Response of turkey pectoralis major muscle satellite cells to hot and cold thermal stress: Effect of growth selection on satellite cell proliferation and differentiation

Satellite cell (SCs), the main progenitors for post-hatch poultry muscle growth, has maximal mitotic activity and sensitivity to temperature during the first week after hatch. The objective of the present study was to determine the effect of hot and cold temperatures on the proliferation and differentiation of SCs from pectoralis major (P. major) muscle of fast-growing 1-week-old Nicholas commercial (NC) turkeys compared to Randombred Control Line 2 (RBC2) turkeys representing commercial turkeys from 1966. Three temperature regimens were used: SCs proliferation at 38 degrees C (control) with differentiation at 43 degrees or 33 degrees C; proliferation at 43 degrees or 33 degrees C with differentiation at 38 degrees C; or both proliferation and differentiation at 43 degrees, 38 degrees, or 33 degrees C. Satellite cell proliferation and differentiation increased at 43 degrees C and decreased at 33 degrees C in both lines. When a thermal challenge was administered during proliferation, greater stimulatory or suppressive effects on differentiation were observed compared to if the thermal challenge was applied only during differentiation in both lines. Expression of myoblast determination protein 1 during proliferation showed a higher increase in the NC line compared to the RBC2 line at 43 degrees C. Increased myogenin expression was observed in all hot treatment groups in the NC line but was only observed in the RBC2 line if the hot treatment was administered throughout proliferation and differentiation. Cold treatment suppressed myogenin expression independent of line. These results suggest turkey P. major muscle SCs are more sensitive to environmental temperatures during proliferation, and SCs from growth-selected NC turkeys are more sensitive to thermal stress compared to the RBC2 turkeys.

Automated summary

This study compared the proliferation and differentiation of SCs from P. major muscle of NC and RBC2 turkeys under different temperature conditions, finding that proliferation and differentiation increased at hot temperatures and decreased at cold temperatures. The impact of thermal challenge on differentiation was more significant than during proliferation, and NC turkeys were more sensitive to thermal stress compared to RBC2 turkeys.