Abstract

ARIAS-RODRIGUEZ, Lenin; RODRIGUEZ-IBARRA, Luz Estela  and  VALLE-PIGNATARO, Gabriela del. Effect of UV radiation on the genetic inactivation of sperm of the bullseye puffer Sphoeroides annulatus (Jenyns, 1842). Cienc. mar [online]. 2004, vol.30, n.3, pp.391-402. ISSN 0185-3880.

Genetic (DNA) inactivation of fish sperm with ultraviolet irradiation is generally accompanied by a paradoxical effect on survival rates (Hertwig effect). In the present study, sperm samples from ten male bullseye puffer fish (Sphoeroides annulatus) were diluted 1:50 using Cortland's extender solution and used to test the effect of nine ultraviolet doses (0.2-1.0 Jcm^-2) on motility time in seconds, motility index, and embryo survival rate after fertilizing eggs from five bullseye puffer females. Motility time of sperm irradiated with 0.2-0.9 J cm^-2 were not statistically different from the controls, but sperm irradiated with a dosage of 1.0 Jcm^-2 dosage had significant lower motility time. Motility indices (MI) allowed for the statistical differentiation offour groups in relation to their response to different radiation doses: the first had high MI, and included the controls and 0.20.3 Jcm^-2 treatments; the second had lower MI and included the 0.4-0.7 Jcm^-2 treatments; the third showed recovery of MI and included the 0.8-0.9 Jcm^-2 treatments; and the fourth showed the lowest MI with the 1.0 Jcm^-2 treatment. Embryo survival was highest for the controls and 0.2 Jcm^-2 treatment, decreasing in the 0.3-0.4 Jcm^-2 treatments, increasing again in the 0.50.8 Jcm^-2 treatments, until reaching lowest survival in the 0.9-1.0 Jcm^-2 treatments. These results indicate that the best ultraviolet dosage to achieve genetic inactivation of sperm of this species is close to 0.7 Jcm^-2, a dosage in which fish fry showed typical haploid syndrome characteristics.

Keywords : Sphoeroides annulatus; sperm; ultraviolet; Hertwig.