Alginate oligosaccharides improve breast muscle quality of heat-stressed broilers by modulating oxidative stability, muscle fiber transformation, and lipid metabolism.

This study investigated the impact of dietary alginate oligosaccharides (AOS) on the meat quality of breast muscle in broilers exposed to heat stress (HS). In broilers exposed to HS, dietary AOS enhanced pH24h and the activities of catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) (P < 0.05), while decreasing drip loss and malondialdehyde (MDA) concentration in breast muscle (P < 0.05). Non-targeted metabolomics analysis revealed that AOS regulates lipid metabolism of breast muscle. Furthermore, AOS upregulated the expression of antioxidant genes GSTA3, GPX3, CAT1, NQO1, and muscle fiber transformation regulators MyH1D, PGC-1α, MEF2C (P < 0.05), while downregulating lipogenic genes SREBP-1, ACC, FAS and FABP3, and the fast muscle marker MyH9 (P < 0.05). Concomitantly, AOS enhanced the phosphorylation modification level of Nrf2 and AMPK proteins (P < 0.05). Therefore, AOS improves the meat quality of breast muscle in broilers exposed to HS by improving the oxidative stability, promoting the transformation of fast muscle fibers into slow muscle fibers, and alleviating lipid metabolism disorders.