Responses of Growth Performance, Bone Measurements, Intestine Measurements, and Plasma Constituents of Muscovy Ducklings to Different Levels of Nonphytate Phosphorus and Dietary Phytase Supplementation During Summer Season

Abstract

A total of 180 one-day old Muscovy ducklings were used in the present study to assess the effect of phytase supplementation on growth performance, feed passage time, small intestine growth, concentration of triiodothyronine (T 3) hormone, and bone measurements during summer season. Ducklings were divided into six equal groups. Three diets were formulated to contain 0.25%, 0.34% and 0.45% nonphytate phosphorus (NPP) for feeding from 1 d to 3weeks of age, and 0.21, 0. 30 and 0.40 % NPP for feeding from 3 to 11 weeks of age, respectively. Phytase enzyme was added to all diets at two levels being. 0 and 750 U\Kg. Performance results show that addition of phytase enzyme to duck diets of high NPP content significantly improved live body weight and weight gain at 1, 3, 5, 7 and (0-1), (1-3), (3-5) weeks of age, respectively. Bone ash percentages, length, width of tibia and concentration of Ca, P of tibia ash significantly increased either as dietary NPP increased or by the addition of phytase enzyme. These results clearly indicated that increasing dietary NPP level and adding phytase enzyme to duckling diets from 1 to 11 weeks of age improved weight of intestinal segments. The main effect of NPP level and phytase supplementation on duodenum morphology (villus height and crypt depth) and pH of intestinal segments significantly increased in the birds fed 100% or 75% NPP level with phytase supplementation compared with other treatments fed diets without phytase addition during summer conditions. Feed passage time was affected by dietary NPP level, however; adding phytase enzyme to duckling diets from 1 to 11 weeks of age fasted passage rate. T3 concentration did not differ significantly due to dietary NPP level with or without enzyme addition. The present data indicate that phytase supplementation pronounced beneficial effects on growth performance, feed passage time, small intestine growth, concentrations of triiodothyronine (T 3) hormone and bone measurements of Muscovy ducklings during summer conditions.