Replacement value of cassava for maize in broiler chicken diets supplemented with enzymes

Objective: Pellet durability, particle size distribution, growth response, tibia bone character istics and energy retention were measured to evaluate cassava as an alternative energy source to replace maize in broiler diets with or without Ronozyme (A+VP) enzyme composites.

Methods: A total of 480 oneday broiler chicks were randomly assigned to 8 treatments in a 4×2 factorial arrangement. Four levels of cassava: (0%, 25%, 50%, 75%) and 2 levels of enzymes (0 and 500 g/tonne) were used. Each treatment was replicated six times, with ten birds per replicate.

Results: The particle size distribution in the diets showed an increasing trend of small particles with increase in cassava level. Pellet durability decreased (p<0.05) with cassava inclusion. Feed intake was highest in birds fed diets with medium cassava level at 1 to 24 d and 1 to 35 d of age. The body weight gain of birds reduced (p<0.037) as cassava level increased, but it increased (p<0.017 when enzymes were added. The feed conversion ratio was high (p<0.05) when cassava level was increased, but it reduced (p<0.05) when enzymes were added. The dressing percentage (DP), and weight of drumsticks reduced (p<0.05) with increasing cassava level. Enzyme supplementation increased (p<0.05) DP, and weight of breast, thighs and drumsticks. Ash content, weight, length, width, and bone strength decreased (p<0.05) when cassava level was increased, however, they were increased with enzyme addition. The contents of Ca, K, and Zn were raised (p<0.001) with increasing cassava level. Enzyme inclusion increased (p<0.001) all mineral contents in tibia bones. Body fat and energy retained as fat decreased (p<0.001) as cassava level increased. Enzyme inclusion increased (p<0.05) body protein content and energy retained as protein.

Conclusion: Although broiler performance was depressed by high levels of cassava inclusion, it was not affected by low levels, which further improved by enzyme supplementation.