EFFECT OF DIETARY RESTRICTIONS AND SOURCE OF RATS ON GROWTH-RATE AND EFFICIENCY OF CONVERSION OF FOOD INTO MUSCLES, BONES AND ORGANS

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 41  (3) , 221-234
Abstract
Differences in body wt, 6 different skeletal muscles, epididymal fat pads, 3 different bones, spleen, heart, kidneys, testes and liver were observed in 21 day old male Sprague-Dawley rats from 2 different suppliers. All rats were pair-fed a 10% casein diet ad lib, 10, 20, 30% restricted for 4 or 8 wk. Original body and tissue wt differences between the 2 strains of rats were maintained in all diets during the 4 and 8 wk feeding periods. Trends in body and tissue wt changes due to dietary restriction were similar in both strains of rats. Diet restrictions for 4 or 8 wk caused similar patterns of wt decrease in most tissues. Feed efficiency ratio (FER) was reduced significantly at the 20% and 30% restriction for 4 wk only in the lighter strain of rats. FER was higher in the heavier strain than in the lighter strain of rats at all levels of diet restriction. Food conversion efficiency with reduced food intake was constant or decreased depending on skeletal muscle studied; decreased significantly for epididymal fat pad, bone wt (1 strain only), kidneys and liver (1 strain only) with the 30% reduced diet for 4 wk and increased for bone length and testes wt. Significant deviations from ad lib controls were found only at 30% diet restriction, and wide differences in body and tissue wt of 2 strains of Sprague-Dawley rats did not affect interpretation of results when fed the same restricted diets.