First Transcriptomic insight into the working muscles of racing pigeons during a competition flight

The currently known homing pigeon is a result of a sharp one-sided selection for flight characteristics focused on speed, endurance, and spatial orientation. This has led to extremely well-adapted athletic phenotypes in racing birds. Here, we identify genes and pathways contributing to exercise adaptation in sport pigeons by applying next-generation transcriptome sequencing of m.pectoralis muscle samples, collected before and after a 300 km competition flight. The analysis of differentially expressed genes pictured the central role of pathways involved in fuel selection and muscle maintenance during flight, with a core set of genes: ARTN, NREP, CAV3, SLC25A30, SLC2A11. Variations in these genes may therefore be exploited for genetic improvement of the racing pigeon population towards specific categories of competition flights. The present study was performed on 12 muscle samples of m. pectoralis collected from 12 racing pigeons (Columba livia). Samples were collected from adult birds never trained for racing (K; n = 5) and birds after competing in a 300 km race (E; n = 7), who have undergone earlier flight training All birds were bred, and raised on a private loft owner, at the same location, with the same environmental and feeding conditions. The E group was basketed the day before and transported to the place of release (300 km away from the loft).