Effects of Dietary Calcium Levels on Productive Performance, Eggshell Quality and Overall Calcium Status in Aged Laying Hens.

S H An,B K An,D W Kim

doi:10.5713/ajas.15.0655

S H An, B K An + Show 1 more

Open Access

https://doi.org/10.5713/ajas.15.0655

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Abstract

This study was conducted to investigate the effects of diets with varying levels of calcium on egg production, shell quality and overall calcium status in aged laying hens. A total of five hundred 70-wk-old Hy-Line Brown layers were divided five groups and fed one of the five experimental diets with 3.5%, 3.8%, 4.1%, 4.4%, or 4.7% Ca, for 10 weeks. There were no significant differences in feed intake, egg production and egg weight among groups. The cracked eggs were linearly reduced as dietary Ca levels increased to 4.7% (p<0.01). A significant linear improvement for eggshell strength and thickness were determined with increasing dietary Ca levels (p<0.01). The contents of serum Ca and phosphorus were not affected by dietary Ca levels. With increase in dietary Ca levels, the tibial breaking strength slightly increased. There were no significant differences in the tibial contents of ash, Ca and phosphorus among groups. In conclusion, eggshell quality, as measured by appearance, strength and thickness of eggshell, were influenced by dietary Ca content as expected (p<0.05). These results suggested that aged laying hens require relatively higher level of Ca than required levels from current Korean feeding standards for poultry.

Highlights

The eggshell quality continues to be a major concern of the egg industry
Decrease in eggshell quality of aged laying hens might be attributed to reduced intestinal Ca uptake and increased egg size (Al-Batshan et al, 1994)
Submitted Aug. 8, 2015; Revised Nov. 23, 2015; Accepted Jan. 15, 2016 shell weight, which leads to a decrease in the shell weight to egg weight ratio

Summary

Introduction

The eggshell quality continues to be a major concern of the egg industry. Eggs with inferior shell quality are a leading economical loss to poultry producers (Roberts, 2004). Most research reported that a linear improvement in eggshell quality was evident with increasing dietary Ca levels. On the other hands, Leeson et al (1993) did not find any effect of higher levels of dietary Ca on eggshell quality and concluded that 3.4 g of daily Ca intake was enough for brown egg layers.

Results

Conclusion