Nitrogen Balance and Bioavailability of Amino Acids in Spirulina Diet-Fed Wistar Rats
Yudai Shioji, Takuma Kobayashi, Takuya Yoshida, Tomoka Otagiri, Keita Onoda, Yasukiyo Yoshioka, Tatsuya Sasada, Noriyuki Miyoshi
Abstract
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.