LAUSR

ABSTRACT Myogenic satellite cells are critical for posthatch muscle growth, and their activity is sensitive to nutritional regime during the immediate posthatch period. The objective of the current study was to determine if the response of satellite cells to nutrient restriction was dependent on bird age and/or growth rate. Satellite cells were isolated from the pectoralis major (p. major) muscle of 1‐d, 7‐wk, and 16‐wk‐old turkeys selected for increased body weight at 16 wk of age (F line) and the randombred control (RBC2) line from which the F line was selected. Nutrient restriction of 0, 5, 10, 20, and 40% of the standard cell culture medium was applied during proliferation with subsequent normal differentiation medium (RN) or during differentiation with preceding normal proliferation medium (NR). Satellite cell proliferation and differentiation decreased with nutrient restriction for all treatment regimens and ages, except for 1‐d cell differentiation with the RN treatment, which increased with nutrient restriction. Interestingly, after 24 h of a 5% nutrient restriction during the RN treatment, proliferation increased for 1‐d and 7‐wk cells. Additionally, after 24 h of 5, 10, and 20% nutrient restriction during the NR treatment, differentiation increased for 1‐d and 7‐wk cells. The 16‐wk cells did not exhibit this response to any treatment regimen. Growth rate had little effect on satellite cell response to nutrient restriction. In this study, satellite cells differentially responded to nutrient restriction depending on age, as well as duration and timing of the nutrient restriction. These data suggest that it is necessary to optimize diets throughout a bird's life to maximize satellite cell activity and p. major muscle growth.