Effects Of Supplemental Microbial Phytase And Cellulase On Performance And Nutrients Utilization Of Layers

Phytate and fiber in plant cells have the potential of binding with protein arid minerals such as P and Ca, Cu, Fe, Mt, Zn4 and so on to form insoluble complexes which may reduce the utilization of these nutrients. Furthermore, phytate and fiber may also form complexes with some digestive enzymes in the gastrointestinal tract and decrease the activity of these enzymes with a subsequent decrease in the digestibility of dietary nutrients. Phytase, myo-inositol hexaphosphate phosphohydrolase, is the enzyme that release P from phytate P. Cellulase tend to destroy cell wall to release nutrients. Respective supplementation of phytase or cellulase in the diets of laying hens has been reported to improve the dietary phytate P bioavailability and other nutrients utilization. But the supplemental interactions of the two enzymes have not been reported. The objective of this experiment was to investigate the effects of supplementation of microbial phytase and cellulase and their interactions on layers based on maize and soybean meal diets by a feeding trial, a digesting trial, a slaughtering trial and laboratory experiments. 192 18-week-old Hisex layers were used in a 31-week feeding trial and were randomly arranged to 8 groups with 4 replicates and 6 for each replicate. A 2 X 2 )< 2 factorial arrangement of treatments was used with two levels of nonphytate P(0.38% and 0.16%),two levels phytase (300U/kg and 0) ,two levels cellulase (0.1% and 0) .The diet was formulated as recommended by National Research Council (1994) What can be concluded from the results is as follows: 1. Performance: Addition of 0.1% cdllulase significantly decreased feed intake(P<0.05) No supplemental effect of phytase on performance was found. 2. Utilization of nutrients: 300UIlcg phytase significantly improved the utilization of dietary cmde ash, cnide protein, calcium, total phosphorus and copper (P<0.05) . Addition of 0.1% celhilase increased the utilization of crude fibber (P<0.05) and calcium (P