The objective of this study was to document the immunological effects of growing shrimp in biofloc
systems. The experiment consisted of four types of biofloc systems in which bioflocs were produced by
daily supplementation of four different carbon sources, i.e. molasses, tapioca, tapioca-by-product, and
rice bran, at an estimated C/N ratio of 15 and a control system without any organic carbon addition. Each
biofloc system was stocked with Pacific white shrimp (Litopenaeus vannamei) juveniles that were reared
for 49 days. The use of tapioca-by-product resulted in a higher survival (93%) of the shrimp as compared
to the other carbon sources and the control. The highest yield and protein assimilation was observed
when tapioca was used as the carbon source. After 49 days, phenoloxidase (PO) activity of the shrimp
grown in all biofloc systems was higher than that of the shrimp from the control system. Following a
challenge test by injection with infectious myonecrosis virus (IMNV), the levels of PO and respiratory
burst (RB) activity in the shrimp of all biofloc treatments were higher than that of the challenged shrimp
from the control treatment. An increased immunity was also suggested by the survival of the challenged
shrimp from the experimental biofloc groups that was significantly higher as compared to the challenged
shrimp from the control treatment, regardless of the organic carbon source used to grow the bioflocs.
Overall, this study demonstrated that the application of biofloc technology may contribute to the
robustness of cultured shrimp by immunostimulation and that this effect is independent of the type of
carbon source used to grow the flocs.