Estimation of true preceacal phosphorus digestibility of phytase supplemented groundnut cake in broiler chicken

An experiment was conducted to investigate effect of phytase supplemented groundnut cake (GNC) on endogenous preceacal phosphorus loss (EPPL) and true preceacal phosphorus digestibility (TPPD) in broiler chickens using regression technique. A total of 300, one-day-old, unsexed broiler chickens were raised on standard commercial starter diet. At day 20, selection for 216 male broilers chicks was made and chicks were completely randomized and allotted to 6 dietary treatments in 3×2 factorial arrangement with 3 levels of P (1.40, 2.66 or 3.96 g/kg diet) obtained from varying proportions of GNC and 2 levels of microbial phytase (0 FTU/kg or 1000 FTU/kg), feeding trial lasted for 7 days. With inclusion of chromic oxide in experimental diets, the index method (Adeola, 2001) was used to calculate apparent preceacal phosphorus digestibility (APPD). Generated regression curve obtained from the relationship between preceacal digested P and dietary P intake was used to calculate EPPL and TPPD. Results showed that increasing P intake had linear effect (p<0.05) on body weight gain and feed to gain ratio. Neither P, phytase nor their interaction affected (p>0.05) feed intake, dry matter intake and tibia ash of the birds. Addition of phytase resulted in 44.1% reduction in preceacal P output, while levels of P, phytase and interaction linearly increased (p<0.05) digested P and retained P from GNC. From the regression curve, phytase improved TPPD of groundnut cake in birds by 34.48% with a 52.27% reduction in EPPL. True preceacal P digestibility of GNC in 28 days-old, broiler chickens improved with 1000units phytase supplementation of GNC .