title: Selection of dietary protein and carbohydrate by rats: changes with maturation.
abstract: Weaning (21-day-old; 40-50 g) male rats given simultaneous access to two foods, containing 18% casein and 15 or 70% carbohydrate (dextrin), tended to consume only 29-35% as much protein as carbohydrate (i.e., protein/carbohydrate ratios were 0.29-0.35). With maturation, when animals weighed 100 g or more, about half continued this pattern of nutrient choice, but the others abruptly began to consume considerably larger proportions of protein, exhibiting protein/carbohydrate ratios as high as 0.80-1.00. Each adult animal's protein/carbohydrate ratio tended to vary only slightly (s.e. = 3% of means). Adult protein/carbohydrate ratios were not correlated with fasting brain 5-HT or 5-HIAA levels. These marked differences among rats in eating behavior would not be observed when--as is usually the case--animals are given access to only one diet.
mesh_terms: D000367:Age Factors; D000818:Animals; D001923:Brain Chemistry; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D005518:Food Preferences; D006897:Hydroxyindoleacetic Acid / Q000032:analysis; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000032:analysis
chemical_list: D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid