Calcium Dynamics Affecting Egg Production, Skeletal Integrity, and Egg Coloration in Ring-necked Pheasants (Phasianus colchicus)

<p>These 4 chapters represent manuscripts formatted for submission to journals based on an experiment conducted on Ring-necked Pheasants (Phasianus colchicus). Calcium limits the distribution of this species, which produces 7-15 eggs per clutch. They may renest up to 5 times per breeding season on a diet low in calcium. The first chapter examines egg production in laying hens on 7 different diets from 0.19-4.47% calcium in the absence of calcium loading. Calcium-loaded pheasants store calcium in medullary bone before an experiment and can draw on this surplus during egg production, possibly skewing experimental results. We measured egg production, egg characteristics, and hen femur ash fraction in a 2-month experiment. Hens in the middle 5 dietary calcium (1.07-3.08%) groups statistically produced the same number of eggs, which differed from reported studies where hens were calcium-loaded. Ash fraction values indicated that hens expended medullary bone reserves to produce eggs when dietary input was low. In Chapter 2, we examined bone properties in the above femurs to determine if pheasant hens on low calcium diets expended enough medullary bone stores to compromise skeletal integrity. We applied a 3-point bending test to find femur breaking strength and examined structural bone properties. Calcium and breaking strength were linearly associated. Femurs of hens given lower calcium diets were easier to break. Structural properties of cortical bone were not correlated with dietary calcium. Pheasants on low calcium, comparable to wild conditions, seemed to sacrifice skeletal integrity to maintain high egg production, although not enough to damage cortical bone. In Chapter 3 we examined 437 eggs laid to determine if egg color correlated with dietary calcium, egg mass, volume or shell thickness. Yellow pigment decreased with increasing calcium. Biliverdin had a higher affinity for calcium than protoporphyrin. In Chapter 4, we examined male pheasants to determine if reduced surface area on one wing (clipped) induced unbalanced pectoralis muscle development and humerous density on the corresponding side after wing-whirring for 2 months. We weighed pectoralis muscles and conducted 3-point bending tests on humeri of 7 pheasant males. We found no difference in pectoralis muscles mass, humeri breaking strength or ash fraction between clipped and unclipped wings. Wing-whirring may only put a negligible strain on male Ring-necked Pheasant pectoralis muscles and humeri.</p>

Name thesis:degree_name

MS

Grantor dc:publisher

Brigham Young University - Provo

Author dc:creator

• Jones, Landon R.

• Ring-necked Pheasant
• Phasianus colchicus
• calcium
• calcium loading
• medullary bone
• breaking strength
• egg color
• biliverdin
• protoporphyrin
• wing-whirring
• Animal Sciences

Language dc:language

English

Repository record dc:identifier

https://scholarsarchive.byu.edu/etd/1259

OAI identifier oai:identifier

oai:scholarsarchive.byu.edu:etd-2258