Lemna Protein Concentrate is derived from the leaves of duckweed, one of several rapidly-growing aquatic plants of the genus Lemna. Duckweed has a number of advantages as a protein source. It is relatively inexpensive to produce and requires less growing area and fewer inputs than other plant protein sources such as soybean products. It also contains relatively little fiber, making it a highly digestible feed ingredient.

An experiment was conducted to determine the digestibility of amino acids and crude protein in Lemna Protein Concentrate fed to weanling pigs and to compare these values to digestibility values obtained for soybean meal and fish meal.

Eight weanling barrows were fed one of four diets. One diet contained 40% soybean meal and no other source of amino acids. Another diet contained 20% soybean meal and 20% Lemna Protein Concentrate, and a third diet contained 20% soybean meal and 15% fish meal. Finally, a nitrogen-free diet was used to determine basal endogenous losses of protein and amino acids.

For crude protein and most amino acids, standardized ileal digestibility (SID) values were greatest in soybean meal, followed by fish meal, followed by Lemna Protein Concentrate (Table 1). However, digestibility of tryptophan in Lemna Protein Concentrate was the same as in soybean meal, and digestibility of histidine in Lemna Protein Concentrate was the same as in fish meal. Although digestibility values for Lemna Protein Concentrate were generally the least among the three ingredients tested, crude protein and amino acids in Lemna Protein Concentrate were well digested by the weanling pigs, with a mean SID value of 81.70% for all amino acids.

Due to its high protein content, Lemna Protein Concentrate contained greater concentrations of standardized ileal digestible crude protein and all indispensable amino acids than soybean meal (Table 2). Lemna protein Concentrate and fish meal contained similar concentrations of SID crude protein and many amino acids. A notable exception was SID lysine, of which there was a significantly greater concentration in fish meal than in Lemna Protein Concentrate.

• Crude protein and amino acids in Lemna Protein Concentrate are as well or nearly as well digested by weanling pigs as crude protein and amino acids in fish meal and soybean meal.
• Lemna Protein Concentrate contains a greater concentration of standardized ileal digestible protein and amino acids compared with soybean meal, and similar amounts of digestible protein and many amino acids compared as in fish meal.
• Lemna Protein Concentrate may be a suitable protein source in weanling pig diets, but performance experiments need to be conducted to confirm this hypothesis.

Table 1.Standardized ileal digestibility (SID) of crude protein and amino acids in Lemna protein, fish meal, and soybean meal (SBM) by weanling pigs

Table 2.Concentrations of as-fed and standardized ileal digestible crude protein and amino acids in Lemna protein, fish meal, and soybean meal (SBM) by weanling pigs

This research report is based on unpublished research by H. H. Stein.