ABSTRACT. The proximate compositions of three Chlorophyta (Caulerpa sp., Halimeda macroloba, and Halimeda opuntia), three Phaeophyta (Sargassum sp., Padina minor, and Dictyota sp.), and one Rhodophyta (Laurencia sp.) were determined in order to evaluate their suitability for feed supplement. The evaluated seaweed showed variable protein content between 4 to 14% (dry weight). The highest protein level of 14% dry weight (lDW) was determined in Sargassum sp., but this species also recorded the lowest level (0.2-0.5%) of lipid. On the other hand, the highest content of 4% (DW) lipid and 11% (DW) protein level was observed in the species Dictyota. Of the other species, Padina minor from the same group, shows 10% (DW) and 1% (DW) levels of protein and lipid respectively. Seaweed meal of these three species was prepared and mixed separately with 2% of Rhodovulum sp. Thus, three types of supplementary diet were prepared for Tilapia fry feeding trials. Rhodovulum sp. bacterium biomass alone was used as control diet. The preliminary feeding trial showed that the growth and survival of fin fish larvae were improved with the supplemented diet made from Dictyota meal mixed with 2% of Rhodovulum sp. Thus, indigenous self-flocculated phototrophic bacterium Rhodovulum sp. is improved when used as a feed additive enhanced with this seaweed meal in Tilapia (Oreochromis niloticus) fry rearing period.
KEYWORDS. Growth, Rhodovulum sp., seaweed meal, survival, Tilapia fry.