Study of biological characteristics of an improved Japanese white crucian carp lineage derived from Carassius cuvieri (♀) × Megalobrama amblycephala (♂)

Abstract

Based on the formation of fertile allotetraploid fish (4nJB, 4n = 148) derived from female Carassius cuvieri (JCC, 2n = 100) × male Megalobrama amblycephala (BSB, 2n = 48), an improved Japanese white crucian carp (IJCC) was obtained by mating female 4nJB and male 4nJB, and thus far, the population of IJCC has reached the fifth generations (F1–F5). The purpose of the present study was to comparatively investigate the biological characteristics of the IJCC lineage (F1–F5) and their original female parent JCC. The results of DNA content and chromosome numbers showed that the IJCC lineage was diploid with 100 chromosomes. For morphological characteristics, it appears that IJCC-F1 has smaller head and a higher body width than that of JCC, and some countable traits as well as the ratio of measurable traits were significantly different (P < 0.05) between these two fish. With the passing of generations, the appearance of the IJCC lineage has been stable. Regarding reproductive characteristics, the fecundity, sperm volume, sperm density, fertilization rate and hatching rate were not significantly different (P > 0.05) between the JCC and IJCC lineages, indicating that the reproductive capacity of the IJCC lineage was similar to that of the JCC. Furthermore, the growth performance showed that the average weight of IJCC-F1 and IJCC-F5 was significantly greater (P < 0.05) than that of JCC both at 6 months and 1 year of age. The good fertility of the IJCC lineage ensures the multigeneration utilization of its advantage, and the IJCC lineage has significant value in aquatic applications.