THE EFFECT OF “BIOFLOC” VS. “SYNBIOTICS” ON THE GROWTH AND IMMUNE SYSTEM OF THE WHITE-LEGGED SHRIMP Litopeneaus vannamei

In recent years, there has been great interest in the use of  various b acterial driven systems,  bioflocs,  probiotics and/or prebiotics in shrimp culture. Probiotics are living microbial cells which are beneficial to the host and/or improve the quality of the environment.  The  synbiotic  concept incorporates  a nutritional supplement which is  a  combination of probiotics and prebiotics. This experiment was conducted to investigate the effects of culturing the white legged shrimp in biofloc type environments vs syn biotics  type  systems on the growth performance, immune system and water quality. Eight-week experiment was conducted at E.W. Shell Fisheries Center , Auburn University, Alabama. Static indoor polypropylene tanks were used . Each  of the twenty-four tanks was stocked with 125 shrimp/m2 . Four treatments  were evaluated including: biofloc (direct addition of rice bran), synbiotics with enzyme ( enzyme, probiotic, fermented rice bran), synbiotics without enzyme (probiotic, fermented rice bran), and control  (no supplements) with six replicates for each treatment .  For the biofloc treatment, C: N ratio of the daily organic matter addition to each of the treatment tanks was approximately 15 : 1. The  results  indicated  that the  final weight and weight gain of the shrimp raised in the biofloc treatment was significantly higher than the others followed by synbiotics with enzyme, synbiotics without enzyme  and then the control (Table 1) . However, survival, biomass (g), biomass gain (g) , weight gain (%) or FCR were not significantly affected by dietary treatment (P < 0.05) . C ulturing the shrimp in Bioflocs and Synbiotics did  numerically  increase the  number of  total Haemocyte count (THC) but there was no significant difference between treatments (P < 0.754). Comparing these culture techniques have numerous confounding factors ; however,  all produced good survival and  good growth and FCR indicating all are viable options.