Eficacia de dos fitasas bacterianas en la liberación de fósforo en dietas para pollos de engorda en crecimiento

Abstract

The efficacy of two phytases (Citrobacter brakii and Escherichia coli) used in different doses (500 and 1,000 FTU) were evaluated in a diet deficient in phosphorus (0.15% available P) formulated with sorghum-soybean meal. To estimate the efficacy of the release of P evaluated phytases, inorganic phosphorus supplemented by mono-phosphate (MDP) to reach a final concentration of available P of 0.23, 0.31 and 0.39 % was used as reference. The basal diet deficient in P was supplemented as follows: 1) Without phytases, without MDP; 2) 0.08% MDP; 3) 0.16% MDP; 4) 0.24% MDP; 5) Citrobacter-500 FTU; 6) coli FTU-500; 7) citrobacter-1,000 FTU and 8) FTU coli-1,000. The treatments were applied to Ross 216 chickens (27 birds/treatment) 7 to 21 d old. Weight gain, feed efficiency and concentration of tibia ash and P was better in chickens receiving 0.39% PMD and 1,000 FTU of both phytase, with no differences in these levels between MDP and phytase treatments. The amount of phosphorus released was not affected (P>0.05) by type of phytase (average 0.142 %), with effect to level of phytase used (0.102 vs 0.182 % for 500 and 1,000 FTU respectively). The results indicate that supplementation 1,000 FTU / kg in both phytase in diets deficient in P results in weight gain and feed efficiency similar when the diets are supplemented with 0.24% MDP. Both phytases improved to 78.4 % utilization of phytate phosphorus in sorghum-soybean meal diets on growing chicks.