High Selenium Concentrations Research Articles

Selenium recovery from wastewater by the green microalgae Chlorella vulgaris and Scenedesmus sp.

Selenium (Se) is an important element for many living organisms and its supplementation may be needed in food, feed, and soil to make up for its deficiency. At the same time, high selenium concentrations can harm the environment, thus its management in sewage and the study of its removal from waste streams are important. Microalgae-based systems may be used for wastewater treatment and nutrients recovery, while producing biomass for bioproducts or bioenergy. In this study, Chlorella vulgaris and Scenedesmus sp. grown in urban wastewater with different selenium concentrations (50–1000 μg Se/L) were evaluated for their resistance and selenium removal/recovery efficiency. Chlorella vulgaris and Scenedesmus sp. were able to remove up to 43 and 52 % of Se from wastewater, respectively. Chlorella vulgaris accumulated up to 323 mgSe/kg DW (in urban wastewater with 1000 μg Se/L). The Se-rich biomass produced may be applied to the supplementation of animal feed or used for biofortification of crops.

Impact of management systems on selenium and zinc levels, heterophil: Lymphocyte ratio as biomarkers of immunity in chickens

This study investigated the impact of poultry management systems (intensive and extensive) on selenium and zinc concentrations and heterophil to lymphocyte ratio in chickens. Sixty chickens comprising 20 broilers, 20 local chickens and 20 layers obtained from poultry markets and houses around Ibadan, Oyo State, Nigeria were used in this study. Five millilitres of blood were collected through the brachial vein to analyse for selenium, zinc and complete blood count using atomic absorption spectrophotometry and standard haematological methods, respectively. There was a significantly (P<0.05) higher red blood cell, haemoglobin and pack cell volume values in local chickens raised in the extensive management system compared to broilers and layers raised in the intensive management system. There was no significant difference (P>0.05) in the white blood cell count between layers and local chickens. However, layers had higher white blood cell counts than local chickens. In contrast, local chickens had significantly (P<0.05) lower white blood cell count than broilers. The respective lymphocyte and heterophil counts were significantly (P<0.05) higher and lower in local chickens raised extensively compared to layers raised intensively. There were no significant differences (P>0.05) in monocyte, eosinophil and basophil count in chickens raised from both management systems. Chickens raised in the extensive management system had a significantly (P<0.05) higher selenium concentration with a lower heterophil to lymphocyte ratio than those raised in the intensive management system but had a significantly (P<0.05) lower zinc concentration. Therefore, high selenium levels and low heterophil to lymphocyte ratio could contribute to the resistance of chickens to various stressors associated with an extensive management system as selenium is a known immunomodulator.

Phragmites rhizoma polysaccharide-based nanocarriers for synergistic treatment of ulcerative colitis

The purpose of this study was to construct Phragmites rhizoma polysaccharide-based nano-drug delivery systems (PRP2-SeNPs-H/Aza-Lips) for synergistically alleviating ulcerative colitis and to investigate the important roles of Phragmites rhizoma polysaccharide-based nanocarriers in PRP2-SeNPs-H/Aza-Lips. Phragmites rhizoma polysaccharide (PRP2) was isolated and used for the preparation of Phragmites rhizoma polysaccharide selenium nanoparticles with low selenium content (PRP2-SeNPs-L) and high selenium content (PRP2-SeNPs-H). Based on the electrostatic attraction between PRP2-SeNPs-H and azathioprine liposomes (Aza-Lips), PRP2-SeNPs-H/Aza-Lips were constructed for precise delivery of the model drug azathioprine (Aza) to colon lesions. Results showed that PRP2 significantly alleviated the clinical symptoms and colon tissue damage and down-regulated the levels of inflammatory factors in serum and colon, demonstrating beneficial effects on mice with ulcerative colitis. PRP2-SeNPs-L had better relieving effects on ulcerative colitis. Phragmites rhizoma polysaccharide-based nanocarriers may protect azathioprine liposomes against gastrointestinal digestion, enhance the therapeutic effects on ulcerative colitis, and significantly reduce liver damage from azathioprine, which helps to improve the efficacy and toxicity of clinical drugs.

