Abstract: This research was conducted to investigate the effects of free gossypol on fatty acid in liver, lipid peroxidation index and serum index of laying hens. A total of 360 healthy 42-week-old Beijing pink 2 laying hens were randomly divided into 4 groups with 3 replicates per group and 30 hens per replicates. Laying hens in 4 groups fed the basal diet supplemented with gossypol acetate 100 mg/kg (group L), 200 mg/kg (group M), 400 mg/kg (group H) and 0 mg/kg (group C). The experiment lasted for 42 days. TG, CHOL, AST, ALT, LDL-C and HDL-C were determined with biochemical analyzer. At the end of the test, laying hens were executed with bleeding, the livers were collected to determine the fatty acids and lipid peroxidation, also pathological and ultrastructure observation. The results showed that the activity of AST, ALT increased with exposed to Gossypol acetate, showing the time and dose effect. At the 4th and 6th week, TG and LDL-C have increased very significantly (P<0.01), TC and HDL-C also increased significantly(P<0.05). Gossypol acetate decreased the unsaturated fatty acid composition and increased the saturated fatty acid proportion in liver. Liver lipid peroxidation index SOD, GSH-Px and GSH decreased significantly(P<0.05) and MDA increased significantly(P<0.05). Gossypol acetate caused laying hens hepatic steatosis, and showed a dose effect. Gossypol acetate caused structural damage of mitochondria in liver of laying hens. In conclusion, gossypol acetate caused the oxidative stress damage in hepatocyte, further caused the structure and function damage of mitochondrial which played an important role in fat depositing in liver of laying hens.

Key words: gossypol acetate, laying hens, liver, fatty acid