Tissue concentrations of sulphaquinoxaline administered in the food of laying hens

1. Sulphaquinoxaline (SQ) was fed to laying hens at a dietary level of 400 mg/kg for 3 successive days. SQ contents (mg/kg) in the blood, kidney, liver, ovary, muscle (thigh) and adipose tissue collected on 1, 2, and 3 d after the start of feeding were determined by HPLC. The relationship between the SQ content in the tissues and times (d) of SQ feeding was analyzed statistically. 2. Dietary SQ was distributed throughout the whole body. 3. Contents in tissues, except the kidney, had already reached a plateau by day 1 after die start of administration whereas in the kidney it increased linearly throughout the 3 days. 4. The plateau values of SQ in the tissues were much greater than those of sulphamonomethoxine and sulphadimethoxine.