Early Posthatch Feeding Stimulates Satellite Cell Proliferation and Skeletal Muscle Growth in Turkey Poults
2003
Halevy, Orna | Nadel, Yael | Barak, Miriam | Rosenboim, Israel | Sklan, David
The effect of early posthatch feeding on skeletal muscle growth and satellite cell myogenesis was studied in turkey poults. Poults were either fed immediately posthatch or food-deprived for the first 48 h and then refed for the rest of the experiment. Body and breast muscle weights were lower in the starved poults than in fed controls throughout the experiment (P < 0.05). Cultures of breast muscle satellite cells revealed significantly higher DNA synthesis in the fed group than in the starved group as early as d 1 (P < 0.05). These levels continued to rise, reaching ∼500-fold those of feed-deprived poults on d 4. In the latter group, thymidine incorporation peaked only on d 6, and then declined. Thereafter, it decreased to the same levels as those in the fed group. Satellite cell number per gram muscle increased until d 4, and was higher in the fed group than in the starved group (P < 0.05). Pax7 levels in cell cultures derived from the fed group were markedly higher than in the starved group on d 2 (P < 0.05). Myogenin levels in both culture and muscle were higher in the fed than in the starved groups until d 4 (P < 0.05). Phosphorylation of the survival factor Akt and cyclin-dependent kinase inhibitor p21 levels were higher in cells derived from the fed group relative to those from the starved group 48 h posthatch (P < 0.05). Similarly, Akt phosphorylation and insulin-like growth factor I (IGF-I) levels were significantly higher in the muscles of the fed group (P < 0.05). Together, these results suggest that immediate posthatch feeding of poults is critical for satellite cell survival and myogenesis probably via IGF-I.
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