Impacts of selenium and vitamin E supplementation on mRNA of heat shock proteins, selenoproteins and antioxidants in broilers exposed to high temperature.

The study was carried out to investigate the effect of dietary selenium (Se) and vitamin E (VE) supplementation on mRNA level of heat shock proteins, selenoproteins, and antioxidant enzyme activities in the breast meat of broilers under summer heat stress conditions. A total of 200 male broilers (Ross 308) of 1 day age were randomly separated into 4 groups in a complete randomized design and were given a basal diet (Control, 0.08 mg Se/kg diet) or basal diet supplemented with VE (250 mg/kg VE), sodium selenite (0.2 mg/kg Se), or Se + VE (0.2 mg/kg Se + 250 mg/kg VE) to investigate the expression of key antioxidant and heat shock protein (HSP) genes under high temperature stress. Dietary Se, VE and Se + VE significantly enhanced the activities and mRNA levels of catalase as well as superoxide dismutase (SOD) but decreased the mRNA levels of HSP70 and HSP90. Se alone or combined with VE increased the concentration of selenoprotein P and selenoproteins mRNA level and decreased the expression of HSP60. In addition, Se and Se + VE significantly enhanced the glutathione peroxidase (GPx) activity and the expression of GPx1 and GPx4 in breast muscle tissues. It is noteworthy that all the treatments significantly decreased malondialdehyde (MDA) level in the breast meat. Overall results showed that Se in combination with VE has maximal effects to mitigate heat stress. Based on given results it can be recommended that Se + VE are a suitable dietary supplement for broilers to ameliorate the negative effects of summer heat stress conditions.

Dietary Supplementation of Selenium-Enriched Probiotics Enhances Meat Quality of Broiler Chickens (Gallus gallus domesticus) Raised Under High Ambient Temperature.

We investigated the effects of selenium-enriched probiotics (SP) on broiler meat quality under high ambient temperature and explore their underlying mechanisms. A total of 200 1-day-old male broiler chicks (Ross 308) were randomly allotted to four treatment groups, each with five replicates, in groups of ten birds. These birds were fed a corn-soybean basal diet (C), a basal diet plus probiotics supplementation (P), a basal diet plus Se supplementation in the form of sodium selenite (SS, 0.30 mg Se/kg), and a basal diet with the addition of selenium-enriched probiotics (SP, 0.30 mg Se/kg). The experiment lasted for 42 days. The birds were sacrificed by cervical dislocation, and the breast muscles were removed for further process. Our results showed that SP diet significantly increased (p < 0.05) the physical (pH, colors, water holding capacity, drip loss, shear force) and sensory characteristics of breast meat. All P, SS, and SP supplementation enhanced the antioxidant system by increasing (p < 0.05) the Se concentrations, glutathione (GSH) levels, activities of glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) whereas decreasing (p < 0.05) malondialdehyde (MDA) levels, with SP being higher than P and SS. Moreover, SP diet significantly upregulated (p < 0.05) the mRNA levels of glutathione peroxidase genes (GPx1, GPx4) while it downregulated heat stress biomarkers such as heat shock protein (HSP) 70 as compared to C, P, and SS diets. In conclusion, our findings suggest that SP may function as beneficial nutritive supplement that is capable of improving meat quality during the summer season.

Effects of Selenium-Enriched Probiotics on Lipid Metabolism, Antioxidative Status, Histopathological Lesions, and Related Gene Expression in Mice Fed a High-Fat Diet.

