Meta-analysis of selenium effects on the meat quality of broilers

The effects of sodium selenite or selenium yeast on the meat quality of broilers were searched in the literature published in the Chinese National Knowledge Infrastructure (CNKI), Wanfang Database, China Science and Technology Journal Database (VIP), PubMed, Web of Science, and Science Direct databases from January 1, 2010 to December 31, 2022. Meta-analysis was performed with Stata software (StataCorp. 2011), and the standardized mean difference (SMD) and its 95% confidence interval (CI) were calculated using a random effects model. Twenty of the identified 846 literature sources, which included 791 broilers, were screened. The meat quality indices considered were shear force, drip loss, cooking loss, water holding capacity (WHC), pH, and color. The source of heterogeneity was studied using sensitivity and subgroup analyses, and publication bias was evaluated using funnel plots. The results showed that the supplementation of selenium in the broiler diet significantly reduced the shear force (SMD = -0.67, 95% CI [-1.12, -0.22], P < 0.05) and drip loss (SMD = -0.84, 95% CI [-1.39, -0.30], P < 0.05) and increased the pH (SMD = 0.38, 95% CI [0.01, 0.75], P < 0.05) of broiler breast muscle; however, it had no significant effects on other indices. Funnel plots revealed a slight publication bias in the shear force and pH of breast muscle but none in the drip loss of breast muscle. The sensitivity analysis showed that the results were stable and reliable. In conclusion, selenium supplementation in broiler feed can improve some indices of broiler meat quality, and its inclusion in broiler diets is recommended, in conjunction with other minerals, which is of great significance to improve the quality, preservation time and economic benefits of chicken products.

Selenium Yeast Alleviates Dextran Sulfate Sodium-Induced Chronic Colitis in Mice by Reducing Proinflammatory Cytokines and Regulating the Gut Microbiota and Their Metabolites

Background

Inflammatory bowel disease (IBD) is a chronic recurrent gastrointestinal inflammatory disease. Selenium has been reported to have therapeutic potential in IBD. Selenium yeast is a common selenium supplement that is convenient to access. This study explored the effect of selenium yeast on dextran sulfate sodium- (DSS-)induced chronic colitis in mice.

Methods

Mice were randomly divided into four groups: the control group, selenium yeast group, chronic colitis group, and chronic colitis+selenium yeast group (n=6). Mice were killed on the 26th day. The disease activity index (DAI) score and histological damage score were calculated. Cytokines, serum selenium, colonic tissue selenium, gut microbiota and their metabolites short-chain fatty acids (SCFAs) were evaluated.

Results

Selenium yeast lowered IL-1β, IL-6, TNF-α, IL-17A, IL-22 and IFN-γ (P<0.05). In addition, selenium yeast significantly elevated Turicibacter, Bifidobacterium, Allobaculum, Prevotella, Halomonas, Adlercreutzia (P<0.05), and butyric acid (P<0.05).

Conclusion

Selenium yeast could improve DSS-induced chronic colitis in mice by regulating cytokines, gut microbiota and their metabolites.

Effects of Dietary Selenium Yeast Supplementation in Pregnant Cashmere Goats on the Development of Offspring Hair Follicles

