Nippon Suisan Gakkaishi 74 (1), 20-25 (2008)

The effect of female presence upon serum levels of vitellogenin in male Japanese whiting Sillago japonica

KOMEI HOTTA,1* TAKAYUKI WATANABE,1a CHIHO KISHIDA,1 YUKIO NAKAMURA,1a
SHIGEHO IJIRI,2 SHINJI ADACHI2 AND KOHEI YAMAUCHI2

1Marine Ecology Research Institute, Kashiwazaki, Niigata 945-0017, 2Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan

To investigate the potential effects of female presence upon serum levels of vitellogenin (Vg) in male fish, we held male Japanese whiting Sillago japonica in the presence (Group FM) or absence (Group M) of females for three weeks. Fish were first reared for three weeks after the grouping and then sampled from each group at four-hourly intervals. Analyses were performed on serum vitellogenin levels, gonad somatic index (GSI: gonad weight/body weight ×100), and testicular histology. Serum levels of Vg in males from Group FM were higher than those of males from Group M. Moreover, GSI of Group FM males was also higher than males in Group M, although histological analysis demonstrated active spermatogenesis in the testes of males from both groups. These results suggest that the presence of females causes an increase in the serum levels of Vg and GSI in male fish.


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