Comparative study of erythrocytes of polyploid hybrids from various fish subfamily crossings

We have undertaken comparative studies of the number and phenotypes of erythrocytes in the peripheral blood of red crucian carp (RCC), blunt snout bream (BSB), and their hybrids, including triploids, tetraploids, and pentaploids. The results indicate that the mean nuclear volume of erythrocytes in peripheral blood increases regularly with increasing ploidy. Furthermore, many more mature erythrocytes have a dumbbell nucleus in the peripheral blood of polyploid hybrids compared with their diploid parents. With the increase in ploidy level, the percentage of such erythrocytes increases. The polyploid hybrids also have a large number of erythrocytes with abnormal shapes. For example, round and tear-shaped erythrocytes have been observed in the peripheral blood of polyploid hybrids. Since the erythrocytes in polyploid hybrids with their larger volume and lower specific surface area are unfavorable for the conveyance of oxygen, morphological variations of erythrocytes might improve defective blood circulation. This research was supported by the National Natural Science Fund for Distinguished Young Scholars (grant no. 30725028), the National Natural Science Foundation of China (grant nos. 30330480 and 30571444), National Basic Research Program (grant no. 2007CB109206), and Key Project of Hunan Province (grant no. 2006NK2008).