Effect of a diet rich in branched chain amino acids on severely burned guinea pigs.

This study was performed to investigate the effects of dietary supplementation with branched-chain amino acids (BCAA) for postburn nutritional management. Seventy-one burned guinea pigs (30% TBSA) with previously placed catheter gastrostomies were divided into six groups. The first, second, and third groups received 10%, 20%, and 30%, respectively, of total calories as whey protein. The other three groups received BCAA supplementation to increase BCAA to 50% of total amino acids, compared to 21.5% BCAA content in whey protein. Groups I and IV received isonitrogenous intake, as did groups II and V, and III and VI, respectively. After an initial 3-day adaptation period, all animals in all groups received continuous isocaloric (175 kcal/kg/day) intragastric tube feeding until postburn day (PBD) 14. At PBD 14, although BCAA-supplemented groups showed very high plasma levels of BCAA (IV: 169%; V: 306%; VI: 770% of normal), no BCAA group showed evidence of any beneficial effect in various nutritional parameters when compared with the corresponding whey protein group with isonitrogenous intake. Cumulative nitrogen balance and mortality during 14 days were significantly worse in BCAA groups IV and VI than in control groups I and III, respectively. It is concluded that BCAA supplementation to enteral diets has no beneficial effect for postburn nutritional management following severe burn injury. It is further suggested that when nitrogen intake is too low or very high, BCAA supplementation may have an adverse effect.