Article info.

ABSTRACT

Received date: 31/08/2015

Accepted date: 30/11/2016

The aims of this study were to evaluate antioxidant activity of polysaccharide extracted from S. microcystum and examine its positive effect on growth performance and survival of whiteleg shrimp (Litopenaeus vannamei). Polysaccharides from brown seaweed Sargassum microcystum were extracted by four methods (1) hot-water within 3 h, (2) hot-water within 6 h, (3) 0.1N HCl (100°C) within 3 h, and (4) 0.1N HCl (100°C) within 6 h. The extracts were then analyzed for chemical composition and antioxidant activities. The extract showed the highest antioxidant activity could be used to examine its effectiveness on whiteleg shrimp culture via dietary administration. For trial on shrimp, whiteleg shrimp were reared in a recirculating seawater system with 500-L tanks and fed the pellet diets containing 0.5, 1.0, and 2.0% of hot-water extract. Shrimp were fed the diet without extract supplemented served as control group (0%). After 60 days of feeding, survival rate and growth parameters of shrimp were evaluated. The results showed that protein concentrations of polysaccharide extracts were low and varied from 1.3 to 6.8%. The polysaccharide extracted with hot-water within 6h was higher phlorotannin, glucose and L-fucose concentrations than those in other extracts. However, higher SO₄^2- concentration was found in 0.1N HCl extract within 3 h extract. The significant interactions between solvent and extraction time were observed that affecting yield of polysaccharide and chemical composition as phlorotannin, glucose and SO₄^2- concentrations. Hot-water within 6 h extract showed the highest antioxidant activity indicating by high DPPH^● free radical scavenging (IC₅₀ = 0.434 mg mL^-1) and ferric reducing power activity (OD_0.5 = 2.55 mg mL^-1). Whiteleg shrimp that being fed the diets incorporating with hot-water extracts at 1.0% had significantly higher growth performance than those in the control diet. However, there was no significant differences in daily length gain and survival rates among treatments. Therefore, it is concluded that polysaccharide extracted from S. microcystum could be growth promoter in whiteleg shrimp culture.

Keywords

Antioxidant activity, growth performance, polysaccharide, Sargassum microcystum, Litopenaeus vananmei

Cited as: Giang, H.T., Giang, T.T., Oanh, D.T.H., Ngoc, T.S. and Ut, V.N., 2016. Chemical composition, antioxidant activity of crude polysaccharide extracted from brown seaweed Sargassum microcystum and its effect on growth performance and survival of whiteleg shrimp Litopenaeus vannamei via dietary administration. Can Tho University Journal of Science. Vol 4: 71-80.