Date of Graduation


Document Type


Degree Name

Master of Science in Animal Science (MS)

Degree Level



Animal Science


Kenneth P. Coffey

Committee Member

Jason K. Apple

Second Committee Member

Dirk Philipp


Biological sciences, Amino acid supplementation, Reduced crude protein, Swine nutrition


Barrows and gilts (215/gender) were used to test the effects of synthetic AA supplementation of reduced CP diets on the growth performance and quality characteristics of the LM and the fatty acid composition of the LM and s.c. jowl fat from growing-finishing swine. Pigs were blocked by BW within gender, and allocated randomly to pens (6 pigs/pen) which were then assigned randomly within each block and gender to either corn-SBM diets 1) that were devoid of synthetic lysine (Ctrl); 2) with reduced CP diets where lysine was added to all diets (RCP1); 3) with reduced CP where lysine, threonine, and tryptophan were added to all diets (RCP2); 4) with where lysine, threonine, and tryptophan were added to all diets (RCP3); or 5) with reduced CP diets where lysine, threonine, tryptophan, and isoleucine was added to all diets (RCP4). During finisher phase 3, 10 mg/kg of ractopamine was included in all diets. A subsample of whole pork loins was processed into chops for data collection. Another subsample from the whole pork loin and the s.c. fat from each jowl was freeze dried for fatty acid determination. Gilts had a greater (P = 0.02) (lightness) L* value and drip loss than barrows, but the ultimate pH, marbling, and intramuscular fat (IMF) of the LM were greater (P < 0.04) for barrows than gilts. Color measurements were not affected (P > 0.06) by the RCP diets, with the exception of redness (a*) which increased (P = 0.01) with decreasing CP levels. There were greater (P < 0.001) proportions of SFA in the LM of barrows than the LM from gilts. However, gilts had an increase in PUFA content with decreasing levels of CP in the diet and barrows had a decrease in PUFA content of the LM (P = 0.056). Barrows had greater (P = 0.008) SFA and less (P < 0.001) PUFA content in the jowl fat than gilts. The results point toward the reduced CP diets improving fresh pork quality, especially IMF. Also, pork lean and jowl fat were altered in their fatty acid composition by the reducing dietary CP.

Included in

Meat Science Commons