Efficient breeding and growth advantage of all-male population in Lanzhou catfish (Silurus lanzhouensis)

Sex is one of the most valuable traits for aquaculture fish with distinct sexual dimorphisms, and breeding of monosexual populations improves aquaculture efficiency. Lanzhou catfish (Silurus lanzhouensis) with XX/XY sex determination system is an endemic fish in the Yellow River of China and exhibits sexual growth dimorphism. Here, we tracked the body weight, length and width of Lanzhou catfish and found out that males displayed faster growth performance than females from 3 months post fertilization, accompanied by sexually dimorphic expression of growth hormone/insulin-like growth factor (GH/IGF) axis genes. Subsequently, we performed genetic analyses in the self-fertilized family obtained from a hermaphrodite individual. Similar to the artificial gynogenetic family, the offspring of the self-fertilized family had significant higher genetic homozygosity and similarity than that of the sexually reproduced family. More importantly, we used the YY male obtained by selffertilization to mate with two XX female individuals and reproduced an all-male population with XY sex chromosomes, saving one generation time (3 years) and avoiding estradiol treatment compared with the conventional way of all-male population production. And the all-male population showed an obvious growth advantage over the normal population with both sexes, facilitating the development of catfish aquaculture.