Theses and Dissertations
Roles of limestone particle size ratios and phytase levels on performance, eggshell quality, and bone health in post-peak and late-lay single-cycled W-36 laying hens
Mississippi State University
Elliot, Michael A.
Wamsley, Kelley G.S.
Date of Degree
Graduate Thesis - Open Access
Master of Science (M.S.)
College of Agriculture and Life Sciences
Department of Poultry Science
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.
Waters, Charis, "Roles of limestone particle size ratios and phytase levels on performance, eggshell quality, and bone health in post-peak and late-lay single-cycled W-36 laying hens" (2023). Theses and Dissertations. 5817.