Biofloc characterization after achieving a stable population of Chlorella sp. for Penaeus vannamei culture (Bonne, 1931)

This study investigated the integration of microalgae into biofloc systems for Penaeus vannamei under controlled photoperiods, assessing effects on growth performance, water quality, and biofloc ecology. Two consecutive experiments were conducted: (1) evaluation of four photoperiod regimes (16:8, 12:12, 8:16, 0:24 light:dark) combined with Chlorella sp. or Phaeodactylum tricornutum , and (2) the comparison of microalgae or probiotic addition in a biofloc system. Chlorella sp. under 16:8 and 12:12 photoperiods maintained stable populations, promoted greater biodiversity, particularly complex zooplankton and improved mineral profiles by increasing boron and arsenic while reducing bromine. In the second experiment, Chlorella sp. persisted up to 32 days, contributing to nitrate reduction and enriching arachidonic and eicosapentaenoic acid content in the biofloc. However, in terms of growth, the better SGR obtained in the first assay was not confirmed in a second trial. Principal component analysis highlighted a consistent correlation between nitrate concentration and the performance of shrimp, as well as microalgae inoculation and PUFA increase on biofloc. Overall, Chlorella sp. under a 12:12 photoperiod enhanced biofloc quality and ecological diversity, supporting its potential for improving aquaculture system performance.