Nucleic acid concentrations and ornithine decarboxylase activity in tissues from three lines of turkeys

Developmental patterns in turkeys of tissue ornithine decarboxylase (ODC) activity and nucleic acid concentrations were studied in a randombred control (RBC2), in a subline of RBC2 selected for increased 16-wk BW (F), and in a commercial sire line (C). Lines F and C were similar in BW, but Line C had greater breast weight than Line F. Lines F and C were heavier and had greater breast weights than the RBC2 population. Tissue ODC activity reached its highest level on Day 2 posthatch, declined rapidly through 13 d of age, and remained relatively low through 144 d of age. The ODC activity of liver tissue was greater than that of either breast or leg muscle. Line C had greater tissue ODC activity at 2 and 8 d of age than the RBC2 population, but Line F was not different from C or RBC2. There were no line differences for ODC activity at the other ages tested, resulting in a age by line interaction. The DNA content of muscle tissue was greatest at hatch and declined to baseline values by 55 d of age. The DNA content of breast muscle was higher than for leg muscle at hatch, but this pattern was reversed following Day 8. Muscle tissue from Lines F and C had a lower DNA content than that of the RBC2 population. Although the RNA content of muscle tissue was similar across lines, the RNA content of breast muscle was greater than for leg muscle during the early posthatch period just prior to the onset of rapid growth in this tissue. Results of the present experiment demonstrate changes in muscle functional cellularity during the growth phase in association with genetic increases in BW, but not breast muscle development. In contrast, tissue ODC activity was increased in association with genetic increases in breast muscle development, but not BW.