Late ad libitum feeding reverses early feed restriction-induced immune deficit in broilers

Restricted feeding mitigates metabolic diseases and offers a cost-saving potential for broiler production. This study investigated a feeding strategy to reduce costs without compromising health. Four hundred and eighty one-day-old male broilers were divided into four groups subjected to 21-day feed restriction with different daily access times (24, 20, 16, or 12 h), followed by <i>ad libitum</i> feeding for 24 h (ADF) until 70 days. Early feed restriction (EFR) significantly decreased body weight, average daily gain, feed intake, and bursa of Fabricius index (<i>p</i> < 0.05), while suppressing intestinal Wnt/β-catenin signaling pathway and enhancing inflammatory responses. Subsequent ADF reversed these effects, restoring growth performance and immune indices to control levels. Butyric acid and butyrate-producing bacteria increased significantly (<i>p</i> < 0.05), accompanied by activated Wnt/β-catenin pathway and enriched beneficial flora. In conclusion, ADF alleviates EFR-induced inflammation and promotes immune recovery via gut microbiota and Wnt/β-catenin pathway, providing a viable cost-effective feeding strategy.