Effects of chlorogenic acid-enriched extract from Eucommia ulmoides leaf on performance, meat quality, oxidative stability, and fatty acid profile of meat in heat-stressed broilers

To investigate the effects of chlorogenic acid-enriched extract (CGAE) from Eucommia ulmoides leaf on performance, meat quality, oxidative stability, and fatty acid profile of breast meat in heat-stressed broilers, 400 28-day-old male Ross 308 broilers were randomly assigned into 4 groups with 10 replicates per group (10 broilers per replicate). Broilers in the normal group (NOR) were kept at 22 +/- 2 degrees C (24 h/D) and fed the basal diet, and the other 3 groups were treated with cyclic heat (34 +/- 2 degrees C from 08: 00 to 18: 00 and 22 +/- 2 degrees C from 18: 00 to 08: 00) and fed the basal diet supplemented with 0 (HT), 500 (CGAE500), and 1,000 mg (CGAE1000) mg of CGAE/kg of diet. The experiment lasted for 14 D. Compared with the HT group, broilers in the NOR and CGAE1000 groups had a higher average daily gain and a lower feed conversion ratio (P < 0.05). CGAE supplementation at 1,000 mg/kg increased pH(24) value, a* value and total superoxide dismutase activity and reduced drip loss, cooking loss, L* value and the contents of malondialdehyde and carbonyl in breast meat of heat-stressed broilers (P < 0.05). Broilers in the HT group showed lower mRNA levels of nuclear factor erythroid 2-related factor 2 (P < 0.001), superoxide dismutase (P = 0.004), and catalase (P < 0.001) in breast meat compared with the other groups. CGAE supplementation at 1,000 mg/kg reduced the stearic acid and saturated fatty acids (SFA) contents and increased the dihomo-gamma-linolenic acid, linoleic acid, linolenic acid, eicosapentaenoic acid, polyunsaturated fatty acids (PUFA), and n-6 PUFA contents and PUFA: SFA ratio in breast meat of heat-stressed broilers (P < 0.05). In conclusion, CGAE supplementation at 1,000 mg/kg could alleviate the adverse effects of heat stress on growth performance and meat quality and improve oxidative stability and fatty acid profile of breast meat in heat-stressed broilers.