Effect of dietary supplementation of phytase on laying hens performance and nutrient metabolism

The effect of the addition of phytase enzyme on performance and metabolism of laying hens was evaluated. Three hundred and sixty Bovans Goldline hens were allotted to a completely randomized design, with 12 replicates of 6 birds per unit and 5 experimental treatments as follows: T-1 = positive control (PC), T-2 = Negative control (NC by 0.15% phosphorus available), T-3 = NC + 200 FTU of phytase, T-4 = NC + 400 FTU of phytase, T-5 = NC + 600 FTU of phytase. The positive control diets were formulated to contain adequate nutrient levels according to recommendations of the Brazilian Tables. Diet of treatments 2, 3, 4 and 5 (Negative Control) were calculated with reduced contents of nutrients present in the nutritional contribution of the enzyme complex evaluated according with recommendations from the manufacturer. The parameters evaluated were: feed intake, egg production, egg weight, egg mass and feed: gain ratio (per g of egg mass and per dozen of egg). In the metabolism trial, feed consumption and total excreta production per replicate were measured to determine the metabolizable energy values (apparent ME and apparent nitrogen corrected ME), metabolizability coefficients of gross energy and nitrogen retention and P and Ca balance of the experimental layer diets. The addition of phytase (200, 400 and 600 FTU) to the negative control diet resulted in layers with egg mass production, feed: gain ratio egg mass similar to layers fed the positive control diet. The egg components parameters were not affected by treatments, except the eggshell weight, which increased with the addition of phytase in the diets. The addition of 600 FTU of phytase improve the metabolism of nutrients in nutritionally deficient diets.