The objective of this study was to investigate the effects of maternal dietary selenium yeast (SY) supplementation during pregnancy on the hair follicle development of kids. Sixty pregnant Hanshan white cashmere goats were randomly divided into the con group (fed with a basal diet) and the SY group (fed with a basal diet with 0.4 mg/kg SY). SY was supplemented during the pregnancy until the birth of the kids. The growth performance, cashmere performance, hair follicle characteristics, and serum antioxidant capacity of the kids were periodically determined. The results showed that the birth weight of the kids in the SY group was significantly higher than that in the con group (p < 0.05), and the average weight at 15 days, 1 month, 3 months, and 5 months of age increased by 13.60%, 8.77%, 8.86%, and 3.90%, respectively (p > 0.05). The cashmere fineness at early birth was dramatically reduced with SY supplementation (p < 0.001), whereas cashmere length and production were significantly increased at 5 months of age (p < 0.05). Histology assays indicated that the primary hair follicles were fully developed at birth, and there was no significant difference in the number of primary hair follicles between the two groups (p > 0.05). The number of secondary hair follicles and the number and density of active secondary hair follicles in the SY group at 15 days were significantly higher than those in the con group (p < 0.05) and were increased by 11.18%, 6.18%, and 22.55% at 5 months of age, respectively (p > 0.05). The serum antioxidant capacity analysis revealed that the SY group had higher levels of T-AOC, SOD, CAT, and GSH-Px activities and lower levels of MDA (p > 0.05). These results reveal that the maternal dietary supplementation of SY in gestation can promote the morphogenesis and maturation of secondary hair follicles and increase the number and density of secondary hair follicles by enhancing the body's antioxidant capacity, contributing to the improvement of cashmere quality and yield.

Enhanced Antioxidative Capacity Transfer between Sow and Fetus via the Gut-Placenta Axis with Dietary Selenium Yeast and Glycerol Monolaurate Supplementation during Pregnancy

This study aims to investigate the impact of dietary supplementation with selenium yeast (SeY) and glycerol monolaurate (GML) on the transfer of antioxidative capacity between the mother and fetus during pregnancy and its underlying mechanisms. A total of 160 sows with similar body weight and parity of 3-6 parity sows were randomly and uniformly allocated to four groups (n = 40) as follows: CON group, SeY group, GML group, and SG (SeY + GML) group. Animal feeding started from the 85th day of gestation and continued to the day of delivery. The supplementation of SeY and GML resulted in increased placental weight and reduced lipopolysaccharide (LPS) levels in sow plasma, placental tissues, and piglet plasma. Furthermore, the redox balance and inflammatory markers exhibited significant improvements in the plasma of sows fed with either SeY or GML, as well as in their offspring. Moreover, the addition of SeY and GML activated the Nrf2 signaling pathway, while downregulating the expression of pro-inflammatory genes and proteins associated with inflammatory pathways (MAPK and NF-κB). Vascular angiogenesis and nutrient transportation (amino acids, fatty acids, and glucose) were upregulated, whereas apoptosis signaling pathways within the placenta were downregulated with the supplementation of SeY and GML. The integrity of the intestinal and placental barriers significantly improved, as indicated by the increased expression of ZO-1, occludin, and claudin-1, along with reduced levels of DLA and DAO with dietary treatment. Moreover, supplementation of SeY and GML increased the abundance of Christensenellaceae_R-7_group, Clostridium_sensus_stricto_1, and Bacteroidota, while decreasing levels of gut microbiota metabolites LPS and trimethylamine N-oxide. Correlation analysis demonstrated a significant negative relationship between plasma LPS levels and placental weight, oxidative stress, and inflammation. In summary, dietary supplementation of SeY and GML enhanced the transfer of antioxidative capacity between maternal-fetal during pregnancy via gut-placenta axis through modulating sow microbiota composition.

Effects of Methyl Sulfonyl Methane and Selenium Yeast on Fatty Liver Syndrome in Laying Hens and Their Biological Mechanisms

The purpose of this study was to explore the effects of MSM and Se-Y on FLS in laying hens during the late peak laying period and the underlying biological mechanisms. Therefore 240 55-week-old Jing-fen No. 6 laying hens were randomly divided into five groups, with eight replicates in each group and six laying hens in each replicate. The hens were fed a basal diet (Control) and diets supplemented with 350 and 700 mg/kg MSM and 25 and 50 mg/kg Se-Y, respectively, for four weeks. The results showed that MSM and Se-Y had no significant effects on the performance of laying hens. With the increasing dosage of MSM and Se-Y, the symptoms of liver steatosis in laying hens were reduced, and MSM and Se-Y could significantly reduce the content of malondialdehyde (MDA) in serum and liver (p < 0.05) and increase the contents of total superoxide dismutase (T-SOD) and glutathione peroxidase (GPX) in serum and liver (p < 0.05). The RNA-seq results showed that 700 mg/kg MSM significantly downregulated the expression levels of the ATP5I, ATP5G1, CYCS, and UQCRQ genes in the liver, and 50 mg/kg Se-Y significantly downregulated the expression levels of MAPK10, SRC, BMP2, and FGF9 genes in the liver. In conclusion, dietary supplementation with MSM and Se-Y can effectively reduce the FLS of laying hens in the late peak laying period and increase their antioxidant capacity. The underlying biological mechanism may be related to the downregulation of genes involved in liver oxidative phosphorylation and inflammation-related pathways.

