In oviparous vertebrates, vitellogenin (Vtg) is synthesized in the liver and endocytosed by oocytes to be used as the precursor of the yolk proteins. The aim of this study was to verify if bluefin tuna (Thunnus thynnus) reared in captivity under experimental conditions exhibited normal levels of liver vitellogenin gene expression and yolk accumulation in growing oocytes. Liver and ovary samples were taken from 27 bluefin tuna reared in captivity in floating cages in Cartagena (Spain), Malta and Vibo Marina (Italy). For comparison, liver and ovary samples from 33 wild individuals were used. Liver samples were stored in RNA later® for molecular biology studies and ovary samples were fixed in 10% buffered formalin, dehydrated in ethanol and embedded in paraffin wax for histological analysis. Vtg cDNA was partly sequenced and a comparative analysis of liver Vtg mRNA between wild and captive individuals was carried out. The diameter of fully vitellogenic oocytes and oocyte surface occupied by yolk granules were compared between wild and captive fish. No significant difference in Vtg mRNA levels was observed between wild and captive individuals. An abnormal yolk accumulation occurred in captive individuals unable to undergo post-vitellogenesis
Liver vitellogenin gene expression and oocyte yolk accumulation in wild and captive bluefin tuna (Thunnus thynnus L.)
Zupa R;Pousis C;CORRIERO, Aldo
2009-01-01
Abstract
In oviparous vertebrates, vitellogenin (Vtg) is synthesized in the liver and endocytosed by oocytes to be used as the precursor of the yolk proteins. The aim of this study was to verify if bluefin tuna (Thunnus thynnus) reared in captivity under experimental conditions exhibited normal levels of liver vitellogenin gene expression and yolk accumulation in growing oocytes. Liver and ovary samples were taken from 27 bluefin tuna reared in captivity in floating cages in Cartagena (Spain), Malta and Vibo Marina (Italy). For comparison, liver and ovary samples from 33 wild individuals were used. Liver samples were stored in RNA later® for molecular biology studies and ovary samples were fixed in 10% buffered formalin, dehydrated in ethanol and embedded in paraffin wax for histological analysis. Vtg cDNA was partly sequenced and a comparative analysis of liver Vtg mRNA between wild and captive individuals was carried out. The diameter of fully vitellogenic oocytes and oocyte surface occupied by yolk granules were compared between wild and captive fish. No significant difference in Vtg mRNA levels was observed between wild and captive individuals. An abnormal yolk accumulation occurred in captive individuals unable to undergo post-vitellogenesisI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
