Effect of dietary high non-phytate phosphorus level on growth performance and metabolism of calcium and phosphorus in Lion-head geese

Abstract

The aim of this study was to investigate the effect of dietary high non-phytate phosphorus (NPP) level on the growth performance and metabolism of Ca and P in Lion-head geese during starter and grower-finisher periods. A total of 384 goslings at d 1 and 240 geese at d 29 were divided into 3 treatments with 4 replicate pens each treatment for Exp. 1 (the starter period for d 1–21) and Exp. 2 (the grower-finisher period for d 29–72), respectively. The 3 supplemental NPP levels (Ca: NPP ratio) in diets were 0.40% (2.38), 0.60% (1.58) and 0.80% (1.19) for Exp. 1 and were 0.30% (2.83), 0.50% (1.70) and 0.70% (1.21) for Exp. 2. In Exp. 1, final body weight, average daily gain and average daily feed intake of goslings fed a diet containing 0.80% NPP (Ca: NPP ratio,1.19) were decreased (P < 0.05) compared to birds fed a diet containing 0.60% NPP (Ca: NPP ratio, 1.58) at the starter period, with no difference (P > 0.05) between the two diets containing NPP of 0.40% (Ca: NPP ratio, 2.38) and 0.80% (Ca: NPP ratio,1.19). At d 21 of goslings, the concentrations of Ca, P, parathyroid hormone and bone gla-protein, and alkaline phosphatase activity in serum were decreased (P < 0.05) linearly in response to the increasing NPP level and decreasing Ca: NPP ratio in diets. At d 72 of geese, tibia bone Ca content was decreased (P < 0.05) linearly as dietary NPP level increased and Ca: NPP ratio decreased. Our results indicated that dietary high NPP level along with low Ca: NPP ratio can reduce growth performance and disrupt Ca and P metabolism together with the changes of serum characteristics in goslings at the starter period.