Selenium Distribution in the Gossan of a Porphyry Copper Deposit, Red Chris Mine, British Columbia, Canada

Abstract In 2015, the Red Chris mine in northwestern British Columbia began processing near-surface ores from the Red Chris copper-gold deposit and encountered higher leachable selenium concentrations in process water than had been anticipated from testing of deeper ores. Samples of gossan, near-surface rock, and deeper hypogene rock were submitted for analytical, mineralogical, and kinetic geochemical testing to investigate the origin of the leachable selenium, its mineralogical form, and the release mechanisms. This paper presents testing results and implications for understanding the selenium distribution in weathered rocks at sulfide mineral deposits. Shallow weathered rock, including the gossan, contained higher selenium concentrations and higher ratios of selenium to sulfur relative to the hypogene bedrock. Laboratory weathering and leaching tests indicated that selenium is released from source sulfides by oxidation and retained in a variety of secondary mineral forms. Mean selenium content in the solids was measured as follows: gossan and shallow bedrock >> deeper near-surface bedrock > hypogene bedrock. Water-leachable selenium varied but generally followed a similar trend, with samples of gossan containing the highest water-leachable selenium. Selenium was determined to be preferentially leached from the gossan samples at high pH values, indicating an adsorbed form. We propose that the weathering profile of the Red Chris deposit was previously capped with a well-developed thick gossan, which formed during the Paleogene and was eroded during the last period of glaciation. The current weathered rock reflects the residual base of the former oxidized profile.

Selenium-containing drug together with the feed additive Benut in the rations of steers

Currently, there is great interest in the use of selenium drugs in animal husbandry. Chickpea is high-containing in selenium and protein. The feed additive Benut, made on the basis of chickpea, has a high content of selenium. At the same time, its active interaction with proteins was revealed. The purpose of the work was to increase the meat productivity and quality of beef of steers when using the selenium-containing drug DAFS-25 in rations together with the feed additive Benut. In order to conduct the experiment, according to the principle of analogues 3 groups of Aberdeen-Angus steers were formed at the age of 9 months for 15 heads in each group. The duration of the experiment was 172 days including the main period 150 days. In the main period, the steers of the 1st control group received the main ration (MR), the 2nd experimental group received MR + DAFS-25 (1,6 mg/kg of concentrates) and the 3rd experimental group received MR + 0,5 kg/head/day of the feed additive Benut (instead of an equivalent amount of concentrates) + DAFS-25 to ensure the content of selenium as in the ration of animals of the 2nd experimental group. The beef productivity of fattened steers of Aberdeen-Angus breed was studied and also indicators of blood composition, digestibility and assimilation of feed nutrients, beef quality and efficiency of its production, when used in rations of the drug DAFS-25 separately and in combination with the feed additive Benut. Profit from the sale of beef in the 2nd experimental group was received by 84,4 rubles more and in the 3rd experimental group by 574,8 rubles more than in the 1st control group. In the 2nd and 3rd experimental groups the profitability level was 1,2 and 13,2 % higher than in the 1st control group (27,3 %).

Ability of the Saccharomyces cerevisiae Y904 to tolerate and adapt to high concentrations of selenium

