Combined supplementation of hydroxyproline and vitamin C improved the growth and flesh quality of Pacific white shrimp (Litopenaeus vanname) cultured in low salinity water

Abstract

This study investigated the effects of hydroxyproline (Hyp) and vitamin C (VC) addition to practical diet on growth and flesh quality of Pacific white shrimp (Litopenaeus vannamei) cultured in low salinity water. The control diet was formulated to contain 200 g/kg fish meal (FM20), and then 14 g/kg coated hydroxyproline (50%) (FM20H), 2 g/kg L-ascorbyl-2-phosphate (38%) (FM20C) and their combination (FM20HC) were added to the control diet to form four isoproteic (41.6%) and isolipidic (6.7%) diets. Pacific white shrimp with initial body weight of (1.50 ± 0.05) g were fed the above four diets in low salinity water (salinity 1‰) for 8 weeks. The results showed that the combined supplementation of Hyp and VC (FM20HC) increased the weight gain by 13.4%, and decreased the feed conversion ratio by 0.18 (P < 0.05), while the individual supplementation (FM20H and FM20C groups) just numerically promoted the growth (P > 0.05). In addition, the FM20HC group also showed higher protein and lipid retention than the FM20 group (P < 0.05). In flesh quality, the supplementation of Hyp (FM20H) increased total collagen and heat-soluble collagen contents, flesh chewiness and free flavor amino acids contents (P < 0.05). The supplementation of VC (FM20C) increased the contents of total collagen, heat-insoluble collagen and free flavor amino acids, and decreased flesh lactic acid, malondialdehyde contents and steaming loss (P < 0.05). The combined supplementation of Hyp and VC (FM20HC) showed higher total collagen and heat-insoluble collagen contents than the individual supplementation (FM20H and FM20C) (P < 0.05), and the myofiber density, flesh hardness and shear force in the FM20HC group were also significantly higher than those in the control (P < 0.05). In summary, the combined supplementation of hydroxyproline and VC in practical diet with fishmeal content of 200 g/kg significantly improved the growth performance and flesh quality of L. vannamei cultured in low salinity water.