The effects of adding different carbon sources in biofloc system on growth performance, feeding and water quality indices in common carp (Cyprinus carpio) culture

Effects of adding various carbon sources in biofloc system on growth, feeding performance and water quality in common carp (mean weight of 11±0.89g) culture during 56 days in five feeding treatments including control (no extra carbon source), second treatment with molasses, third treatment with wheat flour, fourth treatment with bagasse and fifth treatment with corn flour, each with 3 replicates, was investigated. According to the results, growth and feeding indices were not significantly different among the treatments (P>0.05) but the body weight gain, survival, specific growth rate and protein efficiency ratio was higher and the food conversion ratio was better in the second treatment. TSS and FV amounts were lowest in control and highest in the second treatment, while TAN and nitrite showed an opposite trend. The changes trend in TAN and nitrite was correspondent with that of TSS and FV indicating the positive performance of flocs in biofloc system in reducing harmful nitrogenous compounds and converting it to an unharmful range for cultured common carp. In conclusion, the use of carbon sources especially molasses in the biofloc system could be recommended to improve water quality, growth and feeding performance in common carp culture.