Detoxification effects of ascorbic acid on the oxidative stress, neurotoxicity, and metallothionein (MT) gene expression in juvenile rockfish, Sebastes schlegelii by the dietary chromium exposure.

Juvenile rockfish Sebastes schlegelii (mean length 10.8 ± 1.4 cm, and mean weight 31.7 ± 3.6 g) were exposed for 4 weeks with the different levels of dietary chromium (Cr6+) at 0, 120 and 240 mg/L and ascorbic acids (AsA) at 100, 200 and 400 mg/L. Superoxide dismutase (SOD) activity, glutathione S-transferase (GST) activity, and glutathione (GSH) level of liver and gill were evaluated as antioxidant response indicators for the 4 weeks exposure. The SOD and GST activity of liver and gill were substantially increased by the high concentrations of dietary Cr exposure, whereas a significant decrease was observed in the GSH levels of liver and gill. Metallothionein (MT) gene in liver was significant stimulated in the response to the dietary Cr exposure. In neurotoxicity, AChE activity was considerably inhibited in brain and muscle tissues by dietary Cr exposure. The high levels of AsA supplementation were highly effective to attenuate the alterations in the antioxidant responses, MT gene expression, and AChE activity by the dietary Cr exposure.

The mercury accumulation and its effects on antioxidant and immune responses in starry flounder, Platichthys stellatus exposed to dietary mercury.

The purpose of this study is to investigate the effect of inorganic mercury (Hg) on fish. Inorganic Hg is less toxic than organic Hg, but it is used more in human daily life, such as manufacturing Hg batteries and fluorescent lamps. For this reason, inorganic Hg was used in this study. Starry flounder, Platichthys stellatus (mean weight 43.9 ± 4.4 g; mean length 14.2 ± 0.4 cm) were exposed for 4 weeks to the different levels of dietary inorganic Hg at concentrations of 0, 4, 8, 12 and 16 mg Hg/kg, and depuration was performed for 2 weeks after exposure. Bioaccumulation of Hg in the tissues was observed to increase significantly, in following order: intestine > head kidney > liver > gills > muscle. Antioxidant responses (superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and glutathione (GSH)) were significantly increased. Immune responses (lysozyme and phagocytosis activity) were substantially decreased. The results of this study suggest that dietary inorganic Hg induces bioaccumulation in specific tissues, increases antioxidant responses and decreases immune responses. After the depuration period for 2 weeks, it was effective to alleviate bioaccumulation in tissues. However, antioxidant and immune responses were limited to be attenuated for recovery.

Review of cadmium toxicity effects on fish: Oxidative stress and immune responses.

Cadmium (Cd) in aquatic environments can cause environmental toxicity to fish and induce oxidative stress owing to an excessive production of reactive oxygen species in fish bodies. Fish have developed various antioxidant systems to protect themselves from reactive oxygen species; thus, a change in antioxidant responses in fish can be a criterion for evaluating oxidative stress resulting from Cd exposure. Because Cd exposure may be recognized as an exogenous substance by a fish body, it may lead to the stimulation or suppression of its immune system. Various immune responses can be assessed to evaluate Cd toxicity in fish. This review aimed to identify the impacts of Cd exposure on oxidative stress and immunotoxicity in fish as well as identify accurate indicators of Cd toxicity in aquatic ecosystems.

Microplastic polyamide toxicity: Neurotoxicity, stress indicators and immune responses in crucian carp, Carassius carassius.

This study aimed to determine the toxicity standard and potential risks and effects of polyamide (PA) exposure on neurotoxicity, stress indicators, and immune responses in juvenile crucian carp Carassius carassius. Numerous microplastics (MPs) exists within aquatic environments, leading to diverse detrimental impacts on aquatic organisms. The C. carassius (mean weight, 23.7 ± 1.6 g; mean length, 13.9 ± 1.4 cm) were exposed to PA concentrations of 0, 4, 8, 16, 32 and 64 mg/L for 2 weeks. Among the neurotransmitters, the acetylcholinesterase (AChE) activity in the liver, gill, and intestine of C. carassius was significantly inhibited by PA exposure. Stress indicators such as cortisol and heat shock protein 70 (HSP70) in the liver, gill, and intestine of C. carassius were significantly increased, while immune responses to lysozyme and immunoglobulin M (IgM) were significantly decreased. Our study demonstrates the toxic effects of MP exposure on crucian carp's neurotoxicity, stress indicators, and immune responses.

The application and future of biofloc technology (BFT) in aquaculture industry: A review.

