Among vitamin K (VK), VK3 (menadione, 2-methyl-1, 4-naphthoquinone) is used for animal feeds in the form of menadione sodium bisulfite (MSB). It was reported that dietary VK supplementation is not necessary for Pacific white shrimp. Therefore, this study was conducted to determine VK requirement in diet for Pacific white shrimp as well as to verify whether VK supplementation is necessary or not.
Shrimp (initial mean body weight, 0.45±0.00 g) were randomly distributed in 28 acrylic tanks (20 shrimp per tank). To confirm the in vivo synthesis of vitamin K by intestinal bacteria, an antibiotic (tetracycline hydrochloride) was added to a basal diet (Con) and considered as Con_2. MSB was added so that the menadione content of the experimental diets was 50, 100, 200, and 400 mg/kg. The analyzed menadione content of the diets were 0 (Con and Con_2), 40.8 (M50), 113.9 (M100), 195.4 (M200) and 363.2 (M400) mg/kg. Three tanks were randomly assigned to each diet, and the shrimps were fed six times daily for 7 weeks.
At the end of the feeding trial, final body weight, weight gain and specific growth weight were significantly higher in MSB added groups than Con and Con_2 groups. Those of Con group was significantly higher than those of Con_2 group (Table 1). Feed conversion ratio was significantly higher in shrimp fed Con_2 diet than that of other groups. Protein efficiency ratio was significantly lower in Con_2 group than in all other groups. These results indicate that the addition of MSB in diet significantly affects the growth performance and feed utilization of the shrimp and that VK supplementation is necessary for the shrimp diet.