levels were higher in all sturgeon fed extra dietary fats (without vitamin E), when compared with control animals, but fish fed 3 LCPUFA had a significantly lower M^O ₂ than those fed SFA, with intermediate M^O ₂ in controls. In hypoxia, sturgeon 3 LCPUFA did not alter activity or M^O ₂ whereas those fed SFA reduced both and controls reduced M^O ₂. During recovery, both animals fed SFA and controls had a higher M^O ₂ than sturgeon fed 3 LCPUFA. The data indicate that fish fed 3 LCPUFA are more tolerant of hypoxia than controls or those fed SFA, as they did not reduce either activity or M^O ₂, and consumed less O₂ during recovery.Vitamin E supplements modified the effects elicited by dietary fats. All sturgeon fed vitamin E had low activity levels in normoxia and hypoxia. Sturgeon fed vitamin E with 3 LCPUFA had a higher M^O ₂ in normoxia than those fed 3 LCPUFA alone; reduced M^O ₂ in hypoxia, and during recovery increased M^O ₂ to a rate higher than that of animals fed 3 LCPUFA alone. In normoxia, sturgeon fed vitamin E with SFA had a similar M^O ₂ to those fed SFA alone but did not change M^O ₂ in hypoxia or during recovery. Thus, the effects of vitamin E were dependent on fat composition of the diet. Vitamin E with 3 LCPUFA removed the beneficial effects on M^O ₂ and responses to hypoxia obtained with 3 LCPUFA alone, but vitamin E with SFA allowed sturgeon to maintain aerobic metabolism in hypoxia, a more effective response than that observed in fish fed SFA alone.     

Pathogenicity comparison of high- and low-virulence strains of Vibrio scophthalmi in olive flounder Paralichthys olivaceus

Vibrio scophthalmi, a bacterial pathogen of olive flounder Paralichthys olivaceus, exhibits strain-dependent virulence. No information is available on the comparative pathogenicity of different strains of V. scophthalmi toward olive flounder. In this study, high- and low-virulence strains (HVS and LVS, respectively) were compared in terms of their pathogenic characteristics, including adhesion and survival, superoxide dismutase (SOD) activity, and extracellular products (ECP) of bacterial cells. The cell-mediated defense of macrophages from olive flounder against V. scophthalmi infection in vitro was also investigated. The results demonstrated that the SOD activity of the HVS was higher than that of the LVS. The number of viable cells of the HVS in serum increased by two log units after 18 h, whereas that of the LVS decreased. The number of cells of the HVS in skin mucus increased significantly while that of the LVS remained constant. The LD₅₀ values of the HVS and LVS ECP toward olive flounder were 10.14 and 15.99 μg protein/g fish, respectively. The ECP were positive for naphthol-AS-BI-phosphohydrolase, lipase, gelatinase, and leucine arylamidase. The extracellular O₂ ^? overflow and intracellular O₂ ^? concentration of macrophages induced by the HVS were lower than those induced by the LVS. Significantly more nitric oxide was produced by the HVS than by the LVS.     

Effects of myo‐inositol on proliferation,differentiation, oxidative status and antioxidant capacity of carp enterocytes in primary culture

This study investigated the effects of myo‐inositol (MI) on the growth and antioxidant capacity of carp enterocytes. The enterocytes were incubated in media containing 0, 15, 30, 45, 60 and 75 mg MI L^?1 for 96 h. The results indicated that MI could increase cell viability. In addition, the activities of cellular alkaline phosphatase (AKP), gamma‐glutamyl transpeptidase (γ‐GT), Na⁺, K⁺‐adenosine trisphosphatase (Na⁺, K⁺‐ATPase) and creatinkinase (CK) increased with MI supplementation at levels ranging from 15 to 60 mg MI L^?1 medium, indicating an improvement in cell differentiation and function. Further, enzymatic antioxidant ability, as measured by total superoxide dismutase (T‐SOD), Cu/Zn‐SOD, Mn‐SOD, catalase (CAT), glutathione peroxidase (GPx) and glutathione‐S‐transferase (GST) activities, improved with MI supplementation. Finally, cell damage, as indicated by lactic acid dehydrogenase (LDH) activity, malondialdehyde (MDA) content of the medium and cellular protein carbonyls (PC), was all depressed by MI. Correlation analyses showed that cell viability (MTT) was positively related to the antioxidant enzyme activities, but negatively related to cell damage (LDH, MDA and PC). In summary, the data showed that MI could improve the growth of fish enterocytes. This result may be partly due to the enhanced antioxidant status and depressed oxidative damage.     