This review describes the applicability of biofloc technology (BFT) to future aquaculture technologies. BFT is considered an innovative alternative for solving the problems of traditional aquaculture (for example, environmental pollution, high maintenance costs, and low productivity). Extensive research is being conducted to apply BFT to breed and raise many aquatic animal species. In BFT, maintaining an appropriate C:N ratio by adding a carbon source promotes the growth of microorganisms in water and maintains the aquaculture water quality through microbial processes such as nitrification. For the efficient use and sustainability of BFT, various factors such as total suspended solids, water turbidity, temperature, dissolved oxygen, pH, and salinity, stocking density, and light should be considered. The application of the transformative fourth industrial revolution technologies, Information and Communications Technology (ICT) and Internet of Things (IoT), to aquaculture can reduce the risk factors and manual interventions in aquaculture through automation and intelligence. The combination of ICT/IoT with BFT can enable real-time monitoring of the necessary elements of BFT farming using various sensors, which is expected to increase productivity by ensuring the growth and health of the organisms being reared.

Shrimp bacterial and parasitic disease listed in the OIE: A review.

Shrimp aquaculture industry has steadily increased with demand and development of aquaculture technology. In recent years, frequent diseases have become a major risk factor for shrimp aquaculture, such as a drastically reduced the production of shrimp and causing national economic loss. Among them, shrimp bacterial diseases such as hepatopancreatic necrosis disease (AHPND) and necrotizing hepatopancreatitis (NHP-B) and parasitic disease such as Aphanomyces astaci (crayfish plague) are emerging and evolving into new types. OIE (World Organization for Animal Health) regularly updates information on diseases in the Aquatic Code and Aquatic Manual, but in-depth information on the shrimp diseases are lacking. Therefore, the purpose of this review is to provide information necessary for the response and prevention of shrimp diseases by understanding the characteristics and diagnosis of shrimp diseases designated by OIE.

Toxic effects of dietary copper and EGCG on bioaccumulation, antioxidant enzyme and immune response of Korean bullhead, Pseudobagrus fulvidraco.

There are few reports of dietary Cu (copper) toxicity to Korean bullhead, Pseudobagrus fulvidraco, and little is known about recovery from dietary Cu exposure. In this study, P. fulvidraco (mean length 16.9 ± 1.38 cm, and mean weight 53.2 ± 1.22 g) were exposed for 4 weeks to dietary Cu concentration of 0 (control), 700, 900, and 1100 mg Cu kg-1 dry feed to establish maximum tolerable levels of dietary Cu. All fish were then fed the dietary EGCG (Epigallocatechin gallate) concentration of 100 and 500 mg EGCG kg-1 dry feed for a further 2 weeks to assess recovery. We were measured bioaccumulation (in the intestine, liver, and gill tissue), antioxidant enzymes (SOD and CAT) and immune responses (lysozyme and phagocytosis). The Cu exposure induced a significant accumulation in the intestine, liver, and gill tissues and the highest accumulation was observed in intestinal tissues (17-34 fold), but dietary EGCG exposure decreased (about 0.8-fold) Cu concentration in each tissue (ANOVA, P < 0.05). In antioxidant enzymes, SOD and CAT significantly increased by approximately 1.6-fold by dietary Cu exposure in the liver and gill tissue, respectively, but dietary EGCG exposure decreased SOD and CAT by about 1.1-fold, respectively (ANOVA, P < 0.05). For immune responses, lysozyme and phagocytosis in the blood significantly were decreased by approximately 1.5-fold, respectively, by dietary Cu exposure, but dietary EGCG exposure increased lysozyme and phagocytosis by about 1.1-fold, respectively (ANOVA, P < 0.05). During recovery period, bioaccumulation, antioxidant enzymes (SOD and CAT activity), and immune response (lysozyme and phagocytosis activity) tended to alleviate the significant changes by Cu exposure, and the tendency to return normal state was observed in high level of EGCG. The result of this study indicate that Cu exposure to P. fulvidraco affects bioaccumulation, antioxidant enzymes, and immune responses, and high level of EGCG were effective to alleviate the toxic effects of Cu exposure.

Changes in Hematological Parameters and Heat Shock Proteins in Juvenile Sablefish Depending on Water Temperature Stress.

Juvenile Sablefish Anoplopoma fimbria were used to assess the effects of water temperature (8, 10, 12, 14, 16, 18, and 20°C) on hematological parameters and heat shock proteins 70 and 90 for 4 months. Hematological parameters, including red blood cell count, hematocrit, and hemoglobin, were significantly decreased at 18°C. The inorganic plasma components calcium and magnesium were not altered by water temperature. The organic plasma components glucose and cholesterol were notably elevated at 18°C, whereas total protein was reduced. The enzymatic components, including aspartate aminotransferase, alanine aminotransaminase, and alkaline phosphatase, were notably elevated at 16°C or 18°C. The results of this study indicate that a temperature higher than the proper temperature affects the hematological parameters and heat shock proteins of juvenile Sablefish.

