Nutritional Evaluation of Microbial Proteins from Yeast and Fusarium venenatum TB01 mycelium in vivo

Current studies on microbial proteins had not gone deep into the aspects of nutritional evaluation and in-vivo digestion characteristics. In this study, by comparing with casein protein (CP) and soy protein (SP), the digestion and absorption characteristics in-vivo of two microbial proteins from Yeast (YP) and Fusarium venenatum TB01 mycelium (MP) were explored. The results showed that YP and MP had high Total Essential Amino Acid (TEAA), Essential Amino Acid Index (EAAI), Biological Value (BV) and Nutritional Index (NI) compared with SP, but slightly lower than CP, and there was no significant difference (P > 0.05) in the digestibility of the four proteins in rats. Additionally, the average weight and food intake of four treatment groups of rats gradually increased throughout the experiment. There were no significant differences in bone length or maximum bone stress between rats of the same sex fed different protein diets (P > 0.05). Interestingly, YP and MP could improve the metabolisms of amino acids, regulate the immune oxidation and inflammatory responses in rats. The structure of intestinal microbial community was also regulated by these two microbial proteins, MP-fed group decreased Akkermansia and increased Chlamydia abundance (P < 0.05). Overall, YP and MP are high-quality protein sources and excellent substitutes for traditional proteins.