Evaluating dietary supplementation of polysaccharides extracted from green seaweed (Chaetomorpha linum) for white leg shrimp (Litopenaeus vannamei) postlarvae

Abstract

This study evaluated the effects of supplementing polysaccharides extracted from the green seaweed (Chaetomorpha linum) with commercial feed for nursing white leg shrimp (Litopenaeus vannamei). The experiment consisted of four treatments, with each treatment being replicated three times. The control treatment did not receive extract product (0%), while the other three treatments received the extract product at levels of 0.3%, 0.6% and 0.9%. Shrimp postlarvae with an initial weight of 0.038±0.002 g were stocked at a density of 1,000 PL/m3 in 500 L tanks with a salinity of 15 ppt. After rearing the shrimp for 30 days, the treatments showed a survival rate range of 80.22-81.34%. Shrimp weight ranged from 0.93 to 1.08 g, with specific growth rates of 11.39-11.95%/day. The feed conversion ratio (FCR) was 0.67-0.80, and the best performance, with the highest growth and lowest FCR, was achieved by the 0.6% diet treatment compared to the control and other treatments. Moreover, the control treatment had the highest cumulative mortality (46.67% and 11.67%, respectively) when shrimp were exposed to acute salinity shocks from 15 ppt to 0.5 ppt (low alinity shock) and from 15 ppt to 50 ppt (high salinity shock). The treatment with 0.6% had the lowest cumulative mortality in the high salinity stress test and was significantly different from the other three treatments. On the other hand, the 0.9% treatment showed the lowest mortality under low salinity stress, but the difference was not significant among the treatments with seaweed extract addition. Overall, supplementing polysaccharides xtracted from the green seaweed C. linum to commercial feed at a rate of 0.6% improved growth and feed efficiency as well as shrimp quality.