Efficacy of feeding hydroxy-selenomethionine on plasma and milk selenium in mid-lactation dairy cows

In this study, we aimed to determine the amount of Se transferred to milk and blood of mid- to late-lactation dairy cows when supplemental Se from hydroxy-selenomethionine (OH-SeMet) was fed compared with an unsupplemented group and a group supplemented with a seleno-yeast (SY). Twenty-four lactating Holstein cows (178 ± 43 d in milk) were used in a complete randomized block design for 91 d (7-d covariate period and 84-d treatment period). Treatments were (1) basal diet with an analyzed Se background of 0.2 mg of Se per kg as-fed (control); (2) basal diet + 0.3 mg of Se/kg as-fed from SY (SY-0.3); (3) basal diet + 0.1 mg of Se/kg as-fed from OH-SeMet (OH-SeMet-0.1); and (4) basal diet + 0.3 mg of Se/kg as-fed from OH-SeMet (OH-SeMet-0.3). During the trial, plasma and milk were analyzed for total Se, and plasma was analyzed for glutathione peroxidase activity. The mean plasma and milk Se concentrations exhibited the same relationship, where OH-SeMet-0.3 resulted in the highest values (142 µg/L of plasma and 104 µg/kg of milk), followed by SY-0.3 (134 µg/L and 85 µg/kg), OH-SeMet-0.1 (122 µg/L and 67 µg/kg), and the control group had the lowest values (120 µg/L and 50 µg/kg). The increment of Se in milk induced by OH-SeMet-0.3 (+54 µg/kg) was 54% higher than that induced by SY-0.3 (+35 µg/kg). Additionally, dietary supplementation of 0.2 mg/kg Se from OH-SeMet in the total mixed ration was estimated to be similar to 0.3 mg/kg Se from SY in the total mixed ration when considering the level of Se in the milk. There was no difference in plasma glutathione peroxidase activity between groups; however, OH-SeMet-0.3 significantly decreased somatic cell count. The results confirmed that supplementation with organic Se increases milk and plasma Se concentrations. Moreover, when administered at the same level of supplementation, OH-SeMet was shown to be more efficient than SY in improving milk quality by increasing Se content and decreasing milk somatic cell count.

Effects of Selenium Yeast on Egg Quality, Plasma Antioxidants, Selenium Deposition and Eggshell Formation in Aged Laying Hens

Internal egg and eggshell quality are often deteriorated in aging laying hens, which causes huge economic losses in the poultry industry. Selenium yeast (SY), as an organic food additive, is utilized to enhance laying performance and egg quality. To extend the egg production cycle, effects of selenium yeast supplementation on egg quality, plasma antioxidants and selenium deposition in aged laying hens were evaluated. In this study, five hundred and twenty-five 76-week-old Jing Hong laying hens were fed a selenium-deficient (SD) diet for 6 weeks. After Se depletion, the hens were randomly divided into seven treatments, which included an SD diet, and dietary supplementation of SY and sodium selenite (SS) at 0.15, 0.30, and 0.45 mg/kg to investigate the effect on egg quality, plasma antioxidant capacity, and selenium content in reproductive organs. After 12 weeks of feeding, dietary SY supplementation resulted in higher eggshell strength (SY0.45) (p < 0.05) and lower shell translucence. Moreover, organs Se levels and plasma antioxidant capacity (T-AOC, T-SOD, and GSH-Px activity) were significantly higher with Se supplementation (p < 0.05). Transcriptomic analysis identified some key candidate genes including cell migration inducing hyaluronidase 1 (CEMIP), ovalbumin (OVAL), solute carrier family 6 member 17 (SLC6A17), proopiomelanocortin (POMC), and proenkephalin (PENK), and potential molecular processes (eggshell mineralization, ion transport, and eggshell formation) involved in selenium yeast's effects on eggshell formation. In conclusion, SY has beneficial functions for eggshell and we recommend the supplementation of 0.45 mg/kg SY to alleviate the decrease in eggshell quality in aged laying hens.

