Metagenomic characterization of biofloc in the grow‐out culture of Genetically Improved Farmed Tilapia (GIFT)
Menaga Meenakshisundaram, Felix Sugantham, Charulatha Muthukumar, Mohana Sundari Chandrasekar
Abstract
The bacterial community characterization of biofloc in grow-out system of GIFT (Genetically Improved Farmed Tilapia) was carried out to ascertain the dynamics and community structure of the microbiome. GIFT (5.1 ± 0.05 g) were stocked for 180 days at the stocking density of 15/m3 in triplicates. Distillery spent wash as carbon source was used for maintaining the C:N ratio at 10:1. Recorded water quality parameters revealed no significant difference among the replicates. The microscopic characterisation of the floc observed to be of uniform size (5–30 µm) but varied in shape throughout the culture period. Metagenomic profile of the floc was done through shotgun sequencing using Illumina NextSeq500 platform. High-quality data of 9.36 GB were obtained consisting 911,255 genes. The kingdom-level abundance was found in the order of 70.80% of Bacteria, 23.35% of Unclassified, 5.08% Eukarya, 0.62% of Archaea and 0.16% of Viruses. At the generic level composition, Proteobacteria and Caldilinea aerophila were the most abundant genus identified. Gene ontology using KEGG and SEED classification revealed predominantly carbohydrate metabolism associated genes. The present study is the first of its kind to study the microbial composition in biofloc of outdoor GIFT Tilapia grow-out culture and to identify the functional attributes of the microbiome in the biofloc system.