Effects Of Microbial Phytase On Performance And Nutrients Metabolism In Laying Ducks

Phytate in plant cells have the potential of binding with protein and minerals such as Pand Ca²⁺, Cu²⁺, Fe²⁺, Mn²⁺, Zn²⁺ and so on to form insoluble complexes which may reducethe utilization of these nutrients. Phytase, myo-inositol hexaphosphate phosphohydrolase, isthe enzyme that release P from phytate P. Respective supplementation of phytase in the dietsof laying ducks has been reported to improve the dietary phytate P bioavailability and othernutrients utilization. But the supplemental interactions of the two enzymes have not beenreported.The objective of this experiment was to investigate the effects of supplemen-tation ofmicrobial phytase and their interactions on laying ducks based on maize and soybean mealdiets by a feeding trial, a digesting trial, a slaughtering trial and laboratory experiments.270 21-week-old JINGDING laying ducks were used in a 10-week feeding trial and wererandomly arranged to 6 groups with 3 replicates and 15 for each replicate. A 2×3 factorialarrangement of treatments was used with two levels of nonphytate P (0.38% and 0.16%),three levels phytase (500U/kg, 300U/kg and 0). The diet was formulated as recommended byNational Research Council(1994).What can be concluded from the results is as follows:1. Performance: No supplemental effect ofphytase on performance was found. Groupâ… was significantly increased the intensity of eggshell, Groupâ…¡was significantlyincreased the thickness of eggshell (P＜0.05).2. Utilization of nutrients: Addition phytase exhibited obvious positive interactions toenhance the utilization of crude protein (P＜0.05), and also decreased the utilization of acidicwashing fibre. Adding phytase in groupâ… was significantly improved the utilization of dietarycrude ash, calcium, calcium, total phosphorus and copper (P＜0.05). The disposals waserratically infection on iron, manganese and zinc. 3. Plasma biochemical parameters: Addition Phytase supplementation was verysignificantly increased alkaline phosphatase (P＜0.01). Adding phytase in groupâ… wassignificantly decreased plasma P content(P＜0.05).4. Tibia quality:Addition Supplemental microbial phytase significantly improved tibiabreaking strength (P＜0.05), but not increased microelement content in tibia. High phytasewas beneficial to the copper aggradation, and disadvantage to the calcium and manganese.