The effects of dietary myo-inositol on growth and physiological, biochemical, and molecular responses in the Pacific white shrimp Litopenaeus vannamei

Myo-inositol serves as an essential nutrient in many animal species. However, the optimal requirements of myo- inositol and the mechanisms by which myo-inositol is involved in nutritional regulation in crustaceans are un-clear. An 8-week trial was conducted to comparatively evaluate the effects of 6 levels of dietary myo-inositol (20, 528, 1030, 2060, 3180 and 4235 mg/kg diet) on growth performance, body composition, serum metabolite composition, hepatopancreatic metabolite content, and digestive enzyme activity in juvenile Pacific white shrimp Litopenaeus vannamei (0.78 +/- 0.039 g). The weight gain and conditioning factors of shrimp fed myo- inositol were significantly higher than those of the 20 mg/kg myo-inositol group. The maximal hepatosomatic index was found in the 1030 mg/kg myo-inositol group. On the other hand, serum triglyceride, total cholesterol, and low-density lipoprotein contents in the control group were significantly lower than those in the other groups, and glucose content in the hepatopancreas in the control group was significantly lower than that in the 2060 and 3180 mg/kg myo-inositol groups. Metabolome and transcriptome analyses revealed that myo-inositol signifi-cantly affected glycerophospholipid metabolism, transport and catabolism in lysosomes, pancreatic secretion, and bile secretion pathways. The highest growth was achieved with the inclusion of 528 mg/kg dietary myo- inositol. This study has suggested that myo-inositol may promote growth in L. vannamei by improving lipid utilization.