Evaluating Fertilizer Application Rates for Giant Gourami,Osphronemus goramy,Ponds

Twelve, 400‐m² earthen ponds at Walailak University, Thailand, were used to investigate the effects of fertilizer application rates on water quality, bottom soil, and production of giant gourami, Osphronemus goramy. Fertilizer rates of 0, 6, 9, and 12 kg N plus 0, 3, 4.5, and 6 kg P₂O₅ /ha (N:P₂O₅ = 2:1) applied at 3‐wk intervals were replicated three times in a completely randomized design. Ammonium phosphate and ammonium sulfate were sources of nitrogen and phosphorus. Fish averaged 8.8 g and were stocked at 1 fish/m². The highest final weight, growth rate, and net production of giant gourami were achieved with 9 kg N plus 4.5 kg P₂O₅/ha. Chlorophyll a concentration was correlated with total nitrogen concentration (R² = 0.574; P < 0.05) and total phosphorus concentration (R² = 0.600, P < 0.05). Fish production and chlorophyll a concentration were also correlated (0.826; P < 0.05). Chlorophyll a concentration and fish production declined at total hardness concentrations above about 50 mg/L – likely from precipitation of fertilizer phosphorus as calcium phosphate. Pond bottom soil properties did not change in relationship to fertilizer rate.     

Effects of selenium dietary enhancement on hatchery-reared coho salmon, Oncorhynchus kisutch (Walbaum), when compared with wild coho: hepatic enzymes and seawater adaptation evaluated

Hatchery-reared coho salmon, Oncorhynchus kisutch (Walbaum), were fed elevated levels of selenium (as Na₂SeO₃) to raise eviscerated body burdens to the level measured in wild counterparts. The goal was to find a dietary concentration that would achieve the desired effect without causing damage to growth and normal development. To measure some indices of health, the detoxifying enzymes chosen were hepatic glutathione peroxidase (GSH-Px) and hepatic superoxide dismutase (SOD). Eviscerated body selenium (Se) concentration, GSH-Px and SOD levels were measured during and at the end of the 9 month freshwater feeding trial. Selenium retention and enzyme activity were also measured during 6 months’residence in sea water (SW). Selenium supplements were added to a commercial ration to give final concentrations of 1.1, 8.6, 11.1, 13.6 μg g^-1 Se in the four respective diets. The results indicated that a dietary concentration of 8.6 μg g^-1 selenium was capable of inducing eviscerated body burdens similar to those found in wild fish. The elevated selenium levels persisted throughout the freshwater (FW) rearing phase, but declined when the fish were fed an unsupplemented ration upon SW entry. Superoxide dismutase levels did not increase above control levels. Glutathione peroxidase levels increased in fish fed the supplemented diets. GSH-Px activity declined in the higher supplemented dietary groups when all groups were reduced to the control group level of 1.1 μg g^-1. Cumulative mortality in SW was 20% in fish fed either the 1.1 or the 8.6 μg g^-1 Se diets. The 8.6 μg g^-1 Se supplemented diets did produce healthy coho, comparable to their wild counterparts.     

