The present study aims to experiment the Effects of Mannan and β - Glucan as Immuno-stimulants, Prebiotics and Antimycotoxigenic when they are used as a feed additives on Broilers in premix, and then the economical recommendation of the affection of Manna and β – Glucan in premix. In order to achieve such a purpose, six different types of premix with different concentration of Mannan and β– Glucan, to compare the results two groups of broiler been experiments has been done as negative control and positive control. Four bioassays were employed to achieve the purpose of the work.  1) The molecular cytogenetics parameter. 2) The histological parameters. 3) The blood parameters. 4) The physiological parameters 5) The results shows that group (5) and group (6) were the most results which are meets the negative control results in general, that means that the best ratio for Mannan in the premix in between 17% and 25% and the best ratio for B-Glucan in the premix is 25%, also the results indicated that Manna and B-Glucan have immuno-stimulants, prebiotics and antimycotoxigenic when use as a feed additives on Broilers in premix.