Transcriptional Response to Thermal Stress in Turkey Muscle

Thermal stress in poultry causes decreased growth, decreased meat quality, and increased mortality. Young birds and fast growing lines are particularly susceptible to thermal stress. To better understand the response of poultry to thermal stress this study used RNA-Seq to characterize the transcriptional changes in the breast muscle of young turkeys. Therefore, 1-day old poults from the fast growing F-line (selected only for 16wk body weight) and it’s random-bred control (RBC2 line) were brooded for 3 days at one of three temperatures: control (35°C), hot (39°C), and cold (31°C). Twenty-eight libraries were created from muscle and sequenced at an average of 18 million reads per library. Reads were mapped to the current turkey genome assembly and annotation. Read counts were analyzed for differential expression among treatment groups (by both temperature and line). No generalizable response to hot or cold stress, common in both lines of turkey, was observed. Instead, there were line-specific responses to deviation from the control temperature. The F-line responded to thermal stress primarily by up-regulating genes associated with transcriptional control and protein ubiquitination. The RBC2 line responded primarily by down regulating lipid metabolism genes. These differences in response to thermal challenge were further highlighted by comparisons between lines at each temperature. The control brooding temperature (35°C) had the fewest differentially expressed genes between lines relative to the experimental temperature treated groups. These comparisons identify important metabolic pathways underlying the response of turkey muscle to thermal challenge.