RESUMO
Selenium (Se) is an indispensable trace element with versatile functions in antioxidant defense in poultry. In our previous study, we synthesized a novel type of biogenic selenium nanoparticle based on alginate oligosaccharides (SeNPs-AOS), and found that the particles are sized around 80 nm with an 8% Se content, and the dietary addition of 5 mg/kg of SeNPs-AOS could effectively alleviate the deleterious effects of heat stress (HS) in broilers, but it is still unclear whether SeNPs-AOS can improve the meat quality. Therefore, the aim of this study was to evaluate the protective effects of SeNPs-AOS on breast meat quality in heat-stressed broilers, and explore the relevant mechanisms. Birds at the age of 21 days were randomly divided into four groups with six replicates per group (eight broilers per replicate) according to a 2 × 2 experimental design, using HS (33 ± 2 °C, 10 h/day vs. thermoneutral, TN, under 23 ± 1.5 °C) and SeNPs-AOS (5 mg/kg feed vs. no inclusion) as variables. The results showed that dietary SeNPs-AOS decreased the cooking loss (p < 0.05), freezing loss (p < 0.001), and shear force (p < 0.01) of breast muscle in heat-stressed broilers. The non-targeted metabolomics analysis of the breast muscle identified 78 differential metabolites between the HS and HS + SeNPs-AOS groups, mainly enriched in the arginine and proline metabolism, ß-alanine metabolism, D-arginine and D-ornithine metabolism, pantothenate, and CoA biosynthesis pathways (p < 0.05). Meanwhile, supplementation with SeNPs-AOS increased the levels of the total antioxidant capacity (T-AOC), the activities of catalase (CAT) and glutathione peroxidase (GSH-Px), and decreased the content of malondialdehyde (MDA) in the breast muscle (p < 0.05) in broilers under HS exposure. Additionally, SeNPs-AOS upregulated the mRNA expression of CAT, GPX1, GPX3, heme oxygenase-1 (HO-1), masculoaponeurotic fibrosarcoma G (MafG), MafK, selenoprotein W (SELENOW), SELENOK, ferritin heavy polypeptide-1 (FTH1), Ferroportin 1 (Fpn1), and nuclear factor erythroid 2-related factor 2 (Nrf2) (p < 0.05), while it downregulated Kelch-like ECH-associated pro-36 tein 1 (Keap1) and prostaglandin-endoperoxide Synthase 2 (PTGS2) expression (p < 0.05) in broilers under HS. These findings demonstrated that the dietary addition of SeNPs-AOS mitigated HS-induced oxidative damage and metabolite changes in the breast muscle of broilers, which may be related to the regulation of the Nrf2 signaling pathway and selenoprotein synthesis. In addition, SeNPs-AOS upregulated the breast muscle gene expression of anti-ferroptosis-related molecules in broilers under HS, suggesting that SeNPs-AOS can be used as novel Se supplements against HS in broilers.
RESUMO
Selenium (Se) is an essential trace element for maintaining health due to its ideal antioxidant properties. We previously prepared a new type of biogenic selenium nanoparticles based on alginate oligosaccharides (SeNPs-AOS), and this study aimed to investigate the protective effects of SeNPs-AOS (Se particle size = 80 nm, Se content = 8%) on organ health in broilers challenged with HS. A total of 192 21-day-old Arbor Acres broilers were randomly divided into four groups according to a 2 × 2 experimental design, including a thermoneutral zone group (TN, raised under 23 ± 1.5 °C); TN + SeNPs-AOS group (TN group supplemented 5 mg/kg SeNPS-AOS); HS group (HS, raised under 33 ± 2 °C for 10 h/day); and HS + SeNPs-AOS group (HS group supplemented 5 mg/kg SeNPS-AOS). There were six replicates in each group (eight broilers per replicate). The results showed that SeNPs-AOS improved the splenic histomorphology, enhanced the activity of catalase (CAT) and glutathione peroxidase (GSH-Px) of the spleen, as well as upregulating the splenic mRNA expression of antioxidant-related genes in broilers under HS. In addition, SeNPs-AOS reversed the pathological changes in bursa caused by HS increased the activity of GST, GSH-Px, and CAT and upregulated the mRNA expression of Nrf2 and antioxidant-related genes in the bursa of heat-stressed broilers. In addition, dietary SeNPs-AOS improved the hepatic damage, increased the activity of GSH-Px in the liver, and upregulated the mRNA expression of antioxidant-related genes while downregulating the Keap1 gene expression of the liver in broilers during HS. Moreover, dietary SeNPs-AOS upregulated the anti-ferroptosis-related genes expression of liver in broilers under HS. In conclusion, dietary SeNPs-AOS could relieve HS-induced oxidative damage to the spleen, bursa of Fabricius and liver in broilers by upregulating the Nrf2-mediated antioxidant gene expression and SeNPs-AOS could also upregulate the expression of hepatic Nrf2-related anti-ferroptosis genes in heat-stressed broilers. These findings are beneficial for the development of new nano-antioxidants in broilers.
