Effects on Bioaccumulation, Growth Performance, Hematological Parameters, Plasma Components, and Antioxidant Responses in Starry Flounder (Platichthys stellatus) Exposed to Dietary Cadmium and Ascorbic Acid.

This study evaluates the toxic effects of dietary Cd and mitigative effects of AsA supplementation by measuring the growth performance, bioaccumulation, hematological parameters, plasma components, and antioxidant responses of Starry flounder (Platichthys stellatus). Platichthys stellatus (mean weight, 69.5 ± 1.4 g; mean length, 18.2 ± 0.21 cm) was fed with dietary cadmium-ascorbic acid (Cd-AsA) composed of C0A0, C0A500, C0A1000, C40A0, C40A500, C40A1000, C80A0, C80A500, and C80A1000 mg of Cd-AsA per kg diet for four weeks. Our results showed that Cd accumulation significantly increased in proportion to the Cd concentration, where the highest levels were observed in the intestine, followed by the kidney, liver, and gills. Dietary AsA significantly mitigated the Cd accumulation in all tissues, and the reduction in Cd accumulation was proportional to the increase in AsA concentration. Dietary Cd has adverse effects on growth performance (body weight gain, specific growth rate, feed conversion ratio, and hepatosomatic index) and can alter the hematological parameters (red blood cell count, hematocrit, and hemoglobin), plasma components (glucose, total protein, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase), and antioxidant responses (superoxide dismutase, catalase, glutathione S-transferase, and glutathione). Dietary AsA restored the decreased growth performance parameters and the altered hematological parameters, plasma components, and antioxidant responses caused by the dietary Cd exposure. The results of this study showed that dietary Cd is toxic to P. stellatus, while dietary AsA is effective in mitigating the toxic effects of Cd.

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.

Preserving Brain LPC-DHA by Plasma Supplementation Attenuates Brain Injury after Cardiac Arrest.

OBJECTIVE: Cardiac arrest (CA) is a major health burden with brain damage being a significant contributor to mortality. We found lysophosphatidylcholine (LPC), including a species containing docosahexaenoic acid (LPC-DHA), was significantly decreased in plasma post-CA, supplementation of which significantly improved neurological outcomes. The aim of this study is to understand the protective role of LPC-DHA supplementation on the brain post-CA. METHODS: We first evaluated associations between the plasma level of LPC-DHA and neurological injury and outcomes of human patients with CA. We then utilized a rat CA model and cell cultures to investigate therapeutic and mechanistic aspects of plasma LPC-DHA supplementation. RESULTS: We found that decreased plasma LPC-DHA was strongly associated with neurological outcomes and disappearance of the difference between gray and white matter in the brain after CA in human patients. In rats, the decreased plasma LPC-DHA was associated with decreased levels of brain LPC-DHA after CA, and supplementing plasma LPC-DHA normalized brain levels of LPC-DHA and alleviated neuronal cell death, activation of astrocytes, and expression of various inflammatory and mitochondrial dynamics genes. We also observed deceased severity of metabolic alterations with LPC-DHA supplementation using untargeted metabolomics analysis. Furthermore, LPC treatment showed a similar protective effect for neurons and astrocytes in mixed primary brain cell cultures. INTERPRETATION: The observed neuroprotection accompanied with normalized brain LPC-DHA level by plasma supplementation implicate the importance of preventing the decrease of brain LPC-DHA post-CA for attenuating brain injury. Furthermore, the data supports the causative role of decreased plasma LPC-DHA for brain damage after CA. ANN NEUROL 2022;91:389-403.

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.

The effect of concurrent elevation in CO2 and temperature on the growth, photosynthesis, and yield of potato crops.

Global climate change accompanied by continuous increases in atmospheric carbon dioxide (CO2) concentration and temperature affects the growth and yield of important crops. The present study investigated the effect of elevated temperature and CO2 concentrations on the growth, yield, and photosynthesis of potato (Solanum tuberosum L. cv. Superior) crops using Korean Soil-Plant-Atmosphere-Research chambers that allow the regulation of temperature and CO2 concentration under daylight conditions. Based on the average temperature from 1991 to 2010 in the Jeonju area, South Korea, potato plants were exposed to four different conditions: ambient weather (400 µmol mol-1, aCaT), elevated temperature (+4°C, aCeT), elevated CO2 concentration (800 µmol mol-1, eCaT), and concurrently elevated CO2 concentration and temperature (eCeT). Under aCeT conditions, the temperature exceeded the optimal growth temperature range towards the late growth phase that decreased stomatal conductance and canopy net photosynthetic rate and subsequently reduced biomass and tuber yield. Stomatal conductance and chlorophyll concentration were lower under eCaT conditions than under aCaT conditions, whereas late-growth phase biomass and tuber yield were greater. Compared to other conditions, eCeT yielded a distinct increase in growth and development and canopy net photosynthetic rate during tuber initiation and bulking. Consequently, biomass and canopy net photosynthesis increased, and tuber yield increased by 20.3%, which could be attributed to the increased tuber size, rather than increased tuber number. Elevated CO2 reduced chlorophyll, magnesium, and phosphorus concentrations; reducing nitrogen concentration (by approximately 39.7%) increased the C:N ratio. The data indicate that future climate conditions will likely change nutrient concentration and quality of crops. The present study shows that while elevated temperature may negatively influence the growth and yield of potato crops, especially towards the late-growth phase, the concurrent and appropriate elevation of CO2 and temperature could promote balanced development of source and sink organs and positively effect potato productivity and quality.