Effects of selenium yeast and jujube powder dietary supplements on conformational and functional properties of post-mortem chicken myofibrillar protein

The aim of the study was to evaluate the effects of selenium yeast and jujube powder on the structure and functional properties of post-mortem myofibrillar protein (MP) in white feather broilers. Changes in the structure (surface hydrophobicity, secondary structure, and tertiary structure), functional properties (solubility, turbidity, emulsifying, and foaming characteristics), and gel properties (gel strength, springiness, and water-holding capacity) of the MPs of white feather broiler, which were fed with different concentrations of selenium yeast or/and jujube powder (selenium yeast: 0,0.3, and 0.6 mg/kg; jujube powder: 8% to replace corn) for 42 days, were determined at 0, 24, and 72 h post-mortem. The results showed that with increasing concentrations of selenium yeast and jujube powder in the diet, the α-helix content, solubility, emulsification, and foaming of post-mortem chicken MP increased significantly (P < 0.05). The gel strength, springiness, and water-holding capacity of MP also increased, but the differences between the treatment groups were not significant (P > 0.05). In addition, the β-folding content and turbidity of MP decreased significantly (P < 0.05). Both the increase in selenium yeast levels and the addition of jujube powder improved the structural integrity and functional properties of MP. The best improvement effect was found in the combination group of high-dose selenium yeast and jujube powder, and there were significant interactions between them in the indices of α-helix, β-folding, turbidity, emulsification, and foam stability of MP. In conclusion, supplementing diets with seleniumyeast and jujube powder could maintain the structural stability of MPs in post-mortem chicken breast, leading to good functional properties. The results of this study may provide new insights into the effects of pre-slaughter feeding on post-mortem muscle MP conformation control and quality improvement.

italica)

BACKGROUND

Approximately 0.5-1 billion people worldwide face the risk of selenium (Se) deficiency because of the low Se concentration in their diets. Broccoli can accumulate Se and comprises a source of daily Se supplement for humans. Se biofortification is an effective strategy for enhancing Se content in crops. In the present study, the effects of Se yeast and selenite application on the Se content and nutrient quality of broccoli were investigated.

RESULTS

Broccoli growth was promoted by Se yeast but inhibited by selenite. The total Se content of broccoli florets remarkably increased with increasing exogenous Se fertilizer concentrations. The main Se species in broccoli florets were methyl-selenocysteine and selenomethionine, and their contents were significantly higher under Se yeast treatments than under selenite treatments. Se(VI) was detected only under selenite treatments. Se yeast and selenite had different influences on soluble sugar, soluble protein, vitamin C and free amino acid contents in broccoli florets. The total phenolic acid and glucosinolate contents were substantially increased by Se yeast and selenite, although the total flavonoid content was reduced by Se yeast. Tests on antioxidant enzyme activities revealed that several antioxidant enzymes (catalase, peroxidase, superoxide dismutase and glutathione peroxidase) responded to Se yeast and selenite treatments.

CONCLUSION

Se yeast is preferred over selenite for maximizing Se uptake and nutrient accumulation in Se-rich broccoli cultivation. However, an extremely high Se content in broccoli florets cannot be directly consumed by humans, although they can be processed into Se supplements. © 2021 Society of Chemical Industry.

