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. Overall design: 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).