The alcoholic fermentation industry generates a large surplus of yeasts, which, in turn, have the ability to bioaccumulate minerals and enable their bioavailability after cell autolysis. Among these minerals, selenium (Se) stands out, which participates in the formation of antioxidant enzymes. The objectives of the work were to define the minimum and maximum concentration of Se that yeasts (Saccharomyces cerevisiae – Y904) support and the concentrations that they tolerate once adapted. To this end, a test of tolerance to Se was carried out, using treatments with different concentrations of Se. The adaptive process started at the maximum concentration obtained in the tolerance test of 60 mg mL-1, with increasing addition of 6 mg mL-1, reaching up to 246 mg mL-1 of Se. The macromorphological characteristics and number of colony forming units (CFU) were evaluated. It was identified that yeasts without adaptation grew on substrate containing up to 60 mg mL-1 of Se and those adapted, up to 246 mg mL-1 of Se. In addition to the reduction in yeast growth speed, from the concentration of 84 mg mL-1 of Se in the medium, morphological changes in colony color were observed. It is concluded that non-adapted yeasts support up to 60 mg mL-1 of Se and, after the adaptive process, they support 246 mg mL-1 of Se in the medium after the adaptive process, which adds value to the final product, and makes yeasts suitable for human nutrition as a supplement or even in the formulation of probiotics.

Growth and shelf life of basil in response to selenium fertilization

Selenium is essential for human metabolism and its enrichment in vegetables plays an effective role in providing the body with selenium requirements. This factorial experiment was conducted in a greenhouse at Shahrekord University in 2019 to study the effects of selenium on basil growth and shelf life in the conditions of feeding with poultry manure (PM) and chemical fertilizers (CF). Experimental factors included two types of soil amended for plant nutrition (PM and CF) and five selenium concentrations (0, 1.5, 3, 4.5, and 6 mg L − 1) applied as foliar sprays. The results showed that shoot fresh weight in plants receiving PM was 16.6% more than CF fertilizers and foliar application of selenium had no effect on fresh weight. In the PM applied conditions, with the increase of selenium, the chlorophyll b content increased and then decreased. Increasing selenium improved its accumulation in the basil tissue, and the amount of selenium accumulated with poultry manure was more than that accumulated with chemical fertilizer. Whereas, the greatest weight loss in storage was observed in high selenium concentration. In plants receiving PM, increasing concentration of selenium sprays improved the shelf life, then decreased. However, in the amended soil with CF, the shelf life did not change by selenium, except in 1.5 mg L − 1 concentration. It is concluded that the foliar application of moderate amounts of selenium in poultry manure conditions helps to produce more basil, relatively good enrichment of selenium in plant tissue and maintain its optimal quality during the storage.

Comprehensive Effect of Oxidant Addition in an FGD Slurry on the Removal and Distribution of Selenium: A Field Study.

Flue gas desulfurization (FGD) scrubbers capture selenium in coal-fired power plants, leading to a high concentration of selenium in the slurry. This research proves that SO32- is preferentially oxidized compared to SeO32- by S2O82-. With the increase in the oxidation-reduction potential (ORP) caused by S2O82- addition, the conversion rate of SO32- increased and the size of gypsum grains grew from 31.2 to 34.6 μm. SeO32- migrates into gypsum grains during the growth of CaSO4·2H2O, leading to selenium fixation in gypsum. In a field study of a 350 MW unit, the ORP increased from 142 to 450 mV when Na2S2O8 was fed into the FGD slurry. With the addition of the oxidant, 65.1% of selenium in the liquid phase migrated into gypsum. The concentration of selenium in the leachate of gypsum after oxidant addition decreased by 68.0%. A 2.34% increase in the selenium removal rate was observed in the scrubber. This study focuses on the migration and conversion of selenium in an actual FGD slurry via a field test. The results found in the 350 MW unit are consistent with laboratory results. The change in ORP has been proven to be effective in adjusting the selenium distribution in the FGD slurry.

