Transcriptional Changes in the Breast Muscle of Thermally Challenged Turkey Poults

Abstract

Thermal stress in poultry causes reduction in growth, impaired meat quality, and increased mortality. Growth selected and very young birds are especially susceptible. To investigate the transcriptional pathways involved in thermal stress we looked at the breast muscle (an economically important muscle group) of 1-day old turkey poults from a fast growth selected line and a related slow growing line. These young birds were brooded at one of 3 temperatures for 3 days: control (35°C), hot (39°C), or cold (31°C). RNA was isolated from the breast muscle after treatment and euthanasia. 28 libraries were sequenced for analysis (average 18 million reads per library). The reads were mapped to the current turkey genome assembly an analyzed for differential expression. As expected, the fast growing line responded differently to thermal stress than the slow growing line. It had a greater number of differentially expressed genes belonging to pathways that included: transcriptional control and ubiquitination. The slow growing line’s affected pathways were almost exclusively lipid metabolism There are no shared differentially expressed genes or pathways between the two lines. This divergence in response is highlighted by comparing the two lines at each temperature as well as there are more differentially expressed genes between the lines at the treatment temperatures than at the control temperature.