Understanding the impact of glycolysis and oxidative stress on residual feed intake in slow-growing chicken.

Improving feed efficiency (FE) in slow-growing Korat chickens (KRC) is crucial for enhancing productivity and reducing production costs for sustainability. This study aimed to investigate the expression of genes and proteins involved in glycolysis and oxidative stress pathways and to identify potential metabolic biomarkers associated with residual feed intake (RFI). A total of 30 male KRCs were selected based on extreme RFI values at 10 weeks of age, forming low-RFI and high-RFI groups (n = 15/group). Duodenal samples were collected to extract total RNA and protein. Gene expression levels of Aldolase C (ALDOC), Lactate Dehydrogenase B (LDHB), Phosphoglycerate Mutase 1 (PGAM1), Triphosphate Isomerase (TPI1), Superoxide Dismutase 1 (SOD1), and Peroxiredoxin-1 (PRDX1) were analyzed using real-time quantitative PCR, while protein levels of LDHB and SOD1 were analyzed by Western blot. Plasma glucose, pyruvate, and protein carbonyl content were also measured. Low-RFI chickens exhibited significantly higher mRNA and protein expression of LDHB, as well as elevated TPI1 mRNA levels (P < 0.05). Conversely, HRFI chickens showed increased expression of SOD1 at both mRNA and protein levels, along with significantly higher plasma glucose and protein carbonyls and lower pyruvate concentrations (P < 0.05). Principal Component Analysis (PCA) revealed a clear separation between RFI groups, with the LDHB gene associated with the low-RFI group. Whereas the SOD1 gene and SOD1 protein, along with plasma glucose and protein carbonyl content, were positively correlated with the high-RFI group. These findings suggest that LDHB and SOD1 genes may serve as potential biomarkers for FE, reflecting differences in energy metabolism and oxidative stress response in slow-growing chickens. This highlights the potential application of these markers in genetic selection and nutritional strategies to improve FE in poultry.