Nutritional and nutraceutical properties of goat milk for human health: A review

Milk are considered as the best source of nutrients in well balanced ratio, and it also performs a number of beneficial biological activities in the human body that improves digestive system, metabolic activities to ingested nutrients, organ’s growth maintenance, development and resistance against diseases. Goats are considered to be the oldest domestic animals, domesticated for meat and milk and are known as the poor man's animal. Goat milk is nature's closest thing to perfect food. The constituent and composition of goat milk is totally different from cow or buffalo milk. Goat milk is nutritionally more or less matches to human milk which is not very much similar to cow's milk. It also possesses lots of medicinal properties. Lactose intolerance patients will be benefited from goat milk because it has less lactose than human and cow milk. It contains proteins, vitamins, minerals, fatty acids, trace elements and enzymes that can be easily assimilated in our body. Smaller and uniform fat globules of goat milk make them easily digestible in the body. It contains higher selenium concentration which acts on regeneration of blood platelet suffering from dengue fever. Protein content in goat milk is lower than cow milk and is easily digestible when compared to cow or buffalo milk. Taurine is present in goat milk which has inhibitory effect on hypertension, cardiovascular disease and synthesizes essential amino acids in human body. Asthma, anemia, stomach ulcers, constipation, sleeplessness, and neurotic indigestion have all been shown to be treated with goat milk. The goal of this review is to look at the differences in goat milk composition from cow and human milk, as well as the nutraceutical benefits on human health.

Phytochemical, nutritional and antioxidant potential of Panax bipinnatifidus and Panax pseudoginseng: A study of two underutilized and neglected species from the Eastern Himalayan region of India

The world we live in today is rapidly inclining towards plant-based therapeutic and curative medicines. among these phytomedicines, the role of Ginseng's (Panax species) significance as a functional food or nutraceutical has piqued interest in recent years, with a growing market value. Keeping in mind, the present study was intended to analyse the phytochemical, nutritional content and antioxidant activity of two Indian species of Panax viz. P. bipinnatifidus and P. pseudoginseng from the East Himalayan region of India. HPLC studies revealed the presense of four predominant ginsenosides viz. Rg1, Re, Rb1 and Rd in both the Panax species. Analysis of phenolic compounds indicated higher values of gallic acid, chlorogenic acid, and vanillic acid in both species. The tuber contains a good amount of protein, dietary fibre and carbohydrates. Dominant content of arginine and glutamic acid were found with cysteine and methionine as limiting amino acids in both the Panax species. High levels of palmitic, oleic and linoleic acid were observed with higher values of poly-unsaturates in P. pseudoginseng. Analysis of minerals and trace elements reflected high content of phosphorus, potassium, magnesium and selenium in Panax species. The antioxidant study further confirmed the effective potential of these Panax species against several free radicals such as DPPH, ABTS, and superoxide anions. The present findings provide biochemical insights into the diverse aspects of east Himalayan Panax species coupled with their antioxidant potential. These findings could be used as a baseline model for enriching the herbal raw materials required for pharmaceutical as well as nutraceutical formulations. Moreover, a commercially oriented cultivation of these species may be developed by adopting effective conservation strategies to conserve these therapeutically important east Himalayan Panax species.

The influence of redox conditions on aqueous-solid partitioning of arsenic and selenium in a closed coal ash impoundment

A closed coal ash impoundment case study characterized the effects of field redox conditions on arsenic and selenium partitioning through monitoring of porewater and subsurface gas in conjunction with geochemical speciation modeling. When disposed coal ash materials and porewater were recovered for testing, oxidation led to lower arsenic and higher selenium concentrations in leaching test extracts compared to porewater measurements. Multiple lines of evidence suggest multiple mechanisms of arsenic retention are plausible and the concurrent presence of several redox processes and conditions (e.g., methanogenesis, sulfate reduction, and Fe(III)-reduction) controlled by spatial gradients and dis-equilibrium. Geochemical speciation modeling indicated that, under reducing field conditions, selenium was immobilized through the formation of insoluble precipitates Se(0) or FeSe while arsenic partitioning was affected by a progression of reactions including changes in arsenic speciation, reduction in adsorption due to dissolution and recrystallization of hydrous ferric oxides, and precipitation of arsenic sulfide minerals.

