Dietary Phosphorus Requirements of Force-Molted Leghorn Hens

Abstract

Two studies were conducted to determine the phosphorus requirements of forcemolted Leghorn hens. In the first study, diets containing .8, .6, or .4% total phosphorus and 4% calcium were fed. In the second study diets with levels of .7, .6, .5, or .4% total phosphorus and 3.8% calcium were fed.Decreasing the phosphorus level improved shell quality as measured by specific gravity and shell thickness. However, egg production and egg weight decreased as phosphorus level decreased. Thus, in these studies a total phosphorus level of >.5% and <.7% was required for egg production and egg shell quality in force-molted Leghorn hens. (

Determination of Phosphorus Requirement for Post Molted Laying Hens using Nonlinear and Multivariate Nonlinear Mixed Effects Models

“…However, fewer studies have investigated AP requirement of molted laying hens (Holder, 1981;Said et al, 1984;Bar et al, 2002 andSnow et al, 2004). Only two studies by Said et al (1984) and Snow et al (2004) fed different phosphorus levels throughout the second cycle and reported requirement of 0.3 and more than 2 g/kg of diet respectively.…”

“…The researchers suggested that evaluation of AP requirement of post molted laying hens is necessary because of lacking appropriate studies with this concept. Holder (1981) suggested that the available AP requirement in post-molt hens (28-wk study) was greater than 2.4 g/kg AP when calculated using NRC (1994) ingredient table values. Said et al (1984) investigated 2.1 and 3 g/kg AP levels (calculated using NRC, 1994 ingredient composition values) fed from 26 wk of age through an induced molt and during a 40-wk second cycle.…”

Efeito de diferentes níveis de sódio e fósforo sobre o desempenho e a qualidade da casca dos ovos de poedeiras comerciais

“…O desempenho de poedeiras tem sido prejudicado por baixos (SUMMERS et al, 1976;HOLDER, 1981;MILES et al, 1983;BAR e HURWITZ, 1984;JUNQUEIRA, 1988;e LEESON et al, 1993) ou altos níveis de fósforo dietético (MILES et al, 1983;JUNQUEIRA, 1988). Por outro lado, a qualidade da casca dos ovos também pode ser prejudicada por altos (OSTERHOUT, 1980;HARMS, 1982;MILES et al, 1983;SAID e SULLIVAN, 1985;JUNQUEIRA, 1988;SAKOMURA et al, 1993;e LEESON et al, 1993) ou baixos níveis de fósforo dietético (JUNQUEIRA, 1988;LEESON et al, 1993).…”

“…Por outro lado, a qualidade da casca dos ovos também pode ser prejudicada por altos (OSTERHOUT, 1980;HARMS, 1982;MILES et al, 1983;SAID e SULLIVAN, 1985;JUNQUEIRA, 1988;SAKOMURA et al, 1993;e LEESON et al, 1993) ou baixos níveis de fósforo dietético (JUNQUEIRA, 1988;LEESON et al, 1993). Contudo, há referências de melhoria da qualidade da casca dos ovos, quando se empregam baixos níveis de fósforo (HOLDER, 1981).…”

“…Na análise global do experimento, o comprometimento do desempenho das poedeiras alimentadas com o nível de 0,35% de fósforo total é comparável aos resultados obtidos por SUMMERS et al (1976), HOLDER (1981) e JUNQUEIRA (1988. Níveis de fósforo inferiores a 0,35% também prejudicaram o desempenho das aves (MILES et al, 1983;BAR e HURWITZ, 1984).…”