Selenium exerts protective effects against heat stress-induced barrier disruption and inflammation response in jejunum of growing pigs

Lotus Leaf Extract Alleviates Lipopolysaccharide-Induced Intestinal Injury in Mice by Regulating Oxidative Stress and Inflammation

Inflammatory bowel disease, a disease featured by intestinal epithelial barrier destruction and dysfunction, has been a constant threat to animal health. The primary objective of this research was to assess the impact of the extract derived from lotus leaves (LLE) on lipopolysaccharide (LPS) induced damage to the intestines in mice, as well as to investigate the fundamental mechanism involved. The LLE was prepared using ultrasonic extraction in this experiment, and the LLE total flavonoid content was 117.02 ± 10.73 mg/g. The LLE had strong antioxidant activity in vitro, as assessed by 2, 2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) methods. In the vivo experiment, different doses of LLE (50, 100, and 200 mg/kg) were administered for 2 weeks before LPS treatment in mice. The results revealed that LLE alleviates intestinal tissue damage in LPS-induced mice. In the jejunum tissue, LLE significantly upregulated mRNA and protein expression levels of tight junction proteins, such as ZO-1, occludin, and claudin-1, and decreased the contents of the inflammatory cytokines, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α. Furthermore, the malondialdehyde and lactate dehydrogenase contents increased by LPS in the liver were significantly reduced after administration of LLE, and the total antioxidant capacity, superoxide dismutase, and reduced glutathione decreased by LPS were remarkably increased by LLE. It was found that LLE could relieve LPS-induced oxidative stress by upregulating mRNA and protein expression of Nrf2 and HO-1 in jejunum tissue. In conclusion, LLE alleviates LPS-induced intestinal damage through regulation of the Nrf2/HO-1 signal pathway to alleviate oxidative stress, reducing inflammatory factors and increasing the expression of tight junction proteins in mice.

Age-Dependent Developmental Changes of Selenium Content and Selenoprotein Expression and Content in Longissimus Dorsi Muscle and Liver of Duroc Pigs

The trace element selenium (Se) plays a key role in development and various physiological processes, mainly through its transformation into selenoproteins. To investigate the developmental patterns of Se content and expression of selenoproteins, the liver and longissimus dorsi (LD) muscle of Duroc pigs were collected at 1, 21, 80, and 185 days of age (7 pigs each age) for the determination of Se content, mRNA expression of selenoproteins, and concentrations of glutathione peroxidase (GPX), thioredoxin reductase (TrxR or TXNRD), and selenoprotein P (SELP). The results showed that age significantly affected the expression of GPX1, GPX2, GPX3, TXNRD1, TXNRD2, TXNRD3, iodothyronine deiodinases 2 (DIO2), DIO3, SELF, SELH, SELM, SELP, SELS, SELW, and selenophosphate synthetase2 (SPS2) in the liver, as well as GPX3, GPX4, TXNRD1, TXNRD2, DIO2, DIO3, SELF, SELN, SELP, SELR, SELS, and SELW in the LD muscle of Duroc pigs. The concentrations of GPX, TrxR, and SELP showed an increasing trend with age, and they were positively correlated with Se content at 1, 21, and 185 days of age and negatively correlated at 80 days of age, both in the liver and LD muscle. The Se content decreased at the age of 80 days, especially in the LD muscle. In summary, our study revealed developmental changes in Se content and expression of selenoproteins in the liver and LD muscle of Duroc pigs at different growth stages, which provided a theoretical basis for further study of Se nutrition and functions of selenoproteins.

Studies on the ameliorative potential of dietary supplemented different dose of selenium on doxorubicin-induced ovarian damage in rat

Doxorubicin (Dox) may induce loss of follicles, resulting in the depletion of ovarian reserve and consequent premature ovarian failure. Selenium (Se) is an oligoelement with fundamental biological features and is among the most common chemical inhibitor compounds. The present study describes the curative effects of dietary supplementation with different Se doses on Dox-induced ovarian damage in rats. In this study, 64 adult female Wistar rats were randomly separated into eight groups: Control group, Dox group (5 mg/kg intraperitoneal [i.p.]), low-dose Se (0.5 mg/kg i.p.), middle dose Se (1 mg/kg i.p.), high dose (Se 2 mg/kg i.p.), Dox + low-dose Se group (0.5 mg/kg i.p.), Dox + middle dose Se (1 mg/kg i.p.), and Dox + high-dose Se group (2 mg/kg i.p.). After the experiment, ovarian follicles were counted, and Antimüllerian hormone, interleukin 1 beta, tumor necrosis factor alpha, and caspase-3 expression were determined. Levels of malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase were biochemically measured in ovarian tissue. Dox caused ovarian injury, as evidenced by significant changes in ovarian markers, histological abnormalities, and the debilitation of antioxidant defense mechanisms. Furthermore, Dox therapy significantly changed the expression of inflammatory and apoptotic markers. Dox + 1 mg Se with various saturations was studied, and this study demonstrated both histopathological and follicular reserve and more protective features. 1 mg Se pretreatment improved Dox-induced ovarian toxicity through alleviating the antioxidant mechanism, decreasing inflammation and apoptosis, and restoring ovarian architecture. As a result, our findings indicate that 1 mg Se is a promising therapeutic agent for the prevention of ovarian damage associated with Dox.

Tryptophan alleviates intestinal damage through regulating necroptosis and TLR4/NOD signaling pathways in pigs after lipopolysaccharide challenge

This study aimed to test the hypothesis that necroptosis, toll-like receptor 4 (TLR4)/nucleotide-binding oligomerization domain (NOD) signaling pathway in the jejunum of lipopolysaccharide (LPS)-challenged piglets are involved in the alleviation of intestinal injury and inflammation by tryptophan supplementation. Tryptophan supplementation has improved intestinal morphology. Also, tryptophan has been found to increase the mRNA and protein expression of tight junction proteins and decrease the expression of pro-inflammatory cytokines. Dietary tryptophan decreased the mRNA expression of heat shock protein 70, TLR4, NOD1, NOD2, myeloid differentiation primary response gene 88, interleukin 1 receptor-associated kinase 1, TNF receptor-associated factor 6, receptor-interacting serine/threonine-protein kinase 2-like, nuclear factor-kappaB transcription factor P65 in the jejunum of piglets. Tryptophan alleviated LPS-induced necroptosis and decreased the mRNA expression of mixed lineage kinase domain-like, receptor-interacting serine/threonine kinase 1, receptor-interacting serine/threonine-protein kinase 3-like, Fas (TNFRSF6)-associated via death domain, PGAM family member 5. Collectively, our results suggest that tryptophan supplementation helps in the attenuation of intestinal injury and inflammation by alleviating necroptosis and TLR4/NOD in lipopolysaccharide-challenged pigs.

Selenium-enriched Cardamine violifolia protects against sepsis-induced intestinal injury by regulating mitochondrial fusion in weaned pigs

Sepsis is a life-threatening organ dysfunction caused by the dysregulated response of the host to an infection, and treatments are limited. Recently, a novel selenium source, selenium-enriched Cardamine violifolia (SEC) has attracted much attention due to its anti-inflammatory and antioxidant properties, but little is known about its role in the treatment of sepsis. Here, we found that SEC alleviated LPS-induced intestinal damage, as indicated by improved intestinal morphology, and increased disaccharidase activity and tight junction protein expression. Moreover, SEC ameliorated the LPS-induced release of pro-inflammatory cytokines, as indicated by decreased IL-6 level in the plasma and jejunum. Moreover, SEC improved intestinal antioxidant functions by regulating oxidative stress indicators and selenoproteins. In vitro, TNF-α-challenged IPEC-1 cells were examined and showed that selenium-enriched peptides, which are the main functional components extracted from Cardamine violifolia (CSP), increased cell viability, decreased lactate dehydrogenase activity and improved cell barrier function. Mechanistically, SEC ameliorated LPS/TNF-α-induced perturbations in mitochondrial dynamics in the jejunum and IPEC-1 cells. Moreover, CSP-mediated cell barrier function is primarily dependent on the mitochondrial fusion protein MFN2 but not MFN1. Taken together, these results indicate that SEC mitigates sepsis-induced intestinal injury, which is associated with modulating mitochondrial fusion.

Positive effects of selenized-oligochitosan on zearalenone-induced intestinal dysfunction in piglets

This paper assessed the positive effects of selenized-oligochitosan (SOC) on zearalenone(ZEN)-induced intestinal dysfunction in piglets. Sixty piglets were randomly divided into 4 groups. Group C was fed the basal diet as a control and Group Z was supplemented with 2 μg/g ZEN in the basal diet; Group ZS1 and ZS2 were supplemented with 0.3 or 0.5 μg/g SOC (calculated by selenium), in addition to 2 μg/g ZEN in the basal diet. After 42 days, ileal mucosal structure, digestive enzyme activities, tight junction protein mRNA expressions, plasma D-lactate and D-xylose contents, and plasma diamine oxidase activities were determined. Compare with Group C, ileal villus height, value of villus height/crypt depth, trypsin, lipase and α-amylase activities, occluding, claudin-1 and ZO-1 mRNA expressions, and plasma D-xylose levels were significantly decreased (p < 0.01) in piglets of group Z; while compare to Group C, ileal crypt depth, plasma D-lactate contents and diamine oxidase activities were significantly increased in piglets of group Z (p < 0.01 or p < 0.05). Compare with Group Z, ileal villus height, lipase and α-amylase activities, occluding, claudin-1 and ZO-1 mRNA expressions, and plasma D-xylose levels were significantly elevated in piglets of group ZS1 and ZS2 (p < 0.01); while compare to Group Z, plasma D-lactate and diamine oxidase contents were significantly reduced in piglets of group ZS1 and ZS2 (p < 0.01 or p < 0.05). Compare with Group Z, value of villus height/crypt depth and trypsin activity were significantly promoted in piglets of group ZS2 (p < 0.01); whereas ileal crypt depth was significantly reduced in piglets of group ZS2 (p <0.01).Thus, SOC can mitigate ZEN-induced intestinal dysfunction in piglets.

Heat Stress-Induced Intestinal Barrier Impairment: Current Insights into the Aspects of Oxidative Stress and Endoplasmic Reticulum Stress

Heat stress (HS) occurs when the sensible temperature of animals exceeds their thermoregulatory capacity, a condition that exerts a detrimental impact on health and growth. The intestinal tract, as a highly sensitive organ, has been shown to respond to HS by exhibiting mucosal injury, intestinal leakage, and disturbances in the gut microbiota. Oxidative stress and endoplasmic reticulum stress (ERS) are both potential outcomes of long-term exposure to high temperatures and have been linked to apoptosis, autophagy, and ferroptosis. In addition, HS alters the composition of the gut microbiota accompanied by changed levels of bacterial components and metabolites, rendering the gut more vulnerable to stress-related injury. In this review, we present recent advances in mechanisms of oxidative stress-associated ERS in response to HS, which is destructive to intestinal barrier integrity. The involvement of autophagy and ferroptosis in ERS was highlighted. Further, we summarize the relevant findings regarding the engagement of gut microbiota-derived components and metabolites in modulation of intestinal mucosal injury induced by HS.

Hydroxy-Selenomethionine Mitigated Chronic Heat Stress-Induced Porcine Splenic Damage via Activation of Nrf2/Keap1 Signal and Suppression of NFκb and STAT Signal

Chronic heat stress (CHS) compromised the immunity and spleen immunological function of pigs, which may associate with antioxidant suppression and splenocyte apoptosis and splenic inflammation. Selenium (Se) exhibited antioxidant function and immunomodulatory through selenoprotein. Thus, this study aimed to investigate the protective effect of dietary hydroxy-selenomethionine (Selisso®, SeO) on chronic heat stress (CHS)-induced porcine splenic oxidative stress, apoptosis and inflammation. Growing pigs were raised in the thermoneutral environment (22 ± 2 °C) with the basal diet (BD), or raised in hyperthermal conditions (33 ± 2 °C) with BD supplied with 0.0, 0.2, 0.4 and 0.6 mg Se/kg SeO for 28 d, respectively. The results showed that dietary SeO supplementation recovered the spleen mass and enhanced the splenic antioxidant capacity of CHS growing pigs. Meanwhile, SeO activated the Nrf2/Keap1 signal, downregulated p38, caspase 3 and Bax, inhibited the activation of NFκb and STAT3, and enhanced the protein expression level of GPX1, GPX3, GPX4, SELENOS and SELENOF. In summary, SeO supplementation mitigates the CHS-induced splenic oxidative damages, apoptosis and inflammation in pigs, and the processes are associated with the activation of Nrf2/Keap1 signal and the suppression of NFκb, p38(MAPK) and STAT signal. It seems that the antioxidant-related selenoproteins (GPXs) and functional selenoproteins (SELENOS and SELENOF) play important roles in the alleviation processes.

Mogroside-rich extract from Siraitia grosvenorii fruits protects against heat stress-induced intestinal damage by ameliorating oxidative stress and inflammation in mice

Global warming makes humans and animals more vulnerable to heat stress. Heat stress can cause multiorgan dysfunction, especially in the intestine, primarily via oxidative stress and inflammation. Mogroside-rich extract (MGE) is the active ingredient of Siraitia grosvenorii and has significant antioxidant and anti-inflammatory activity. However, whether MGE can alleviate the intestinal damage caused by heat stress has not been explored. In this study, mice were given 600 mg kg^-1 MGE followed by exposure to high temperature (40 °C for 2 h per day), and the structures and molecular changes in the ileum were examined. Our findings showed that body weight was decreased by heat stress, while the activity of serum superoxide dismutase (SOD) was increased. We further found that heat stress impaired the intestinal barrier by reducing the number of goblet cells and mRNA levels of the tight junction proteins zona occludens protein 1 (ZO-1), Occludin (OCLD) and recombinant mucin 2 (MUC2 mucin), but it increased the mRNA level of trefoil factor 3 (TFF3). Interestingly, MGE treatment reversed these changes. Furthermore, heat stress increased the activity of SOD in the intestine, downregulated the expression of the oxidative stress-related genes glutathione peroxidase 1 (GPX1), SOD2 and nuclear factor erythroid 2-related factor 2 (NRF2), and upregulated the expression of catalase (CAT). Moreover, heat stress increased tumor necrosis factor-α (TNF-α) levels in the intestine and upregulated the expression of the inflammation-related genes interleukin 10 (IL-10), TNF-α, Interferon-γ (IFN-γ), toll like receptor 4 (TLR4) and nuclear factor-kappa B (NF-kB). However, MGE treatment effectively reduced TNF-α levels and restored the normal activity of SOD and normal mRNA levels for both oxidative stress-related and inflammation-related genes. In summary, our results showed that MGE can protect against heat stress-induced intestinal damage by ameliorating inflammation and oxidative stress.

Novel organic selenium source hydroxy-selenomethionine counteracts the blood-milk barrier disruption and inflammatory response of mice under heat stress

Heat stress (HS) in summer has caused huge economic losses to animal husbandry production recently. When mammary gland is exposed to high temperatures, it will cause blood-milk barrier damage. Hydroxy-selenomethionine (HMSeBA) is a new selenium source with better guarantee of animals' production performance under stress, but whether it has protective effect on heat stress-induced blood-milk damage is still unclear. We established mammary epithelial cells and mice heat stress injury models to fill this research gap, and hope to provide theoretical basis for using HMSeBA to alleviate heat stress damage mammary gland. The results showed that (1) Heat stress significantly decreases in vitro transepithelial electrical resistance (TEER) and cell viability (P < 0.01), and significantly decreases clinical score, histological score, and total alveoli area of mice mammary gland tissue (P < 0.01). (2) HMSeBA significantly increases TEER and fluorescein sodium leakage of HS-induced monolayer BMECs (P < 0.01), significantly improves the milk production and total area of alveoli (P < 0.01), and reduces clinical score, histological score, mRNA expression of heat stress-related proteins, and inflammatory cytokines release of heat-stressed mice (P < 0.01). (3) HMSeBA significantly improves tight junction structure damage, and significantly up-regulated the expression of tight junction proteins (ZO-1, claudin 1, and occludin) as well as signal molecules PI3K, AKT, and mTOR (P < 0.01) in heat-stressed mammary tissue. (4) HMSeBA significantly increases glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and superoxide dismutase release (SOD) (P < 0.01) and significantly reduce malondialdehyde (MDA) expression (P < 0.01) in heat-stressed mammary tissue. In conclusion, this study implemented heat-stressed cell and mice model and showed that HMSeBA significantly regulate antioxidant capacity, inhibited inflammation, and regulate tight junction proteins expression in blood-milk barrier via PI3K/AKT/mTOR signaling pathway, so as to alleviate mammary gland damage and ensure its structure and function integrity.

Ameliorative effects of supranutritional selenium on TLR-4-NF-kB-TNF-α-mediated hepatic oxidative injury and inflammation in goats fed high concentrate diet

We examined whether surplus dietary selenium (Se) supply could alleviate high concentrate (HC) diet-induced hepatic oxidative stress (OS) and inflammation. Eighteen young goats were distributed into three groups; were fed low (LC, concentrate: forage; 35: 65), high concentrate (HC, 65: 35), or Se-supplemented HC (HCSe, 65: 35 + 0.5 mg Se kg-1 diet) diets for 10 weeks. Short chain fatty acids, OS markers and immunoinflammatory genes expressions were assessed through gas chromatograph, kits, and RT-qPCR, respectively. Compared with LC, HC diet increased (p < .05) colonic and serum lipopolysaccharide (LPS) levels and induced hepatic oxidative injury by increasing (p < .05) malondialdehyde (MDA) levels and decreasing (p < .05) activities of glutathione peroxidase, superoxide dismutase, and catalase. HC diet altered hepatic mRNA expressions of toll-like receptor-4 (TLR-4), cluster of differentiation-14 (CD-14), tumor necrosis factor-α (TNF-α), TNF receptor-associated factor-6 (TRAF-6), nuclear factor kappa B (NF-κB), interleukin-1β (IL-1β), IL-10, IL-13, LPS-binding protein (LBP), serum amyloid A (SAA), α-acid glycoprotein (AGP), and albumin (ALB). Conversely, extra-Se supply lowered LPS and attenuated antioxidant status and inflammation in liver. In conclusion, HC diet induced oxidative lesions and TLR-4 pathway-mediated inflammation, whereas supranutritional Se alleviated oxidative and inflammatory lesions through TLR-4 pathway regulation in goat liver.

Selenium-enriched Cardamine violifolia improves growth performance with potential regulation of intestinal health and antioxidant function in weaned pigs

This study was conducted to evaluate the effects of different Selenium (Se) sources on growth performance, intestinal function and antioxidant status of weaned piglets. A total of 300 weaned pigs were randomly allocated to 5 treatment groups with 5 replicates of 12 pigs/pen. The control group was corn-soybean basal diet without any additional Se supplement. The experimental diets were supplemented with 0.3 mg/kg of Se from sodium selenite (SS), Se-enriched yeast (SEY), Se-enriched Cardamine violifolia (SEC) and 0.3+0.3 mg/kg of Se from SEY and SEC, respectively. The trial lasted for 4 weeks. The results showed that diets supplementation with SEY, SEC or SEY+SEC could improve average daily gain and reduce feed/gain ratio during the entire study. Compared with the control group, SEC or SEY+SEC improved intestinal morphology, indicated by greater villus height and villus height/ crypt depth ratio. In addition, SEC or SEY+SEC also increased maltase and lactase activities as well as tight junction protein expression. Different Se sources decreased malondialdehyde (MDA) concentration and improved superoxide dismutase (SOD) activity in serum. In the jejunum, SEY or SEC reduced MDA concentration and increased total antioxidant capacity (T-AOC) compared with the control group. Moreover, SEY+SEC increased the antioxidant parameters including SOD and T-AOC in the jejunum. Dietary SEY or SEC supplementation significantly increased the mRNA expression of selenoproteins including thioredoxin reductase 1 (TXNRD1), selenoprotein I (SELENOI), selenoprotein S (SELENOS), and selenoprotein P (SELENOP) in the jejunum. In conclusion, organic Se sources, especially Cardamine violifolia, improve growth performance, potentially by regulating intestinal function, antioxidant capacity and selenoprotein expression in piglets.

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.

Effects of Selenium as a Dietary Source on Performance, Inflammation, Cell Damage, and Reproduction of Livestock Induced by Heat Stress: A Review

Heat stress as a result of global warming has harmful consequences for livestock and is thus becoming an urgent issue for animal husbandry worldwide. Ruminants, growing pigs, and poultry are very susceptible to heat stress because of their fast growth, rapid metabolism, high production levels, and sensitivity to temperature. Heat stress compromises the efficiency of animal husbandry by affecting performance, gastrointestinal health, reproductive physiology, and causing cell damage. Selenium (Se) is an essential nutritional trace element for livestock production, which acts as a structural component in at least 25 selenoproteins (SELs); it is involved in thyroid hormone synthesis, and plays a key role in the antioxidant defense system. Dietary Se supplementation has been confirmed to support gastrointestinal health, production performance, and reproductive physiology under conditions of heat stress. The underlying mechanisms include the regulation of nutrient digestibility influenced by gastrointestinal microorganisms, antioxidant status, and immunocompetence. Moreover, heat stress damage to the gastrointestinal and mammary barrier is closely related to cell physiological functions, such as the fluidity and stability of cellular membranes, and the inhibition of receptors as well as transmembrane transport protein function. Se also plays an important role in inhibiting cell apoptosis and reducing cell inflammatory response induced by heat stress. This review highlights the progress of research regarding the dietary supplementation of Se in the mitigation of heat stress, addressing its mechanism and explaining the effect of Se on cell damage caused by heat stress, in order to provide a theoretical reference for the use of Se to mitigate heat stress in livestock.

Apple polyphenols improve intestinal barrier function by enhancing antioxidant capacity and suppressing inflammation in weaning piglets

This study aimed to examine the effects of apple polyphenols (APPs) on antioxidant capacity, immune and inflammatory response, and barrier function in weaning piglets. Results showed that APPs improved jejunal barrier function by increasing the villus height, villus height/crypt depth, the mRNA levels of occludin, mucin-1, and mucin-4 and up-regulating the protein expression of occluding (P < 0.05). As for antioxidant capacity, APPs increased the activities of total superoxide dismutase and glutathione peroxidase and total antioxidant capacity level in jejunum (P < 0.05). Besides, APPs up-regulated the protein expressions of NAD(P)H quinone dehydrogenase 1 (NQO1), heme oxygenase-1 (HO-1), and nuclear-related factor 2 (NRF2) and down-regulated the protein expression of kelch-like ECH-associated protein 1 (Keap1). As regard to immune and inflammatory response, APPs increased the immunoglobulin A content in serum and decreased the mRNA levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB), and IL-8 in jejunum (P < 0.05). Overall, dietary APPs supplementation improves the jejunal barrier function by enhancing antioxidant capacity and suppressing the mRNA expression related to inflammation, which may be related to the NRF2 signal and TLR4/NF-κB signal.

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.