Alterations in growth performance and stress responses in juvenile rockfish, Sebastes schlegelii, exposed to dietary chromium with varying levels of dietary ascorbic acid supplementation.

Juvenile rockfish Sebastes schlegelii (mean length 10.8 ± 1.4 cm, and mean weight 31.7 ± 3.6 g) were exposed for 4 weeks to different levels of dietary chromium (Cr6+) at 0, 120, and 240 mg/L and ascorbic acid (AsA) at 100, 200, and 400 mg/L. Growth performance of S. schlegelii was significantly decreased due to dietary Cr exposure, whereas lysozyme activity was notably increased. Exposure to dietary Cr resulted in substantial accumulation of Cr in the blood. Levels of two stress indicators, plasma cortisol and heat shock protein 70, of S. schlegelii were increased due to dietary Cr exposure. The results indicated that dietary Cr exposure affected growth performance, lysozyme activity, and stress responses of S. schlegelii, and high levels of AsA supplementation significantly attenuated dietary Cr-induced toxicity.

Floating rice-culture system for nutrient remediation and feed production in a eutrophic lake.

The increased inputs of nutrients have been demonstrated to be a major contributing factor to the eutrophication of lakes and reservoirs which can lead to the production of harmful algal/cyanobacterial blooms and deleteriously affect the aesthetics of water-bodies. Floating plant-culture systems have been widely used for the ecological remediation of eutrophic water in a cost-effective manner. We investigated the applicability of Korean japonica rice variety 'Nampyeong' in a floating-culture system in a eutrophic lake for nutrient uptake and biomass production. Chemical and organic compound compositions were analyzed two times during the growth stages of the rice plant: 98 DAT (days after transplanting) and 165 DAT. Total nitrogen and phosphorus contributed around 1.36 and 0.15 (% dry weight), respectively, in rice plant components at 165 DAT. Crude protein, lipids, fiber and ash were 4.35, 1.91, 23.66 and 5.55 (% dry weight), respectively. In addition, microcystin levels in the rice plant components ranged from 0.0008 to 0.002 µg/g and did not exceed the recommended tolerable limits. These results suggested that the developed floating rice-culture system showed a good potential as a holistic management approach in terms of nutrient reduction, rice production for further use as feed and for bloom control.

Toxic effects on bioaccumulation and hematological parameters of juvenile rockfish Sebastes schlegelii exposed to dietary lead (Pb) and ascorbic acid.

Juvenile rockfish, Sebastes schlegelii (mean length 11.3 ± 1.2 cm, and mean weight 32.5 ± 4.1 g) were exposed for four weeks to dietary lead (Pb2+) at 0, 120, and 240 mg/L and ascorbic acid (AsA) at 100, 200, and 400 mg/L. The exposure concentrations and duration of significant Pb-induced accumulations in specific tissues of S. schlegelii were assessed. High levels of ascorbic acid significantly attenuated accumulations following exposure to dietary Pb. Dietary Pb exposure caused a significant increase in blood Pb concentrations, whereas red blood cell (RBC) count, hematocrit, and hemoglobin were significantly decreased. Notable changes were also observed in plasma calcium, magnesium, glucose, cholesterol, glutamic oxaloacetic transaminase (GOT), and glutamic pyruvate transaminase (GPT). The growth performance of S. schlegelii was significantly decreased. High doses AsA supplemention were effective in attenuating the changes brought about by dietary Pb exposure.

Effects of sub-chronic exposure to lead (Pb) and ascorbic acid in juvenile rockfish: Antioxidant responses, MT gene expression, and neurotransmitters.

Juvenile rockfish Sebastes schlegelii were exposed to varying levels of dietary lead (Pb2+) at 0, 120 and 240 mg/L, and ascorbic acid (AsA) at 100, 200 and 400 mg/L for four weeks. Antioxidant responses such as superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione (GSH) were analyzed to assess oxidative stress. SOD and GST activity in the liver and gills were considerably elevated by dietary Pb. In contrast, GSH levels in the liver and gills were significantly reduced following Pb exposure. High levels of AsA supplementation attenuated the increase in SOD and GST activity and reduction in GSH levels. The metallothionein gene (MT) in the liver was notably stimulated by Pb exposure, and AsA supplementation attenuated this increase. With respect to neurotoxicity, acetylcholinesterase (AChE) activity was substantially inhibited in the brain and muscle following Pb exposure. AsA supplementation also attenuated AChE inhibition following Pb exposure. The results of this study presented Pb exposure affected rockfish as toxicity, and AsA was effective to alleviate toxic effects of Pb.