Serum selenium concentrations and risk of all-cause and heart disease mortality among individuals with type 2 diabetes

The impact of selenium status on the long-term health of people with type 2 diabetes (T2D) remains unclear. To prospectively examine the association of serum selenium concentrations with all-cause and heart disease mortality among individuals with T2D. This analysis included 3199 adults with T2D from the third NHANES (NHANES III) and NHANES (2003-2004, 2011-2014). Mortality from heart disease and all causes was linked to National Death Index mortality data. Cox proportional hazard models were used to estimate HRs and 95% CIs. The median (IQR) concentration of serum selenium was 127.0 (115.0, 139.1) µg/L. During an average 12.6-y follow-up, 1693 deaths were documented, including 425 heart disease deaths. Compared with participants in the lowest quartile of selenium, the multivariate-adjusted HRs (95% CIs) for participants in the highest quartile were 0.69 (0.54, 0.89) for all-cause mortality (P-trend=0.002) and 0.66 (0.45, 0.99) for heart disease mortality (P-trend=0.03). In addition, a linear dose-response relation between serum selenium (range: 89-182µg/L) and mortality was observed. For per-unit increment in natural log-transformed serum selenium, there was a 64% lower risk of all-cause mortality and a 66% lower risk of heart disease mortality (both P<0.05). Similar results were observed when stratifying by age, sex, race, smoking status, BMI, physical activity, diabetes duration, and HbA1c concentrations. Our study suggested that higher selenium concentration was associated with lower all-cause and heart disease mortality among individuals with T2D. More studies are needed to confirm these findings.

Selen - uloga u očuvanju i unapređenju zdravlja i sprečavanju bolesti

Introduction: Selenium is a trace element whose importance for the functioning of the organism in health and disease is very intensively studied in modern research. This scientific evidence is constantly being supplemented, which requires monitoring and evaluation. Aim: The aim of this review paper is to systematize the results of relevant scientific research on the role of selenium in health preservation and promotion and the prevention of disease. Method: Available literature in English from the PubMed database was searched using the keywords "selenium"; "health"; "disease"; "toxicity"; "food"; "deficiency"; "cancer" and "diabetes mellitus". Results: Selenium is a microelement that manifests a powerful antioxidant effect within the enzyme phospholipid hydroperoxide glutathione peroxidase, while as a part of the enzyme deiodinase plays a role in the transformation of thyroxine into triiodothyronine. Brazilian nut is a food with an extremely high concentration of selenium, followed by tuna and oysters. Selenium deficiency in the body manifests as cardiomyopathy (Keshan disease) or osteoarthritis (Kashin-Beck's disease). Selenium poisoning is characterized by gastrointestinal and neurological symptoms, changes in the skin, on nails and garlic breath. Although a negative correlation has been observed between selenium concentration and the risk of carcinoma (breast, prostate, cervical, liver, gastric, thyroid, colorectal and bladder), studies have not shown so far a significant effect of selenium nutritional intake or supplementation in the prevention of cancer. Selenium concentrations are significantly lower in hepatitis, cirrhosis of the liver, obesity, autoimmune diseases (Hashimoto's disease, psoriasis, rheumatoid arthritis, ulcerous colitis, Crohn's disease), AIDS, and COVID-19, compared to healthy people. On the other hand, excessive selenium intake can increase the risk of diabetes mellitus type 2. Conclusion: Selenium has a significant physiological role in preserving health, primarily as an antioxidant and in the functioning of the thyroid gland, while selenium deficiency can be manifested by cardiomyopathy and osteoarthritis. Low concentrations of selenium in the body may increase the risk of several diseases: cancer, autoimmune diseases, AIDS and COVID-19. On the other hand, excessively high doses of selenium may increase the risk of diabetes mellitus or even poisoning - selenosis.

Effects of Dietary Selenium Sources on Physiological Status of Laying Hens and Production of Selenium-Enriched Eggs.