胰蛋白酶酶解制备孔鳐软骨蛋白寡肽及其抗氧化活性

以孔鳐软骨为材料，采用盐酸胍抽提、丙酮分级沉淀，制备孔鳐软骨蛋白；以DPPH·和HO·清除活性为导向，采用胰蛋白酶酶解、膜超滤、DEAE-52阴离子交换层析、Sephadex G-15凝胶层析和反相高效液相色谱(RP-HPLC)等技术，制备抗氧化肽，并对其活性进行系统评价。结果显示，孔鳐软骨蛋白经胰蛋白酶酶解和分离纯化得到2个抗氧化肽RCPE-A和RCPE-B，经氨基酸序列分析确定其序列分别为Gly-Glu-Glu-Gly-Pro-Arg-Gly (GEEGPRG)和Gly-Glu-Glu-Gly-Thr-Met-Gly-Leu (GEEGTMGL)，质谱(ESI-MS)测定其分子量分别为700.71和792.87 u。体外自由基清除实验结果显示，RCPE-A与RCPE-B对DPPH·(EC₅₀ 2.94和1.16 mg/mL)、HO·(EC₅₀ 0.34和0.54 mg/mL)、ABTS⁺·(EC₅₀ 0.34和0.10 mg/mL)和O₂^-·(EC₅₀ 0.11和0.03 mg/mL)具有良好的清除作用，RCPE-A与RCPE-B亦显示出较强的脂质过氧化抑制作用。研究表明，孔鳐软骨蛋白酶解物及制备多肽可用于抗氧化相关的功能食品开发，也可以用作抗氧化剂延长相关产品的货架期。     

Effect of heat stress and recovery on viability,oxidative damage,and heat shock protein expression in hepatic cells of grass carp (Ctenopharyngodon idellus)

In this study, we investigated the effects of hyperthermia and recovery on cell viability, lactate dehydrogenase (LDH) activity, superoxide dismutase (SOD) activity, malondialdehyde (MDA), total antioxidant capacity (T-AOC), and heat shock protein (HSP60, 70, and 90) mRNA expression in the hepatic cells of the grass carp, Ctenopharyngodon idellus. Triplicate groups of cultured cells were exposed to 30, 32, or 34 °C for 0.5 h and then immediately incubated at 27 °C in 5 % CO₂ for 6, 12, 24, or 48 h. Hyperthermia stress greatly reduced cell viability and increased LDH release. Cell damage declined after recovery. Hyperthermia stress increased the lipid peroxide levels and reduced the antioxidant capacity (e.g., reduced SOD and T-AOC) of the cells. However, oxidative damage declined as the recovery period increased, and the levels of MDA, SOD, and T-AOC were restored. After cells were exposed to 32 °C, the expression of HSP60 after recovery for 1, 2, and 4 h (P < 0.05), the expression of HSP70 after recovery for 0.5 and 1 h (P < 0.01), and the expression of HSP90 throughout recovery were significantly higher (P < 0.01) than the prestress levels. During the recovery period, the variations in HSP gene expression reflected the transition period from a state of cellular growth to one of the cellular repairs. In conclusion, hyperthermia depresses cell viability, induces oxidative damage, and increases HSP expression, which plays an important role during hyperthermic stress in grass carp hepatic cells.     

Effects of calorie restriction on the expression of manganese superoxide dismutase and catalase under oxidative stress conditions in the rotifer <Emphasis Type="Italic">Brachionus plicatilis</Emphasis>

Calorie restriction (CR) in the rotifer Brachionus plicatilis extends its lifespan, as it enhances the expression of antioxidant enzymes such as manganese superoxide dismutase (Mn SOD) and catalase. Here we show that CR also increased the mRNA levels of these antioxidant enzymes upon exposure to oxidative stress. Rotifers cultured under CR showed a higher survival rate than those fed ad libitum (AL) upon exposure to 0.05–0.2 μM juglone, an oxidative stress inducer. The relative mRNA levels of Mn SOD and catalase before exposure to juglone were slightly higher in the CR rotifers than in their AL counterparts, although these differences were not statistically significant. AL rotifers showed no apparent upregulation of the mRNA levels of these antioxidant enzymes upon exposure to 0.025 and 0.05 μM juglone. In contrast, the CR rotifers increased the mRNA levels of Mn SOD and catalase by up to 5.4-fold and 4.2-fold, respectively, resulting in significant differences between their levels in AL and CR rotifers under oxidative stress conditions. Furthermore, the protein level of catalase was clearly higher in CR than in AL rotifers 6 h after exposure to oxidative stress. These results suggest that the upregulation of Mn SOD and catalase genes is involved in CR-induced resistance to oxidative stress in the rotifer.