Toxic Effects and Depuration on the Antioxidant and Neurotransmitter Responses after Dietary Lead Exposure in Starry Flounder.

Starry Flounder Platichthys stellatus were exposed to dietary lead (Pb) at concentrations of 0, 30, 60, 120, and 240 mg/kg for 4 weeks. Recover period was conducted for 2 weeks after the exposure. Exposure to Pb concentrations over 60 mg/kg induced significant changes in the antioxidant responses in the liver, kidney, and gill and continued even after the depuration period in the liver (over 120 mg/kg for superoxide dismutase [SOD] activity) and kidney (at 240 mg/kg for glutathione [GSH] levels). Glutathione S-transferase (GST) activity in liver, kidney, and gill were increased by dietary Pb exposure, and recovery was observed in all groups during the recovery period. Acetylcholinesterase (AChE) activity was significantly inhibited in the brain and muscle of flounder at Pb exposure over 120 mg/kg, and no restoration was observed after the depuration period. Lysozyme activity in the plasma was significantly increased at Pb exposures greater than 60 mg kg but was restored after the depuration period. The results of this study indicate that dietary Pb exposure induces toxic effects on antioxidant responses, neurotransmitter, and immune responses of Starry Flounder.

Effects of dietary chromium exposure to rockfish, Sebastes schlegelii are ameliorated by ascorbic acid.

Juvenile rockfish Sebastes schlegelii (mean length 10.8±1.4cm, and mean weight 31.7±3.6g) were exposed for 4 weeks with the different levels of dietary chromium (Cr6+) at 0, 120 and 240mg/L and ascorbic acids (AsA) at 100, 200 and 400mg/L. Significant accumulation occurred in specific tissues and hematological parameters were altered: red blood cell count, hematocrit, and hemoglobin increased; plasma components were altered including calcium, glucose, cholesterol, total protein, glutamic oxalate transaminase, and glutamic pyruvate transaminase. However, magnesium and alkaline phosphatase concentrations were unchanged. Ascorbic acids reduced both chromium uptake into tissues and altered hematological parameters.

Growth performance, oxidative stress, and non-specific immune responses in juvenile sablefish, Anoplopoma fimbria, by changes of water temperature and salinity.

Juvenile sablefish, Anoplopoma fimbria (mean length 15.5 ± 1.9 cm, mean weight 68.5 ± 4.8 g), were used to evaluate the effects on growth, oxidative stress, and non-specific immune responses by changes of water temperature (8, 10, 12, 14, 16, 18, and 20 °C) and salinity (100 (35.0), 90 (31.5), 80 (28.0), 70 (24.5), 60 (21.0), 50 (17.5), and 40% (14.0) (‰)) for 4 months. The growth performance was significantly increased at the temperature of 12 and 14 °C, and the feed efficiency was notably decreased at the temperature of 18 °C. The growth performance and feed efficiency were also significantly decreased at low salinity. The antioxidant responses such as superoxide dismutase and catalase were significantly increased by the high temperature and decreased by the low salinity. The immune responses such as lysozyme and phagocytosis were elevated by the temperature of 18 °C and decreased by the salinity of 50%. The results of this study indicate that the growth performance of juvenile sablefish, A. fimbria, is influenced by the temperature and salinity, and the excessive temperature and salinity levels can affect the antioxidant and immune responses.

Antioxidant Responses, Neurotoxicity, and Metallothionein Gene Expression in Juvenile Korean Rockfish Sebastes schlegelii under Dietary Lead Exposure.

This study was conducted to assess toxic effects of dietary lead (Pb) exposure on Korean Rockfish Sebastes schlegelii. Juvenile rockfish were used to evaluate the oxidative stress, neurotoxicity, and metallothionein (MT) gene expression after dietary exposure to lead (as Pb2+; 0, 30, 60, 120 and 240 mg/kg). Superoxide dismutase (SOD) activity, a measure of oxidative stress, was substantially elevated in the livers and gills of fish given dietary Pb greater than 60 mg/kg. Glutathione S-transferase (GST) activity in the liver and gill was significantly increased by dietary Pb > 60 mg/kg. A significant decrease in glutathione (GSH) level was observed in fish liver after exposure to dietary Pb > 30 mg/kg and in the gill after treatment with dietary Pb > 120 mg/kg. Acecyltholinesterase (AChE) was noticeably decreased in the brain by dietary Pb > 120 mg/kg and in the muscle by dietary Pb > 60 mg/kg. Metallothionein gene expression in the liver was stimulated significantly by the Pb exposure. Because dietary Pb exposure had a toxic effect on antioxidant responses, a neurotransmitter, and a specific immune expression in rockfish, the results of this study can be used to determine potential useful markers of Pb toxicity. Received June 11, 2016; accepted March 10, 2017.