Developing new sources of organic selenium (Se) has potential benefits for animal production and human nutrition via animal-based foods enriched with Se. The objective of this study was to evaluate the effects of Se-enriched insect protein (SEIP) in comparison with other sources, such as sodium selenite (SS) and selenium-enriched yeast (SEY), on performance, egg quality, selenium concentration in eggs, serum biochemical indices, immune capacity, and intestinal morphology of laying hens. Four hundred and fifty 24-week-old Hy-Line Brown laying hens with 94.0 ± 1.5% laying rate were randomly allocated to five groups with six replicates of 15 hens each. The control diet was prepared without adding exogenous selenium (calculated basal Se content of 0.08 mg/kg). The normal group was fed basal diets supplemented with 0.3 mg/kg of Se provided by sodium selenite. Three treatment groups (SS, SEY, and SEIP, respectively) were fed basal diets supplemented with 2 mg/kg of Se provided by sodium selenite, Se-enriched yeast, and SEIP, respectively. The feeding trial lasted for 12 weeks. Results revealed that dietary supplementation of 2 mg/kg of Se increased egg weight, decreased feed conversion ratio, and enhanced the antioxidant capacity of eggs in laying hens relative to the control group, whereas no significant differences were observed among SS, SEY, and SEIP treatment groups for the same. The organic source of Se provided by SEY or SEIP showed higher bio efficiency, as indicated by higher selenium content in eggs of SEY and SEIP compared with SS, although higher content was observed in SEY compared with SEIP. Also, the organic Se source significantly improved antioxidant capacity and immune functions of laying hens than the inorganic Se source. Diets supplemented with SEIP and SS significantly improved jejunal morphology of the laying hens compared with SEY, whereas SEIP was more effective than SEY to improve the oviduct health of laying hens. The results of this work evidently points the additive effect and nontoxicity of SEIP. Thus, SEIP could be used as another organic source of Se in the diet of laying hens and production of selenium-enriched eggs for humans.

Persistence of the Effects of Se-Fertilization in Olive Trees over Time, Monitored with the Cytosolic Ca2+ and with the Germination of Pollen.

Selenium (Se) is an important micronutrient for living organisms, since it is involved in several physiological and metabolic processes. Biofortification with Se increases the nutritional and qualitative values of foods in Se-deficient regions and increases tolerance to oxidative stress in olive trees. Many studies have shown that Se, in addition to improving the qualitative and nutritional properties of EVO oil, also improves the plant’s response to abiotic stress. This study addressed this issue by monitoring the effects of Se on cytosolic Ca2+ and on the germination of olive pollen grains in oxidative stress. The olive trees subjected to treatment with Na-selenate in the field produced pollen with a Se content 6–8 times higher than the controls, even after 20 months from the treatment. Moreover, part of the micronutrient was organic in selenium methionine. The higher selenium content did not produce toxic effects in the pollen, rather it antagonized the undesirable effects of oxidative stress in the parameters under study. The persistence of the beneficial effects of selenium observed over time in pollens, in addition to bringing out an undisputed adaptability of olive trees to the micronutrient, suggested the opportunity to reduce the number of treatments in the field.

Synthesis, characterization, and anti-tumor properties of O-benzoylselenoglycolic chitosan

This study introduces a facile method for synthesizing O-benzoylselenoglycolic chitosan with a high selenium concentration of 45.32 mg/g. The characterizations of the chemical structure via FTIR, 1H NMR, 13C NMR, TGA, and XRD analyses indicated that benzoylselenoglycolic acid was successfully grafted onto the C6 hydroxyl group of chitosan. The anti-cancer activity of the O-benzoylselenoglycolic chitosan was investigated in vitro using a HepG2 cell model, and the results indicated that it has excellent anticancer activity against HepG2 cancer cells with an IC50 value of 0.53 μg/mL while exhibiting non-toxicity against normal cells (L-02). Furthermore, a mechanistic study revealed that the O-benzoylselenoglycolic chitosan could induce early apoptosis, G2/M, S phase arrest, and activation of caspase-3 activity to inhibit the HepG2 cell growth. This study has led to novel organic selenium species, and the results suggest its potential to be used as an effective ingredient for cancer prevention and therapy in the food and pharmaceutical fields.

