Background:

Proteins having structural and various regulatory functions are essential components of all unicellular and multicellular organisms. The only source of proteins and their building blocks, amino acids, for human and many animals are the proteins and amino acids in their foods. Although qualitative and quantitative protein malnutrition are common problems in animals and men, the impacts of dietary proteins on serum electrolytes are still controversial. Materials, Methods &

Results:

Adult male Wistar rats were randomly divided into three groups of 6 or 7 animals serving as controls, and quantitative or qualitative protein malnutrition groups. Animals were held in metabolic cages individually in a conventional room with 1212 h day/night cycle, 29°C temperature and 50-70% relative humidity. After a 10-day acclimation period controls (n = 7) were given rat chow diet consisting of 24% protein, while other groups received an almost N-free diet (quantitative malnutrition) or a diet containing 20% gelatin as protein source (qualitative malnutrition) for 35 days. Food and tap water were given animals ad libitum during acclimation period and throughout the experiment. At the end of experiment, blood samples were collected and Na+, K+ and Cl- concentrations in serum were determined. Data were analyzed by ANOVA, ANCOVA and Pearson's correlation test. Dietary interventions had significant effects on mean body weights of animals (P = 0.000), but not on their food consumptions. However, in the last week controls consumed significantly more food than both malnourished groups (P = 0.001). If row data were used for statistical evaluation, it was seen that qualitative and quantitative protein malnutrition affected only the serum K+, and Cl- concentrations significantly (P = 0.003, P = 0.000). Controls had higher K+ concentrations than those of gelatin-given group (P = 0.002) and N-free group had higher Cl- concentrations than control and gelatin-given groups (P = 0.001). However, if body-weight corrected electrolyte values were considered, compared to controls a two-fold increase in mean concentrations of all three electrolytes in sera of both malnourished groups were seen (P = 0.000). There were certain negative or positive correlations between different variables interested.

Discussion:

The findings of this study revealed that, on the basis of the row data, the dietary protein inanition increase serum Cl - concentration, while gelatin in the diet decrease the K+ concentration in sera of rats. Because of the body weights of malnourished animals decreased while controls continued to gain weight throughout the experiment, a substantial difference in body weights of malnourished animals and controls occurred. And, because of physiological variables are reflections of body weights, it was necessary to eliminate the possible effects of the body weights of animals. If the effect of the body weights of animals eliminated, a two-fold increase of all three electrolytes studied was seen. It was concluded that dietary proteins exert signifi cant control on the homeokinesis of serum electrolytes. If physiopathological conditions are questioned, standardization for comparison of the results from control and experimental groups in a study as well as from different studies is indispensible