Influence of the biochemical composition of food on the biochemical composition of the rotifer Brachionus plicatilis

Abstract

The influence was investigated of the biochemical composition of different kinds of food on the protein, lipid and carbohydrate content, protein composition and fatty acid composition of total, polar and neutral lipids, and alterations in these compounds during the secondary cultivation period (48 h) on the alga Monochrysis lutheri (the rotifers were originally fed with baker's yeast, Saccharomyces cerevisiae). Positive correlations between the protein and lipid content of rotifers and the content of these compounds in their food were noted. No correlations were established for carbohydrates. The most significant and the least alterations occurred in the content of lipids and proteins, respectively. No correlations were found between the amino acid composition of rotifers and that of their food. The total content of amino acids in proteins and their amino acid composition were constant. The concentration of diacylglycerols, monoacylglycerols and free fatty acids in rotifer lipids did not depend on the content of these compounds in food lipids, and was rather constant. We observed a positive correlation between the content of triacylglycerols and sterol esters in rotifers and in their food. Most significant alterations took place in the triacylglycerol content. As a whole, the fatty acid composition of rotifers was similar to that of their food. A greater degree of unsaturation of the fatty acids of the neutral lipids, and a greater variation in this fraction, as compared to polar lipids were observed. Alteration of the general biochemical composition begins with an increase in the lipid content after l h of feeding. The lipid content reaches a maximum after about 6 h of feeding, and then decreases to a level exceeding the primary one. The carbohydrate content begins to decrease after 6 h of feeding and reaches a minimum after about 24 h of feeding, then rises and becomes stable at a level lower than the primary one. The phospholipid content decreases insignificantly after 12 h of feeding, whereas the triacylglycerol content increases after 6 h much more than that of phospholipids. Changes in the sterol and sterol ester content appear after 12 h of feeding and disappear completely after approximately 36 h. Alterations of the lipid fatty acid composition begin with a change in polar lipids (after 1 h). Alterations of the fatty acid composition occur between 6 and 12 h of feeding and practically cease after 24–36 h.