Faculty of Veterinary Medicine, Urmia University Veterinary Research Forum 2008-8140 15 8 2024 08 01 Using a combination of phospholipid fatty acids profiles and DNA-based sequencing analyses to detect shifts in the biofloc microbial community in different carbon sources and carbon/nitrogen ratios 425 434 714398 10.30466/vrf.2024.2015189.4060 EN Ebrahim Hossein Najdegerami Department of Biology, Faculty of Science, Urmia University, Urmia, Iran 0000-0001-9180-081X Ramin Manaffar Department of Fisheries, Faculty of Natural Resources, Urmia University, Urmia, Iran 0000-0002-6818-0760 Journal Article 2023 11 11 A 35-day study investigated the impact of carbon sources and carbon/nitrogen (C/N) ratios on the microbial community of biofloc. For this purpose, we utilized a combination of phospho-lipid fatty acids (PLFAs) profiles and DNA-based sequencing methods to investigate changes in the microbial community composition and structure. The experiment involved three carbon sources including Dextrin (DEX), corn starch (CS) and wheat bran (WB) at two C/N ratios (19 and 30). The results indicated that WB and CS were found to decrease nitrogen metabolite concentration while increasing total suspended solids and bacterial density compared to DEX. The treatments exhibited variations in microbial communities and the use of polymerase chain reaction/ denaturing gradient gel electrophoresis analysis revealed distinct dominant bacterial species linked to carbon sources and C/N ratios. Furthermore, the highest levels of bacteria and protozoa PLFAs biomarkers were observed in the C/N30 ratio and WB treatment while the ratio for poly-β-hydroxybutyrate/PLFAs and fungi biomarkers displayed a decrease. Also, by incorporating the results of PLFAs profile and conducting a principal component analysis, the treatments were categorized into distinct groups based on both the carbon source and C/N ratios. Overall, both methods yield consistent results. PLFAs offered additional insights into the microbial composition beyond bacterial structure while DNA-based analysis provided finer taxonomic resolution. https://vrf.iranjournals.ir/article_714398_b2ff4e664ed7f7d3f6c91a5f593c35f1.pdf