Assessment of different levels of green and brown seaweed meal in experimental diets for whiteleg shrimp (Litopenaeus vannamei, Boone) in recirculating aquaculture system

A feeding trial was conducted to evaluate digestibility and growth of whiteleg shrimp Litopenaeus vannamei in a recirculating aquaculture system (RAS), fed with diets that included the commercial seaweed meals Nutrigreen (NG) and Nutrikelp (NK). The experimental diets were isonitrogenous (300 g kg(-1)) and isoenergetic (3.3 Mcal kg(-1)), and were formulated to include 4 and 8 % of the seaweed meal resulting in five experimental diets: NG4 % and NG8 % of the green seaweed and NK4 % and NK8 % of the brown seaweed, and a control diet without seaweed meal. Juvenile L. vannamei (1.42 g) were stocked in 15 60 L clean-water tanks at 70 shrimp m(-2) to evaluate growth. Shrimps of 4.0 and 9.0 g were used for the digestibility trial. Survival in NK8 % (93.3 %) was the highest as compared to the control and the other diets. Apparent digestibility coefficients for dry matter and crude protein were over 80 % in the seaweed meal treatments, and higher (P < 0.05) than in the control diet. However, no significant differences (P > 0.05) were found for final weight, feed conversion ratio, specific growth rate, protein efficiency ratio and individual consumption. This result indicates that an inclusion of 4 and 8 % of brown and green meal in commercial shrimp feed supported adequate growth and survival of juvenile L. vannamei reared in RAS.