METAGENOMIC ANALYSIS OF MICROBIAL POPULATION IN IN SITU BIOFLOC BASED CULTURE PONDS OF GIFT AND CHITRALADA STRAIN OF NILE TILAPIA
Metagenome technology - a culture-independent approach is exploited to identify microbial ecology and physiology present in the biofloc that are not readly culturable. GIFT (Genetically Improved Farm Tilapia) Tilapia and Chitralada strain of Nile Tilapia juveniles (5±0.2g) were stocked at a density of 15/m3 in triplicates for 180 days. The experimental groups consist of culture of GIFT Tilapia in biofloc as T1, culture of Chitralada strain of Nile Tilapia in biofloc as T2 and C- Control without biofloc. Distillery Spent wash was used as a carbon source to maintain the C/N ratio of 10:1 for floc development. The metagenomic DNA sample was isolated from biofloc culture pond water of GIFT Tilapia and Chitralada strain of Nile Tilapia. The QC passed metagenomic DNA sample was then processed for Shotgun paired-end sequencing library construction followed by sequencing on NextSeq500. High quality data of 9.36 GB and 3.31 GB were generated from the biofloc culture water of GIFT Tilapia and Chitralada strain of Nile Tilapia. The kingdom level abundance in pond water of GIFT Tilapia was found to be 70.80% of bacteria, 0.62% of archaea, 23.35% of unclassified, 5.08 % eukaryote and 0.16% Viruses. Whereas in pond water of Chitralada strain of Nile Tilapia 62.47% of bacteria, 0.32% of archaea, 36.77% of unclassified, 0.4% eukaryote and 0.04% Viruses was found. Proteobacteria was the most abundant phylum in both GIFT and Chitralada strain of Nile Tilapia biofloc culture water whereas. Caldilinea aerophila and Leptolyngbya sp at the species level. These results revealed large differences in the frequency distribution of high quality reads in determining the major taxonomic groups Based on the functional classification performed most of the genes were found to be involved in Carbohydrate metabolism. The present study aimed to identify the ecology and the function of microorganisms involved in the ideal biofloc formation.