A total of 80 female albino mice were randomly allotted into five groups (n = 16) as follows: (A) normal control, (B) high-fat diet (HFD),; (C) HFD + probiotics (P), (D) HFD + sodium selenite (SS), and (E) HFD + selenium-enriched probiotics (SP). The selenium content of diets in groups A, B, C, D, and E was 0.05, 0.05, 0.05, 0.3, and 0.3 µg/g, respectively. The amount of probiotics contained in groups C and E was similar (Lactobacillus acidophilus 0.25 × 10(11)/mL and Saccharomyces cerevisiae 0.25 × 10(9)/mL colony-forming units (CFU)). The high-fat diet was composed of 15 % lard, 1 % cholesterol, 0.3 % cholic acid, and 83.7 % basal diet. At the end of the 4-week experiment, blood and liver samples were collected for the measurements of lipid metabolism, antioxidative status, histopathological lesions, and related gene expressions. The result shows that HFD significantly increased the body weights and liver damages compared to control, while P, SS, or SP supplementation attenuated the body weights and liver damages in mice. P, SS, or SP supplementation also significantly reversed the changes of alanine aminotransferase (AST), aspartate aminotransferase (ALT), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), total protein (TP), high-density lipoprotein (HDL), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalasa (CAT), and malondialdehyde (MDA) levels induced by HFD. Generally, adding P, SS, or SP up-regulated mRNA expression of carnitine palmitoyltransferase-I (CPT1), carnitine palmitoyltransferase II (CPT2), acetyl-CoA acetyltransferase II (ACAT2), acyl-coenzyme A oxidase (ACOX2), and peroxisome proliferator-activated receptor alpha (PPARα) and down-regulated mRNA expression of fatty acid synthase (FAS), lipoprotein lipase (LPL), peroxisome proliferator-activated receptor gamma (PPARγ), and sterol regulatory element-binding protein-1 (SREBP1) involved in lipid metabolism. Among the group, adding SP has a maximum effect in improving lipid metabolism, antioxidative status, histopathological lesions, and related gene expression in mice fed a HFD.

Protective effects of Selenium-enriched probiotics on carbon tetrachloride-induced liver fibrosis in rats.

This study aimed to investigate the effects of Se-enriched probiotics (SP) on the liver fibrosis induced by CCl4 in rats. The results showed that SP significantly decreased serum alanine aminotransferase (87.0 ± 1.96 U/L), aspartate aminotransferase (101 ± 3.13 U/L), hepatic hydroxyproline (898 ± 72.5 µg/g), and malondialdehyde (2.39 ± 0.34 nmol/mg) levels, but increased glutathione peroxidase (37.2 ± 3.19 U/mg), superoxide dismutase (201 ± 19.2 U/mg), and glutathione levels (3.32 ± 0.25 mg/g) (P < 0.05) in rats treated by CCl4. SP suppressed hepatic inflammation and necrosis induced by CCl4. Moreover, SP significantly reduced the expression of α-smooth muscle actin, collagen, TGF-ß1, TIMP-1, and inflammation-related gene and induced apoptosis of activated hepatic stellate cells (P < 0.05) in rats treated by CCl4. Our results suggest that SP could protect the liver from fibrosis by attenuating hepatic oxidative stress, suppressing hepatic inflammation, and inducing apoptosis of hepatic stellate cells.

Protective effect of selenomethionine on aflatoxin B1-induced oxidative stress in MDCK cells.

AFB1 is a mycotoxin which exerts their cytotoxicity through increasing oxidative damage in target organ. Kidney is one of target organs vulnerable to damage caused by AFB1. In this study, Madin-Darby canine kidney (MDCK) cells were used to evaluate the AFB1-induced cell damage by the MTT assay. The results revealed that the toxic effect of AFB1 on MDCK cells is both dose and time dependent. Half maximal toxic concentration (IC50) was noted at 0.25 µg/ml of AFB1. Further, protective effect of six different concentrations (0.2, 0.8, 1, 2, 4, and 8 µM) of selenomethionine (SeMet) was observed against 0.25 µg/ml of AFB1-induced damage. The results showed that 0.25 µg/ml of AFB1 caused significant increase in oxidative stress, which was demonstrated by significant increase of malondialdehyde (MDA) level, reduction of intracellular GSH level, as well as GPX1 activity and mRNA level in MDCK cells when compared with control. SeMet protected the cells from AFB1-induced oxidative damage in a dose-dependant manner. Good protection could be achieved between 1 and 4 µM of concentration. Amid this range, MDA level significantly decreased while intracellular GSH level and GPX1 activity in addition to mRNA level significantly increased. Moreover, cell viability was significantly improved. It could be concluded that SeMet is a potential antioxidative agent to alleviate AFB1-induced oxidative stress.