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

Abstract

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.

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

“…Heat stress directly affects the organ and muscle metabolism of pigs which can continue after slaughtering [11,23], as the metabolism of energy and protein continues with related enzymes in the muscular tissues affecting aspects of meat quality [32,53]. In this study, CHS caused significant down-regulation of mRNA expression of SREBP1 and upregulation of the mRNA expression of INSR.…”

“…Total mRNA isolation and reverse transcription were performed using a commercial reagent kit (Invitrogen, Carlsbad, CA, USA), and the subsequent quantitative real-time PCR (Q-RT-PCR) was carried out by QuantStudio Real-Time PCR system (QuantStudio 6 Flex, Applied Biosystems, Foster City, CA, USA) as described in our previous study [11]. The primer sequences used for the assayed genes of 12 metabolism-related genes, 25 selenoprotein encoding genes, and 2 house-keeping genes (β-ACTIN and GAPDH) were referenced in our previous study and shown in (Supplementary Table S1) [11].…”

“…The skeletal muscle tissues were homogenized with the cell disruption buffer (RIPA lysis Buffer, Beyotime, Shanghai, China), then the total protein concentration was measured using the BCA kit (Jiancheng Bioengineering, Nanjing, China). The subsequent Western blot process was performed as previously described [11,29]. The primary antibodies were used at the following dilutions: HSP70 (1:5000; ab5439; Abcam, Cambridge, UK), GPX1 (1:1000; 616958; Zen BioScience, Chengdu, China), GPX3 (1:2000; sc-58361, Santa Cruz Biotechnology, Santa Cruz, CA, USA), GPX4 (1:2000; 513309, Zen BioScience, Chengdu, China), SELENOP (1:2000; sc-376858, Santa Cruz Biotechnology, Santa Cruz, CA, USA), SELENOS (1:1000, 15591-1-AP, ProteinTech Group, Chicago, IL, USA) and GAPDH (1:5000; 200306-7E4, Zen BioScience, Chengdu, China).…”

“…As we know, Se exerts its biological function mainly through selenoproteins [16], and in total 25 porcine selenoprotein genes have been identified [17]. Our previous study indicates that several selenoprotein encoding genes are involved in the remission of CHSinduced metabolic disorder [11]. Although the exact mechanisms remain unclear, studies have observed the alternation of the protein synthesis pathway (mTOR, 4E-BP1, and RPS6/S6), lipogenesis (FOXO1, FAS, ACC1, and SREBP1), and glucose metabolism-(INSR, IRS1, AKT, PCK2, and GCK) related genes are associated with the abnormal expression of GPX1, GPX4, SELENOH, SELENOP, SELENOS, DIO1, and TXNRD1 [14,15,[18][19][20][21][22].…”

“…The micronutrient trace element selenium (Se) is an essential cellular antioxidant. Se supplementation relieves the HS-induced damage in C2C12 cells, IPEC-J2 cells, and hepatic injury in growing pigs by enhancing antioxidant capacity [11][12][13]. Recent studies reported that Se affects the metabolic process of carbohydrates, proteins, and lipids [14,15].…”