Abstract: 【Objective】 This experiment was conducted to study the effects of dietary fermented cottonseed meal level on growth performance, meat quality and antioxidation activity of Yellow-feathered broilers aged 1 to 63 days.【Method】 A total of 960 1-day-old Lingnan Yellow-feathered broilers were randomly divided into 4 treatment groups with 6 replicates per treatment and 40 chickens per replicate.The supplemental levels of fermented cottonseed meal in starter (1-21 d) diets was 0,5%,7.5% and 10%,in grower diets (22-42 d) was 0,6%,9% and 12%,and in finisher diets (43-63 d) was 0,10.5%,14.0% and 17.5%,respectively.The experiment lasted for 63 days.During the experiment,ADFI was recorded every day, and body weigh was recored at 1,21,42 and 63 days of age, and growth performance was calculated in units of replicate.Two chickens were selected from each replicate for blood collection and sample collection,and immune organ index,plasma and liver antioxidant indexes and meat quality were determined.【Result】 Compared with the control group,the F/G in high-supplemental group was significantly decreased from 1 to 21 days of age (P＜0.05). At 43 to 63 days of age,the ADFI of low-supplemental group was significantly decreased(P＜0.05),but the F/G had no significant difference (P＞0.05).The ADFI and ADG were significantly decreased in low-supplemental groups during the whole experiment period (1 to 63 days of age) (P＜0.05),but the F/G had no significant difference (P＞0.05).There were no significant difference on thymus index,spleen index,bursa index,shear force of chest muscle,water drop loss,pH value (45 min and 96 h) and meat color (45 min and 96 h) of 63-day-old Yellow feathered broilers among 4 groups (P＞0.05),and no obvious changes were found in liver section analysis.Plasma MDA content in medium-supplemental group was significantly higher than that in other experimental groups (P＜0.05).The liver T-AOC in low and medium supplemental groups were significantly higher than that in control group (P＜0.05).【Conclusion】 In conclusion,dietary supplementation of 10%,12% and 17.5% fermented cottonseed meal (free gossymol content was 12.21 mg/kg) to replace the same amount of soybean meal in Yellow-feathered broilers had no negative effects on the growth performance and meat quality,and the lowest F/G could be obtained by supplemented with 7.5%,9.0% and 14.0% fermented cottonseed meal in starter,grower and finisher stage,respectively.

Key words: fermented cottonseed meal; Yellow-feathered broilers; meat quality; growth performance; antioxidation activity