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Dietary 17 β‐oestradiol and 17 α‐ethinyloestradiol alter gonadal morphology and gene expression of the two sex‐related genes, dmrt1 and cyp19a1a , in juvenile barramundi ( Lates calcarifer Bloch)
Author(s) -
Banh Quyen Q. T.,
Domingos Jose A.,
Pinto Ricardo C. C.,
Nguyen Kien T.,
Jerry Dean R.
Publication year - 2021
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.14996
Subject(s) - barramundi , biology , gonad , feminization (sociology) , endocrinology , medicine , downregulation and upregulation , andrology , lates , gene expression , gene , fish <actinopterygii> , fishery , genetics , social science , sociology
This study investigated the effect of 17 β‐oestradiol (E 2 ) and 17 α‐ethinyloestradiol (EE 2 ) on the feminization of barramundi ( Lates calcarifer ). Fish were fed pellets containing 10 mg E 2 /kg food, 20 mg E 2 /kg food, 5 mg EE 2 /kg food and 10 mg EE 2 /kg food from 30 to 160 days post hatch (dph), which covers the period of initial male gonad differentiation. The effect of E 2 and EE 2 treatment on gonadal morphology and dmrt1 and cyp19a1a gene expression was analysed by histology and RT‐qPCR. Orally delivered E 2 and EE 2 induced observable changes in gonad morphology. Previtellogenic oocytes (PO) were observed in 33% and 50% of the fish fed with 20 mg E 2 /kg at 160 dph and 12 months post hatch (mph), respectively, while PO were not observed in control fish. 10 mg E 2 /kg treatment did not induce feminization, but significantly suppressed testicular development. Treatment with EE 2 resulted in fibrosis within gonad tissues at a dose‐dependent rate. E 2 administration resulted in upregulation of the gene cyp19a1a and downregulation of dmrt1 . EE 2 significantly suppressed expression of dmrt1 at 160 dph and 12 mph, while cyp19a1a was not significantly different at 160 dph and was significantly downregulated at 12 mph. The result of this study showed that E 2 is a more suitable hormone than EE 2 to induce precocious feminization of barramundi, and when delivered through the feed it has a dose‐dependent feminizing effect.