Oxidative stress, neurotoxicity, and metallothionein (MT) gene expression in juvenile rock fish Sebastes schlegelii under the different levels of dietary chromium (Cr(6+)) exposure.

Juvenile Sebastes schlegelii were exposed for 4 weeks with the different levels of dietary chromium (Cr(6+)) concentration (0, 30, 60, 120 and 200mg/kg). The superoxide dismutase (SOD) activity, glutathione S-transferase (GST) activity, and glutathione (GSH) level of liver and gill were evaluated after 4 weeks exposure. The SOD and GST activity of liver and gill was significantly increased in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks, whereas a considerable decrease in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks was observed in the GSH levels of liver and gill. In neurotoxicity, AChE activity was significatly inhibited in brain in the concentration of 240mg/kg after 2 weeks and over 60mg/kg after 4 weeks and muscle in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks. Metallothionein (MT) gene in liver was considerably increased over 120mg/kg after 2 weeks and at 30, 120, and 240mg/kg after 4 weeks by dietary chromium exposure. The results indicate that dietary Cr exposure over 120mg/kg can induce substantial alterations in antioxidant responses, AChE activity and MT gene expression.

Growth performance and immunological and antioxidant status of Chinese shrimp, Fennerpenaeus chinensis reared in bio-floc culture system using probiotics.

Chinese shrimp Fennerpenaeus chinensis (mean length 1.86 ± 0.15 cm, and weight 137.4 ± 12.7 mg) were reared in the different concentrations of bio-floc (control, 60, 80, 100, 120, and 140%) for 90 days. The growth rate was significantly increased over 100% bio-floc concentrations. In the immunological parameters, the gene expression of proPO and lysozyme was considerably increased over 120% bio-floc concentrations. The gene expression of SP was notably elevated at 140% bio-floc concentration. In the antioxidant enzymes, the activity of SOD was considerably decreased over 80% bio-floc concentrations. A notable decline in the activity of CAT was observed over 120% bio-floc concentrations. The results indicate that rearing of Chinese shrimp in bio-floc system can induce the increase of growth performance, enhancement of immune responses, and reduction of oxidative stress.

Cascading effects from survival to physiological activities, and gene expression of heat shock protein 90 on the abalone Haliotis discus hannai responding to continuous thermal stress.

Increasing temperatures can be a significant stressor for aquatic organisms. Abalones, a type of large marine gastropods, are the most commercially important species in aquaculture for Asia. To evaluate the potential ecological risk posed by temperature stress, we measured biological responses such as survival rate, adhesion ability (falling rate), and foot abnormalities in the abalone Haliotis discus hannai. Additionally, biochemical and molecular responses were evaluated in H. discus hannai exposed to various temperature gradients. The survival rate was reduced in abalones exposed to relative high temperatures (more than 26 °C). Increased temperature stress induced a higher falling rate and abnormal foot structure. Furthermore, increased antioxidant enzyme activities were observed in abalones exposed to relative high temperatures (26 and 28 °C). The activities of superoxide dismutase were induced in a time-dependent manner after high temperature stress. Generally, heat shock protein 90 also increased significantly in H. discus hannai exposed to temperature gradients (more than 24 °C) for 12 h. These results provide valuable information regarding stress responses to increased temperatures, in H. discus hannai: adverse biological and molecular outcomes could be utilized as risk assessments and stress monitoring of marine ecosystems under increased water temperatures.

The lead accumulation and hematological findings in juvenile rock fish Sebastes schlegelii exposed to the dietary lead (II) concentrations.

Juvenile rockfish (mean length 14.2 ± 1.9 cm, and mean weight 57.3 ± 5.2g) were exposed for 4 weeks with the different levels of dietary lead (Pb(2+)) at 0, 30, 60, 120 and 240 mg/L. The exposure concentration and period of Pb have induced significant amount of it the specific tissues of rockfish. The highest Pb accumulation was observed in the kidney tissue by the dietary lead exposure. The growth rate and hepatosomatic index were considerably inhibited over 120 mg/kg. The hematological parameters such as red blood cell (RBC) counts, hematocrit (Ht) value, and hemoglobin (Hb) concentration were significantly decreased over 60 mg/kg Pb concentration. In the inorganic components, the values of calcium and magnesium in plasma were significantly decreased. The glucose and cholesterol values were notably increased, whereas total protein was decreased. The enzyme components, glutamic oxalate transaminase (GOT) and glutamic pyruvate transaminase (GPT), were significantly elevated by the dietary lead exposure, but no change was observed in alkaline phosphatase (ALP).

