Effect of chronic low dose exposure to lead on male reproduction in rabbits

ABSTRACT

The present study aimed to investigate the effect of exposure to a low dose of lead for a long time on male reproductive performance. Therefore, 60 weaned white Newzealand rabbits were reared in automatic battery system, randomly divided into two groups; a control group that received distilled water and a treated group that received 100 micro g lead acetate micro g/ kg body weight orally/day. Libido, semen characteristics and mating performance were investigated in mature rabbits [20[th] - 35 [th] week after starting the experiment]. Blood samples and testes were collected after sacrificing at 4, 8,12,16, 20 and 36 weeks after the start of the experiment. Androstenedione, testosterone and estradiol-17 B levels were assayed [RIA] in blood plasma. Relative weight, total testosterone in homogenate and histopathological changes of the testes were recorded. Also, residual lead in blood and testes was determined. Results showed that plasma total testosterone and androstenedione levels were significantly lower in lead treated [114 and 7.2 ng/dl, respectively] than control [241 and 12.3 ng/dl, respectively] groups. Estradiol-17B level was not significantly different. Total testosterone concentration in testicular homogenate was significantly decreased in lead treated [3.68 +/- 0.68 micro g /100 mg] than that in control [17.47 +/- 3.71 micro g /100 mg] groups. Relative testicular weight, libido, sperm motility, sperm abnormalities, fertility% and average litter size was significantly lower than that of the control group while a significant increase of sperm abnormalities was noticed than that of control. All these results and others proved that even a marginal lead level could provoque reproductive disorders in male rabbits