Melamine residues in eggs of quails fed on diets containing different levels of melamine

Abstract

1. An experiment was conducted to determine residual melamine concentrations in eggs of quail given diets containing different concentrations of melamine, and to estimate the time at which withdrawing melamine from the diet would result in undetectable concentrations in eggs. A total of 600 Japanese quails (Coturnix coturnix japonica) were randomly divided into 5 treatments, and given melamine at concentrations of 0, 2, 10, 50, and 100 mg/kg diet respectively for 30 d. From d 31 to 41, all quails were given a diet without melamine. Each diet was offered to 4 replicates (cages) of 30 quails each. On d 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, and 41, eggs were collected for the determination of melamine and cyanuric acid levels. 2. Throughout the 41 d experimental period, inclusion levels of melamine in the diets of quails had no significant effect on daily feed intake, egg production percentage, and feed efficiency. No detectable amount of cyanuric acid was found in all eggs. When the diets contained melamine at 2 mg/kg, the amounts of melamine in eggs were below the detection limit. During the entire 30 d exposure, the maximum melamine concentrations in eggs were 0·162, 0·998 and 1·784 mg/kg for the 10, 50 and 100 mg/kg treatment groups, respectively, which demonstrated a linear dose-response relationship. 3. Upon feeding a diet without melamine, the melamine concentration in eggs decreased rapidly. The time taken for the amounts of melamine to decline below the detection limit were 1, 5, and 5 d for quails fed on the diets containing melamine at 10, 50, and 100 mg/kg respectively. 4. Melamine is not metabolised into cyanuric acid in quails, and a positive relationship exists between the concentrations in feed and in eggs.