The contribution of diatoms to bioflocs lipid content and the performance of juvenile Litopenaeus vannamei (Boone, 1931) in a BFT culture system

Abstract

This study aimed to evaluate the contribution ofthree diatom species on the lipid content of bio-flocs, their permanence on the bioflocs and influ-ence on the growth performance of juvenileshrimps. Juveniles of Litopenaeus vannamei werereared (30 days; three replicates per treatment)in biofloc systems inoculated with diatomsAmphora coffeaeformis (A), Cylindrotheca closterium(C), Conticribra weissflogii (W), or biofloc only(BF, chlorophycean rich). Water quality parame-ters were monitored daily and the microbiota ondays 1, 10, 20 and 30. The lipid content andfatty acid profiles of bioflocs were analyzed at theend of the experiment. Shrimp survival rate(99%) at treatment A was significantly higherthan at BF. The bioflocs in A treatment pre-sented the highest lipid content, differing signifi-cantly from BF and W. The content of EPA(20:5) (n-3) was significantly higher in A andlower in BF, while linoleic acid (18:2) (n-6) wassignificantly higher in BF. The results indicatethat high cell density of diatoms can be success-fully maintained with silicate addition in bioflocsystems and that the pennate A. coffeaeformis andthe centric C. weissflogii are potentially better sui-ted than the pennate C. closterium as food sup-plements for shrimp diets in biofloc nurseriessystem.