DHA-supplemented diet increases the survival of rats following asphyxia-induced cardiac arrest and cardiopulmonary bypass resuscitation.

Accumulating evidence illustrates the beneficial effects of dietary docosahexaenoic acid (DHA) on cardiovascular diseases. However, its effects on cardiac arrest (CA) remain controversial in epidemiological studies and have not been reported in controlled animal studies. Here, we examined whether dietary DHA can improve survival, the most important endpoint in CA. Male Sprague-Dawley rats were randomized into two groups and received either a control diet or a DHA-supplemented diet for 7-8 weeks. Rats were then subjected to 20 min asphyxia-induced cardiac arrest followed by 30 min cardiopulmonary bypass resuscitation. Rat survival was monitored for additional 3.5 h following resuscitation. In the control group, 1 of 9 rats survived for 4 h, whereas 6 of 9 rats survived in the DHA-treated group. Surviving rats in the DHA-treated group displayed moderately improved hemodynamics compared to rats in the control group 1 h after the start of resuscitation. Rats in the control group showed no sign of brain function whereas rats in the DHA-treated group had recurrent seizures and spontaneous respiration, suggesting dietary DHA also protects the brain. Overall, our study shows that dietary DHA significantly improves rat survival following 20 min of severe CA.

Influence of Dietary Ascorbic Acid on the Immune Responses of Juvenile Korean Rockfish Sebastes schlegelii.

Juvenile Korean Rockfish Sebastes schlegelii (length, 13.6 ± 1.4 cm [mean ± SD]; weight, 53.6 ± 4.2 g) were fed twice daily with diets containing varying levels of ascorbic acid (0, 50, 100, 200, and 400 mg/kg) for 4 weeks. Significant increases in daily weight and length occurred in fish fed more than 50 mg/kg ascorbic acid. The lysozyme activity of fish fed diets containing ascorbic acid was considerably increased in rockfish plasma at 400 mg/kg ascorbic acid and in kidney at over 50 mg/kg ascorbic acid. Total plasma immunoglobulin M (IgM) levels were markedly elevated in fish fed 400 mg/kg ascorbic acid. The results suggest that dietary ascorbic acid supplementation in juvenile rockfish can induce a significant increase in growth and in immunological features such as lysozyme activity and plasma IgM levels.

Oxidative stress, neurotoxicity, and non-specific immune responses in juvenile red sea bream, Pagrus major, exposed to different waterborne selenium concentrations.

Juvenile Pagrus major (mean length 15.8±1.6 cm, and mean weight 90.4±4.7 g) were exposed for 4 weeks with waterborne selenium concentration (0, 50, 100, 200, and 400 µg L(-1)). In oxidative stress indicators, liver and gill superoxide dismutase (SOD) activity and glutathione S-transferase (GST) activity were markedly elevated after 4 weeks exposure. Similarly, glutathione (GSH) level in liver and gill was also increased in response to the highest Se exposure after 4 weeks exposure. In neurotoxicity, AChE activity was inhibited in brain and muscle tissues by waterborne Se exposure. In the non-specific immune responses, lysozyme activity of plasma and kidney was significantly increased by waterborne Se exposure. Peroxidase activity and anti-protease activity were decreased at high Se concentration. The results suggest that waterborne Se exposure can induce significant oxidative stress, inhibition of AChE activity, and immunological alterations.

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.

Improved mitochondrial function with diet-induced increase in either docosahexaenoic acid or arachidonic acid in membrane phospholipids.

Mitochondria can depolarize and trigger cell death through the opening of the mitochondrial permeability transition pore (MPTP). We recently showed that an increase in the long chain n3 polyunsaturated fatty acids (PUFA) docosahexaenoic acid (DHA; 22:6n3) and depletion of the n6 PUFA arachidonic acid (ARA; 20:4n6) in mitochondrial membranes is associated with a greater Ca(2+) load required to induce MPTP opening. Here we manipulated mitochondrial phospholipid composition by supplementing the diet with DHA, ARA or combined DHA+ARA in rats for 10 weeks. There were no effects on cardiac function, or respiration of isolated mitochondria. Analysis of mitochondrial phospholipids showed DHA supplementation increased DHA and displaced ARA in mitochondrial membranes, while supplementation with ARA or DHA+ARA increased ARA and depleted linoleic acid (18:2n6). Phospholipid analysis revealed a similar pattern, particularly in cardiolipin. Tetralinoleoyl cardiolipin was depleted by 80% with ARA or DHA+ARA supplementation, with linoleic acid side chains replaced by ARA. Both the DHA and ARA groups had delayed Ca(2+)-induced MPTP opening, but the DHA+ARA group was similar to the control diet. In conclusion, alterations in mitochondria membrane phospholipid fatty acid composition caused by dietary DHA or ARA was associated with a greater cumulative Ca(2+) load required to induced MPTP opening. Further, high levels of tetralinoleoyl cardiolipin were not essential for normal mitochondrial function if replaced with very-long chain n3 or n6 PUFAs.