Extracts of red yolk from duck eggs inhibit metastasis of human mammary carcinoma (4T1) cells in mice

the aim of the present study was to investigate the in vivo anti-metastatic activity of the red pigments of red yolk eggs laid by the ducks dieting on potamogeton cripus l on the mammary carcinoma (4t1). the pigments were extracted with petroleum ether and acetone (2:1, v/v). balb/c mice were divided into three groups (n=6), fed with the extracts at 150 mg/kg body weight (bw)/day (deye-h) or at 50 mg/kg bw/day (deye-l) and identical buffer without the extract (control group). the extracts were administered for 34 days. the treatment significantly inhibited the growth of orthotopical 4t1 tumour (deye-h vs control, 1:2; deye-l vs control, 2:3) and reduced the metastasis of tumour in the lungs (deye-h vs control, 4:7; deye-l vs control, 5:7), without statistical difference of body weight among the three groups.