The effects of selenium supplementation on antibody titers in patients with Hashimoto's thyroiditis

OBJECTIVE

To evaluate the effect of selenium supplementation on autoantibody titers, thyroid ultrasonography and thyroid function in patients with Hashimoto's thyroiditis (autoimmune thyroiditis) and normal thyroid reference range.

METHODS

A total of 100 patients were given 200 ug/d selenium yeast orally, their thyroid function, levels of serum selenium, thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TGAb) and urine iodine were measured and thyroid ultrasonography was performed before administration and three and six months afterwards, and the data were statistically analysed.

RESULTS

The subjects exhibited a selenium deficiency before the administration of selenium, and the serum levels increased to moderate levels three and six months after the selenium supplementation (p<0.05). The titers of TGAb decreased significantly in patients after six months of Selenium lack prevention measure(p<0.05). In the high antibody group, TgAb decreased after 6 months compared with baseline (P<0.05), and TPOAb decreased after 3 and 6 months of selenium supplementation compared with baseline (P<0.05).

CONCLUSION

In patients with autoimmune thyroiditis and normal thyroid reference range, there was a general selenium deficiency but, after six months of treatment, it was shown that the Selenium lack prevention measure may be effective in reducing the titers of TGAb and TPOAb.

The Effect of Different Sources of Selenium Supplementation on the Meat Quality Traits of Young Charolaise Bulls during the Finishing Phase

The aim of the study was to compare the effects of sodium selenite (SS), selenium yeast (SY), and hydroxy-selenomethionine (OH-SeMet) on the meat quality and selenium (Se) deposition of finishing beef cattle. Sixty-three bulls were distributed over 3 treatments and fed SS, SY, or OH-SeMet at 0.2 mg kg⁻¹ dry matter (DM) for 60 d. None of the Se sources affected the growth performance or carcass characteristics. OH-SeMet showed a higher Se transfer to the meat than SS or SY (p < 0.01). SY and OH-SeMet reduced the shear force of the meat (p < 0.0001), improved pH (p < 0.001), and reduced the drip losses (p < 0.001) and the lipid oxidation of the meat (p < 0.001). During 8 d of storage, OH-SeMet showed higher levels of meat lightness (L*) and yellowness (b*) than SS (p < 0.001), while the SY meat showed a higher L* than SS, albeit only on d 6. OH-SeMet improved b*, compared to SS, and also compared to SY on days 4, 7, and 8 (p < 0.001). Supplementing beef with SY and OH-SeMet improved several meat quality parameters. OH-SeMet appears to be the most effective strategy to improve the Se content and color stability of beef cattle meat.

Relative bioavailability of selenium yeast for broilers fed a conventional corn-soybean meal diet

The present study was conducted to assess the relative bioavailability of selenium (Se) as Se yeast (SY) relative to sodium selenite (SS) for broilers fed a conventional corn-soybean meal diet. A total of 360 one-d-old Arbor Acres commercial broilers were randomly assigned to 5 treatments with 6 replicates per treatment in a completely randomized design involving a 2 (Se sources: SY and SS) × 2 (added Se levels: 0.20 and 0.40 mg Se/kg) factorial design of treatments plus 1 (a Se-unsupplemented control diet) for 42 days. The results showed that Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney of broilers on d 21 and 42, glutathione peroxidase (GSH-Px) activity in the pancreas on d 21 as well as in the breast muscle and pancreas on d 42, and GSH-Px mRNA levels in the liver, heart, breast muscle and pancreas on d 21 increased linearly (p < .03) as levels of added Se increased. Furthermore, a difference (p ≤ .05) between SY and SS was detected for Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney, GSH-Px activity in pancreas on both d 21 and 42, as well as pancreatic GSH-Px mRNA level on d 21. Based on slope ratios from the multiple linear regressions of the above indices, the Se bioavailabilities of SY relative to SS (100%) were 111%-394% (p ≤ .05) when calculated from the Se concentrations in plasma, liver, heart, breast muscle, pancreas, kidney and GSH-Px activities in pancreas on d 21 and 42, as well as GSH-Px mRNA level in pancreas on d 21. The results from this study indicated that the Se from SY was more available for enhancing the Se concentrations in plasma or tissues and the expression and activity of GSH-Px in pancreas of broilers than the Se from SS.

