Moreover, the concentration of acetic acid in portal vein blood for each respective group [HF group, 3.59 ± 0.10 mg/dl; HF-cel(−) group, 3.86 ± 0.19 mg/dl; HF-BCAA group, 5.75 ± 0.32 mg/dl; and HF-cel(−)-BCAA group, 3.78 ± 0.12 mg/dl] indicated that cellulose deficiency inhibited BCAA-induced elevation of portal acetic acid levels and that the proliferation of R. flavefaciens is related to the increase in portal acetic acid levels caused by BCAA supplementation (Fig. 3B). The gene discussed is CEL; the disease is hydrops fetalis.