Date of Graduation

8-2014

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level

Graduate

Department

Poultry Science

Advisor

Nick Anthony

Committee Member

William Huff

Second Committee Member

Fred Pohlman

Third Committee Member

Susan Watkins

Keywords

Broilers, DFD, Muscle Color, Pre-slaughter Environment, PSE, Selection

Abstract

Two broiler lines divergently selected for high (HMC) and low (LMC) muscle lightness (L*) were formed from a random bred control line (RBC). After eight generations of selection, three experimental trials were conducted to investigate the correlated response to selection and effects of pre-slaughter environment on meat quality in all three lines.

In the first experiment, a total of 100 birds from each line were bled for blood chemistry analysis and were evaluated for meat quality the following day. The HMC line had higher fillet drip loss (DL), L*, heterophil to lymphocyte ratio (H:L), and platelet count (Plt), and lower postmortem muscle pH, lower red blood cell count (RBCC) and hematocrit (HCT) than the LMC line.

In the second experiment, the effects of pre-slaughter transportation on meat quality were investigated. Sixty birds from each line were selected and placed into transport (T) and non-transport (NT) groups. The T group was transported for approximately 3 h prior to processing. In both treatments, the HMC line had higher DL, L*, and b*, and lower postmortem muscle pH and a* than the LMC line. Within the HMC line, the T group had higher DL, and L*, and lower postmortem pH. Within the LMC line, the T group had higher a*, and lower L* and b*.

In the third experiment, the effects of pre-slaughter temperature (40°C, 22°C, 1°C) on meat quality were investigated. Twenty birds from each line were selected and placed into heat stress (HS), cold stress (CS), and control groups for 2 h prior to processing. In all treatments, the HMC line had higher DL and L*, and lower muscle pH than the LMC line. In all lines, the HS group had lower DL and muscle pH than the control, whereas the CS group just had lower DL than the control, however within the LMC line the CS group had higher a*, and lower L* and b* than the control group.

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