passages.id: split_4_test_2111_passage
passages.type: progene_text
passages.text: Vitellogenin ( Vg ) and its corresponding yolk protein ( YP ) products , YP1 , YP2 and YP3 , were isolated from serum of estrogen - treated hybrid sturgeon ( bester ; Huso huso X Acipencer ruthenus ) and eggs from untreated fish , respectively .