Dietary phosphatidylinositol promotes ovarian maturation in Pacific white shrimp (Penaeus vannamei) via altered lipid mobilization and hormonal regulation.

Phosphatidylinositol (PI) is an important phospholipid involved in membrane structure, lipid transport, and cellular signaling, but its nutritional role in regulating ovarian maturation in crustacean broodstock remains poorly understood. To elucidate the effects and mechanisms by which dietary PI modulates ovarian development in female broodstock of Pacific white shrimp (Penaeus vannamei), five isonitrogenous, isolipidic, and semi-purified diets containing 0.0, 0.2%, 0.4%, 0.6%, or 0.8% PI (dry-matter basis) were formulated and fed to shrimp for 28 d. A total of 160 seven-month-old females (initial body weight 39.70 ± 1.80 g) at ovarian stage I were allocated to five treatments with four replicates each and eight shrimp per replicate. Compared with the control group (0.0 PI), the 0.6% PI diet significantly increased the gonadosomatic index (P < 0.001) and reduced the hepatosomatic index (P = 0.030) and shortened each of the ovarian stages I-III by approximately two days (stage I, P = 0.056; stage II, P = 0.159; stage III, P = 0.007). Mean oocyte area in the ovary (P < 0.001) and lipid-droplet area in the hepatopancreas (P < 0.001) were both greatest in the 0.6% PI group compared with the other dietary groups. Ovarian total cholesterol was highest in the 0.6% group (P = 0.029). Serum high-density lipoprotein and low-density lipoprotein declined in most PI-supplemented groups, reaching their lowest levels at 0.6% (P < 0.05). Endocrine profiling showed increased estradiol at 0.6% and 0.8% (P < 0.001), elevated progesterone across all supplemented groups (P = 0.007), and reduced molt-inhibiting hormone at 0.2% and 0.6% (P = 0.043). Transcriptomics identified 421 differentially expressed genes enriched for lipid synthesis and transport and for transforming growth factor (TGF)-β/Notch signaling, while metabolomics revealed upregulation of D-sphingosine, palmitic acid, and stearic acid, with decreased levels of purines (guanine and hypoxanthine) and B-vitamin intermediates (riboflavinand and pantothenate). Multi-omics integration indicated potentiation of sphingolipid metabolism and fatty-acid biosynthesis, alongside heightened consumption within purine metabolism, as a potential regulatory pathway promoting ovarian maturation. In summary, dietary PI may facilitate ovarian maturation by coordinating lipid mobilization and steroidogenesis, potentially interacting with developmental signaling pathways. A recommended supplementation range of 0.442%-0.586% (dry-matter basis) is suggested based on dose-response modeling, with 0.6% yielding the significant response. These findings provide new insights into broodstock nutrition strategy in shrimp aquaculture.