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.