Biofloc formation without occurrence of cultured organisms (P. vannamei post-larvae) to sustain high density of biofloc concentration - A preliminary study

Carbon-nitrogen ratio, micro-fauna abundance, water flow rate, water quality parameters were several factors studied by researchers. Unfortunately, main nutrient source and occurrence of organisms were as critically important to be investigated for biofloc formation. In this study, biofloc was formed without the occurrence of organisms (P. vannamei post-larvae) with the additional of an economical nutrient source and inoculum to speed-up and increase the concentration of biofloc formation. The triplicate experimental set-up was prepared under two condition - Treatment A (30% protein pellet feed and molasses) and Treatment B (30% protein pellet feed, molasses, wheat flour, urea, superphosphate and clay) where P. vannamei post-larvae was used as control of each treatment. Water quality parameters, biofloc volume and P. vannamei post-larvae survival rate were observed within 30 days. There was no significant difference (P < 0.05) between the water quality parameters, however, biofloc volume showed a significant difference with and without the occurrence of P. vannamei. Treatment B shows a progressive result where biofloc volume was indicated up to 90.0±4.58 mL/L at day 30. Formation of biofloc without the addition of P. vannamei post-larvae was successful within 5 days with the addition of inoculum and can be used as a starter stock in forming biofloc.