Ovarian histological and gene expression analysis of two Rutilus kutum (Kamensky ۱۹۰۱) races during spawning migration

Caspian kutum, Rutilus kutum is the most common species of the Cyprinidae family in the Iranian coastal waters of the Caspian Sea and comprises, on average, more than ۷۰% of the annual commercial bony fish catch. This species consists of two migratory forms, the spring race (SR) and autumn race (AR), which show morphological identities. The morphological differences are classified as phenotypic markers and cannot be a reliable method for distinguishing individuals and populations. Therefore, we performed histological analysis concerning ovarians, as well as gene expression profiling differences, to gain more knowledge about the differential migratory behavior of the races. Ovary and liver samples were collected to observe the reproductive performance based on ovarian histology and related gene expression using real-time quantitative polymerase chain reaction (qRT-PCR). Histological study of the AR and the SR broodstocks showed that the ovaries were at vitellogenic (oocyte diameter = ۹۷۸.۴ ± ۳۲.۳ µm) and maturation (oocyte diameter = ۱۲۲۵ ± ۲۷.۶ µm) stages, respectively. The steps identified were predictable because the ARs needed a hibernation after migration for spawning, while the SRs were ready for spawning after moving into the spawning grounds. Additionally, we performed qRT-PCR to confirm the genes involved in the vitellogenic and maturation stages of ovarian development in R. kutm. Given the lack of information about the population aspects of this species, histological and gene profiling analyses in the current study showed evidence of different migratory behaviors in the two races. These valuable results can be used in fishery management programs.

کلیدواژه ها:

Caspian kutum ، Ovarian histology ، Gene Expression