Phytase and 1alpha-hydroxycholecalciferol supplementation of broiler chickens during the starting and growing/finishing phases

Abstract

Supplemental 1alpha-hydroxycholecalciferol (1alpha-OHD3) has been shown to have qualitatively similar and quantitatively additive effects to exogenous phytase. Two experiments were conducted from 0 to 35 d in floor pens to determine the additive effect of phytase and 1alpha-OHD3 when supplemented to Ca- and P-deficient diets. In both experiments, at least 4 replicates per treatment (50 chicks per replicate) were used. Corn-soybean-meal-and soybean-oil-based diets were fed and birds were raised in a house impervious to ultraviolet light. During the starter phase (ST), from 0 to 18 d, chicks were fed a 23% CP diet containing 0.60% Ca and 0.47% total P (tP). During the grower/finisher phase (GF), from 19 to 35 d, birds were fed a 19% CP diet containing 0.30% Ca and 0.37% tP. A combination of 1,000 phytase units/kg of Natuphos phytase and 5 microg/kg of 1alpha-OHD3 (P+1A) was supplemented to some of the feed during the ST and GF. Diets containing adequate Ca and P were also fed during the ST (0.90% Ca, 0.68% tP) and GF (0.80% Ca, 0.67% tP). Performance characteristics and the incidence of rickets and tibial dyschondroplasia were measured at 18 and 35 d. In experiment 1, unsupplemented chicks performed well but had considerable leg problems. Chicks fed P+1A during the ST or GF did not perform as well as birds fed P+1A throughout. Birds fed P+1A throughout performed as well birds fed the adequate diets without any indication of leg problems. In experiment 2, unsupplemented birds performed similarly to unsupplemented birds in experiment 1. However, chicks fed the supplements or the control diets did not perform as well or accumulate as much bone ash as birds in experiment 1, although the diets were formulated identically in both experiments. Diets with as little as 0.30% Ca and 0.37% tP appear to be adequate for broilers older than 18 d if supplemented with the correct amounts of phytase and 1alpha-OHD3. However, there are unknown variables that may limit the potential of broilers in terms of bone mineralization and bone pathology, even when adequate diets are fed.

The effects of dietary cholecalciferol and 1α-hydroxycholecalciferol levels in a calcium- and phosphorus-deficient diet on growth performance and tibia quality of growing broilers

“…Driver et al (2005) also found that Ca-and P-deficient broilers fed 1α-OH D 3 and phytase had equal growth performance and tibia ash weight compared with birds fed diets with adequate Ca and P. In the present study, no significant difference was observed in the growth rate as well as ash weight, breaking strength, and Ca and P contents of the tibia among the broilers fed 25 to 1000 µg . kg -1 vitamin D 3 and those fed the control diets.…”

Dietary Calcium Levels Reduce the Efficacy of One Alpha-Hydroxycholecalciferol in Phosphorus-Deficient Diets of Broilers

“…30%, although it increased tibia ash and P utilization. Further study indicated that addition of 5 μg/kg of 1α-OH D 3 and 1,000 U/kg of phytase improves growth and tibia ash in broilers fed with Ca-and P-deficient diets (Driver et al, 2005).…”

One Alpha-hydroxycholecalciferol Improves Growth Performance, Tibia Quality, and Meat Color of Broilers Fed Calcium- and Phosphorus-Deficient Diets

“…Previous studies on 1α-OH D 3 have been based on adequate dietary vitamin D 3 (Biehl and Baker, 1997a, 1997b; Snow et al, 2004; Driver et al, 2005). Edwards (2002) found that an interaction between vitamin D 3 and 1,25-(OH) 2 D 3 exists in tibia ash.…”