Total mercury exposure risk and selenium content measuring on fishery products consumed by women of childbearing age from Bogota, Colombia

Background. Dietary exposure to mercury in women of childbearing age could result in neurological effects on the fetus. A health risk assessment of total mercury by fishery products intake has not been conducted in this population group in Bogota, Colombia. On the other hand, it has been suggested that selenium content on fishery products may have a protective effect against mercury toxicity. Nevertheless, selenium content on fish species marketed in Bogotá has not been determined. Objective. Exposure risk to total mercury and selenium content on fishery products consumed by women of childbearing age from Bogota, Colombia, were assessed. Methods. Total mercury and selenium concentrations for products available at fish stores and supermarkets were determined. The exposure risk to total mercury was estimated considering the intake of these products by women of childbearing age group. Results. Total mercury highest concentrations were 0.8166 mg/kg in mota (Calophysus macropterus), and 0.6275 mg/kg in catfish (Pseudoplatystoma tigrinum). On the other hand, the highest selenium concentration was 0.6471 mg/kg in nicuro (Pimelodus blochii). Finally, it was established that for women of the childbearing age group, health risk of exposure to total mercury due to mota intake exceeded by 8.56-fold the reference dose. Conclusions. Mota intake considerably increases exposure risk to total mercury on women of childbearing age from Bogota, Colombia. The selenium levels established in the fishery products assessed, except for catfish and mota, are theoretically suggestive of a protective effect of selenium against mercury toxicity. Consequently, continuous total mercury concentrations monitoring is required to protect health of the women of childbearing age and the general population from Bogota, Colombia.

Study on the Ecological Circulation Agricultural System of Combining Planting and Raising of Berry Tea

Berry tea is a perennial vine. Its scientific name is ampelopsis grossedentata. It belongs to vitaceae and is widely spread in the Tujia people of Xiangxi, Hunan Province. By adopting appropriate agricultural planting technology, rational use of organic selenium fertilizer and nutritional conditioner, we can produce high-quality berry tea with more healthy and even medicinal value and high selenium content, and realize double protection of human health with high selenium content and high flavonoids. Under the existing planting system, through the supplement of breeding links, constructing ecological recycling agricultural system combining planting and raising, not only can greatly enrich the supply of table agricultural products, but also can effectively ensure the high quality and high safety of agricultural products, and can effectively enrich the local agricultural industrial structure.

Addition of Bamboo Charcoal to Selenium (Se)-Rich Feed Improves Growth and Antioxidant Capacity of Blunt Snout Bream (Megalobrama amblycephala).

