Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2002
Publication Date: 1/1/2003
Citation: Ding ST, Li YC, Nestor KE, Velleman SG, Mersmann HJ. Expression of turkey trenscription factors and acyl-coenzyme oxidase in different tissues and genetic populations. Poultry Science, 82(1):17-24, 2003 Interpretive Summary: In turkeys, as in other birds and mammals, genetic selection has produced divergent lines that differ in body composition. Selection has produced highly muscular, as well as, obese strains with accompanying les muscle mass. Two genetic population of turkeys with divergent body composition were studied. Expression of genes associated with fat deposition and fat utilization (fatty acid oxidation) was measured in adipose, liver, and muscle tissues. A gene associated with adipose tissue PPAR gamma was highly expressed in adipose tissue, but there was no difference between the turkey populations. One gene associated with fatty acid oxidation, PPAR alpha was highly expressed in the liver with lower, but significant expression in adipose and muscle. Another gene associated with fatty acid oxidation, acylCoA oxidase was highly expressed in all three tissues. There was no difference in expression for either fatty acid oxidation gene in the two turkey populations. The data suggest that considerable fatty acid oxidation may occur in the adipose tissue, a tissue not usually thought to utilize this function to a great extent. The expression of these three genes associated with lipid metabolism in three important lipid metabolizing tissues, liver, muscle, and adipose tissue does not explain the divergence in body composition between the turkey strains.
Technical Abstract: Several transcription factors are involved in regulating lipid metabolism in various animal tissues. Peroxisome proliferator-activated receptor (PPAR) gamma and PPARalpha regulate lipogenesis and fatty acid oxidation. Gene fragments for PPARgamma, PPARalpha, and acyl-coenzyme A oxidase (ACO) have been cloned in turkeys, and the sequences of these genes were highly homologous to those of chickens, pigs, and humans. Data showed that turkey PPARgamma and PPARalpha were highly homologous (>97%) with that of the chicken, indicating the genetic relationship between those two species was close. The tissue distribution and genetic effect on mRNA concentrations of PPARgamma, PPARalpha, and ACO in two genetic populations of turkeys [randombred control (RBC2) and growth selected (F line)] was determined. The PPARgamma mRNA was highly expressed in adipose tissue in both populations, but there was no difference between the two populations. The PPARalpha mRNA concentration was high in the liver with less expression in adipose tissue and skeletal muscle. The PPARalpha mRNA concentration was similar between the two genetic populations. The ACO mRNA was expressed in adipose tissue, skeletal muscle, and liver with no difference between the genetic populations. The data suggest that both turkey liver and adipose tissue have considerable capability for fatty acid oxidation and synthesis. Long-term selection for increased 16-wk BW in the F line had no effect on the expression of PPARgamma, PPARalpha, and ACO.