초록 |
The effects of dietary antioxidant [saltwort (SW), leek (LK), and dandelion (DD)] supplementation on the growth, body composition, serum chemistry, and challenge test results of juvenile rockfish, Sebastes schlegelii, were determined. In an experiment, 320 fish were randomly distributed into eight, 50-L flow-through tanks (40 fish per tank). Four experimental diets were prepared: the control diet (Con) with synthetic antioxidant: and diets with SW, LK, or DD from natural sources. Each diet was randomly assigned to duplicate tanks of fish, which were hand-fed to satiation twice daily for 8 weeks. After the 8-week feeding trial, 20 fish from each tank were artificially infected with Streptococcus iniae and monitored for 6 days. The dietary additives did not affect survival, weight gain, specific growth rate, feed efficiency (FE), protein efficiency ratio (PER), or plasma chemistry. However, the cumulative mortality of fish fed the SW, LK and DD diets was lower than that of fish fed the control diet beginning 4 days after infection. In conclusion, dietary supplementation with SW, LK, and DD did not affect the growth, FE, PER, or plasma chemistry of rockfish. However, dietary inclusion of SW, LK, and DD lowered the mortality of rockfish following infection with S. iniae. |