Abstract
An investigation was conducted to examine two levels (T1 and T2) of a commercial solid-state phytase preparation (Ronozyme® P product activity 2,500 FYT/g ) during feed milling and to evaluate it’s effect on broiler (Ross hybrid mixed sex/ straight run) performance when fed with reduced levels of di-calcium phosphate (varying from 17.5 to 34.4)%. Levels of phytase inactivated in starter and grower samples taken from the pelletizer ranged from 19-41% and 35-38%, respectively. Experimental data showed that serum P was significantly lower (p=0.017) for treatment T2 with the recommended commercial phytase inclusion level in the diet with di-calcium phosphate dietary reduction of 32.9% and 34.4% in the starter and grower diets compared to T0 and T1, respectively. The value obtained for serum P was 12.12, 12.03 and 10.14 mgdL-1 for broilers on treatment T0, T1 and T2, respectively. P reduction in excreta was 23.17% when phytase was added to broiler diets at the recommended commercial rate. Alternatively, there were no significant differences in body weight and eviscerated carcass yield of male and female birds with varying levels of phytase and reduced levels of di-calcium phosphate; nor were there significant differences in feed intake, feed conversion or calorific conversion among the different treatments, for birds grown to 21 days and 42 days, respectively. The economic significance of results on the use of phytase enzyme for broilers in the tropics and the resulting environmental effects of reduced faecal P were discussed. It was concluded that the use of phytase in broiler diets would be beneficial to the Trinidad and Tobago broiler industry.
