Abstract: The aim of this experiment was to investigate whether kushen-cangzhu (Sophora flavescens Ait. and Atractylodes Lancea) granules could improve the abnormal cholesterol synthesis induced by Escherichia coli (E. coli) through regulating liver cholesterol metabolism in broilers. Forty 21 days old white-feathered broilers were randomly divided into 5 groups (8 in each group): Blank control group, model control group, low-, medium-and high-dose of kushen-cangzhu groups. The model control group and different doses of kushen-cangzhu groups were intramuscular thoracic injection treated with pathogenic E. coli bacterial solution for 0.7 mL (8.37×10⁸ CFU·mL^-1). After inoculating pathogenic E. coli bacterial solution for 24 h, different doses of kushen-cangzhu granules (low-dose group: 3.6 g·L^-1, medium-dose group: 5.5 g·L^-1, high-dose group: 7.3 g·L^-1) were supplemented in drinking water for chickens in low-, medium-and high-dose groups, respectively, and the trail lasted for 7 days. At the end of the experiment, all the broilers were slaughtered, body and organs were weighed, blood and tissue samples were collected. The morphological changes of liver were observed by hematoxylin-eosin (HE) staining. The levels of serum and liver total cholesterol (TCH), hepatic triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were detected, RT-qPCR was used to detect the expression of cholesterol metabolism-related genes in liver. The results showed that, compared with the blank control group, the broilers in the model control group had significantly lower body weight, higher liver index and serum TG content (P＜0.05), while infiltrated inflammatory cells in the central vein and the hepatic sinusoid and disordered hepatocyte was observed in model control group. TG and SCAP mRNA expression was significantly lower (P＜0.05) in liver of model control group compared with blank control group. Compared with the model control group, the body weight and liver LDL-C content was significantly increased in the low-dose group (P＜0.05), while the liver index and serum TG content were significantly decreased (P＜0.05), and the hepatic morphological structure was at a better state. The HDL-C, LDL-C and the LDL-C/HDL-C ratio in liver were significantly increased in the medium-dose group compared with model control group. Meanwhile, the mRNA expression of HMGCR, SREBP2 and SCAP was significantly enhanced (P＜0.05) in medium-dose group than model control group. In the high-dose group, the serum TG concentration was significantly reduced (P＜0.05) but hepatic LDL-C was significantly increased (P＜0.05), and the ratio of LDL-C/HDL-C was significantly raised (P＜0.05) compared with the model control group. In conclusion, the liver abnormal synthesis of cholesterol in broilers induced by E. coli was alleviated by kushen-cangzhu granules through regulating cholesterol metabolic pathway.

Key words: kushen-cangzhu granules, E. coli, white-feathered broilers, liver, cholesterol metabolism