Date of Graduation

8-2016

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor

Nicholas B. Anthony

Committee Member

Susan E. Watkins

Second Committee Member

Fred W. Pohlman

Abstract

An increase in the consumption of poultry has generated an increase in demand for higher yielding broilers. This has led to an increase in atypical meat and issues with appearance. Color is a direct result of a pH decline as meat goes through rigor mortis with meat generally becoming lighter. If the pH declines too rapidly or too slowly, meat quality can suffer. Physical properties of meat can be altered by pH. A fast pH decline results in pale meat with decreased tenderness. A slow pH decline can result in darker meat with a reduced shelf-life. With a known relationship between pH and color, lines were divergently selected for breast muscle color (L*). After 10 generations of selection, the HMC and LMC lines (selected for high and low L* respectively) as well as a random bred control base population (RBC) were characterized through several studies. Experiment 1 characterized the pH decline of the lines under two different chill methods. The chill method did not have an effect on the rate of decline or final pH. The HMC line exhibited a quicker pH decline and a lower pH when compared to both the RBC and LMC line. Although there were no statistical differences between the LMC and RBC line, the general trend showed the LMC line having a slower pH decline and higher pH. Experiment 2 characterized all lines for pH and color, drip loss, and moisture uptake at the processing ages of 5, 6, 8 and 10wks of age. For the HMC and RBC lines, 24h color did not differ between the processing ages. For the LMC line, the 5wk group was significantly lighter than the remaining age groups, possibly due to the thickness of the muscle at 5 wks. Experiment 3 looked at the effect of feed-withdrawal times. Birds were separated randomly be line into groups and feed was removed at 0, 6, 12, 18 and 24h prior to processing. Line differences were detected for color and pH but not for treatment groups. In muscle color lines, feed-withdrawal times did not appear to have a significant impact on meat-quality.

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