Each type of bioflocs grown on a different carbon source
(molasses, tapioca, tapioca by-product, rice bran) was adequate in
maintaining the overall water quality parameters in a normal range
for shrimp growth. The lower level of dissolved inorganic nitrogen
generally observed in the tanks with biofloc treatment as compared
to the control with regular water replacement confirmed previous
reports regarding the effect of BFT application on water quality in
shrimp culture. Avnimelech [6] pointed out different effects ofsimple versus more complex carbohydrates applied as the carbon
source in biofloc-based ponds. Simple sugars, such as sucrose,
result in a faster ammonia removal, while more complex carbohydrates
require more time for decomposition into simple sugars,
thereby resulting in slower ammonia removal. This may explain the
higher TAN levels at several time points during the experimental
period for the rice bran treatment, the carbon source that contained
the highest fibre level, as compared to the other carbon source
treatments. In this regards, fermentation of the complex carbon
sources prior to application in biofloc system could be an alternative
solution and interesting subject for further investigation for the
use of complex or fibrous carbon sources.