Comparative Analysis of Growth Performance, Intestinal Enzyme and Body Composition of Common Carp ( <i>Cyprinus carpio</i> ) Cultured in Different C/N Ratio of Biofloc System

ABSTRACT Biofloc technology (BFT), an eco‐friendly aquaculture system, was evaluated for its effects on growth performance, digestive physiology, gut microbiota, and carcass quality in juvenile common carp ( Cyprinus carpio ) using cane molasses as a carbon source at carbon‐to‐nitrogen (C/N) ratios of 15, 20, and 25. Compared to conventional intensive farming (control), carp reared in BFT systems (over 90 days) exhibited significantly improved growth performance, including weight gain, specific growth rate, and feed conversion ratio, particularly at C/N ratios of 20 and 25. The BFT groups also demonstrated enhanced digestive enzyme and antioxidant activity, higher proportion of beneficial lactic acid bacteria, and improved carcass composition. These findings indicate that BFT using sugarcane molasses at a C/N ratio of 20 offers a sustainable alternative to conventional carp farming. Beyond improving growth performance, BFT positively influenced fish health indicators and carcass quality.