The optimal branched-chain to total amino acid ratio in the injury-adapted amino acid formulation.

Several recent studies have suggested that solutions containing increased amounts of branched-chain amino acids (BCAA) might be useful in the treatment of patients with trauma and/or sepsis. In this study we investigated the optimal amount of BCAA in a balanced nutritional solution in an injured rat laparotomy model. The amino acid content of a standard BCAA-enriched amino acid solution was enriched to 40, 45, and 50% by the addition of equimolar amounts of the three BCAA. Rats were infused with either 3.6 cal/100 g body weight/24 hr or with 18 cal/100 g body weight/24 hr with either a 40, 45, or 50% BCAA mixture and evaluated for nitrogen balance, plasma amino acid levels, and levels of plasma blood urea nitrogen, creatinine, glucose, albumin, and blood ammonia. Nitrogen balance was negative in rats receiving only 3.6 cal/100 g body weight/24 hr, but was least negative in the group receiving 45% BCAA. Nitrogen balance was positive in groups receiving 18 cal/100 g body weight/24 hr, but was most positive in groups receiving 40 or 45% BCAA-containing solutions. Plasma amino acid patterns were least distorted in the 40 and 45% formulations. Blood ammonia was highest in the 40% BCAA group and plasma albumin was best maintained in the 45% BCAA group regardless of the amount of caloric supply. The results suggest that a 45% BCAA-enriched solution is the most appropriate in this injured rat model.