Effect of Different Selenium Sources on Growth Performance, Tissue Selenium Content, Meat Quality, and Selenoprotein Gene Expression in Finishing Pigs

Prevotella copri Improves Selenium Deposition and Meat Quality in the longissimus dorsi Muscle of Fattening Pigs

Selenium is among the important trace elements that influence the quality of meat. Although it has been established that the gut microbiota is closely associated with selenium metabolism, it has yet to be determined whether these microbes influence the accumulation of selenium in muscles. To identify gut microbiota that potentially influence the deposition of selenium in muscles, we compared the colonic microbial composition of pigs characterized by high and low contents of selenium in the longissimus dorsi muscle and accordingly detected a higher abundance of the bacterium Prevotella copri (P. copri) in pigs with a higher muscle selenium content. To verify the effect of P. copri, 16 pigs weighing approximately 61 kg were fed either a basal diet or a basal diet supplemented with P. copri (1.0 × 1010 CFU/kg feed) for 45 days. The results revealed significant increases in the contents of selenium and selenoprotein in the serum and longissimus dorsi muscle of fattening pigs fed the P. copri-supplemented diet. Moreover, supplementing the feed of pigs with P. copri was observed to promote significant improvement in the antioxidant capacity and quality of meat, including drip loss, pH, and meat color. In conclusion, our findings in this study indicate that P. copri has potential utility as a dietary supplement for improving the selenium status and meat quality in fattening pigs.

Synthesis of glucosamine-selenium compound and evaluation of its oral toxicity and in vitro anti-hepatitis B virus activity

Selenium supplements are beneficial to human health, however, concerns regarding the toxicity of inorganic selenium have stimulated research on safer organic compounds. The main objective of this study was to develop a novel glucosamine-selenium compound (Se-GlcN), clarify its structure, and subsequently investigate its oral toxicity and in vitro anti-hepatitis B virus (HBV) activity. Electron microscopy, infrared, ultraviolet spectroscopy, nuclear magnetic resonance and thermogravimetric analyses revealed a unique binding mode of Se-GlcN, with the introduction of the Se-O bond at the C6 position, resulting in the formation of two carboxyl groups. In acute toxicity studies, the median lethal dose (LD50) of Se-GlcN in ICR mice was 92.31 mg/kg body weight (BW), with a 95 % confidence interval of 81.88-104.07 mg/kg BW. A 30-day subchronic toxicity study showed that 46.16 mg/kg BW Se-GlcN caused livers and kidneys damage in mice, whereas doses of 9.23 mg/kg BW and lower were safe for the livers and kidneys. In vitro studies, Se-GlcN at 1.25 μg/mL exhibited good anti-HBV activity, significantly reducing HBsAg, HBeAg, 3.5 kb HBV RNA and total HBV RNA by 45 %, 54 %, 84 %, 87 %, respectively. In conclusion, the Se-GlcN synthesized in this study provides potential possibilities and theoretical references for its use as an organic selenium supplement.

Inhibitory effects of glutathione peroxidase on microbial spoilage of crayfish (Procambarus clarkii) during refrigerated storage

The variety of enzyme-based biological preservatives is limited. This study evaluated the effects of glutathione peroxidase (GSH-Px) on the quality of crayfish during refrigerated storage by measuring the pH, total volatile basic nitrogen, trimethylamine, and microbial contamination in crayfish muscle simulation system. The results revealed that 0.3% GSH-Px (CK3) not only suppressed the degradation of nitrogenous substances but also decreased the contamination levels of total viable, Enterobacteriaceae, and Pseudomonas counts (P < 0.05). Furthermore, the populations of Lactococcus, Aeromonas, and Massilia differed in the CK3 group compared to the other groups (P < 0.05) at the end of the storage (day 15). Moreover, the principal coordinate analysis showed that the colony composition of CK3 stored for 15 days was similar to that of the control group stored for 10 days. Therefore, GSH-Px exhibits antibacterial activity against Gram-negative bacteria and has good application potential in freshwater aquatic product preservation.

Exploring effects of organic selenium supplementation on pork loin: Se content, meat quality, antioxidant capacity, and metabolomic profiling during storage

This research was conducted to study the effects of organic selenium (Se) supplements at different levels on pork loin quality during storage. Fifteen pork loins were procured randomly from three groups, Con (fed basal diet), Se15 (fed 0.15 ppm organic Se along with 0.10 ppm inorganic Se), and Se45 (fed 0.45 ppm organic Se along with 0.10 ppm inorganic Se). Each sample was analyzed for Se contents, antioxidant properties (glutathione peroxidase [GPx] activity, 2,2'-azinobis-[3-ethylbenzothiazoline-6-sulfonic acid] [ABTS] and 2,2-diphenyl-1-picrylhydrazyl [DPPH] radical scavenging activities, 2-thiobarbituric acid reactive substances), physicochemical properties (water holding capacity, pH, color), and metabolomic analysis during 14-day storage period. Se45-supplemented group showed significantly higher Se contents and GPx activity than the other groups throughout the storage period. However, other antioxidant properties were not significantly affected by Se supplementation. Selenium supplementation did not have an adverse impact on physicochemical properties. Nuclear Magnetic Resonance-based metabolomic analysis indicated that the selenium supply conditions were insufficient to induce metabolic change. These results suggest that organic Se (0.15 and 0.45 ppm) can accumulate high Se content in pork loins without compromising quality.

Se-methylselenocysteine ameliorates mitochondrial function by targeting both mitophagy and autophagy in the mouse model of Alzheimer's disease

Background: Alzheimer's disease (AD) exerts tremendous pressure on families and society due to its unknown etiology and lack of effective treatment options. Our previous study had shown that Se-methylselenocysteine (SMC) improved the cognition and synaptic plasticity of triple-transgenic AD (3 × Tg-AD) mice and alleviated the related pathological indicators. We are dedicated to investigating the therapeutic effects and molecular mechanisms of SMC on mitochondrial function in 3 × Tg-AD mice. Methods: Transmission electron microscopy (TEM), western blotting (WB), mitochondrial membrane potential (ΔΨm), mitochondrial swelling test, and mitochondrial oxygen consumption test were used to evaluate the mitochondrial morphology and function. Mitophagy flux and autophagy flux were assessed with immunofluorescence, TEM and WB. The Morris water maze test was applied to detect the behavioral ability of mice. Results: The destroyed mitochondrial morphology and function were repaired by SMC through ameliorating mitochondrial energy metabolism, mitochondrial biogenesis and mitochondrial fusion/fission balance in 3 × Tg-AD mice. In addition, SMC ameliorated mitochondria by activating mitophagy flux via the BNIP3/NIX pathway and triggering autophagy flux by suppressing the Ras/Raf/MEK/ERK/mTOR pathway. SMC remarkably increased the cognitive ability of AD mice. Conclusions: This research indicated that SMC might exert its therapeutic effect by protecting mitochondria in 3 × Tg-AD mice.

Precise Determination of Selenium Forms and Contents in Selenium-Enriched Rapeseed Seedlings and Flowering Stalks by HPLC-ICP-MS

Rapeseed (Brassica napus L.) has the ability of selenium (Se) enrichment. Identification of selenides in Se-rich rapeseed products will promote the development and utilization of high value. By optimizing the Se species extraction process (protease type, extraction reagent, enzyme sample ratio, extraction time, etc.) and chromatographic column, an efficient, stable, and accurate method was established for the identification of Se species and content in rapeseed seedlings and flowering stalks, which were cultured by inorganic Se hydroponics. Five Se compounds, including selenocystine (SeCys2), methylselenocysteine (MeSeCys), selenomethionine (SeMet), selenite (SeIV), and selenate (SeVI) were qualitatively and quantitatively identified. Organoselenium was absolutely dominant in both seedlings and flowering stalks among the detected rapeseed varieties, with 64.18-90.20% and 94.38-98.47%, respectively. Further, MeSeCys, a highly active selenide, predominated in rapeseed flowering stalks with a proportion of 56.36-72.93% and a content of 1707.3-5030.3 μg/kg. This study provides a new source of MeSeCys supplementation for human Se fortification.

Cadmium as a male reproductive toxicant and natural and non-natural ways to tackle it: a review

Cadmium (Cd) is a naturally occurring environmental pollutant, a toxic substance that causes oxidative stress. According to epidemiological studies, the data suggested that environmental and occupational Cd exposure may be related to several diseases and severe testicular damage. However, studies are going on to explore the mechanism of Cd-induced male reproductive toxicity and its treatment strategies. Currently, researchers are focusing on naturally occurring bioactive compounds, plant extracts, and biochemical, which have better efficacy, less toxicity, and high bioavailability. This review focuses on the mechanistic effect of Cd on testicular toxicity and different categories of compounds having a beneficial impact on Cd-induced male reproductive toxicity. Some potent bioactive antioxidants are quercetin, caffeic acid phenethyl ester, cyanidin-3-O-glucoside, curcumin, and silymarin. In comparison, plant extracts are Costus afer leaf methanol extract, methanol root extract of Carpolobia lutea, red carrot methanolic extract, Panax ginseng extract, and biochemicals including melatonin, progesterone, glutamine, L-carnitine, and selenium. Advanced and more detailed studies are needed on these compounds to explore their mechanism in attenuating Cd-induced testicular toxicity and can be potential therapeutics in the future.

Selenium yeast improve growth, serum biochemical indices, metabolic ability, antioxidant capacity and immunity in black carp Mylopharyngodnpiceus

This experiment was conducted to investigate the impacts of dietary selenium yeast (SeY) on the growth performance, fish body composition, metabolic ability, antioxidant capability, immunity and inflammatory responses in juvenile black carp (Mylopharyngodn piceus). The base diet was supplemented with 0.00, 0.30 and 0.60 g/kg SeY (0.04, 0.59 and 1.15 mg/kg of selenium) to form three isonitrogenous and isoenergetic diets for juvenile black carp with a 60-day. Adequate dietary SeY (0.30 and 0.60 g/kg) could significantly increase the weight gain (WG), special growth rate (SGR) compared to the SeY deficient groups (0.00 g/kg) (P < 0.05). Meanwhile, 0.30 and 0.60 g/kg SeY elevated the mRNA levels of selenoprotein T2 (SEPT2), selenoprotein H (SEPH), selenoprotein S (SEPS) and selenoprotein M (SEPM) in the liver and intestine compared with the SeY deficient groups (P < 0.05). Adequate dietary SeY could promote glucose catabolism and utilization through activating glucose transport (GLUT2), glycolysis (GCK, HK, PFK, PK, PDH), tricarboxylic acid cycle (ICDH and MDH), glycogen synthesis (LG, GCS and GBE) and IRS/PI3K/AKT signal pathway molecules (IRS2b, PI3Kc and AKT1) compared with the SeY deficient groups (P < 0.05). Similarly, adequate dietary SeY could improve lipid transport and triglycerides (TG) synthesis through increasing transcription amounts of CD36, GK, DGAT, ACC and FAS in the fish liver compared with the SeY deficient groups (P < 0.05). In addition, adequate SeY could markedly elevate activities of antioxidant enzymes (T-SOD, CAT, GR, GPX) and contents of T-AOC and GSH, while increased transcription amounts of Nrf2, Cu/Zn-SOD, CAT, and GPX in fish liver and intestine (P < 0.05). However, adequate SeY notably decreased contents of MDA, and the mRNA transcription levels of Keap1 in the intestine compared with the SeY deficient groups (P < 0.05). Adequate SeY markedly increased amounts or levels of the immune factors (ALP, ACP, LZM, C3, C4 and IgM) and the transcription levels of innate immune-related functional genes in the liver and intestine (LZM, C3 and C9) compared to the SeY deficient groups (P < 0.05). Moreover, adequate SeY could notably reduce levels of IL-8, IL-1β, and IFN-γ and elevate TGF-1β levels in fish intestine (P < 0.05). The transcription levels of MAPK13, MAPK14 and NF-κB p65 were notably reduced in fish intestine treated with 0.30 and 0.60 g/kg SeY (P < 0.05). In conclusion, these results suggested that 0.30 and 0.60 g/kg SeY could not only improve growth performance, increase Se, glucose and lipid metabolic abilities, enhance antioxidant capabilities and immune responses, but also alleviate inflammation, thereby supplying useful reference for producing artificial feeds in black carp.

Trace Minerals in Laying Hen Diets and Their Effects on Egg Quality

With the advancement in the egg industry sector, egg quality has assumed great significance in certain countries. Enhancements in the nutritional value of eggs may have direct affirmative consequences for daily nutrient intake and therefore for human health. Thus, affirmative improvement in egg quality boosts consumer preferences for eggs. Also, the improvement in eggshell quality can avoid the disposal of broken eggs and consequently economic losses. Therefore, poultry nutrition and mineral supplements have a significant impact on egg quality. Minerals are crucial in poultry feed for a number of biological processes, including catalytic, physiologic, and structural processes. For instance, they contribute to the biological processes necessary for forming and developing eggshells. To produce high-quality eggs for sale, diets must therefore contain the right amount of minerals. This review aims to highlight the role of both organic and inorganic minerals in improving egg quality, in addition to reviewing the interactions of mineral supplements with intestinal microbiota and subsequent effects on the egg quality.

Effect of Prepartum Maternal Supplementation with Diphenyl Diselenide on Biochemical, Immunological, and Oxidative Parameters of the Offspring

This study aimed to assess the impact of prepartum maternal diphenyl diselenide (PhSe)2 supplementation on the development, biochemical, immune, and antioxidant parameters of calves. Eighteen Holstein breed calves were used, born to females who were or were not subjected to supplementation, at 42, 28, and 14 days prior to calving. The (PhSe)2 group (DDG) was administered 3 μmol/kg of (PhSe)2 in 4 mL of dimethyl sulfoxide (DMSO), while the DMSO and NaCl groups were administered 4 mL of DMSO and 0.9% NaCl, subcutaneously. The calves were evaluated based on their weight, withers height, body condition score 24 h post-birth (0), as well on days 14, 28, 42, 56, 70. Blood samples were also taken to determine serum variables. Calves on the DDG showed higher average levels of total protein, albumin, and globulins on day 0, and the immunoglobulin G level was significantly higher than the other groups on days 0, 14, 56, 70. Maternal supplementation showed immunomodulatory effect on calves, evidenced by the exceptional rates of passive immunity transfer, as well as the enhancement of humoral immunity. Our research offers fresh insights into the immunomodulatory potential of (PhSe)2, making it a viable alternative in facing this challenging phase, rearing dairy calves.

