Abstract
Heat stress (HS) is one of the major challenges in the current poultry industry. HS leads to the deterioration of meat quality by inducing oxidative stress and metabolic disorders, which have a significant adverse impact on broiler production. Alginate oligosaccharides (AOS), recognized for their natural antioxidant properties, may have the potential to improve the meat quality of broilers under HS. The current study aimed to investigate the effects of dietary AOS on meat quality, oxidative stability and metabolome of thigh muscle in broilers challenged to HS. A total of 108 29-day-old male Arbor Acres broilers were randomly divided into three treatment groups: (i) thermoneutral (TN) group (fed with basal diet); (ii) HS group (fed with basal diet); (iii) HS + AOS group (HS group supplemented with 600 mg/kg AOS). The feeding trial lasted for 14 d. The results showed that dietary supplementation with AOS increased pH45min, yellowness (b*) values, the total antioxidant capacity (T-AOC) level, and the enzyme activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST), while decreasing drip loss, shear force and the concentration of malondialdehyde (MDA) of thigh muscle in broilers under HS (P < 0.05). Compared to HS group, untargeted metabolomics results suggested that the concentrations of six differential metabolites were increased, including eicosanoic acid, PC (22:2(13Z,16Z)/14:0), capric acid, suberic acid, gingerol, and 4-methyl-2-pentyl-1,3-dioxolane, and the differential metabolites were enriched in nine metabolic pathways, including fatty acid biosynthesis, glycerophospholipid metabolism, lipopolysaccharide biosynthesis, alpha-linolenic acid metabolism, etc. in the HS + AOS group (P < 0.05). Moreover, dietary supplementation with AOS upregulated the mRNA expression level of Nrf2 and GSTT1, GPX4, NQO1, SOD1, SOD2, MafF, MafG, MafK, MEF2C, SREBP-1, FAS, and downregulated the mRNA expression level of Keap1 and GSTO1 in broilers under HS (P < 0.05). In conclusion, dietary supplementation with 600 mg/kg AOS could improve the oxidative stability and alleviate lipid metabolism disorders, ultimately helping prevent HS-induced meat deterioration in broilers. These findings suggest that dietary AOS is a promising strategy to enhance meat quality in heat-stressed broilers.