Glucose‐Maltodextrin as Synergistic Carbon Sources Enhance Biofloc Technology: Stabilizing Water Quality, Enriching Microbial Diversity, and Boosting Production in Cherax quadricarinatus Aquaculture

Global aquaculture expansion necessitates sustainable technologies like biofloc technology (BFT), and the type of carbon source exerts a crucial impact on the functionality of biofloc systems. This study aimed to evaluate the effects of single carbon sources (glucose [G] and maltodextrin [M]) and their 1:1 mixture (GM) on water quality, microbial communities, growth performance, and physiological status of redclaw crayfish ( Cherax quadricarinatus ) in BFT systems, with a clear‐water group (F) as the control. A 70‐day experiment was conducted in triplicate tanks per treatment, with key parameters (water quality indices, microbial diversity via 16S rRNA sequencing, growth metrics, and hepatopancreatic antioxidant enzyme activities) measured. Data were analyzed using one‐way ANOVA followed by Tukey’s Honestly Significant Difference (HSD) test ( p < 0.05). Key findings showed that the GM group exhibited significantly higher microbial alpha diversity (Shannon index and Simpson index; p < 0.05 vs. all groups) and stronger functional redundancy, enriched with synergistic taxa such as Dechloromonas and Chryseolinea . Compared to the F group, all BFT groups significantly improved production yield (GM: 135.72 g vs. F: 119.35 g; p < 0.05), survival rate (GM: 88.89% vs. F: 70.22%; p < 0.05), and feed conversion ratio (GM: 1.72 vs. F: 1.89; p < 0.05), with GM performing optimally among BFT groups. The GM group also maintained a balanced carbon‐to‐nitrogen ratio (C:N) and stable total suspended solids (TSS) dynamics, while crayfish in GM showed significantly enhanced superoxide dismutase (SOD) and total antioxidant capacity (T‐AOC) and reduced malondialdehyde (MDA) levels ( p < 0.05). All biofloc systems demonstrated economic viability (benefit‐cost ratios (BCRs) > 1.40). This research provides a practical microbial‐based strategy for improving redclaw crayfish culture and crustacean aquaculture sustainability via optimized carbon source management in BFT.