In order to provide a basis for the research and development of formulated cuttlefish feeds for juvenile cuttlefish,the nutrient composition was investigated in 800 yolks of fertilized eggs of S.pharaonis.The contents of moisture,ash,crude protein,crude fat,amino acids and fatty acids of yolk of S.pharaonis fertilized eggs were determined by adopting national standard method.The results showed as follows:The content of crude protein in yolk of fertilized eggs of S.pharaonis was 76.33%(dry weight basis),and the contents of total amino acid(TAA)and essential amino acids(EAA)were 71.22% and 32.38%(dry weight basis).The ratio of EAA to TAA was 45.46%,and Glu was 9.97%.The content of crude fat was 12.71%(dry weight basis).A total of 17 fatty acids were found,including 8 saturated fatty acids SFA,5 monounsaturated fatty acids(MUFA),and 4 polyunsaturated fatty acids(PUFA).And they accounted for 43.47%,7.54% and 49.25% of total fatty acids,respectively.Moreover,the content of EPA and DHA in yolk was 32.80%,7.70%,respectively.The ratio of EPA to DHA was 4.26.The yolk was rich in Ca,Mg,Zn and Al.The content of Zn.Al and Fe in yolk was 0.77,0.71 and 0.43 mg/kg(fresh weight basis),respectively.In conclusion,the yolk of fertilized eggs of S.pharaonis has high contents of protein,low content of fat,various kinds and high contents of amino acids,and lots of PUFA,especially DHA.The formulated cuttlefish feeds should be high in protein,low in fat and rich in EAA and n-3 polyunsaturated fatty acids.For example,protein requirement is 76.33%,Lys requirement is 5.49%,fat requirement is 12.71%,DHA requirement is 4.17%,EPA requirement is 0.98%,and Cu requirement is 0.19 mg/kg,and Zn requirement is 2.77 mg/kg(dry weight basis).