Effects of high dose of vitamin A on reproduction and egg quality of Japanese flounder Paralichthys olivaceus
H. Furuita, H. Tanaka, T. Yamamoto, M. Shiraishi, T.
Takeuchi-2001
Fisheries Science, 67(4): 606-613
(from Current Contents)
Abstract :
The present study was conducted to investigate the
effects of dietary vitamin A on reproduction and egg quality in Japanese
flounder Paralichthys olivaceus. Broodstock were fed experimental pellets
containing two levels of vitamin A [11 x 10(3) IU/100 g (control diet; CD),
337 x 10(3)IU/100 g (experimental diet; ED)] for approximately 2 months
before spawning and during the spawning period. Two groups of five females
(average weight 1.4 kg) and 10 males (average weight 0.7 kg) were randomly
allocated to two 30 m(3) indoor tanks. Total egg production of the CD group
was slightly higher than the ED group. Percentage of buoyant eggs and
hatching rate of the ED group were significantly higher than the CD. In
other egg quality parameters, such as percentage abnormal larvae and
starvation tolerance of larvae, no notable difference was found between
these two groups. At the end of the experiment, the skin color of broodstock
in the ED group was darker than that of the CD group. Vitamin A content in
eggs of the ED group was significantly higher than that of the CD group.
However, the difference in vitamin A content in eggs between the ED and CD
groups was much smaller than that in the liver of the females between the
two groups. These results indicate that feeding broodstock a higher level of
vitamin A increases the vitamin A content in eggs but does not affect egg
quality in Japanese flounder because excess dietary vitamin A was stored
mainly in the broodstocks' liver.
(Natl
Res Inst Aquaculture, Inland Stn, Tamaki, Mie 5190423, Japan, e-mail: furuita@fra.affrc.go.jp)