Increase in milt production by hormonal treatment in the pejerrey fish Odontesthes bonariensis (Valenciennes 1835)

Abstract

In spite of interest in the cultivation of the pejerrey fish Odontesthes bonariensis (Cuvier & Valenciennes 1835), there are few studies on subjects required to advance this activity. One of the problems is the synchronization of female and male maturation to provide eggs and sperm for larval production. The low volume of expressible milt, either in wild or culture fish, is a major problem. The aim of this work was to study the effectiveness of the administration of different hormones on sperm production in pejerrey. Milt production was enhanced by the injection of human chorionic gonadotropin (hCG) (16.7-fold increase, 625 IU kg−1), carp pituitary extracts (13.5-fold increase, 30 mg kg−1), salmon pituitary extracts (12.8-fold increase, 30 mg kg−1), salmon-type gonadotropin-releasing hormone analogue (GnRH) (16.7-fold increase, 10 μg kg−1) and mammalian-type GnRH analogue (10.8-fold increase, 20 μg kg−1). Sperm concentration, motility and the fertilization rate were not statistically different compared with control groups. It was also demonstrated that sperm could be obtained off-season. Taken together, hCG is recommended to stimulate pejerrey spermiation because it is effective in low doses is inexpensive and is widely available.