Dietary Chlorogenic Acid Attenuates Liver Injury, Lipid Metabolic Disturbance, and Inflammatory Responses in Broilers Under High Stocking Density

This study evaluated whether chlorogenic acid (CGA) attenuates hepatic injury in broilers under high stocking density (HSD). A total of 216 experimental male Arbor Acres broilers were assigned to normal density without CGA (ND; 14 birds/m2), high density without CGA (HD; 22 birds/m2), normal density with 0.1% CGA (NDCGA), or high density with 0.1% CGA (HDCGA) groups, with six cages per treatment. CGA was supplied from day 7 to 42. At 42 d, live-weight densities were 35.00, 50.25, 34.48, and 49.38 kg/m2, respectively. Compared with their corresponding normal-density groups, the high-density groups had lower body weights at 21, 28, 35, and 42 d, and lower average daily gain (ADG) during days 21–42 (p < 0.05), whereas CGA did not significantly alter body weight or ADG within either stocking density (p > 0.05). At 35 and 42 d, the HD group had lower hepatic T-AOC, SOD, and CAT activities and higher MDA content than the ND group (p < 0.05). Compared with the HD group, the HDCGA group had higher T-AOC and CAT activities and lower MDA content at both ages, and higher SOD activity at 42 d (p < 0.05). Qualitative histological and transcript-level alterations were evident at 28 d. Compared with HD, the HDCGA group showed treatment-associated shifts in AMPK, SREBP1, ACACA, PLA2G4A, COX-2, ALOX5, and NOX5 mRNA abundance (p < 0.05). Under the experimental conditions, 0.1% CGA was associated with partial attenuation of HSD-related hepatic oxidative, lipid-metabolic, and inflammatory disturbances without a significant growth response.