An imbalance in the methionine content of the maternal diet reduces postnatal growth in the rat.
The pregnant rat fed a low-protein diet has become widely used as a model system in the study of the prenatal programming of adult metabolism and disease. When pregnant rats of the hooded Lister strain were fed semisynthetic diets containing 18% or 9% casein supplemented with 0.5% dl-methionine, there was significant postnatal mortality in the group fed the low-protein diet. In a second experiment, dams were fed diets containing 9% casein supplemented with varying concentrations of dl-methionine up to 0.4% (w/w) and compared with a group fed a diet containing 18% casein supplemented with 0.5% dl-methionine. At birth, the pups from dams fed the low-protein diets supplemented with 0.2% dl-methionine or greater were significantly smaller than those of the dams fed the diet containing 18% protein. By 25 weeks of age, the body weight of the offspring of dams fed the low-protein diet supplemented with 0.2% or 0.3% dl-methionine were approximately 10% lower than those in the control group of offspring from dams fed 18% protein supplemented with 0.5% dl-methionine. There were corresponding changes in the weights of the major organs. These data suggest that increasing the dl-methionine supplement in the low-protein diet retards the growth of the fetus and affects the mature adult body weight. In contrast to the findings of other studies that used different formulas of the low-protein diet, the glucose tolerance in the offspring was unaffected by the protein content of the maternal diet at all levels of dl-methionine supplementation. These results suggest that the changes in metabolism of the offspring result from interactions between protein, lipids, and carbohydrates in the maternal diet, rather than a consequence of postnatal growth retardation per se and highlight the importance of considering all components of the maternal diet in the programming mechanism.
Rees
William D
WD
The Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen, AB21 9SB Scotland, UK. wdr@rri.sari.ac.uk
Hay
Susan M
SM
Cruickshank
Morven
M
D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D002364:Caseins / Q000008:administration & dosage / Q000494:pharmacology; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D005951:Glucose Tolerance Test; D006128:Growth / Q000187:drug effects*; D008297:Male; D018811:Maternal Exposure; D008715:Methionine / Q000008:administration & dosage / Q000494:pharmacology*; D009929:Organ Size; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D012737:Sex Factors
D002364:Caseins; D004044:Dietary Proteins; D008715:Methionine