Selenium Yeast Alleviates Ochratoxin A-Induced Hepatotoxicity via Modulation of the PI3K/AKT and Nrf2/Keap1 Signaling Pathways in Chickens

The aim of this study was to investigate the protective effects of selenium yeast (Se-Y) against hepatotoxicity induced by ochratoxin A (OTA). The OTA-induced liver injury model was established in chickens by daily oral gavage of 50 µg/kg OTA for 21 days. Serum biochemistry analysis, antioxidant analysis, as well as the qRT-PCR and Western blot (WB) analyses were then used to evaluate oxidative damage and apoptosis in chicken liver tissue. The results showed that Se-Y significantly increased liver coefficient induced by OTA (P < 0.05). OTA + Se-Y treated group revealed that Se-Y reduced the OTA-induced increase in glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST) and malonaldehyde (MDA) content, and reversed the decrease in antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) (P < 0.05). In this study, we found that OTA is involved in the mRNA expression levels about Nrf2/Keap1 and PI3K/AKT signaling pathways, such as oxidative stress-related genes (Nrf2, GSH-Px, GLRX2 and Keap1) and apoptosis-related genes (Bax, Caspase3, P53, AKT, PI3K and Bcl-2). Besides, significant downregulations of protein expression of HO-1, MnSOD, Nrf2 and Bcl-2, as well as a significant upregulation of Caspase3 and Bax levels were observed after contaminated with OTA (P < 0.05). Notably, OTA-induced apoptosis and oxidative damage in the liver of chickens were reverted back to normal level in the OTA + Se-Y group. Our findings indicate that pretreatment with Se-Y effectively ameliorates OTA-induced hepatotoxicity.

Effect of Selenium Source and Level on Performance, Egg Quality, Egg Selenium Content, and Serum Biochemical Parameters in Laying Hens

The objective of this study was to compare the effect of sodium selenite (SS) and selenium yeast (SY) on performance, egg quality, and selenium concentration in eggs and serum biochemical indices in laying hens. Seven hundred twenty healthy Roman laying hens (21 weeks old, 18 weeks in lay) with a similar laying rate (90.27% ± 1.05%) were randomly divided into 5 groups with 6 replicates of 24 hens each. Five diets were prepared as a 1+2×2 factorial arrangement with control and two sources of Se at two levels. Control diet (control) was prepared without adding exogenous selenium (analyzed basal Se content of 0.178 mg/kg). The other four diets were prepared with the control diet supplemented with SY or SS at 0.3 mg/kg (low; L) or 0.5 mg/kg (high; H) to give 5 diets designated as control, SY-L, SY-H, SS-L, and SS-H. The analyzed selenium content in the SY-L, SY-H, SS-L, and SS-H diets were 0.362, 0.572, 0.323, and 0.533 mg/kg respectively. The pre-trial period lasted 7 d, and the experimental period lasted 56 d (30 weeks old), during which the egg production, egg quality, and hen serum parameters were measured. Results showed that selenium source and level had no effect (P > 0.05) on average daily egg weight and feed conversion ratio (FCR). However, the laying rate was different at the L and H levels of supplementation, regardless of source, such that hens that were supplemented had a higher performance than that of the control, and the H level of supplementation lead to a higher laying rate than that of the L level (P < 0.05). There was a difference in average daily feed intake (ADFI) with an interaction in selenium source and level (P < 0.05), such that SS-L was higher than other selenium supplemented treatment or control. There were no significant differences in egg quality (P > 0.05); at the high level, SY had higher egg yolk selenium compared with SS. However, within SY, adding 0.5 mg/kg selenium led to higher egg yolk selenium than 0.3 mg/kg selenium (P < 0.05). Moreover, adding 0.3 mg/kg SY, 0.3 mg/kg, or 0.5 mg/kg SS to the basal diet had no significant effect on the selenium content in the egg (P > 0.05). There were no significant differences in serum biochemical indices among the five groups (P > 0.05). In conclusion, adding a high level of selenium in the diet of laying hens significantly increased egg production, and addition of a high level of selenium in the form of SY led to a higher deposition of selenium in the yolk than that of SS. These results indicate that adding 0.5 mg/kg of SY in the diet of laying hens would result in Se-enriched eggs.

