Nitrogen Balance and Bioavailability of Amino Acids in Spirulina Diet-Fed Wistar Rats

Spirulina widely known to consumers as a health food is mainly a dried product. Since data for raw spirulina as a protein source are insufficient, the nutritional values of dry and raw spirulina diets in Wistar rats were determined. Digestibility coefficients were significantly lower in the dry (84.1 +/- 0.5%) and raw (85.7 +/- 0.4%) spirulina diets than that in the casein diet (96.6 +/- 0.2%), although biological values of dry (86.3 +/- 1.3%) and raw (77.9 +/- 2.6%) spirulina diets were significantly higher than that of the casein diet (71.9 +/- 2.5%). The protein digestibility-corrected amino acid score of raw spirulina (86.6 +/- 0.5%) was significantly higher than that of dry spirulina (85.1 +/- 0.5%). Additionally, amino acid profiling of portal/venous blood in spirulina diet-fed rats revealed that Ala, Gly, Val, and Leu/Ile were markedly decreased after systemic circulation. These results suggest that dry and raw spirulina diets may be effective not only as a protein source but also as a supplement to support protein/amino acid bioavailability.

Automated summary

Research shows that both dried and raw spirulina diets have lower digestibility coefficients but higher biological values in Wistar rats as compared to the casein diet. The protein digestibility-corrected amino acid score of raw spirulina is significantly higher than that of dried spirulina, indicating their potential as effective protein and amino acid supplements. Additionally, amino acid profiling of blood in spirulina-fed rats suggests a positive impact on protein/amino acid bioavailability.