The effect of phytase supplementation on broiler and interaction between phytase and intermittent feeding and structural components

Abstract

An experiment was conducted to investigate the effect of exogenous phytase supplementation and the interaction between phytase and feeding regime and between phytase and component structures on the performance, bone ash content, jejunal P digestibility, jejunal phytic acid (IP6) degradation and AME of broiler chickens. 308 broiler chickens (Ross 308) either were intermittently or ad libitum fed a diet with or without oat hulls and with or without phytase (2x2x2) from 7 to 21 days of age. Ad libitum fed birds were fed continuously, while intermittently fed birds had access to feed four times a day with three 1 hour and one 2 hour feeding bout a day from 7 to 14 days of age and four 1 hour feeding bout a day from 14 days of age until the end of experiment. At 21 days of age, two birds per cage were killed, and contents from crop, gizzard, duodenum+ jejunum and ileum were quantitatively collected and frozen in liquid nitrogen. Exogenous phytase supplementation increased feed intake (P< 0.001), weight gain (P< 0.001) and feed/gain ratio (P=0.0162). There was an interaction between phytase and structural components on weight gain (P= 0.031) and feed/gain ratio (P< 0.001). Both of toe ash (P= 0.0012) and tibia ash (P< 0.001) were increased with phytase addition, while no interaction between phytase and intermittent feeding and structure components was found on bone ash content. Phytase addition also improved jejunal P digestibility (P= 0.003), jejunal phytic acid degradation (P= 0.003) and AME (P= 0.0188). Moreover, an interaction between phytase and intermittent feeding was found on phytic acid degradation.