Cholesterol metabolism changes in the early stages of ascites in broiler chickens

Cholesterol is essential for life, and disorders related to cholesterol metabolism may become metabolic diseases. To investigate the changes that occur in cholesterol metabolism in broiler chickens with cold-induced ascites syndrome (AS), 216 one-day-old male broilers were randomly assigned to two groups (Control and AS), with 6 replicates of 18 birds each. Starting on day 14, the birds in the AS group were exposed to low ambient temperatures (17 degrees C during the daytime and 14 degrees C at night) to induce AS. The serum total cholesterol (TC) content of the AS group was significantly increased at day 21; however, there was no significant difference between groups at day 35. Additionally, there was no significant difference in the hepatic mRNA expression of 3-hydroxy-3-methyl-glutaryl-CoA reductase, low-density lipoprotein receptor, apolipoprotein AI, ATP-binding cassette transporter G5 and ATP-binding cassette transporter G8 at days 21 and 35. The hepatic mRNA expression of cholesterol 7 alpha-hydroxylase (CYP7A1) and liver X receptor a of the AS group was significantly decreased at day 21, whereas there was no significant difference at day 35, as was the hepatic CYP7A1 protein content. The results of this study indicate that in the AS group, the increased serum TC at day 21 may be the result of unchanged cholesterol synthesis, uptake, transport and reduced cholesterol decomposition in the liver. The unchanged serum TC content at day 35 may be the result of unchanged cholesterol synthesis, uptake, transport and decomposition in the liver.