Replacement of fresh algae with commercial formulas to enrich rotifers in larval rearing of yellowtail kingfish Seriola lalandi (Valenciennes, 1833)

This study compared the efficacy of four products that are commonly used in hatchery for nutritional enhancement of rotifer Brachionus plicatilis as the starter food for yellowtail kingfish Seriola lalandi larvae. This experiment consisted of one fresh algae and three enrichment products: (1) Fresh algae were a mixture of Nannochloropsis and Isochrysis at 2:1 on a cell concentration basis; (2) S.presso, (Selco S.presso ^®, INVE Aquaculture); (3) Algamac 3050^® (Aquafauna, USA); (4) Nutrokol ^® (Nutra-Kol, Australia). Survival rates of the fish fed rotifers enriched with fresh microalgae (40.69%) and S.presso (31.21%) were higher than those fed Algamac 3050 (10.31%). On 3 day post hatch (DPH), fish feeding incidence in the fresh algae treatment was significantly higher than that in other treatments. On 6 DPH, fish showed the lowest feeding incidence in the Algamac 3050 treatment. The methods of enrichment did not affect total lipid levels in either rotifer or fish larvae, but Algamac 3050 enrichment achieved the highest DHA/EPA ratio and lowest EPA/ARA ratio in both rotifers and fish larvae. This study indicates that fresh algae can be replaced by S.presso, but Algamac 3050 is not as good as other formula for rotifer enrichment in rearing yellowtail kingfish larvae in this system.