Live diet for first feeding of Brazilian sardine, Sardinella brasiliensis (STEINDACHNER, 1879), larvae in captivity

Abstract

Previous studies indicate that Brazilian sardine can be produced in captivity as an alternative to fishing their overexploited stock. However, no research has been conducted about how to improve efficiency in larviculture, a bottleneck phase in aquaculture. Therefore, the aim of this study was to define the optimal live diet in the first feeding of Brazilian sardine larvae, testing five diets of (a) microalgae, (b) rotifer, (c) microalgae plus rotifer, (d) microalgae plus enriched rotifer and (e) microalgae plus wild zooplankton. After eight days, the larvae were sampled to verify survival, growth, digestive enzyme activities (lipase and alkaline protease) and RNA:DNA ratio. Separately, microalgae and rotifer were not enough to support the larvae, resulting in low survival (0% and 3.2 ± 2.9% respectively). However, when offered together they promoted higher survival (up to 40 ± 7.3%). Diets of rotifer enriched with oil emulsion or not produced similar growth (9.23 ± 0.16 mm and 9.13 ± 0.13 mm length respectively). The ingestion of microalgae plus zooplankton significantly increased larvae growth (10.26 ± 0.25 mm length and 2.49 ± 0.20 mg weight), lipase activity and RNA:DNA ratio after eight days. Therefore, the first feeding of Brazilian sardine larvae has better results when microalgae and zooplankton are offered together.