The Effect of Early Post-hatch Dietary Amino Acid Levels on Satellite Cell Dynamics in Turkeys

NIEROBISZ, LIDIA SYLWIA. The Effect of Early Post-Hatch Dietary Amino Acid Levels on Satellite Cell Dynamics in Turkeys. (Under the direction of Paul Mozdziak.) Satellite cells are defined as myonuclear myogenic stem cells residing between sarcolemma and basal lamina of the myofiber. Myofiber number is established during embryonic development. Post-hatch and post-natal muscle growth occurs exclusively through an increase in myofiber size. The increase of myofiber size in early post-hatch turkeys is predominantly dependent on the contribution of new myonuclei to pre-existing myofibers by the mitotically active satellite cell population. Preliminary data in broilers has revealed that supplementation with amino acid deficient diet immediately post-hatch results in an increase satellite cell mitotic activity in Pectoralis thoracicus muscle in 3-day-old chicks as compared to birds fed adequate and above requirement amino acid levels. Additionally, chicks denied feed for first three days post-hatch exhibited significantly lower satellite cell mitotic activity in Pectoralis thoracicus muscle as compared to remaining treatment groups. The hypothesis tested in the current study was that turkeys supplemented with crude protein and amino acid deficient diet early post-hatch would produce higher meat yield at 140 days. Since very little is known about the impact of early nutrition on the satellite cell activity in commercially raised turkeys, the objective of the present study was to measure the effect of different levels of dietary crude protein and amino acids (0.88 NRC, 1.00 NRC, and 1.12 NRC) as well as feed deprivation on the satellite cell mitotic activity, Pectoralis thoracicus muscle weight, and body weight of commercially raised turkey males. At 3, 4, 5, 8, and 11 days of age, birds from each treatment group were injected with 5bromo-2’-deoxyuridine (BrdU) to label mitotically active cells. The right Pectoralis thoracicus muscle was harvested one hour after BrdU injection followed by BrdU and PI immunohistochemistry and measurement of myofiber diameters. On the third day post-hatch satellite cell mitotic activity was the highest (P<0.05) in 0.88 NRC treatment group and the lowest (P<0.05) in the feed deprived group. On the fourth day post-hatch, feed deprived birds exhibited the lowest (P<0.05) satellite cell mitotic activity and muscle weight. At market age (140 days), there were no significant differences (P>0.05) between treatments in body weight and Pectoralis thoracicus muscle weight. Further evaluation of mechanistic pathways governing satellite cell mitotic activity and muscle growth are necessary to devise early post-hatch feeding strategies that would lead to improvement in Pectoralis thoracicus muscle yield in male turkeys. THE EFFECT OF EARLY POST-HATCH DIETARY AMINO ACID LEVELS ON SATELLITE CELL DYNAMICS IN TURKEYS by LIDIA SYLWIA NIEROBISZ A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science NUTRITION Raleigh, North Carolina 2007