Research Progress of Selenium-Enriched Foods

Selenium is an essential micronutrient that plays a crucial role in maintaining human health. Selenium deficiency is seriously associated with various diseases such as Keshan disease, Kashin-Beck disease, cataracts, and others. Conversely, selenium supplementation has been found to have multiple effects, including antioxidant, anti-inflammatory, and anticancer functions. Compared with inorganic selenium, organic selenium exhibits higher bioactivities and a wider range of safe concentrations. Consequently, there has been a significant development of selenium-enriched foods which contain large amounts of organic selenium in order to improve human health. This review summarizes the physiological role and metabolism of selenium, the development of selenium-enriched foods, the physiological functions of selenium-enriched foods, and provides an analysis of total selenium and its species in selenium-enriched foods, with a view to laying the foundation for selenium-enriched food development.

Advances in selenium supplementation: From selenium-enriched yeast to potential selenium-enriched insects, and selenium nanoparticles

Selenium (Se) is an essential micronutrient that plays an important role in animal and human development and physiological homoeostasis. This review surveys the role of Se in the environment, plants and animal bodies, and discusses data on Se biofortification with different sources of supplementation, from inorganic to organic forms, with special focus on Se-enriched yeast (Se-yeast). Although Se-yeast remains one of the main sources of organic Se, other emerging and innovative sources are reviewed, such as Se-enriched insects and Se-nanoparticles and their potential use in animal nutrition. Se-enriched insects are discussed as an option for supplying Se in organic form to livestock diets. Se-nanoparticles are also discussed, as they represent a more biocompatible and less toxic source of inorganic Se for animal organisms, compared to selenite and selenate. We also provide up to date information on the legal framework in the EU, USA, and Canada of Se that is contained in feed additives. From the scientific evidence available in the literature, it can be concluded that among the inorganic forms, sodium selenite is still one of the main options, whereas Se-yeast remains the primary organic form. However, other potential sources such as Se-enriched insects and Se-nanoparticles are being investigated as they could potentially combine a high bioavailability and reduced Se emissions in the environment.

Gut Health and Influencing Factors in Pigs

The gastrointestinal tract (GIT) is a complex, dynamic, and critical part of the body, which plays an important role in the digestion and absorption of ingested nutrients and excreting waste products of digestion. In addition, GIT also plays a vital role in preventing the entry of harmful substances and potential pathogens into the bloodstream. The gastrointestinal tract hosts a significant number of microbes, which throughout their metabolites, directly interact with the hosts. In modern intensive animal farming, many factors can disrupt GIT functions. As dietary nutrients and biologically active substances play important roles in maintaining homeostasis and eubiosis in the GIT, this review aims to summarize the current status of our knowledge on the most important areas.

Serine Administration Improves Selenium Status, Oxidative Stress, and Mitochondrial Function in Longissimus Dorsi Muscle of Piglets with Intrauterine Growth Retardation

Intrauterine growth retardation (IUGR) causes oxidative stress in the skeletal muscle. Serine and selenoproteins are involved in anti-oxidative processes; however, whether IUGR affects selenium status and whether serine has beneficial effects remain elusive. Here, we investigated the effects of serine administration on selenium nutritional status and oxidative stress in the longissimus dorsi muscle of piglets with IUGR. Six newborn Min piglets having normal birth weight were administered saline, and 12 IUGR piglets were either administered saline or 0.8% serine. The results showed a lower selenium content in skeletal muscle in IUGR piglets, which was restored after serine administration. IUGR piglets showed a disturbed expression of genes encoding selenoproteins, with decreased expression of GPX2, GPX4, TXNRD1, and TXNRD3 and increased expression of DIO1, DIO2, SELF, SELM, SELP, and SELW. Notably, serine administration restored the expression levels of these genes. In accordance with the changes in gene expression, the activity of GPX, TXNRD, and DIO and the content of GSH and SELP were also altered, whereas serine administration restored their contents and activities. Moreover, we observed severe oxidative stress in the skeletal muscle of IUGR piglets, as indicated by decreased GSH content and increased MDA and PC content, whereas serine administration alleviated these changes. In conclusion, our results indicate that IUGR piglets showed a disturbed expression of genes encoding selenoproteins, accompanied by severe oxidative stress. Serine administration can improve selenium status, oxidative stress, and mitochondrial function in the longissimus dorsi muscle of piglets with IUGR. These results suggest that serine could potentially be used in the treatment of IUGR in piglets.

Effects of organic and inorganic selenium on selenium bioavailability, growth performance, antioxidant status and meat quality of a local beef cattle in China

Selenium (Se) is an essential nutrient with multiple health benefits to humans and animals. Cattle generally require dietary Se supplementation to meet their daily requirements. The two main forms of dietary Se in cattle are organic Se and inorganic Se. Data comparing the health and productivity effects of organic Se and inorganic Se on cattle are still insufficient, and it is necessary to conduct more research to evaluate the bioavailability, nutritional value, deposition, and body functions of Se sources in different breeds and physiological stages of cattle raised in areas with different Se levels. The objectives of this study were to determine the effects of organic and inorganic sources of Se on plasma biochemical indices, Se bioavailability, deposition in body tissues and organs, growth performance, antioxidant capacity and meat quality of beef cattle raised in Se-deficient areas. Fifteen Chinese Xiangzhong Black beef cattle with an average weight of 254.5 ± 8.85 kg were assigned to three dietary groups. The three groups were fed the same basal ration and supplemented with either an inorganic [sodium selenite (SS)] or organic [selenomethionine (SM) or Se-enriched yeast (SY)] source of Se (0.1 mg/kg dry matter) for 60 days. At the end of the experiment, three cattle from each group were randomly selected and slaughtered, and samples were collected from tissues and organs for analysis. The results revealed that growth performance, slaughter performance, Se content of tissues and organs, meat quality characteristics including chemical composition, pH_45min, pH_24h, drip loss, and cooking losses did not differ (p > 0.05) due to supplementation of the different organic and inorganic sources of Se. SM and SY were more effective in increasing (p < 0.05) immunoglobulin M (IgM) concentrations in the blood and reducing (p < 0.05) malondialdehyde (MDA) content in the longissimus dorsi than SS. In conclusion, organic Se is more effective than inorganic Se in improving the immune and antioxidant capacity of Chinese Xiangzhong Black beef cattle.

