Quantitative trait loci controlling swimming performance and their effect on growth in Nile tilapia (Oreochromis niloticus)

Critical swimming speed (Ucrit) is an important measurement of swimming performance and a good indicator for cardio-respiratory health. It offers a new opportunity to select fish with better fitness. However, the genomic architecture of swimming performance at whole genome level is not clear in Nile tilapia. For this study, swimming performance was measured in 1500 fish from GIFT strain in their early life, which were subsequently grown in a non-aerated pond (nocturnal hypoxia) until harvest. We aimed to estimate the genetic correlations between Ucrit with growth traits at early life stage, and with growth traits at later life stage using a genomic relationship matrix under hypoxia the same condition as used by most smallholder tilapia farmers, to identify QTLs associated with swimming performance, and estimate the effect of significant QTLs for Ucrit on the growth traits under hypoxia.