Theses and Dissertations

ORCID

https://orcid.org/0009-0008-3094-2142

Issuing Body

Mississippi State University

Advisor

Adhikari, Pratima

Committee Member

Elliot, Michael A.

Committee Member

Wamsley, Kelley G.S.

Date of Degree

5-12-2023

Document Type

Graduate Thesis - Campus Access Only

Major

Agriculture

Degree Name

Master of Science (M.S.)

College

College of Agriculture and Life Sciences

Department

Department of Poultry Science

Abstract

The objective of this study was to investigate the role of fine (F) and coarse (C) limestone ratios and exogenous phytase at standard and superdosing activity on performance, egg quality, and bone quality of post-peak and late-lay Hy-Line W-36 hens. For post-peak, treatments with 40F:60C at 0 and 400 FTU/kg (standard phytase activity) increased hen-day egg production (HDEP). Treatments with 15F:85C decreased feed intake (FI) but also increased unsaleable eggs (UE) and eggshell-breaking strength (EBS). Treatments with 0 and 400 FTU/kg increased albumen quality and treatments with 1500 FTU/kg increased bone quality and phytate breakdown. For late-lay, interaction effects of limestone and phytase were observed for FI, HDEP, UE, bone, and egg quality. Treatments with 40F:60C decreased UE and increased EBS and bone mineral content of aluminum (Al). Treatments with 0 FTU/kg increased eggshell proximate of phosphorus (P) and gizzard pH, but 400 and 1500 FTU/kg increased phytate breakdown and bone quality.

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