Relations between enzyme activities connected with energy metabolism and parameters of food energy utilization in young and adult rats Part 1. Studies on dietary effects on weight, body composition and energy gain

Abstract

Weaned male Wistar rats were fed ad libitum besides standard pellets a normal-protein (NP), a low-protein (LP) and a high-fat (HF) diet for different periods of time. In comparison to rats on the NP diet the body weight of the LP group was significantly lower after seven weeks feeding, not after a duration of about forty weeks. No remarkable diet-related differences were detected by determination of the mean body composition and of the relative gross energy content of the body neither after seven nor forty weeks. Total gross energy intake was practically identical both for the NP and LP rats irrespective on the duration of the feeding period. A significantly lower quotient of body energy gain/total gross energy intake under the protein-restrictive LP diet after seven weeks suggests the expression of an energy dissipation obviously no longer visible after a long time feeding period.

Prediction of total body lipid from total body water in rats. Part 1. Relations between directly measured major body components

“…The other groups comprise male rats (i) receiving pellets and water and being studied after a two days fasting period including two nights (Study 2), (ii) being under special experimental diets (normal-protein NP; low-protein LP and high-fat HF diet [7]) (Study 3), (iii) or being provided by cooperators (Study 4-7).…”

“…After thawing and weighing, the individual animal bodies were placed in a beaker with 20-70 ml5 96 HCI and softened in an autoclave (at 121 T and 0.206 MPa for 4 h), homogenized (Ultra-Turrax) and analyzed for moisture content, lipid and crude protein as described earlier [7]. All determinations were carried out in duplicate or triplicate.…”