Evaluation of Crinkle Grass Rhizoclonium riparium in a Diet for Pacific White Shrimp Penaeus vannamei Post Larvae

A feeding experiment to evaluate the inclusion of Rhizoclonium raw meal (RM) in diets for growth and feed efficiency in Pacific white shrimp, Penaeus vannamei was conducted. Five diets were formulated containing increasing levels of RM inclusion: 0%, (control), 5.25%, 10.50%, 15.75%, and a diet with 15.75% RM totally replacing the mineral mix. The diets were fed to shrimp post larvae for 60 days with 4 replicates. Survival rates were excellent (98-93%) and similar for all treatments. Final average body weight (FABW) was highest in shrimp fed the diet containing 5.25% RM, and lowest with the 10.50% RM diet; FABW of the other groups were either statistically similar or lower than the control group. A similar pattern was also observed for specific growth rate (SGR) and protein gain (PG). Food conversion efficiency (FCE) was highest in shrimp fed the diet containing 5.25% RM; protein efficiency ratio (PER) was higher in all groups fed diets containing RM than the control group. Replacing the dietary mineral component with RM did not significantly affect the growth, feed efficiency, and survival rate. The present study demonstrated that Rhizoclonium riparium var. implexum is a possible complementary protein source and could replace from 15%-45% imported soybean meal (SBM) in the P. vannamei post larvae diet. An additional 1% RM could replace the dietary minerals.