| Popis: |
Phytate phosphorus in a 4:4:1 (by weight) mixture of ground maize, soya-bean meal and wheat bran was decreased by 81% when treated with native phytase in wheat bran and ground maize by a 2-step process. The first step consisted of two successive 2-h conditioning periods at 55°C for maize and soya-bean meal; one at pH 3.5 with citric acid followed by another at pH 5.1. In the second, or hydrolysis step, wheat bran (0.25 parts), a rich source of phytase, was mixed with the wet, citric acid-conditioned maize and soya-bean meal, and the mixture was held for 8 h at 45 C and pH 5.1. After the enzymatic reaction, the increase in orthophosphate accounted for 78% of the phytate phosphorus released and the mixture contained 0.42% inorganic phosphorus in dry matter. A 17-day chick feeding trial showed that tibia bone ash weights tended to be higher (P < 0.1) for chicks eating the low-phytate feed than for those fed on the control feed. |
