Replacement of Soybean Meal with Rhizoclonium riparium Protein Concentrate in the Diet of Pacific White Shrimp Litopenaeus vannamei Postlarvae

The biological value of incorporating Rhizoclonium riparium var. implexum protein concentrate (RPC) meal in the diet of Pacific white shrimp Litopenaeus vannamei, postlarvae was evaluated for 60 days. Four diets were prepared: no seaweed inclusion (0%, control diet), 5.25% seaweed inclusion, 10.5% seaweed inclusion, and 15.75% seaweed inclusion with equivalent replacement rates of soybean meal at 0, 15%, 30% and 45%. Final average body weight (FABW) and weight gain (WG) of the shrimp were not significantly affected by the RPC supplementation (P>0.05) except those of shrimp fed the highest level of 15.75% RPC, which showed lower values but were statistically similar to those of the 5.25% group. Specific growth rate (SGR) and protein gained (PG) values of shrimp were not affected by the dietary RPC except those of the 15.75% group, which showed significantly lower values. Neither feed conversion efficiency (FCE) nor protein efficiency ratio (PER) showed a clear trend for graded concentration of RPC. Survival of shrimp was relatively good and statistically similar ranging from 76.0%-84.0%. In conclusion, Rhizoclonium protein concentrate can replace 30% soybean meal in the diet of Penaeus vannamei postlarvae or an equivalent of 10.5% inclusion rate without negative effects on the survival, growth, and feed conversion efficiency of white shrimp.