New horizons for selenium in animal nutrition and functional foods

Selenium (Se), one of the indispensable nutrients for both human health and animal growth, participates in various physiological functions, such as antioxidant and immune responses and metabolism. The role of dietary Se, in its organic and inorganic forms, has been well documented in domestic animals. Furthermore, many feeding strategies for different animals have been developed to increase the Se concentration in animal products to address Se deficiency and even as a potential nutritional strategy to treat free radical-associated diseases. Nevertheless, studies on investigating the optimum addition of Se in feed, the long-term consequences of Se usage in food for animal nutrition, the mechanism of metallic Se nanoparticle (SeNP) transformation in vivo, and the nutritional effects of SeNPs on feed workers and the environment are urgently needed. Starting from the absorption and metabolism mechanism of Se, this review discusses the antioxidant role of Se in detail. Based on this characteristic, we further investigated the application of Se in animal health and described some unresolved issues and unanswered questions warranting further investigation. This review is expected to provide a theoretical reference for improving the quality of food animal meat as well as for the development of Se-based biological nutrition enhancement technology.

Maternal organic selenium supplementation during gestation enhances muscle fiber area and muscle fiber maturation of offspring in porcine model

Background

Organic selenium supplementation during gestation improves the antioxidant status and reproductive performance of sows and increases the antioxidative capacity of the intestines of their offspring. This study was conducted to investigate the effect of maternal basel diet (control) supplemented with an organic Se, 2-hydroxy-4-methylselenobutanoic acid (HMSeBA), or inorganic sodium selenite (Na₂SeO₃) during gestation on the antioxidant status and development of muscle in newborn and weaned piglets. Newborn piglets before colostrum intake and weaned piglets were selected for longissimus dorsi (LD) muscle collection and analysis.

Results

The results showed that maternal HMSeBA supplementation increased the muscle area and content of Se in the LD muscle of newborn piglets, improved gene expression of selenoproteins, and decreased oxidative status in the LD muscle of both newborn and weaned piglets compared with the control. The expression of muscle development-related genes of newborn piglets in the HMSeBA group was lower than in the control group, whereas the expression of MRF4 in weaned piglets was higher in the HMSeBA group than in the control and Na₂SeO₃ groups. In addition, HMSeBA supplementation decreased the mRNA expressions of myosin heavy chains (MyHC) IIx and MyHC IIb and the percentage of MyHC IIb; increased the expression of PGC-1α in the LD muscle of newborn piglets; increased the gene expression of MyHC IIa; and decreased the protein expression of slow MyHC and the activity of malate dehydrogenase in the LD muscle of weaned piglets compared with the control group.

Conclusions

Maternal HMSeBA supplementation during gestation can improve the antioxidative capacity of the muscle of their offspring and promote the maturity of muscle fibres in weaned offspring.

Selenium-Enriched Mushroom Powder Enhances Intestinal Health and Growth Performance in the Absence of Zinc Oxide in Post-Weaned Pig Diets

This study was conducted to examine the effects of varying selenium (Se) inclusion levels, in the form of Se-enriched mushroom powder (SeMP) and selenite, on post-weaning growth performance (Period 1; day 1−21), intestinal health and antioxidant capacity (Period 2; day 21−39). Weaned pigs were blocked according to live weight, sex and litter of origin and randomly assigned to the following experimental groups: basal (basal + selenite (0.3 ppm Se)); ZnO (basal + ZnO + selenite (0.3 ppm Se)); 0.15 SeMP (basal + SeMP (0.15 ppm Se)); 0.3 SeMP (basal + SeMP (0.3 ppm Se)) and 0.6 SeMP/Sel (basal + SeMP (0.3 ppm Se) + selenite (Sel) (0.3 ppm Se)) with eight replicates/experimental group. After 21 days, the ZnO experimental group was removed from the experiment and the remaining pigs continued on their respective diet until day 39 post-weaning (Period 2). In Period 1, 0.15 SeMP supplementation reduced (p < 0.05) average daily gain (ADG), average daily feed intake (ADFI) and day 21 body weight, and increased (p < 0.05) faecal scores compared to the ZnO group. Supplementation with 0.3 SeMP and 0.6 SeMP/Sel during Period 1 resulted in similar (p > 0.05) ADG, ADFI, gain-to-feed ratio (G:F) and body weight compared to the ZnO group. However, 0.6 SeMP/Sel supplementation increased (p < 0.05) faecal scores compared to the ZnO group. In Period 2, 0.6 SeMP/Sel increased (p < 0.05) ADG, feed efficiency and day 39 body weight compared to the basal group. Supplementation with Se-enriched mushroom powder, at all inclusion levels, increased (p < 0.05) the abundance of Prevotellaceae and Prevotella, decreased (p < 0.05) the abundance of Sporobacter and increased (p < 0.05) the expression of SELENOP in the jejunum compared to the basal group. Lactobacillaceae and Lactobacillus was increased (p < 0.05) in 0.15 SeMP and 0.3 SeMP pigs compared to the basal group. Selenium deposition in muscle and liver tissue increased (p < 0.001) as a function of inclusion level while pigs supplemented with 0.3 ppm organic Se (0.3 SeMP) had an increase (p < 0.05) in total Se in the muscle compared to pigs supplemented with 0.3 ppm inorganic Se (basal). In conclusion, 0.3 SeMP supplementation led to positive effects on faecal scores and had similar pig performance compared to ZnO in Period 1, while the addition of 0.3 ppm selenite to 0.3 SeMP (0.6 SeMP/Sel) in Period 2 led to enhanced pig performance and aspects of gastrointestinal health.

Dietary Selenium Across Species

This review traces the discoveries that led to the recognition of selenium (Se) as an essential nutrient and discusses Se-responsive diseases in animals and humans in the context of current understanding of the molecular mechanisms of their pathogeneses. The article includes a comprehensive analysis of dietary sources, nutritional utilization, metabolic functions, and dietary requirements of Se across various species. We also compare the function and regulation of selenogenomes and selenoproteomes among rodents, food animals, and humans. The review addresses the metabolic impacts of high dietary Se intakes in different species and recent revelations of Se-metabolites, means of increasing Se status, and the recycling of Se in food systems and ecosystems. Finally, research needs are identified for supporting basic science and practical applications of dietary Se in food, nutrition, and health across species. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Label-Free Mass Spectrometry-Based Proteomic Analysis in Lamb Tissues after Fish Oil, Carnosic Acid, and Inorganic Selenium Supplementation

Simple Summary

Advances in proteomics and bioinformatics analysis offer the potential to investigate nutrients’ influence on protein expression profiles, and consequently on biological processes, molecular functions, and cellular components. However, knowledge in this area, particular about the exact way selenium modulates protein expression, remains limited. Therefore, in this project, global differential proteomic experiments were carried out in order to identify changes in the expression of proteins in animal tissues obtained from lambs on a specific diet involving the addition of a combination of different supplements, namely, inorganic selenium compounds, fish oil, and carnosic acid. Following inorganic selenium supplementation, a protein-protein interaction network analysis of forty differentially-expressed proteins indicated two significant clusters.

