A Comparison of the Response of Woodchucks and Rats to Variations in Dietary Lipotrope and Protein Content

Résumé

Juvenile woodchucks and weanling Fisher F344 rats were fed puri fied diets with or without supplemental lipotropic factors (choline, methionine, folie acid and vitamin B-12). The diets contained 10 or 20% protein. Lower weight gain due to low protein was observed in both species, while lipotrope depletion resulted in lower gain in male rats only. Urinary excretion of formimino-glutamic acid was higher due to low lipotrope in both species, as was relative liver weight. In rats, lipo trope depletion resulted in hepatic fatty metamorphosis at both levels of dietary pro tein with the low protein diet resulting in more severe lesions. No liver lesions were observed in woodchucks fed low lipotropes at the higher level of dietary protein, but fatty metamorphosis was observed in those fed the lower protein diets. The lesion was more severe in the low lipotrope group. The woodchuck appears to be less sensitive than the rat to induction of fatty liver by lipotrope deficiency, although the lesion was induced by lowering dietary protein.