Effects of the Supplementation of Lysophospholipid in Low-Lipid Diets on Juvenile Pacific White Shrimp

The shortage of lipid sources has been a limiting factor of the aqua-feed industry. Lysophospholipid (LPL) is a highly efficient lipid emulsifier, which may help improve lipid utilization efficiency and thus spare the dietary lipid. This study aimed to evaluate the effects of LPL on growth performance, fatty acid composition, and lipid metabolism of juvenile Litopenaeus vannamei (averagely, 2.4 g). Five diets were prepared: a control diet with 6.5% lipid, the control diet supplemented with 0.05% or 0.1% LPL (0.05% LPL and 0.1% LPL), a moderately low-lipid (MLL) diet supplemented with 0.05% LPL (0.05% LPL-MLL), and an extremely low-lipid (ELL) diet supplemented with 0.1% LPL (0.1% LPL-ELL). Each dietary group had triplicate tanks (30 shrimp in each tank). The feeding experiment lasted 8 weeks. Compared with the control group, the addition of 0.05% LPL promoted the growth by 9.95%; diet 0.05% LPL-MLL resulted in a comparable growth to the control, but diet 0.1% LPL-ELL tended to adversely affect the growth. Dietary LPL had little effect on the whole-body proximate composition. The content of 18:2n−6 and 18:3n−3 was significantly higher in the 0.05% LPL group compared to the control. The 20:5n−3 content was the highest in the 0.05%LPL-MLL group. In addition, the 0.05% LPL and 0.1% LPL group increased the plasma high-density lipoprotein-cholesterol content. Meanwhile, all LPL groups reduced the low-density lipoprotein-cholesterol content. The addition of LPL significantly regulated the messenger RNA (mRNA) expression of genes related to cholesterol homeostasis, such as ldlr, srb1, abca1, and abcg8. In conclusion, dietary supplementation with 0.05% LPL tended to promote shrimp growth and can spare 15% dietary lipid. However, when the dietary lipid content decreased from 6.5% to an extremely low level of 4.8%, dietary LPL was ineffective to spare lipids. This was the first study to validate the lipid-sparing effect of dietary LPL in shrimp.