Abstract

Selenium is an essential nutrient, building twenty five identified selenoproteins in humans known to perform several important biological functions. The small amount of selenium in the earth’s crust in certain regions along with the risk of deficiency in organisms have resulted in increasingly popular dietary supplementation in animals, implemented via, e.g., inorganic selenium compounds. Even though selenium is included in selenoproteins in the form of selenocysteine, the dietary effect of selenium may result in the expression of other proteins or genes. Very little is known about the expression effects modulated by selenium. The present study aimed to examine the significance of protein expression in lamb tissues obtained after dietary supplementation with selenium (sodium selenate) and two other feed additives, fish oil and carnosic acid. Label-free mass spectrometry-based proteomic analysis was successfully applied to examine the animal tissues. Protein-protein interaction network analysis of forty differently-expressed proteins following inorganic selenium supplementation indicated two significant clusters which are involved in cell adhesion, heart development, actin filament-based movement, plasma membrane repair, and establishment of organelle localization.

The health benefits of selenium in food animals: a review

Selenium is an essential trace mineral important for the maintenance of homeostasis in animals and humans. It evinces a strong antioxidant, anti-inflammatory and potential antimicrobial capacity. Selenium biological function is primarily achieved by its presence in selenoproteins as a form of selenocysteine. Selenium deficiency may result in an array of health disorders, affecting many organs and systems; to prevent this, dietary supplementation, mainly in the forms of organic (i.e., selenomethionine and selenocysteine) inorganic (i.e., selenate and selenite) sources is used. In pigs as well as other food animals, dietary selenium supplementation has been used for improving growth performance, immune function, and meat quality. A substantial body of knowledge demonstrates that dietary selenium supplementation is positively associated with overall animal health especially due to its immunomodulatory activity and protection from oxidative damage. Selenium also possesses potential antiviral activity and this is achieved by protecting immune cells against oxidative damage and decreasing viral replication. In this review we endeavor to combine established and novel knowledge on the beneficial effects of dietary selenium supplementation, its antioxidant and immunomodulatory actions, and the putative antimicrobial effect thereof. Furthermore, our review demonstrates the gaps in knowledge pertaining to the use of selenium as an antiviral, underscoring the need for further in vivo and in vitro studies, particularly in pigs.

Multi-Omics Profiling Reveals Se Deficiency-Induced Redox Imbalance, Metabolic Reprogramming, and Inflammation in Pig Muscle

BACKGROUND

Nutritional muscle dystrophy is associated with selenium (Se) deficiency; however, the underlying mechanism remains unclear.

OBJECTIVES

This study aimed to understand the crosstalk among redox status, energy metabolism, and inflammation in nutritional muscle dystrophy induced by dietary Se deficiency.

METHODS

Eighteen castrated male pigs (Yorkshire, 45 d old) were fed Se-deficient (Se-D; 0.007 mg Se/kg) or Se-adequate (Se-A; in the form of selenomethionine, 0.3 mg Se/kg) diets for 16 wk. The muscle Se concentrations; antioxidant capacity; and gene expression, transcriptome, global proteome, metabolome, and lipidome profiles were analyzed. The transcriptome, metabolome, and proteome profiles were analyzed with biostatistics, bioinformatics, and pathway enrichment analysis; other data were analyzed with Student's 2-sided t tests.

RESULTS

The muscle Se content in the Se-D group was 96% lower than that in the Se-A group (P < 0.05). The activity of glutathione peroxidase (GPX) and thioredoxin reductase (TXNRD) in the Se-D group was 42%-69% lower than that in the Se-A group (P < 0.05). The mRNA levels of 10 selenoprotein genes were 25%-84% lower than those in the Se-A group (P < 0.05). Multi-omics analyses indicated that the levels of 1378 transcripts, 83 proteins, 22 metabolites, and 55 lipid molecules were significantly altered in response to Se deficiency. Se deficiency-induced redox imbalance led to muscle central carbon and lipid metabolism reprogramming, which enhanced the glycolysis pathway and decreased phospholipid synthesis. Inflammation and apoptosis were observed in response to Se deficiency-induced muscle oxidative stress, which may have been associated with extracellular matrix (ECM) remodeling, suppressed focal adhesion and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling, and activation of the NF-κB signaling pathway.

CONCLUSIONS

These results contributed to understanding the crosstalk among redox, energy metabolism, and inflammation in Se deficiency-induced muscle dystrophy in pigs, and may provide intervention targets for muscle disease treatment.

Selenium-enriched Polysaccharide: an Effective and Safe Selenium Source of C57 Mice to Improve Growth Performance, Regulate Selenium Deposition, and Promote Antioxidant Capacity

Selenium-enriched polysaccharide (SeEPS) was prepared by reducing Se(IV) to elemental selenium and organic selenium in polysaccharide medium by the obtained Enterobacter cloacae strain Z0206 under aerobic conditions. In the present study, we focused on investigating the role of short-term supplementation of SeEPS at supernutritional doses in the regulation of growth performance, liver damage, antioxidant capacity, and selenium (Se) accumulation in C57 mice. Thirty-two C57 mice were randomly divided into four groups: the control group was gavaged with equal volume of phosphate-buffered saline, while the sodium selenite (Na2SeO3), selenomethionine (SeMet), and SeEPS groups were gavaged with 0.5 mg Se/kg BW of Na2SeO3, SeMet, and selenium-enriched polysaccharide (n = 8), respectively. We examined liver injury indicators, antioxidant capacity in the serum and liver, selenium deposition at different sites, selenoprotein levels, and selenocysteine-synthesizing and degradation-associated gene expression in mouse livers. SeEPS supplementation dramatically increased average daily weight gain but reduced the feed-to-gain ratio (F/G) of mice (P < 0.05). Compared to Na2SeO3 and SeMet supplementation, SeEPS supplementation at supernutritional doses did not cause the liver damage. SeEPS supplementation also markedly enhanced total antioxidant capacity (T-AOC), catalase (CAT), glutathione peroxidase (GSH-PX), and total superoxide dismutase (T-SOD) activities but reduced malondialdehyde (MDA) levels in the liver and serum (P < 0.05), while significantly increasing selenocysteine-synthesizing and degradation-related gene (SEPHS2, SEPSECS, Secisbp, Scly) expression at the mRNA level (P < 0.05), thus upregulating the mRNA levels of selenoproteins (SELENOP, SELENOK) (P < 0.05). We suggest that SeEPS could be a potential replacement for inorganic selenium to improve animals' growth performance, promote antioxidant capacity, and regulate selenium deposition.

