Positive effects of optimal dietary cholesterol levels on the ovary development and health of female Pacific white shrimp, Litopenaeus vannamei broodstock

Abstract

Cholesterol is an important precursor necessary for the synthesis of steroid hormones and other functional substances. This study conducted a 28-day feeding experiment to assess the effects of different levels of dietary cholesterol (0.2%, 0.8%, 1.4%, 2.5%, or 3.2%) on the ovarian development and health status of female Litopenaeus vannamei broodstock (initial weight 39.5 ± 4.3 g). The results showed that dietary supplementation with 1.4% cholesterol can significantly increase the GSI and HSI of shrimp. Meanwhile, the 1.4% cholesterol group significantly increased the antioxidant capacity of shrimp, and increased mRNA expression of transcription factors (FoxO, GST) was also coordinated to regulate the antioxidant system. The TG and T-CHO contents were significantly accumulated in the hepatopancreas of shrimp fed a 1.4% cholesterol diet compared to other treatments. In addition, in the 1.4% group, the concentration of estrogen (E2, PROG, MF) was significantly increased compared to that in the other experimental feed groups. This was achieved by upregulating the mRNA expression of Vg, Vgr, StAR3, 3β-HSD, 17β-HSD, and ERR associated with the steroid hormone synthesis pathway. Correlation analysis of serum metabolomics and ovarian transcriptomics found that differential metabolites and differentially expressed genes were commonly significantly enriched in the glutathione metabolism pathway. Increased GST activity further enhances shrimp antioxidant capacity, which may also promote steroid hormone synthesis. In conclusion, dietary supplementation with 1.4% cholesterol can significantly promote ovarian development and strengthen the antioxidant system of female L. vannamei broodstock. To improve reproductive performance and health status, it is suggested that the appropriate dietary cholesterol supplementation content for female broodstock of L. vannamei is 1.606%–1.680%.