The Protective Roles of Dietary Selenium Yeast and Tea Polyphenols on Growth Performance and Ammonia Tolerance of Juvenile Wuchang Bream (Megalobrama amblycephala)

In order to investigate protective roles of dietary selenium yeast (SY) and tea polyphenols (TPs) on growth of juvenile Wuchang bream (Megalobrama amblycephala) and its resistance under ammonia stress, juvenile Wuchang bream were randomly assigned into four groups: a control group fed basal diets and three treatment groups fed basal diets supplemented with 0.50 mg/kg SY, 50 mg/kg TPs and a combination of 0.50 mg/kg SY and 50 mg/kg TPs, respectively. After 60 days of feeding, growth parameters of Wuchang bream were measured along with serum hormones and the transcription of growth axis-related genes. Then fish were exposed to ammonia stress of 22.5 mg/L total ammonia nitrogen. Hepatic oxidative damage parameters, antioxidant responses and ultrastructure were evaluated before ammonia exposure (0 h) and at 3, 6, 12, 24, and 48 h after ammonia exposure. Results show that before ammonia exposure, the growth parameters, serum GH and IGF-1 levels as well as the growth axis-related gene expression (gh, ghr2 and igf-1) for the SY and combination groups were higher than those determined for the fish on the control diet. In contrast, the administration of TP alone didn't have significant effects on the growth parameters and growth-related hormones. After ammonia exposure, compared with the control, remarkable increases in the activity and mRNA expression of hepatic antioxidant enzymes (glutathione peroxidase and catalase superoxide dismutase) in three treatment groups were observed along with decreases of hepatic malondialdehyde and protein carbonylation levels, indicating that the single and combined supplementation of SY and TPs could enhance antioxidant capacity to alleviate oxidative stress and damage by ammonia. Consistent with this finding, alterations of the liver ultrastructure in three treatment groups were less severe and faster recovery than in the control group after ammonia exposure. In conclusion, a basal diet supplemented with the combination of 0.50 mg/kg SY and 50 mg/kg TPs could has very beneficial effects on the whole aspects of the growth and ammonia resistance in Wuchang bream juveniles.

Effect of sodium selenite and selenium yeast on performance, egg quality, antioxidant capacity, and selenium deposition of laying hens

This study compared the effects of sodium selenite and selenium yeast and their combination on laying performance, egg quality, antioxidant capacity, and selenium (Se) contents in tissues and eggs. Two-hundred-eighty-eight Jing Hong layers that were similar in laying rate (87.5 ± 0.38%) and body weight (1.70 ± 0.02 kg) were randomly distributed into 4 treatments for 11 wk (from 203 d old to 279 d old) with 9 replicates of 8 hens per replicate. The diets (corn-soybean meal diet) were supplemented with 0 [blank control (BC)], 0.3 mg/kg Se from sodium selenite (SS), 0.15 mg/kg Se from sodium selenite and 0.15 mg/kg Se from Se yeast (SS+SY), or 0.3 mg/kg Se from Se yeast (SY). Results showed that the laying rate of the SS+SY group increased significantly (P < 0.05) compared to the BC and SY groups. There were no differences (P > 0.05) in egg quality between the Se-supplemented diets and the BC diet. The serum glutathione peroxidase (GSH-Px) activity was increased (P < 0.01) in hens fed Se-supplemented diets compared to the BC diet. The liver superoxide dismutase (SOD) activity of the SY group was increased significantly (P < 0.05) compared to the BC group. Significant increase (P < 0.01) due to SY supplementation was noted in the serum vitamin E content compared to BC and SS. Layers fed Se-supplemented diets had higher (P < 0.01) contents of Se in the serum, liver, and kidney compared to the BC diet. Compared to BC, Se content in eggs was significantly increased (P < 0.05) by feeding supplementary Se. In conclusion, the effects of SS and Se yeast were approximately equal in promoting antioxidant capacity of laying hens, while Se yeast is easier to deposit into eggs and tissues. The diet with added equal amounts of the 2 sources of Se was more cost effective and affordable than a comparable amount of Se yeast to obtain the promising production performance and nearly similar Se deposition.

