EFFECT OF BIOFLOC ON THE SURVIVAL AND GROWTH OF THE POSTLARVAE OF THREE PENAEIDS (LITOPENAEUS VANNAMEI, FENNEROPENAEUS CHINENSIS, AND MARSUPENAEUS JAPONICUS) AND THEIR BIOFLOC FEEDING EFFICIENCIES, AS RELATED TO THE MORPHOLOGICAL STRUCTURE OF THE THIRD MAXILLIPED

Bioflocs contribute to the nutrition and growth of some penaeid shrimp, such as L. vannamei, by providing an additional food source in intensive, limited exchange production systems. However, it remains unclear whether other penaeids could use bioflocs as food sources. Furthermore, little is known concerning the feeding mechanism of shrimp for harvesting and consuming bioflocs. This study determines whether three penaeid species could use bioflocs as food sources and suggests mechanical functions of the third maxilliped to collect bioflocs in a water column. The postlarvae of L. vannamei, E chinensis, and M. japonicus were assessed in 14-day culture trials with four treatments: biofloc water with feeding (BF-f), natural seawater with feeding (SW-f), biofloc water without feeding (BF-nf), and natural seawater without feeding (SW-nf). Litopenaeus vannamei exhibited a significantly higher specific growth rate (SGR) in the BF-f treatment than in the SW-f treatment, whereas the other two species did not demonstrate any differences in their SGR and survival rate between BF-f and SW-f treatments, suggesting that bioflocs might contribute to the growth of L. vannamei postlarvae but do not affect the survival and growth of F. chinensis or M. japonicus. The results obtained from the non-feeding experiments implied a filter feeding habit of L. vannamei and a cannibalistic habit of E chinensis. Differences in the third maxillipeds are relevant in this regard. The feeding mechanism of M. japonicus with intermediate features of setae requires further study. The present study may contribute to understanding the different feeding abilities of bioflocs as food source in currently farmed penaeid shrimp in the Far East Asian countries.