Duckweed protein supports the growth and organ development of mice: A feeding study comparison to conventional casein protein

Abstract As global population growth and meat consumption increases, sustainable alternatives to conventional protein‐rich fodder crops for livestock are needed to reduce negative environmental impacts. Duckweed, a small floating aquatic plant, can generate 5 to 10 times higher protein yields than conventional land‐grown crops. Although some in vivo feeding trials with duckweed have been conducted, those measuring animal weight are limited, and those examining organ development are nonexistent. To secure broad acceptance of new protein sources, such controlled studies are critical. This study measured the food intake, growth, and final organ and adipose tissue mass of male CF‐1 mice fed a semi‐purified diet containing casein or diets in which 10% or 25% of the casein was replaced with duckweed protein (DWP). Proximate analysis showed that the DWP preparation used contained 39.9% protein (w/w), and contained all of the essential amino acids with Met as the limiting amino acid. The average growth rates were not significantly different among the treatment groups: 0.21 g/day; 0.24 g/day; and 0.25 g/day for the control, 10%, and 25% DWP protein diets, respectively. The daily food intake of both DWP diets was 6.5% to 8.0% higher than the control diet, but feeding efficiency did not differ among diets. The relative weight of the liver, spleen, kidneys, heart, and epidydimal fat, and colon length were not significantly different between treatment groups. The results from this study show that replacement of up to 25% dietary casein with DWP has no adverse effects on the growth rate and final organ and adipose tissue weights of laboratory mice. Practical Application Duckweed can produce 5 to 10 times more protein per area than land‐grown crops such as soybean. In this study, up to a 25% replacement of casein with duckweed protein had no observable effect on the growth or organ development of laboratory mice. Thus, duckweed has the potential to be used as a protein supplement for livestock, poultry, and fish, thereby decreasing environmental impacts from land‐grown crops used for animal feed.