Comparative study on the role of various sterols in enhancing ovarian development and metabolic functions in Pacific white shrimp ( Litopenaeus vannamei) broodstock

In this study, the Pacific white shrimp ( Litopenaeus vannamei) broodstock was considered to rely on dietary sterols for ovarian development because of the inability of the animals to synthesize sterols endogenously. Therefore, we investigated the effects of cholesterol, ergosterol, beta- sitosterol, and fucosterol as sterol sources, compared with a control group lacking sterols, on the growth, reproduction, and metabolism of shrimp for a 28-day feeding trial, with an average weight of 32.28 +/- 2.00 g in female L. vannamei broodstock. The results demonstrated that cholesterol supplementation significantly enhanced shrimp growth, the gonadosomatic index, and yolk particle deposition, outperforming the other sterol groups and the control group. Notably, while broodstock in the ergosterol group presented the greatest weight gain and yolk granule deposition, they did not achieve the same level of gonadal development or metabolic efficiency as those receiving cholesterol. Additionally, the beta- sitosterol group demonstrated a favorable hepatosomatic index but still fell short of the benefits provided by cholesterol. Cholesterol has unique advantages in promoting growth and ovarian development, which may be attributed to its more efficient metabolic utilization and enhanced hormone synthesis, as indicated by the significantly higher serum levels of 17 beta-estradiol and progesterone in the cholesterol group. Furthermore, cholesterol supplementation significantly upregulated vitellogenin mRNA expression in the hepatopancreas and ovaries, thereby promoting ovarian maturation. Additionally, gamma- linolenic acid and 9,10-epoxyoctadecenoic acid were significantly upregulated in the cholesterol group, facilitating ovarian lipid accumulation. In conclusion, the use of cholesterol as a sterol source in the diet significantly promoted the growth and ovarian development of L. vannamei by regulating lipid metabolism and hormone synthesis.