Dietary Eucommia ulmoides Extract Alleviates the Effect of Cold Stress on Chick Growth Performance, Antioxidant and Immune Ability

SIMPLE SUMMARY: The cold stress that chicks suffer from has caused huge losses to the chicken industry. It is very important to find an effective way to alleviate cold stress in chicks. This study was designed to test the hypothesis that dietary Eucommia ulmoides extract alleviates the effect of cold stress on chick growth performance, antioxidants, and immune ability. Interestingly, Eucommia ulmoides extract supplementation improved the growth performance, antioxidant status, and immune response and reduced the organ damage of chicks caused by cold stress, which shows that Eucommia ulmoides extract has potent protective effects against cold stress. These findings will be very beneficial to break down the bottleneck issue of chick production caused by cold stress. ABSTRACT: This study aimed to investigate the protective value of Eucommia ulmoides extract (EUE) on chicks under cold stress. A total of 21 compounds were identified in EUE using mass spectrometry (LC-MS). Ninety chicks were divided into a control group (CS) fed a basal diet and an experimental group supplemented with EUE, exposed to 10 ± 1 °C for 8 h per day. Results showed, compared with the CS group, the body weights (BW) (p < 0.01) and average daily gains ADG (p < 0.05) of the EUE group were increased throughout the study period. Chicks fed EUE had higher AFI (0–7 d, p < 0.001) and lower feed-to-gain ratios (F/G) (0–15 d, p < 0.001). EUE increased the activities of superoxide dismutase (SOD) (15 d, p < 0.05) and glutathione peroxidase (GSH-Px) (7 d, p < 0.05), whereas it decreased malondialdehyde (MDA) (15 d, p < 0.01). The contents of IgA (7 d, p < 0.05), IgG (7 d; 15 d, p < 0.01), and IgM (15 d, p < 0. 001) were higher in the EUE group. Dietary EUE could also reduce chick organ damage. Overall, EUE as a natural feed additive can improve the growth performance, antioxidant capacity, and immune level, and reduce the organ damage of cold-stressed chicks.