The selenium accumulation and its effect on growth, and haematological parameters in red sea bream, Pagrus major, exposed to waterborne selenium.

Juvenile Pagrus major (mean length 15.8±1.6cm, and mean weight 90.4±4.7g) were exposed for 4 weeks with waterborne selenium concentration (0, 50, 100, 200, and 400µg/L). The profile of Se accumulation among tissue in P. major is dependent on the exposure periods and Se concentration. After 4 weeks, the highest accumulation of Se was observed in the kidney, and the order of Se accumulation in tissues was kidney≈liver>spleen>intestine>gill>muscle. Se decreased the growth rate, and there was an inverse proportion between growth and Se concentration. The major hematological findings were significant decrease in the RBC count, Ht value, and Hb concentration exposed to ≥100µg/L Se concentrations. Se exposure (≥100µg/L) led to significant increase in the glucose, GOT, and GPT levels, whereas the levels of calcium, magnesium, cholesterol, and total protein did not increase. The results suggest that waterborne Se exposure can induce significant Se accumulation in tissues, inhibition of growth, and hematological alterations.

Cocktail effects of clothianidin and imidacloprid in zebrafish embryonic development, with high and low concentrations of mixtures.

There is growing concern that sprayed neonicotinoid pesticides (neonics) persist in mixed forms in the environmental soil and water systems, and these concerns stem from reports of increase in both the detection frequency and concentration of these pollutants. To confirm the toxic effects of neonics, we conducted toxicity tests on two neonics, clothianidin (CLO) and imidacloprid (IMD), in embryos of zebrafish. Toxicity tests were performed with two different types of mixtures: potential mixture compounds and realistic mixture compounds. Potential mixtures of CLO and IMD exhibited synergistic effects, in a dose-dependent manner, in zebrafish embryonic toxicity. Realistic mixture toxicity tests that are reflecting the toxic effects of mixture in the aquatic environment were conducted with zebrafish embryos. The toxicity of the CLO and IMD mixture at environmentally-relevant concentrations was confirmed by the alteration of the transcriptional levels of target genes, such as cell damage linked to oxidative stress response and thyroid hormone synthesis related to zebrafish embryonic development. Consequently, the findings of this study can be considered a strategy for examining mixture toxicity in the range of detected environmental concentrations. In particular, our results will be useful in explaining the mode of toxic action of chemical mixtures following short-term exposure. Finally, the toxicity information of CLO and IMD mixtures will be applied for the agricultural environment, as a part of chemical regulation guideline for the use and production of pesticides.

Toxic effects of microplastic (Polyethylene) on fish: Accumulation, hematological parameters and antioxidant responses in Korean Bullhead, Pseudobagrus fulvidraco.

Plastic waste discharged into the aquatic environment decomposes into microplastics (MP), which have toxic effects on fish species. Korean bullhead, Pseudobagrus fulvidraco is widely distributed in freshwater ecosystems in Korea, and it is important as an ecological indicator species to evaluate MP toxicity in Korea. In this study, the accumulation and physiological effects of juvenile P. fulvidraco exposed to microplastics (Polyethylene: PE-MPs with white surface and spherical shape) at control (0 mg/L), 100, 200, 5000 and 10,000 mg/L for 96 h were confirmed. Exposure to PE-MPs showed significant bioaccumulation of P. fulvidraco, and the accumulation profile was in the order of gut > gills > liver. Hematological parameters such as the red blood cell (RBC), hemoglobin (Hb) and hematocrit (Ht) were significantly decreased over 5000 mg/L In plasma components, calcium, magnesium and total protein were significantly decreased over 5000 mg/L, whereas glucose, cholesterol, aspartate aminotransferase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) were significantly increased over 5000 mg/L or at 10,000 mg/L In antioxidant responses, superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) were significantly increased over 5000 mg/L, whereas glutathione (GSH) was significantly decreased over 5000 mg/L. The results of this study suggest that acute exposure to PE-MPs induced all physiological changes in a concentration-dependent manner, and it affects the hematological parameters, plasma components and antioxidant response of juvenile P. fulvidraco after accumulation in specific tissues.