the effect of microbial phytase on apparent digestibility of crude protein, amino acids, minerals and performance of female broiler chickens

an experiment was conducted to evaluate the effects of microbial phytase on apparent digestibility of crude protein (cp), amino acids (aa), and apparent retention of calcium (ca), total phosphorus (tp), iron (fe) and zinc (zn) in female broiler chickens diet. the experiment was designed as a completely randomized design. each treatment consisted of 4 replicates of 10 broilers in battery cages, for a total of 240 chicks. the birds were fed similar diets containing six levels of microbial phytase (0, 250, 500, 750, 1000 and 1250 ftu/kg of diet) during 1-28 days of age. excreta were quantitatively collected during 21-24 days of age. the excreta stored at -20ºc, freeze-dried and analyzed for aa, cp, ca, tp, fe and zn. during the experiment, body weight gain, feed intake, and feed conversion ratio were measured weekly interval basis. 250 and 500 ftu phytase significantly improved apparent digestibility of cp and aa (except than alanine, valine and threonine) (p 0.05). phytase had no significant effect on body weight gain, feed intake and feed efficiency (p>0.05).