Effects of high dose of vitamin A on reproduction and egg quality of Japanese flounder Paralichthys olivaceus
Fisheries Science, 67(4): 606-613
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 × 103 IU/100 g
(control diet; CD), 337 × 103 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 m3 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.
(Inland Station, National Research Institute of
Aquaculture, Tamaki, Mie, 519-0423, Japan, Tel: 81-596-58-6411. Fax: 81-596-58-6413. Email: furuita@fra.affrc.go.jp)