SUMMARY: A total number of 320 one day old of mixed Hubbard
chicks were randomly allotted into four collections, each
subdivided to two groups, 40/each. Chicks were
experimented to investigate the effect of four dietary
levels of crude fiber (3.5, 5.0, 6.5, and 8.0%) without or
with enzymes in a factorial arrangement 4 x 2 during
growing-finishing period. All the single groups were fed on
the diets free enzyme, while the enzyme was added to the
diet of the paired groups. The best BWG and FCR were
recorded by the groups fed diets having 3.5 and 5.0% CF
with enzyme supplementation (2232.94 g & 1.89) and
(2116.47 & 1.90) respectively, while the worest values
recorded by the groups fed diets having 8.0% CF with or
without enzyme(1759.41g & 2.37) and (1748.82 g &2.51)
respectively. There were no significant differences in the
dressed carcass and proventriculus percentages among all
the treated groups. The spleen and gizzard percentages in
the birds fed diets having 8% CF with or without enzyme
supplementation were significantly increased, while the
liver percentages of the same groups were significantly
decreased compared with the control. The results
obtained concluded that addition of enzyme improved
growth performance of broilers up to 6.5 % crude fiber