[Intervention effects of selenium yeast on fine particulate matters-induced lung injury in rats]

OBJECTIVE

To evaluate if selenium yeast could inhibit the rat lung injury induced by ambient fine particulate matter( PM_(2. 5) ).

METHODS

Fifty-six male SpragueDawley rats were randomly allocated in seven groups( n = 8 each). Saline control group, the rats were exposed to 0. 9% saline by instillation. PM_(2. 5) exposure group, rats were exposed to PM_(2. 5) by intra-tracheal instillation every other day for three times with the accumulated dose of 40 mg/kg. Selenium yeast treatment groups, three groups of rat were exposed to PM_(2. 5) . Then the rats were given low, middle and high dose of selenium yeast, and the doses were 8. 75, 17. 5 and 35 mg/kg, respectively. High dose selenium yeast control group, rats were given high dose of selenium yeast only. Solvent control group, therats were given 1% carboxymethyl cellulose. Saline and PM_(2. 5) were given in the first week. In the second week, selenium yeast and solvent were given by gavage. The rats were sacrificed 24 hours after the last gavage. The bronchoalveolar lavage fluid( BALF)was collected to count the neutrophils numbers and analyze the markers related to inflammation, oxidative stress and cell damage. The lung lobe that was not been lavaged was processed for light microscopic examination.

RESULTS

The proportions of neutrophils in BALF and the pathologic scores of lung in PM_(2. 5) - exposed groups were significantly higher than control( P < 0. 05). Selenium yeast treatment caused decrease in tumor necrosis factor-α( TNF-α), interleukin-1β( IL-1β), lactate dehydrogenase( LDH), total protein( TP), alkaline phosphatase( AKP) and malondialdehyde( MDA) compared with the only PM_(2. 5) exposure group. Meanwhile, the dose-dependent increase in totalsuperoxide dismutase( T-SOD) and glutathione peroxidase( GSH-Px) activities were observed. There were no significant differences among the groups of saline control group, high dose selenium yeast control group and solvent control group.

CONCLUSION

Selenium yeast treatment may protect against acute injury induced by PM_(2. 5) in rat lung.

Absorption, excretion, and retention of selenium from a high selenium yeast in men with a high intake of selenium

OBJECTIVE

The purpose of this study was to evaluate the pharmacokinetics of a single dose of Selenium (Se) from yeast given to humans with a habitual long-term daily intake at a supra-nutritional level.

METHODS

Twelve healthy males with a daily supplemental intake of 300 microg Se as selenised yeast over 10 weeks were supplemented with a single dose of 327 microg as stable (77)Se incorporated into selenised yeast manufactured by the same standardised process (SelenoPrecise(R), Pharma Nord, Denmark).

RESULTS

Absorption of Se from (77)Se-enriched yeast was 89+/-4% and the retention was 74+/-6%. The (77)Se excretion from the single-dose was 47+/-15 microg in urine and 37+/-13 microg in faeces. The maximum, enriched (77)Se concentration in plasma was 9.8+/-1.5 microg/l and the time to maximum was 9.2 hours. The plasma halftime of (77)Se was longer with increasing time; 1.7 days for the initial phase ((1/2)-2 days), 3.0 days for the middle phase (2-3 days) and 11.1 days for the later phase (3-14 days).

CONCLUSION

The Se from the standardised Se-enriched yeast was well absorbed and retained in the body.