The effects of biofloc technology (BFT) on growth and hepatopancreas histology of speckled shrimp Metapenaeus monoceros (initial weight: 8.32 +/- 0.69 g) were investigated for 30 days. The trial was conducted in fiberglass tanks (45 L) with biofloc (zero-water exchange) and without biofloc (water exchange 50% day(-1)). Different carbon sources (corn starch: CS and glycerine: G) and mannan oligosaccharides (MOS) supplementation (with and without BFT) were tested in triplicate groups. At the end of the experiment, better growth performances, feed conversion ratio, and specific growth rates were detected in shrimps reared in BFT (CS, G, CS+MOS, G+MOS) groups. Measured water quality parameters (dissolved oxygen, pH, temperature, salinity, ammonium-NH4 and nitrate-NO3) did not differ between BFT and control groups. The total number of bacteria count of shrimp reared in the biofloc groups were higher (4.9x10(-6) +/- 8.5x10(-4) CFU mL(-1)) than that of in the without biofloc (3.7x10(-6)+/- 5.4x10(-4) CFU mL(-1)) groups. In this study BFT had no negative effects on hepatopancreatic tissue by histological assessment. It is suggested that corn starch as a carbon source in BFT with 3 g kg(-1) MOS supplementation could be applied as healthy growth enhancer in speckled shrimp culture.