The Role of Beta-Carotene Oxygenase 2a Gene Expression and Food Carotenoids in Modulating Egg Carotenoid Content and Larval Performance in Kutum (Rutilus frisii sp.)
摘要
Egg coloration in Kutum (Rutilus frisii) is evolutionarily significant, yet its genetic mechanisms remain unclear. This study investigated the relationship between food carotenoid content and egg carotenoid levels and coloration, focusing on the expression of the bco2a gene in the liver of wild female Kutum. The study was conducted in two phases. In the non-reproduction season (December), wild females were sampled to measure intestinal food carotenoid content, egg carotenoid levels, and hepatic bco2a expression. In the reproduction season (March–May), females with green and orange eggs were sampled to assess egg parameters and larval survival. Larvae obtained from both egg types were exposed to light (200, 1000, 2000, and 3000 lux) and hypoxia (3 mg/L O2 for 3 h) to assess stress resilience. Results showed that females with orange eggs had significantly higher bco2a gene expression and egg carotenoid content. A positive association was found between gene expression and dietary carotenoid levels. While no significant differences were observed in larval survival under different light intensities, a notable difference was observed between the two larval groups under hypoxia conditions. In overall, bco2a expression and dietary carotenoids influence egg pigmentation and potentially impact larval performance under environmental stress. These findings suggest that egg color may serve as a visual indicator of maternal nutritional and genetic status, relevant for broodstock selection in conservation or aquaculture programs.