Effects of roxazyme-G on growth indices and haematological variables of broilers fed maize offal-based diets

Abstract

Influence of roxazyme–G on the utilization of maize offal was investigated using 420 broiler chicks and 210 (5-week old) growing broilers at starter and finisher phases, respectively. A basal diet that met the nutrient requirement for each phase was formulated and used for the trial. Basal diet meant for starter phase contained 529 g kg^-1 maize while basal diet for finisher phase contained 569 g kg^-1 maize. For each phase, 25% or 50% maize component of each basal diet were replaced with maize offal. Thereafter, the maize offal-based diets were divided into 3 equal parts and designated diets 2, 3 and 4 for diets in which its 25% maize component was replaced with maize offal and diets 5,6 and 7 for those with their 50% maize components replaced with maize offal. Roxazyme-G was added to the diets at levels of 100, 200 and 300 mg kg^-1 in diets 2 & 5, 3 & 6 and 4 &7, respectively. The birds were fed their respective diets for 21 days. At the close of the starter (2-4 weeks of age) and finisher (5-8 weeks of age) phases 10 chicks and 10 chickens per replicate, respectively were sacrificed conventionally and their blood collected for blood analysis. Of the growth indices measured only the final weight of chicks was significantly (P≤0.05) influenced by the dietary treatment. The entire haematological indices measured were not significantly (P≥0.05) influenced by dietary treatment in both starter and finisher birds. At starter phase, the optimum level of maize offal inclusion could be achieved at 132.3 g kg^-1 + 200 mg kg^-1 roxazyme–G while 142.3 g kg^-1 maize offal + 200 mg kg^-1 roxazyme-G was for finishers. Conclusively, the use of maize offal and roxazyme -G at these optimal levels could lead to more of maize offal being included in broiler diets in tropical countries.

Keywords: Finisher, maize offal, starter, roxazyme-G