Some nutritional characteristics of a naturally occurring alga (Microcystis sp.) in a Guatemalan Lake

Abstract

The nutritional characteristics of an alga (Microcystis sp.) that occur naturally in a Guatemalan lake were determined. The sun dried material proved to have a high protein content (55.6%) and to be a possible good source of calcium and phosphorus (1,169.1 and 633.4 mg/100 mg, respectively). Amino acid analysis showed that total sulfur amino acids were the most deficient ones, giving a protein score of 42 to the material. The in vitro protein digestibility of the material was 69.5%. Biological trials demonstrated that when the material was offered as the only protein source, very low consumption and a high mortality rate were obtained whether or not the diet was supplemented with 0.4% DL methionine. However, when the material supplied 25% of the total protein of a corn algae diet, the protein quality of the cereal was significantly improved (P<0.05).