The resistance to physical
stresses by Penaeus monodon juveniles fed diets supplemented with
astaxanthin
Yew-Hu Chien, Chih-Hung Pan, B. Hunter-2003
Aquaculture, 216(1-4): 177-191
Abstract:
This study was aimed to determine if the increase of
body astaxanthin content through dietary supplementation in tiger prawn Penaeus
monodon juvenile could enhance its antioxidant defense capability and
resistance to thermal and osmotic stress. Hemolymph total antioxidant status
(TAS) and superoxide dismutase (SOD) were chosen as indices of shrimp
antioxidant capacity. Resistance to thermal and osmotic stress was expressed
as shrimp recovery, and hemolymph aspartate aminotransferase (AST) and
alanine aminotransferase (ALT). Tiger prawn 5-day postlarvae were fed diets
supplemented with 0 or 80 mg astaxanthin/kg diet for 8 weeks so that the
resulting juveniles contained two levels of astaxanthin. Subsequently,
shrimp were subjected to a rapid change in water temperature (27 to 5°C)
and/or salinity (32 ppt to 0 ppt) for 5 min. The treated shrimp contained
markedly higher body astaxanthin than the control shrimp. Significantly
higher average recovery in treated shrimp (56%) than control shrimp (48%)
suggested that astaxanthin supplement had improved the resistance against
thermal and osmotic stress. Thermal stress had a more profound effect than
osmotic stress on the recovery of shrimp, as indicated by the difference in
recovery, 73% versus 24%. TAS was improved and SOD was reduced by the
presence of dietary astaxanthin. The enhancement of antioxidation capacity
by dietary astaxanthin and consequently, the improvement of recovery against
thermal and osmotic stress have demonstrated that astaxanthin is a
`semi-essential' nutrient for tiger prawn. The presence of astaxanthin can
become critical when the animal is under physiological stress caused by
abiotic changes. However, complicated interactions were observed among
thermal and osmotic stresses and improvement of resistance conferred by
dietary astaxanthin. Shrimp hepatopancreatic function may have been improved
by dietary astaxanthin since hemolymph AST of the control shrimp was
significantly higher than that of the treated shrimp. However, hemolymph AST
and ALT content of shrimp did not reflect improvement in health following
thermal and osmotic stresses, respectively.
(Department of Aquaculture, National Taiwan Ocean
University, Keelung 202, Taiwan, Tel.: +886-2-24622192x5204; fax:
+886-2-24625393; email: yhchien@mail.ntou.edu.tw)