Optimizing Cassava Starch Residue Inclusion in Broiler Diets: Balancing Growth Performance, Liver Health and Gut Microbial Dynamics

Background: The current study was conducted to investigate the effects of adding cassava starch residue (CSR) at different dietary levels on growth response, caecal microbial population and intestinal histopathology in broilers during a period of 6 weeks. Methodology: In total, 360 one-week-old Ross 308 broiler chicks of similar body weight were randomly distributed into six dietary treatments of five replicates of 12 birds each. The treatment groups consisted of standard diets incorporated with 0% (control), 20%, 30%, 40%, 50% and 60% CSR as a partial replacement for maize in a completely randomized design. Results: Overall body weight and weight gain were statistically heavier (p = 0.001) in the control group. The feed conversion ratio was significantly lower (p = 0.0001) for the control and CSR at 20%. Total cholesterol and high-density lipoprotein levels increased linearly with increasing CSR levels. A linear and quadratic effect (p = 0.0001 and p = 0.004) on total cholesterol, triglycerides and high-density lipoprotein was observed at the starter phase. Aspartate transaminase, alanine transaminase and alkaline phosphate were significant at the finisher phase (p < 0.05|). Villus height and crypt depth were significantly longer (p = 0.011 and p = 0.006) in the 50% CSR group. Escherichia coli counts were also significantly lower in the CSR groups at 28 days (p = 0.0001). Conclusion: It is suggested that moderate CSR inclusion (20%–30%) can be utilized in broiler diets with minimal adverse effects; however, higher rates require further evaluation to balance growth performance and health outcomes.