LAUSR

The present study aimed to investigate the effects of environmental heavy metals on sperm morphology and motility of Bufo raddei. We collected B. raddei from Baiyin (BY) and Liujiaxia (LJX); BY is an area heavily polluted by heavy metals, while LJX is a relatively unpolluted area. Significant accumulations of copper, zinc, lead and cadmium were observed in B. raddei from BY, together with relatively smaller sperm size and higher sperm abnormality rate. Unexpectedly, sperm velocity, percentages of sperm motility and viability of B. raddei from BY were significantly higher than those from LJX. Similarly, when sperm was suspended in heavy metal solutions, sperm velocity, percentages of sperm motility and viability significantly increased compared with those suspended in distilled water. These results indicate that environmental heavy metal stress may decrease sperm size, meanwhile enhance sperm motility through increasing the ratio of head length to total sperm length of B. raddei.