DOI: 10.36347/sajb.2018.v06i01.010

Pages: 71-83

The main aim of this study was to see the primary and secondary phytochemicals of the common water hyacinth, Eichhornia crassipes and the marine brown alga, Sargassum cristaefolium, and evaluation of their effects on the growth of the freshwater prawn, Macrobrachium rosenbergii post-larvae (PL). The phytochemical properties of E. crassipes and S. cristaefolium were analyzed using petroleum etheric (non-polar solvent) and ethanolic (polar solvent) extracts. Presence of primary phytochemical components, such as alkaloids, terpenoids, flavonoids, tannins, polyphenols, saponins, cardiac glycoside and quinines, and significant amounts of total phenolic and total antioxidant contents were recorded in E. crassipes, and S. cristaefolium. E. crassipes showed the presence of totally 14 secondary metabolic components, of which 5 from petroleum etheric extract and 9 from ethanolic extract. Among these 3 compounds, Dodecanoic acid; 6,7-Dimethoxy-2-tetralone; and, 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, and 5 compounds, Phenol, 2-methoxy-5-(1-propenyl)-, (E); Cycloheptane, 1,3,5-tris(methylene); 4-(6,6-Dimethyl-2-methylenecyclohex-3-enylidene) pentan-2-ol; Tetradecanoic acid; and, Loliolide of the respective solvent extracts possessed bioactive properties. In S. cristaefolium, totally 13 secondary metabolic components were detected, of which 6 from petroleum etheric extract and 7 from methanolic extract. Among these, one compound in each extract, Docosane, and cis-2-[2-(hydroxymethyl)cyclopentyl] ethanol, respectively possessed bioactive properties. The basal diet was prepared using fish meal, groundnut oilcake, soy bean meal, wheat bran, sunflower oil tapioca flour, egg albumin and vitamin-B complex with vitamin-C and used as control diet. The fishmeal was replaced with raw powder of E. crassipes, and S. cristaefolium, independently at 5, 10 and 15%. Similarly, each solvent extract of E. crassipes, and S. cristaefolium, was independently incorporated with the basal diet at 0.5,