The determination of the leaching ratios of microdiets containing algae used as direct and indirect in aquaculture

Abstract

The purpose of the study was to determine the biochemical compositions and the leaching ratios according to different times (1 minute, 3 minutes, 5 minutes and 15 minutes) of microdiets containing Spirulina sp., Chlorella sp. and Sargassum sp. in different sizes (100-200m, 200-300m, 300-500m and 500-800m). The lowest and highest ash, lipid and protein values of algae tested were 3.29 +/- 0.031% (Chlorella sp.)-27.94 +/- 0.023% (Sargassum sp.), 0.91 +/- 0.024% (Sargassum sp.)-8.91 +/- 0.04% (Spirulina sp.) and 20.69 +/- 0.07% (Sargassum sp.)-56.98 +/- 0.216% (Chlorella sp.), respectively. The 2532 Da leaching ratio of Chlorella sp. was lower than those of Sargassum sp. and Spirulina sp. (p<.05). The highest and lowest values for microdiets containing Spirulina sp. and Sargassum sp. were 2532 Da and 2532-13,000Da, respectively. However, the highest and lowest values for microdiets containing Chlorella sp. were 13,700-67,000Da and 67,000 Da, respectively. In conclusion, the alginate method showed good performance because the biochemical compositions of microdiets produced reflected the ash, lipid and protein levels of algae tested. Results cautioned that the use of Spirulina sp. and Sargassum sp. in microdiets may yield the high leaching ratios containing 2532 Da molecular weight. However, the use of Chlorella sp. results in the high leaching ratios containing 13,700-67,000Da molecular weight.