The effects of food restriction on some biochemical parameters and certain bacterial groups in the cecum in Sprague Dawley rats

Abstract

Objective: Moderate food restriction, such as a 20 Á40% reduction of the ad libitum intake without causing malnutrition, delays or prevents morphological and functional changes related to aging and overnutrition. This study was performed to evaluate the effects of moderate to severe food restriction (20%, 40%, and 60% of ad libitum intake) for 28 days on some bacterial groups in the cecum and certain biochemical variables in male Sprague Dawley rats. Materials and methods: One group was allowed free access to food (control), while the others were given food restricted to 20%, 40%, and 60% of the ad libitum consumption for 28 days. At the end of the experiment control and food-restricted animals were sacrificed and cecum weight, pH of cecal contents, and counts of total anaerobes, total aerobes, lactobacilli, and coliform bacteria in cecal contents were determined. Metabolic effects of food restriction were evaluated by analyzing some biochemical parameters in plasma and serum. Results: The effect of 60% restriction was severe; three animals died before the 28th day of experiment in this group. In general, biochemical variables did not change in 20% and 40% food-restricted groups. Although lactobacilli counts of the 20% and 40% restricted groups were significantly increased when compared with the 60% restricted group, none of the three groups were differed from the control group. Furthermore, the total aerobe bacteria counts of the 20% restricted group were significantly lower than those of the 60% restricted group. Conclusion: The results of this study suggest that restriction of food by 20% and 40% may affect cecal microbiota beneficially without causing considerable changes in the metabolism of the host, while 60% restriction causes dietary stress.

The Effect of Fasting Duration on Baseline Blood Glucose Concentration, Blood Insulin Concentration, Glucose/Insulin Ratio, Oral Sugar Test, and Insulin Response Test Results in Horses

“…The reasons are not well understood, but may relate to alterations in glucose transport function and the effects of increased free fatty acid concentrations on insulin utilization. Stress, as measured by increased cortisol concentrations, does not appear to be an important factor in this phenomenon, and serum cortisol concentrations did not change with fasting duration in our study. Previous studies in horses have identified insulin resistance after ≥17 hours of fasting .…”

“…Starvation and very low calorie diets have been shown to cause insulin resistance and diabetes in rodents and humans . The reasons are not well understood, but may relate to alterations in glucose transport function and the effects of increased free fatty acid concentrations on insulin utilization.…”

Effect of thyrotropin‐releasing hormone stimulation testing on the oral sugar test in horses when performed as a combined protocol

“…One possible explanation for the increased insulin concentrations appreciated during the third OST could be because of the effect of stress from multiple periods of fasting, environment change, and administration of each test. Stress from fasting and transport increased insulin concentrations in equids, although in another experimental model fasting did not affect cortisol levels . More research on the effect of environmental and handling stress on insulin concentration in horses is needed.…”

“…Stress from fasting and transport increased insulin concentrations in equids, although in another experimental model fasting did not affect cortisol levels. [43][44][45] More research on the effect of environmental and handling stress on insulin concentration in horses is needed.…”

Glucocorticoids and the Intestinal Environment

“…However, various stress factors such as heat, cold, nutritional alterations, overcrowding, physical restraints and transporting or fouled or contaminated foods can destroy the microbial balance in the gastrointestinal system [66,67,[191][192][193][194][195] and alter their relationships with each other and with their hosts. Stressful stimuli can affect gastrointestinal microbiota directly, for example via limited availability of food ingredients or direct actions of stress mediators such as adrenaline or noradrenaline on microbiota [27,196], and indirectly via altering the intestinal environment of bacteria such as intestinal secretion, motility, permeability and immune functions as reviewed above.…”