Control of Food Intake in the Rat by Dietary Protein Concentration

Abstract

Male, weanling Sprague-Dawley rats were fed isocaloric diets containing graded levels of protein or amino acid mixtures. Food intakes and weight gains were recorded daily or every other day. Both short-term and long-term (64 days) experiments were carried out. Linear regressions of food intake versus time and weight gain versus time were used to establish daily weight gains and food intakes. The four-parameter mathematical model for physiological responses was used to predict daily food intake, daily weight gain, daily food intake per 100 g weight and efficiency of food conversion (daily weight gain/daily food intake) as functions of dietary protein concentration. The changes in the four parameters generated from the four-parameter model were examined as a function of time. Several aspects of food intake, weight gain and efficiency were shown to be functions of concentration of dietary protein.

Effect of chronic undernutrition on body mass and mechanical bone quality under normoxic and altitude hypoxic conditions

“…This characteristic growth trajectory can be altered in rate and timing by exogenous modifiers. Two important non-genetic, environmental effects on the growth pattern are undernutrition (1)(2)(3)(4)(5)(6)(7)(8) and hypoxia (defined in terms of hypoxaemia, anaemia or increased Hb-oxygen affinity at sea level) (9)(10)(11)(12)(13) .On the basis of clinical paediatric findings (13)(14)(15) , we have developed a nutritional stress model in rats (nutritional growthretarded rats): weanling male rats placed on a 20 % restricted balanced diet for a 28-d period closely resembled the suboptimal nutrition observed in children who consume inappropriate diets with insufficient total energy to sustain normal growth and weight gain (16) . Rats maintained on this type of chronic suboptimal nutrition decreased their body mass growth rate, which was one of several described manifestations of nutritional inadequacy.…”

“…This characteristic growth trajectory can be altered in rate and timing by exogenous modifiers. Two important non-genetic, environmental effects on the growth pattern are undernutrition (1)(2)(3)(4)(5)(6)(7)(8) and hypoxia (defined in terms of hypoxaemia, anaemia or increased Hb-oxygen affinity at sea level) (9)(10)(11)(12)(13) .…”

Morphometric and quantitative study of the myenteric neurons of the stomach of malnourished aging rats

“…Molinari et al 7 verified that young rats (90-210-day-old) subjected to a 8%-protein diet, when compared to animals receiving 22%-protein diet, gained 30.33% less weight, demonstrating that, at this age range protein, restriction has more drastic effects than those of the present experiment. Mercer et al 8 demonstrated, through mathematical modeling and experimentation, that the ingestion of chow by rats is strictly related to the proportion of proteins in the diet, with the highest level of sensitivity around 6%, when slight changes in the concentration of protein would result in large alterations in the ingestion of food. When the mean weight gain of the two groups is compared, it is observed that the differences are small and also that the rats subjected to protein restriction, although eating less food, did not lose weight at the same rate.…”

Evaluation of a Calcium- and Protein-Fortified Pasta Designed for the Older Population

“…The implication was that a diet with higher protein concentration supported greater weight gain than did the same amount of feed with a lower protein concentration. Others (Anthony & Edozien, 1975;Mercer, Watson, & Ramlet, 1981) found that growth of rats was retarded by low-protein diets. Edozien and Switzer (1978) also concluded that rat growth increased as dietary protein concentration increased up to 25%.…”