The catfish Sorubim cuspicaudus is a species with the potential to diversify Colombian fish farming. Despite advances in its reproduction in captivity, problems of asynchrony in maturation and low semen volume in males persist. Laserpuncture is an alternative technology to accelerate gonadal maturation and improve reproduction in captivity by applying a low-power laser beam to reproductive acupoints that stimulate the production of hormones and enzymes that control the reproductive cycle. The study aimed to evaluate testicular maturation and semen quality of S. cuspicaudus subjected to laserpuncture.
The immature males (n=15) were treated with a Helium-Neon low-laser (17 Mw) at different exposure times: 10, 20 and 25 sec. The laser generated different powers: 0.85, 1.7 and 2.1 Joules (J). The laser was applied to the reproductive acupoints at 2/3 of the ventral region once a week for one month. In addition, a group of immature males without laserpuncture (negative control, n=5) and naturally mature males in earthen ponds (positive control, n=3) were evaluated. Finally, all males (treated and controls) and a group of females in final maturation (n=3) were induced with Ovaprim® (0.5 ml/kg of weight body) to evaluate the seminal quality and fertilizing capacity of the semen. Semen quality was assessed using the computer-assisted semen analysis system (SCA®, Microptic, Spain) and fertilizing capacity was evaluated using fertilization and hatching rates. Testicular maturity was also analyzed using histological sections, and the gonadosomatic index (GSI) was estimated.
The results indicate that males treated with 2.1 J presented mature testicles. Males treated with less potency (0.85 and 1.7 J) were found to be maturing and did not release semen, as well as the negative control. Males treated with 2.1 J (0.8±0.1) and the positive control (0.9±0.6) registered similar GSI (p>0.05). Total motility ranged between 90.6±5.8% (2.1 J) and 90.9±8.2% (positive control) (p>0.05) (Table 1). The semen obtained by induction with Ovaprim®, both from males matured with laserpuncture (2.1 J) and from the positive control, did not show statistical differences (p>0.05) in fertilizing capacity (Figure 1).
The results suggest that laserpuncture accelerates testicular maturity and produces good-quality semen with fertilizing capacity when stimulated with 2.1 J (17 mW for 25 sec) once a week for one month.