HSF1-SELENOS pathway mediated dietary inorganic Se-induced lipogenesis via the up-regulation of PPARγ expression in yellow catfish

At present, studies involved in the effects of dietary Se sources on lipid metabolism were very scarce and the underlying mechanism remains unknown. Previous studies reported that dietary Se sources differentially affected selenoprotein S (SELENOS) expression and SELENOS affected lipid metabolism via the inositol-requiring enzyme 1α (IRE1α)- spliced X-box binding protein 1 (XBP1s) pathway. Thus, we used yellow catfish as an experimental model to explore whether dietary selenium sources affected the hepatic lipid metabolism, and further determined the role of SELENOS-IRE1α-XBP1s pathway in dietary selenium sources affecting hepatic lipid metabolism. Compared with the selenomethionine (S-M) group, sodium selenite (SS) group possessed higher liver triglycerides (TGs) (34.7%), lipogenic enzyme activities (57.9-70.6%), and lower antioxidant enzyme activities (23.3-35.5%), increased protein levels of heat shock transcription factor 1 (HSF1) and SELENOS (1.17-fold and 47.4%, respectively), and XBP1s- peroxisome proliferators-activated receptor γ (PPARγ) pathway. Blocking SELENOS and PPARγ by RNA interference demonstrated that the SELENOS/XBP1s/PPARγ axis was critical for S-S-induced lipid accumulation. Moreover, S-S-induced upregulation of SELENOS was via the increased DNA binding capacity of HSF1 to SELENOS promoter, which activated the XBP1s/PPARγ pathway and promoted lipogenesis and lipid accumulation. XBP1s is required for S-S-induced upregulation of PPARγ expression. Our finding elucidated the mechanism of dietary Se sources affecting the lipid metabolism in the liver of yellow catfish and demonstrated novel function of SELENOS in metabolic regulation. Our study also suggested that seleno-methionine was a better Se source than selenite against abnormal lipid deposition in the liver of yellow catfish.

A naphthimide fluorescent probe for the detection of selenols in selenium-enriched Tan sheep

An "off-on" fluorescent probe, Nap-DNB, which is based on naphthimide, was designed and developed for the detection of biological selenols in vitro. We have adopted a combination of a low-pH detection environment and reaction sites that are more difficult to destroy to avoid the interference of a large number of biological thiols in biological samples. Nap-DNB can completely respond to selenocysteine within 15 mins, with a detection limit of 92 nM. Nap-DNB was successfully used for the detection of selenols in the serum, liver, and longissimus dorsi of selenium-enriched Tan sheep. Through comparison, we found that the detection of selenols by the Nap-DNB is similar to that by thioredoxin reductase and glutathione peroxidase in a commercial kit method. Nap-DNB can be used for the detection of selenols in selenium-enriched Tan sheep.

Serine Supplementation in the Diets of Late Gestating and Lactating Sows Improves Selenium Nutritional Status in Sows and Their Offspring

Serine can regulate selenoprotein expression, and dietary serine is correlated with the contents of plasma selenoprotein P (Sepp1) and milk selenium (Se) in lactating mothers. Based on this, we investigated the effects of serine supplementation in the diets of late gestating and lactating sows on Sepp1 and Se contents in sows and their offspring. A total of 72 sows were assigned to four groups. During the experiment, sows were fed either a basal diet or basal diets supplemented with three different levels of serine. The results showed that maternal dietary serine had no effect on the Se content in the serum of sows and their offspring, whereas it significantly increased the Se content in the liver of piglets at the age of 21 days. Maternal dietary serine significantly increased Sepp1 content, either in the serum of sows or that in their offspring at the ages of 3 days, 7 days, and 21 days. Additionally, maternal dietary serine significantly increased litter weight and the average body weight of piglets at the age of 11 days. Notably, a positive correlation was found between the average body weight of piglets at the age of 11 days and serum Sepp1 content in piglets, at the age of either 3 days or 7 days. In conclusion, maternal dietary serine supplementation could improve Se nutritional status in sows and their offspring. These beneficial changes may contribute to the higher body weight of the offspring.

Effects of Selenium Supplementation on Rumen Microbiota, Rumen Fermentation, and Apparent Nutrient Digestibility of Ruminant Animals: A Review

Enzymes excreted by rumen microbiome facilitate the conversion of ingested plant materials into major nutrients (e.g., volatile fatty acids (VFA) and microbial proteins) required for animal growth. Diet, animal age, and health affect the structure of the rumen microbial community. Pathogenic organisms in the rumen negatively affect fermentation processes in favor of energy loss and animal deprivation of nutrients in ingested feed. Drawing from the ban on antibiotic use during the last decade, the livestock industry has been focused on increasing rumen microbial nutrient supply to ruminants through the use of natural supplements that are capable of promoting the activity of beneficial rumen microflora. Selenium (Se) is a trace mineral commonly used as a supplement to regulate animal metabolism. However, a clear understanding of its effects on rumen microbial composition and rumen fermentation is not available. This review summarized the available literature for the effects of Se on specific rumen microorganisms along with consequences for rumen fermentation and digestibility. Some positive effects on total VFA, the molar proportion of propionate, acetate to propionate ratio, ruminal NH3-N, pH, enzymatic activity, ruminal microbiome composition, and digestibility were recorded. Because Se nanoparticles (SeNPs) were more effective than other forms of Se, more studies are needed to compare the effectiveness of synthetic SeNPs and lactic acid bacteria enriched with sodium selenite as a biological source of SeNPs and probiotics. Future studies also need to evaluate the effect of dietary Se on methane emissions.

Selenium can regulate the differentiation and immune function of human dendritic cells

Selenium is an essential trace element that can regulate the function of immnue cells via selenoproteins. However, the effects of selenium on human dendritic cell (DCs) remain unclear. Thus, selenoprotein levels in monocytes, immature DCs (imDCs) and mature DCs (mDCs) treated with or without Na₂SeO₃ were evaluated using RT-PCR, and then the immune function of imDCs and mDCs was detected by flow cytometry, cell counting and the CCK8 assay. In addition, the effects of Se on cytokine and surface marker expression were investigated by RT-PCR. The results revealed different expression levels of selenoprotein in monocytes, imDCs and mDCs, and selenoproeins could be regulated by Se. Moreover, it was indicated that anti-phagocytic activity was improved by 0.1 µM Se, whereas it was suppressed by 0.2 µM Se in imDCs; The migration of imDCs and mDCs was improved by 0.1 µM Se, whereas their migration was inhibited by treatment with 0.05 or 0.2 µM Se; The mixed lymphocyte reaction of mDCs was improved by 0.1 µM Se, and it was inhibited by 0.05 and 0.2 µM Se. In addition, 0.1 µM Se improved the immune function of DCs through the regulation of CD80, CD86, IL12-p35 and IL12-p40. Wheres 0.05 and 0.2 µM Se impaired immune function of DCs by up-regulation of interleukin (IL-10) in imDCs and down-regulation of CD80, CD86, IL12-p35 and IL12-p40 in mDCs. In conclusion, 0.1 µM Se might improve the immune function of human DCs through selenoproteins.

