Physiological change and nutritional requirement of Pacific white shrimp Litopenaeus vannamei at low salinity

The Pacific white shrimp Litopenaeusvannamei is a euryhaline species with optimal salinity of 20-25 practical salinity unit (psu) for growth and survival, but has been cultured in inland water with salinity <5psu worldwide. In the past decade, much research progress has been made on the physiological and nutritional requirements of white shrimp at low salinity. This study reviews the recent findings in the aspects of growth, survival, energy metabolism, stress resistance and immunity of white shrimp at low salinity and synthesizes recent research outcomes in nutritional requirements in an attempt to improve the shrimp performance in aquaculture at low salinity. The white shrimp at low salinity usually show slow growth, low immunity, high susceptibility to pathogens and high energy demand. The diet containing 30-36% protein, 15-20% carbohydrate and supplementations of potassium, sodium, vitamin E and C, free amino acids (gly-cine, alanine, proline and taurine), antioxidants and probiotics can improve shrimp growth and immunity at low salinity. The white shrimp has demonstrated the ability to synthesize DHA and EPA from LNA at low ambient salinity, but further studies are needed to further confirm this finding. Future research should focus on the understanding of physiological mechanism and adaptation associated with salinity change and nutritional manipulation. The specific dietary requirements of essential fatty acids, essential amino acids, vitamins and minerals and the nutrition-mediated immune response also warrant further study on shrimp at low salinity.