Effect of stocker management program on beef cattle skeletal muscle growth characteristics, satellite cell activity, and paracrine signaling impact on preadipocyte differentiation

• Published in: Journal of animal science and technology 2019, 61(5), , pp.260-271
• Main Authors: Vaughn, Mathew A., Lancaster, Phillip A., Roden, Kelly C., Sharman, Evin D., Krehbiel, Clinton R., Horn, Gerald W., Starkey, Jessica D.
• Format: Article
• Language: English
• Subjects: beef stocker cattle; dormant native range; marbling development; satellite cell activity; skeletal muscle growth; winter wheat pasture; 축산학
• ISSN: 1598-9429; 2055-0391; 2672-0191; 2093-6281
• DOI: 10.5187/jast.2019.61.5.260

The objective of this study was to determine the effect of different stocker management programs on skeletal muscle development and growth characteristics, satellite cell (SC) activity in growing-finishing beef cattle as well as the effects of SC-conditioned media on preadipocyte gene expression and differentiation. Fall-weaned Angus steers (n = 76; 258 ± 28 kg) were randomly assigned to 1 of 4 stocker production systems: 1) grazing dormant native range (NR) supplemented with a 40% CP cottonseed meal-based supplement (1.02 kg · steer −1 · d −1 ) followed by long-season summer grazing (CON, 0.46 kg/d); 2) grazing dormant NR supplemented with a ground corn and soybean meal-based supplement fed at 1% of BW followed by short-season summer grazing (CORN, 0.61 kg/d); 3) grazing winter wheat pasture (WP) at high stocking density (3.21 steers/ha) to achieve a moderate rate of gain (LGWP, 0.83 kg/d); and 4) grazing winter WP at low stocking density (0.99 steers/ha) to achieve a high rate of gain (HGWP, 1.29 kg/d). At the end of the stocker (intermediate harvest, IH) and finishing (final harvest, FH) phases, 4 steers / treatment were harvested and longissimus muscles (LM) sampled for cryohistological immunofluorescence analysis and SC culture assays. At IH, WP steers had greater LM fiber cross-sectional area than NR steers; however, at FH, the opposite was observed ( p < 0.0001). At IH, CORN steers had the lowest Myf-5+:Pax7+ SC density ( p = 0.020), while LGWP steers had the most Pax7+ SC ( p = 0.043). At FH, CON steers had the highest LM capillary density ( p = 0.003) and their cultured SC differentiated more readily than all other treatments ( p = 0.017). At FH, Pax7 mRNA was more abundant in 14 d-old SC cultures from HGWP cattle ( p = 0.03). Preadipocytes exposed to culture media from proliferating SC cultures from WP cattle isolated at FH had more PPARγ ( p = 0.037) and less FABP4 ( p = 0.030) mRNA expression compared with NR cattle. These data suggest that different stocker management strategies can impact skeletal muscle growth, SC function, and potentially impact marbling development in growing-finishing beef cattle.