A 40-year-old male with a 4-year history of cirrhosis is admitted due to hematemesis and melena for 10 hours. Physical exam: somnolence, behavioral abnormalities, icteric sclera, liver not palpable below the costal margin, spleen 2 cm below the costal margin, ascites, positive flapping tremor. The patient regained consciousness after treatment. Which of the following measures is NOT beneficial for preventing recurrence of hepatic encephalopathy?