Interactive Effects of Cassava Starch Residue and Multi-Enzyme Supplementation on Growth Performance, Carcass Traits, Blood Metabolites and Cecal Microbiota of Broilers

This study evaluated the influence of cassava starch residues (CSR) supplemented with or without multi-enzyme (ENZ) on growth performance, hematological parameters, blood chemistry, and carcass traits, as well as intestinal bacterial populations in broiler chickens. 360 Ross 308 broiler chicks were randomly allotted into six treatments in a 3 × 2 factorial with three CSR inclusion levels (0%, 20% and 30%) and two enzyme levels (0% and 0.05%) over a 42-day feeding period. The results revealed that birds fed a CSR supplemented with ENZ had significantly better (p = 0.008) feed conversion ratio (FCR). At the starter phase, birds fed nonenzyme diets had significantly higher feed intake (p < 0.0001), while daily weight gain was significantly higher in the control and 20% CSR enzyme-supplemented groups (p = 0.003). During the finisher phase, enzyme supplementation significantly improved feed conversion ratio (p = 0.008) and influenced final body weight across treatment groups (p = 0.024). There were significantly lower white blood cells and high-density lipoprotein in the control and CSR (20 and 30%) with ENZ groups than in the control without ENZ supplementation (p = 0.0033; p = 0.0028). Total viable count, coliform count, and lactic acid bacteria (LAB) populations showed strong interaction effects (p < 0.0001), while E. coli and Enterococcus populations were significantly higher in higher CSR nonenzyme groups (P = 0.036). It can be concluded that enzyme supplementation in 20% CSR diets optimized broiler growth performance, improved feed efficiency, and promoted a more balanced gut microbial environment.