Determination of calcium digestibility and bioavailability on five limestone sources

Drysdale, Rebekah

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https://hdl.handle.net/2142/117746 Copy

Description

Title

Determination of calcium digestibility and bioavailability on five limestone sources

Author(s)

Drysdale, Rebekah

Issue Date

2022-11-10

Director of Research (if dissertation) or Advisor (if thesis)

Parsons, Carl M

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Calcium
• Digestibility
• Bioavailability
• Laying hen performance
• calcium retention
• broiler performance
• limestone

Abstract

Four experiments were conducted to evaluate the effect of 5 limestones (L1-L5) varying in calcium (Ca) solubility on Ca utilization in laying hens, broiler chickens, and crossbred chickens using different methods. The 5 commercial limestones varied in solubility (88-97%), mean particle size (500-700 microns), and geographical origin and were evaluated for digestibility and bioavailability of Ca. The first experiment was conducted on Lohman LSL Lite hens which were used to determine if the different limestones can impact laying hen performance and egg quality when fed in diets containing different dietary Ca levels. Hens were randomly allotted to and fed 1 of 10 corn soybean meal-based diets containing 1 of 5 limestones at 2 different dietary Ca levels of 3.8% and 2.65%. Results from the laying hen trial indicated there was a significant (P < 0.05) main effect for dietary Ca level for the hen-day egg production, egg mass, feed efficiency, egg specific gravity, and eggshell breaking strength, with the values being decreased for hens fed the lower 2.65% Ca level. No effect of limestone source was observed for feed consumption, egg weight, egg specific gravity and eggshell breaking strength, except the hens fed L2 has significantly lower (P < 0.05) egg specific gravity and eggshell breaking strength, than hens fed L3 at the higher dietary Ca level. The results of this study indicated that the L2 limestone source had the lowest solubility (88%) and was generally inferior to the other 4 commercial limestones, primarily based on responses for egg production, egg mass, and feed efficiency. In Experiment 2, both crossbred and commercial chicks were used to determine the effect of dietary Ca levels on tibia bone ash to develop a slope-ratio Ca bioavailability assay. The chicks were fed diets containing increasing levels from 0.2 to 0.95% Ca from 8 to 22 d of age. Regressions of bone ash in mg/tibia and % on supplemental Ca intakes yielded linear and quadratic responses for supplemental Ca intake in both types of chicks. Experiment 3 was performed to determine bioavailability of Ca in the 5 limestones using bone ash as the primary response criterion. Commercial Ross 308 broiler males were fed 1 of 13 diets which consisted of a Ca deficient diet (0.3% Ca) or that diet supplemented with 0.15% or 0.30% Ca from either reagent grade calcium carbonate (CaCO3) or 1 of the 5 commercial limestones from 8 to 22 d of age. Multiple linear regression of bone ash (mg/tibia and %) on supplemental Ca intake yielded slope-ratio relative Ca bioavailability values ranging from 90 to 106%. In Experiment 4, a broiler chicken assay was conducted to determine apparent ileal Ca digestibility and total tract Ca retention for the 5 limestones using corn-based diets. The ileal Ca digestibility (%) and total tract Ca retention (%) values at 21 d of age were low and variable with a range of 20 to 34% for ileal Ca digestibility and 12 to 31% for total tract Ca retention among limestones. The results of these studies indicate a slope-ratio bone ash assay can be used to measure relative bioavailability of Ca in limestones, and relative Ca bioavailability, ileal Ca digestibility, and total tract Ca retention generally did not differ significantly among the 5 commercial limestones.

Graduation Semester

2022-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Rebekah Drysdale

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