L-tryptophan alleviates fatty liver and modifies hepatic microsomal mixed function oxidase in laying hens

1. Three experiments were conducted to study the effect of dietary L-tryptophan supplementation (250-1000 ppm) on lipid accumulation, an occurrence of hemorrhages and microsomal mixed function oxidase in the liver of laying hens. 2. Dietary L-tryptophan supplementation resulted in significant decreases in hepatic lipids, in particular triglyceride, and occurrence of hemorrhage in laying hens. 3. Hepatic lipid accumulation by estrogen injection in starved-refed growing chicks decreased as dietary tryptophan content increased. 4. Supplementation of L-tryptophan at 1000 mg/kg diet enhanced alanine aminotransferase activity in the hepatic tissue and at 500 mg/kg diet, increased cytochrome b5, a component of the mixed function oxidase, in the hepatic microsomes. 5. These results demonstrate that L-tryptophan alleviates fatty liver in laying hens and modifies microsomal mixed function oxidase in the liver.