Hydroxy Selenomethionine Improves Meat Quality through Optimal Skeletal Metabolism and Functions of Selenoproteins of Pigs under Chronic Heat Stress

Chronic heat stress (CHS) induces metabolic changes in skeletal muscle from growth to maintenance that jeopardizes growth performance, carcass traits, and meat quality of pigs. We investigated the protective effect of dietary organic selenium (hydroxy-4-methylselenobutanoic acid, OH-SeMet) on CHS-induced skeletal muscle damages of growing pigs, and the corresponding responses of selenoproteins. A total of 40 ((Landrace ×Yorkshire) × Duroc) pigs with an average live weight of 49.64 ± 2.48 kg were used in this 4-week trial. Pigs were randomly allotted to 5 groups: The control group was raised on a basal diet in a thermoneutral environment (22 ± 2 °C); and four CHS groups were raised on a basal diet and supplemented with Se 0.0, 0.2, 0.4, and 0.6 mg/kg as OH-SeMet, respectively, in hyperthermal condition (33 ± 2 °C). CHS resulted in significant decrease of growth performance, carcass traits, and meat quality, which were associated with reduced (p < 0.05) serum alkaline phosphatase (ALP) and total superoxide dismutase (T-SOD) and increased (p < 0.05) serum creatine (CK), sarcous heat shock protein 70 (HSP70), glucokinase (GCK), phosphoenolpyruvate carboxykinase (PEPCK), and malondialdehyde (MDA) contents. Meanwhile, four metabolism-related genes and seven selenoprotein encoding genes were abnormally expressed in skeletal muscle. Dietary OH-SeMet addition partially alleviated the negative impact of CHS on carcass traits and improved meat quality. These improvements were accompanied by the increase in Se deposition, the anti-oxidative capacity of serum and muscle, and protein abundance of GPX1, GPX3, GPX4, and SELENOP. Supplementation with 0.6 mg Se/kg (OH-SeMet) restored the sarcous PEPCK, and 0.4 and 0.6 mg Se/kg (OH-SeMet) restored all abnormally expressed metabolism-related and selenoprotein encoding genes. In summary, dietary supplementation with OH-SeMet beyond Se requirement mitigated CHS-induced depression of carcass traits and meat quality of pigs associated with optimal skeletal metabolism, enhanced antioxidant capacity, and regulation of selenoproteins in skeletal muscle of pigs.

Effect of supplementing hydroxy selenomethionine on meat quality of yellow feather broiler

This study was conducted to evaluate the effect of supplementing hydroxy selenomethionine (OH-SeMet) on performance, selenium (Se) deposition in the breast muscle, quality and oxidative stability, and expression of selenoprotein encoding genes of breast meat of the native slow-growing yellow-feathered broiler birds. A total of 375 one-day-old local yellow male birds were randomly assigned into 5 dietary treatments, supplemented with Se 0.0, 0.2, 0.4, 0.6, and 0.8 mg/kg in the form of OH-SeMet. Each treatment consisted of 5 replicates and each replicate had 15 birds, the birds were fed on basal diet containing corn and soybean meal, and the experiment lasted for 63 d. The results showed that dietary Se supplementation linearly increased (P < 0.001) Se contents in both serum and muscle, no significant changes (P > 0.05) were observed on growth performance, yield of breast, meat color, and intramuscular fat deposition of the breast muscle. Dietary Se addition improved water-holding capacity, the pH_24h value, and tenderness of breast muscle, evidenced by a linear decreases of shear force (P < 0.05), accompanied by lower thiobarbituric acid reactive substances and higher glutathione reductase activity. The mRNA abundance of selenoprotein encoding genes also responded to dietary Se levels. It is concluded that, dietary supplementation with OH-SeMet improved muscular Se deposition and meat quality of the native yellow birds, with enhanced antioxidant capability and regulation in selenogenome.

Can selenium-enriched spirulina supplementation ameliorate sepsis outcomes in selenium-deficient animals?

In intensive care units, sepsis is the first cause of death. In this pathology, inflammation and oxidative status play a crucial role in patient outcomes. Interestingly, 92% of septic patients exhibit low selenium plasma concentrations (a component of antioxidant enzymes). Moreover, Spirulina platensis, a blue-green algae, demonstrated anti-inflammatory effects. In this context, the main purpose of our study was to analyze the effect of a selenium-enriched spirulina after a selenium deficiency on sepsis outcome in rats. Sixty-four rats were fed 12 weeks with a selenium-deficient food. After 8 weeks, rats were supplemented (via drinking water) for 4 weeks with sodium selenite (Se), spirulina (Spi), or selenium-enriched spirulina (SeSp). Sepsis was then induced by cecal ligature and puncture, and survival duration was observed. The plasma selenium concentration was measured by ICPMS. Expression of GPx1 and GPx3 mRNA was measured by RT-PCR. Blood parameters (lactates and HCO3- concentrations, pH, PO2 , and PCO2 ) were analyzed at 0, 1, and 2 h as well as inflammatory cytokines (IL-6, TNF-α, IL-10). Sodium selenite and SeSP supplementations restored plasma selenium concentration prior to sepsis. The survival duration of SeSP septic rats was significantly lower than that of selenium-supplemented ones. Gpx1 mRNA was increased after a selenium-enriched spirulina supplementation while Gpx3 mRNA levels remained unchanged. Furthermore, sodium selenite prevented sepsis-induced acidosis. Our results show that on a basis of a Se deficiency, selenium-enriched spirulina supplementations significantly worsen sepsis outcome when compared to Se supplementation. Furthermore, Se supplementation but not selenium-enriched spirulina supplementation decreased inflammation and restored acid-base equilibrium after a sepsis induction.

Selenogenome and AMPK signal insight into the protective effect of dietary selenium on chronic heat stress-induced hepatic metabolic disorder in growing pigs

BACKGROUND

Chronic heat stress (CHS) disrupts hepatic metabolic homeostasis and jeopardizes product quality of pigs. Selenium (Se) may regulate the metabolic state through affect selenoprotein. Thus, we investigate the protective effect of dietary hydroxy-4-methylselenobutanoic acid (HMSeBA) on CHS induced hepatic metabolic disorder in growing pigs, and the corresponding response of selenoprotein.

METHODS

Forty crossbreed growing pigs were randomly assigned to five groups: control group raised in the thermoneutral environment (22 ± 2 °C) with basal diet; four CHS groups raised in hyperthermal condition (33 ± 2 °C) with basal diet and supplied with 0.0, 0.2, 0.4, and 0.6 mg Se/kg HMSeBA, respectively. The trial lasted 28 d. The serum biochemical, hepatic metabolism related enzyme, protein and gene expression and 25 selenoproteins in liver tissue were determined by real-time PCR, ELISA and western blot.

RESULTS

CHS significantly increased the rectal temperature, respiration rate, serum aspartate aminotransferase (AST) and low-density lipoprotein cholesterol (LDL-C) of pigs, up-regulated hepatic heat shock protein 70 (HSP70) and induced lower liver weight, glycogen content, hepatic glucokinase and glutathione peroxidase (GSH-Px). The CHS-induced liver metabolic disorder was associated with the aberrant expression of 6 metabolism-related gene and 11 selenoprotein encoding genes, and decreased the protein abundance of GCK, GPX4 and SELENOS. HMSeBA improved anti-oxidative capacity of liver. 0.4 or 0.6 mg Se/kg HMSeBA supplementation recovered the liver weight, glycogen content and rescue of mRNA abundance of genes related to metabolism and protein levels of GCK. HMSeBA supplementation changed expressions of 15 selenoprotein encoding genes, and enhanced protein expression of GPX1, GPX4 and SELENOS in the liver affected by CHS. CHS alone showed no impact while HMSeBA supplementation increased protein levels of p-AMPKα in the liver.

