Tilapia is a freshwater fish with high economic value , so many tilapia are cultured intensively to increase production value . To maximize production using the biofloc technique generally uses 2 types of bacteria that are commonly found in probiotic products . They are namely lactobaccilus sp and baccilus sp because they are considered sufficient to maximize the application to optimize tilapia fish production . In this activity , Nitrobacter was included to complete the function of Lactobaccilus sp and Bacillus sp.
Culture intensification , especially increasing stocking density , has an adverse impact on environmental . The decrease in environmental quality is caused by organic waste from leftover feed and manure , this waste is generally dominated by toxic organic nitrogen compounds.
Biofloc tehcnology is an alternative solution to the problema of intensive cultivation waste . This technology is considered the most profitable beacuse apart from being able to reduce organic nitrogen waste and feed residue , it can increase fish growth and feedefficency . Biologically , in nature , ammonia can actually be converted into nitrate (NO³ ), a form that is not dangerous in the nitrification process , however , the high levels ofammonia in intensive culture give and idea that the amount of Nitrobacter present is still no table to balance the amount of amonia produced . The refore , the addition of Nitrobacter in intensive culture systrem is expected to improve water quality due to high fish density so that it can increase fish growth and production.
In this activity , 3 biofloc tanks with a diameter of 3 meters were used using different types of bacteria and stocking dendensities , in the first tank , the types of bacteria used were Lactobaccilus sp and bacillus sp with a density of tilapia sedes of 120 fish/m³ , in the second tank apart the type of bacteria used Lactobacillus sp and Bacillus sp with density of 200 fish/ m³ and in 3rd tank apart from the bacteria Lactobacillus sp and Bacillus sp there was the adition of Nitrobacter and the stocking density of Tilapia sedes was 200 fish/ m³ .
Based on the results of applying this method , the following results were obtained , in summarized in table 1.
Key words
Probiotic , lactobacillus sp , Bacillus sp, Nitrobacter