Monosex production of African catfish, Heterobranchus longifilis, through gynogenesis and androgenesis

Abstract

Chromosome engineering is a biotechnology tool currently used for fish improvement. Heterobranchus longifilis 
gynogens were produced by fertilizing eggs with irradiated sperm of the same species and subjecting the zygote to 
cold shock at 5°C, 40 min after fertilization for 15 min. To induce androgens, irradiated eggs were fertilized with normal 
spermatocytes and allowed to incubate for 40 min, then cold-shocked at 5°C for 15 min in a thermoregulated chamber 
to restore diploidy. Induction of gynogenesis and androgenesis was possible as 50.7 and 6.7% hatchability were 
obtained, respectively. After six days of rearing, the percentage survival of gynogens (97.8%) was better than that of 
the androgens (6.25%).