The effects of dietary vitamin A in rotifers on the performance and skeletal abnormality of striped trumpeter Latris lineata larvae and post larvae

Abstract

Several nutritional studies have linked dietary vitamin A (VA) to skeletogenesis in marine fish larvae. In our study, rotifers were enriched with eight levels of retinyl palmitate. Striped trumpeter (Latris lineata) larvae were fed rotifers twice daily, VA-enriched rotifers (morning feed) and Algamac−3050 enriched rotifers (afternoon feed), in greenwater systems from 6 to 18days post-hatch (dph). The VA-enriched rotifers had incorporated 0, 6, 14, 26, 57, 109, 215 and 388ng retinyl palmitatemg−1 dry weight (DW) following 2h enrichment with emulsions containing 0 (control), 68, 187, 532, 1402, 2670, 4808 and 9523ng retinyl palmitatemg−1 emulsion. After the rotifer feeding phase (6 to 18dph), the larvae were fed Algamac−3050 enriched Artemia until 43dph. The pattern of increasing VA in the enriched rotifers was not reflected in the larvae. Larvae incorporated 11.08±0.27ng total retinolmg−1 DW (mean±SD) when fed rotifers containing 0.93 to 2.32ng total retinolmg−1 DW (6 to 14ng retinyl palmitatemg−1 DW) and incorporated a lower level of 5.57±0.30ng total retinolmg−1 DW when fed rotifers with 0.52 (control) or ≥16.31ng total retinolmg−1 DW (0 and ≥57ng retinyl palmitatemg−1 DW). By 43dph, neither larval growth in length (16.0±0.1mm) or dry weight (4.57±0.20mg), nor survival (34.8±10.6%), were significantly affected by increasing dietary levels of retinyl palmitate. The prevalence of vertebral column malformations in 43dph post larvae was positively correlated with total retinol content of larvae at 16dph (R2=0.55, P<0.001). Unlike other studies on a range of marine fish species, retinyl palmitate enrichment in rotifers did not affect the type or severity of jaw malformations. By 43dph, 81±9% of post larvae displayed severe jaw malformations. Vitamin A daily inclusion of more than 123ng total VAmg−1 DW rotifer, equivalent to more than 35ng total retinol mg−1 DW rotifer (109ng retinyl palmitatemg−1 DW rotifers), is recommended to reduce vertebral column malformations when L. lineata larvae are reared in greenwater.