CONCLUSIONS

In summary, HMSeBA supplementation beyond nutrient requirement mitigates CHS-induced hepatic metabolic disorder, recovered the liver glycogen content and the processes that are associated with the activation of AMPK signal and regulation of selenoproteins in the liver of growing pigs.

Effect of Selenium Sources on Laying Performance, Egg Quality Characteristics, Intestinal Morphology, Microbial Population and Digesta Volatile Fatty Acids in Laying Hens

The use of toxic and less bioavailable inorganic selenium can now be supplemented with an alternative organic source from bacterial species in nutrition for human and animal benefit. This study investigated the effects of selenium sources on laying performance, egg quality characteristics, intestinal morphology, caecum microbial population, and digesta volatile fatty acids in laying hens. One hundred and forty-four Lohman Brown Classic laying hens, at 23 weeks of age, were divided into four experimental groups (36 hens in each), differing in form of Se supplementation: no Se supplementation (Con), 0.3 mg/kg of inorganic Se in the form of sodium selenite (Na2SeO3), 0.3 mg/kg of organic Se from selenium yeast (Se-Yeast), and 0.3 mg/kg of organic Se from Stenotrophomonas maltophilia (bacterial organic Se, ADS18). The results showed that different dietary Se sources significantly affected laying rate, average egg weight, daily egg mass, feed conversion ratio (FCR), and live bodyweight (LBW) (p < 0.05). However, average daily feed intake and shell-less and broken eggs were unaffected (p > 0.05) among the treatment groups. The findings revealed that selenium sources had no (p > 0.05) effect on egg quality (external and internal) parameters. However, eggshell breaking strength and Haugh unit were significantly (p < 0.05) improved with organic (ADS18 or Se-yeast) Se-fed hens compared to the control group. In addition, egg yolk and breast tissue Se concentrations were higher (p < 0.05) in the dietary Se supplemented group compared to the control. Intestinal histomorphology revealed that hens fed ADS18 or Se-Yeast groups had significantly (p < 0.05) higher villi height in the duodenum and jejunum compared to those fed Na2SeO3 or a basal diet. However, when compared to organic Se fed (ADS18 or Se-Yeast) hens, the ileum villus height was higher (p < 0.05) in the basal diet group; with the lowest in the SS among the treatment groups. A significant increase (p < 0.05) of Lactobacilli spp. and Bifidobacteria spp., and a decrease of Escherichia coli and Salmonella spp. population were observed in the organic (ADS18 or Se-yeast) compared to inorganic supplemented and control hens. The individual digesta volatile fatty acid (VFA) was significantly different, but with no total VFA differences. Thus, bacterial selenoprotein or Se-yeast improved the performance index, egg quality characteristics, egg yolk and tissue Se contents, and intestinal villus height in laying hens. Moreover, caecum beneficial microbes increased with a decrease in the harmful microbe population and affected individual cecal volatile fatty acids without affecting the total VFA of the laying hens digesta.

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.

Dietary Serine Supplementation Regulates Selenoprotein Transcription and Selenoenzyme Activity in Pigs

The synthesis of selenocysteine and its incorporation into selenoproteins require serine during the action of seryl-tRNA synthetase. In view of this, we conducted this study to explore the effects of dietary serine supplementation on selenoprotein transcription and selenoenzyme activity in pigs. A total of 35 crossbred barrows (28 days old) were randomly assigned to five treatment groups. During the 42-day growth experiment, pigs were fed either a basal diet with no supplemented serine or diets supplemented with 0.25%, 0.5%, 0.75%, or 1% serine. The results showed that serine supplementation had no effect on the selenium content in the serum, skeletal muscle, and kidney of pigs. However, dietary supplementation with 0.5% serine significantly increased the selenium content in the liver. Diets supplemented with different levels of serine significantly increased the gene expression of glutathione peroxidase 1 (Gpx1), Gpx2, thioredoxin reductase 1 (Txnrd1), Txnrd2, and selenoprotein P (Sepp1) in the skeletal muscle and liver of pigs. Moreover, pigs supplemented with 0.5% serine had the highest selenoprotein P concentration and glutathione peroxidase (GPx) and thioredoxin reductase (TrxR) activities in the skeletal muscle, which were significantly higher than those in the control pigs. Additionally, pigs supplemented with 0.25% serine had the highest GPx and TrxR activities in the liver, which were significantly higher than those in the control pigs. In conclusion, dietary serine supplementation could improve selenoprotein transcription and selenoenzyme activity in pigs, with the appropriate concentrations of serine to be included in the diet being 0.25% or 0.5%.

Effects of Different Selenium Sources on Meat Quality and Shelf Life of Fattening Pigs

Simple Summary

This study was conducted to assess the effects of different Se sources on the growth performance, carcass performance, meat quality and shelf life of fattening pigs. A control diet was supplemented with SS, and experimental diets were supplemented SY, Se-Met, and SS + Se-Met, respectively. The data showed that using organic Se in fattening pig’s diet could improve meat quality and prolong the shelf life of pork. Thus, replacing inorganic Se in diet with organic Se improved meat quality and pork shelf life of fattening pigs significantly under the conditions of the current study.

Abstract

The aim of this study was to evaluate the effects of different Se sources on the meat quality and shelf life of fattening pigs. The control diet was supplemented with 0.3 mg/kg of Se from sodium selenite (SS), and experimental diets included 0.3, 0.3 and 0.15 + 0.15 mg/kg of Se from Se-enriched yeast (SY), selenomethionine (Se-Met) and SS + Se-Met, respectively. The results showed that using organic Se or Se + Se-Met in fattening pigs’ diet could increase average daily gain (ADG) (p < 0.05), decrease F/G (p < 0.05), reduce (p < 0.01) moisture, drip loss and cooking loss of longissimus thoracis, as well as increase (p < 0.05) protein and fat contents of longissimus thoracis. Diet supplementation with SY or Se + Se-Met could increase (p < 0.01) back fat thickness and skin thickness, and SY could increase (p < 0.01) belly fat rat. Adding SY or Se + Se-Met could reduce (p < 0.01) L value (45 min, 24 h). Adding Se-Met could decrease (p < 0.01) b value (45 min, 24 h), adding Se + Se-Met could reduce b value (45 min), and adding SY could reduce the b value (24 h). However, there were no (p < 0.05) significant effects on dressing percentage, carcass sloping length, eye muscle area, pH, a value (45 min) and a value (24 h) of longissimus thoracis. Moreover, the TVB-N contents of longissimus thoracis on the first and fifth days, the numbers of Lactobacillus on the third to seventh days and the numbers of E. coli in in the fifth to seventh days of longissimus thoracis were reduced (p < 0.01) by diet supplementation with organic Se. In conclusion, all the results indicate that replacing inorganic Se in diet with organic Se could improve meat quality of fattening pigs. In addition, organic Se could reduce the total volatile basic nitrogen (TVB-N) contents of longissimus thoracis and reduce the numbers of E. coli and Lactobacillus in longissimus thoracis, prolonging the shelf life of pork. These results demonstrated that organic Se supplementation was more effective than SS supplementation for meat quality and the shelf life of fattening pigs.