Nutritional evaluation of rotifers in rearing tanks without water exchange during seed production of amberjack Seriola dumerili

Abstract

We evaluated the nutrient contents of rotifers sampled from larval-rearing tanks (tank rotifers) without water exchange during the seed production of amberjack Seriola dumerili at three facilities (Kamiura, Kagoshima, and Miyazaki) and compared them with the nutrient contents of freshly enriched rotifers. Compared to the enriched rotifers, the lipid contents, especially neutral lipids and proportion of 22:6n-3, tended to decrease in the tank rotifers. These trends were clearer at Miyazaki where the tank rotifers were sampled before daily supplementation of microalgae (Nannochloropsis). Crude protein content of the tank rotifers did not decrease markedly although the proportion of lysine tended to decrease. Vitamin C and E contents of the tank rotifers decreased significantly only at Miyazaki. Calcium content of the tank rotifers increased at Kamiura and Miyazaki, and the increases in iron and manganese contents of the tank rotifers at Miyazaki and zinc content at Kagoshima were pronounced. These results suggest that the nutritional value of rotifers in larval-rearing tanks without water exchange can be maintained by appropriate supplementation of microalgae. The effect of certain minerals that became high in tank rotifers on subsequent larval development requires further investigation.

Influence of hormonal induction and broodstock feeding on longfin yellowtailSeriola rivolianamaturation, spawning quality and egg biochemical composition

“…; Yamamoto et al . ). Indeed, increase in polyunsaturated fatty acids in diets for broodstock of several species markedly reduces the percentage of abnormal embryo, improving egg viability (Izquierdo et al .…”

The effect of different rotifer feeding regimes on the growth and survival of yellowtail kingfish Seriola lalandi (Valenciennes, 1833) larvae

“…Rotifers metabolize the nutrients they acquire during enrichment, resulting in a deterioration in their nutritional quality over time (Yamamoto, Teruya, Hara, Hokazono, Kai, Hashimoto, Furuita, Matsunari & Mushiake ). Although our loss modelling demonstrates the greater potential for nutritional depletion of enriched rotifers in the high density treatment, we witnessed no difference in growth or survival between treatments.…”

Visualization of skeletons and intervertebral disks in live fish larvae by fluorescent calcein staining and disk specific GFP expression

“…Epinephelus sp.) exhibited skeletal deformities particularly in craniopharyngeal skeletons (Nagano et al., 2007; Yamamoto et al., 2009). Calcein staining of cranial and jaw skeletons have been potentially useful for screening of deformed larvae of these species.…”