Zhang Naijing, Zhang Huabin, Fan Guangwei, Sun Ke, Jiang Qingqing, Lv Zhuowen, Han Boyang, Nie Zhenyuan, Shao Yujie, Zhou Yongkang, Zhang Baowei, Wu Xiaobing, Pan Tao
College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
Animals (Basel). 2023 Apr 19;13(8):1405. doi: 10.3390/ani13081405.
The Chinese alligator (), found only in a small region in southeastern Anhui Province, is listed as critically endangered (CR) by the International Union for Conservation of Nature (IUCN) due to its current declining population trend. Any abnormalities in the physical properties of an egg can decrease the hatching rate. In particular, eggshells play an essential role in embryo development, motivating us to analyze the microstructures of the eggshells of Chinese alligators. In this study, we categorized the eggshells into two groups, based on the hatching rates, and analyzed the relationship between the eggshell parameters (eggshell thickness, calcium content, and number of pores in erosion craters) and the hatching rate, as well as the relationships between the eggshell parameters. We found that the shells of the eggs with high hatching rates were thicker than those of the eggs with low hatching rates. There were also fewer erosion-crater pores on the surfaces of the eggs with high hatching rates than on the surfaces of the eggs with low hatching rates. Moreover, the shell Ca content was significantly higher in the eggs with high hatching rates than in the eggs with low hatching rates. Cluster modeling indicated that the highest hatching rate occurred when the eggshell thickness was 200-380 µm and there were 1-12 pores. These results suggest that eggs with adequate Ca contents, thicker shells, and less air permeability are more likely to hatch. Furthermore, our findings can inform future studies, which will be vital for the survival of the critically endangered Chinese alligator species.
扬子鳄仅分布于中国安徽省东南部的一小片区域，由于其种群数量呈下降趋势，被国际自然保护联盟（IUCN）列为极度濒危（CR）物种。卵的物理性质出现任何异常都可能降低孵化率。特别是蛋壳在胚胎发育中起着至关重要的作用，这促使我们对扬子鳄蛋壳的微观结构进行分析。在本研究中，我们根据孵化率将蛋壳分为两组，并分析了蛋壳参数（蛋壳厚度、钙含量和蚀坑中的气孔数量）与孵化率之间的关系，以及蛋壳参数之间的关系。我们发现，孵化率高的卵的蛋壳比孵化率低的卵的蛋壳更厚。孵化率高的卵表面的蚀坑气孔也比孵化率低的卵表面的少。此外，孵化率高的卵的蛋壳钙含量明显高于孵化率低的卵。聚类模型表明，当蛋壳厚度为200 - 380微米且有1 - 12个气孔时，孵化率最高。这些结果表明，钙含量充足、蛋壳较厚且透气性较小的卵更有可能孵化。此外，我们的研究结果可为未来的研究提供参考，这对极度濒危的扬子鳄物种的生存至关重要。
