Feeding trial was conducted to evaluate the effects of dietary fucoidan supplementation on biological performance and bacterial
resistance of early larval stage of Penaeus japonicus. Four microbound semi-purified diets containing graded levels of fucoidan (0.0, 100,
500, 1000 mg/kg diet) were formulated and fed to zoea larval stage of P. japonicus. Each diet was fed to three replicate groups of larvae and
the feeding trial was terminated after the larvae had metamorphosed to the mysis stage. Results indicate that supplementation level of 500
mg fucoidan/kg diet is adequate to improve the zoea metamorphic survival to the mysis stage and this supplementation level was also found
to be optimum in enhancing the bacterial resistance of zoea larvae against pathogenic Vibrio harveyi infection. The present results suggest
that Undaria pinnatifida fucoidan at a dose of 500 mg/kg diet could be used as a dietary supplement to improve the metamorphic survival
and enhance bacterial resistance of zoea larval stage of P. japonicas