Simple SummaryIn our previous studies, we determined that juvenile blunt snout bream (Megalobrama amblycephala) require a selenium (Se) dietary intake of 0.958–0.959 mg/kg based on the quadratic fitting method. Nevertheless, growth rates were significantly affected, and the expression of anti-inflammatory factors was inhibited when the feed contained excessively high Se concentrations. Given its activity as an insoluble carrier, bamboo charcoal can be used as a dietary supplement in fish feed to absorb and slowly release excess nutrients. However, these hypotheses have not been evaluated in diets containing excess Se. The present study determined that 2–3 g/kg bamboo charcoal inclusion in Se-rich feed could improve the growth performance of blunt snout bream. Dietary bamboo charcoal supplementation mobilized the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 signaling while suppressing NF-κB signaling.The ability of bamboo charcoal to reduce the negative effects of high dietary selenium (Se) concentrations was assessed by feeding juvenile blunt snout bream (Megalobrama amblycephala) one of five Se-rich diets (1.5 mg/kg Se; 36% protein, 8.7% lipid) containing graded levels (0–4 g/kg) of bamboo charcoal powder for eight weeks. There were four tanks (350 L) of fish (initial weight 16.0 ± 0.5 g) for each treatment, and the fish were fed to satiation four times each day. At the end of the feeding trial, all of the fish from each tank were weighed to calculate the growth performance. Blood samples were firstly obtained to collect plasma for the biochemical indexes determination. Liver tissues were then collected to determine the antioxidant enzyme activities and gene expression. Dorsal muscles were also collected to determine the nutrient composition. The results show that when the bamboo charcoal content in the Se-rich feed ranged between 0 and 3 g/kg, the weight growth rate (WGR) and specific growth rate (SGR) values increased with the higher dietary bamboo charcoal content, and the maximum WGR and SGR values were achieved when the bamboo charcoal content in the Se-rich feed was 2–3 g/kg (p < 0.05). The Se content in muscle tissues decreased significantly with the increased bamboo charcoal content (p < 0.05) in the Se-rich feed, which ranged from 0 to 4 g/kg. When the bamboo charcoal content in the Se-rich feed was 2–3 g/kg, the levels of glucose (GLU) and albumin (ALB) in plasma reached a maximum (p < 0.05), whereas the level of alkaline phosphatase (ALP) reached a minimum (p < 0.05). Additionally, the activities of catalase (CAT), total superoxide dismutase (T-SOD), total antioxidative capacity (T-AOC), and glutathione peroxidase (GSH-Px) were significantly enhanced (p < 0.05) when the bamboo charcoal content was 3 g/kg. In contrast, the malondialdehyde (MDA) level increased sharply when the bamboo charcoal content in the Se-rich feed was 1 g/kg, compared to the control group and the groups supplemented with 2–3 g/kg bamboo charcoal (p < 0.05). Regarding mRNA-level gene expression, the results show that dietary supplementation with 0 to 3 g/kg of bamboo charcoal increased the expression of keap1 and nrf2, whereas nfkb expression was inhibited (p < 0.05). The mRNA expression of the antioxidant enzymes cat, gpx, and mn-sod was consistently enhanced in the group fed with the 3 g/kg bamboo charcoal diet (p < 0.05). The expression of the pro-inflammatory cytokines tnfα and tgfβ was inhibited in the groups supplemented with 2–3 g/kg bamboo charcoal, whereas the expression of anti-inflammatory cytokines (il10) increased in the bamboo charcoal supplementation groups compared to the control group (p < 0.05). Generally, supplementation with 2–3 g/kg of bamboo charcoal in Se-rich feed improved the growth performance, physiological status, and antioxidant enzyme activities of blunt snout bream. Moreover, bamboo charcoal supplementation in Se-rich diets stimulated the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 and suppressing NF-κB.

Condensation and adsorption characteristics of gaseous selenium on coal-fired fly ash at low temperatures

Gaseous selenium is of high saturated vapor pressure, making its retention in solid phases quite difficult during coal combustion. The selenium transformation from gaseous form into solid phases at low temperatures can be essential to control selenium emission. To understand the migration of SeO2 (g) on ash particles in the low-temperature zone, this study investigated the speciation of selenium in fly ash and simulated the physical retention of SeO2 (g) on fly ash. The results demonstrated that there was a large proportion of physically-bound Se in the fly ash of pulverized-coal-fired boiler (22.62 %–58.03%), while the content of physically-bound Se in fly ash of circulated fluidized-bed boiler was lower (∼6%). The physically-bound Se was formed through selenium condensation and physical adsorption. The decrease of temperature or the increase of cooling rate could promote the transformation of gaseous selenium to solid phase and the presence of HCl might suppress SeO2 transformation into Se in the condensation process. Meanwhile the compositions of fly ash had a great influence on the selenium adsorption process. Among typical coal-fired ash components, mullite showed the best performance in the selenium capture in the temperature range of 90–200 °C, contributing to the high content of physically-adsorbed selenium in PC fly ash. These findings provided new ideas for improving the removal rate of volatile selenium.