Changes in serum lipid, lipoprotein and corticosterone concentrations during neonatal chick development.

Broiler chicks were given a standard commercial starter diet from day 0 (day of hatch) to 9 days of age. Body weight and concentrations of the following serum constituents were measured daily: glucose (GLU), triglycerides (TRI), corticosterone (CORT), cholesterol (CHOL), and high (HDL) and low (LDL) density lipoproteins. Serum GLU and TRI increased at each sampling day to reach a peak on days 3 and 4, respectively, and then decreased thereafter. However, CHOL, HDL, and LDL decreased sharply by day 1 and then gradually decreased to day 5. Conversely, CORT peaked on day 1 and then decreased to day 4. It peaked again on day 5 and remained at that level throughout the remainder of the experiment. In summary, serum concentrations of all constituents measured fluctuated drastically between 1 and 5 days of age, with few changes occurring between days 6 and 9.