## 3 Results  
Body weights (BWs) were measured weekly to calculate the BW gain in animals during the feeding experiment. There were no significant differences in body weights between the LCHPch and AINch groups (\(p\) > 0.05). However, a decreasing tendency was observed after week 5 until the end of the study. Moreover, taking into consideration three groups (AINch, WDch and LCHPch), the lowest body weight was noticed in LCHPch-fed rats (Figure 1). No significant difference (\(p\) > 0.05) was found in the final body weight between groups at the end of the experiment. The intake of diets was significantly differentiated only at week 6, with the highest value obtained for group WDch (+25% vs. LCHPch, +20% vs. AINch) (Figure 2). Statistically significant differences in the weights of the kidneys and hearts were observed after 8 weeks of feeding (Table 2). The organs mentioned above were considerably heavier in the rats from the LCHPch group in comparison to the animals from the control group. In turn, the livers of rats were not significantly affected (\(p\) > 0.05). Figure 1: Body weight gain (g) of rats fed AINch, WDch (Western diet) or LCHPch (low-carbohydrate–high-protein) diets enriched with 1% cholesterol during the experiment (0–8 weeks). Serum lipid profile was measured in all experimental groups--after 4 and 8 weeks of feeding (Table 3). Serum total cholesterol (TCH) in rats fed the LCHP diet was not varied from that in the other groups. However, the difference between the AIN\({}_{\text{ch}}\) and LCHP\({}_{\text{ch}}\) group was at a level of 50% after 8 weeks of the experiment compared to 20% after 4 weeks. Meanwhile, animals from the WD\({}_{\text{ch}}\) group were characterized by significantly higher concentrations of TAG and LDL + VLDL cholesterol (vs. AIN\({}_{\text{ch}}\)), whereas the LCHP diet intake caused a significant increase in LDL + VLDL levels after 8 weeks, with a simultaneous enhancement in atherogenic index (AI), as well as TAG/HDL ratio (Table 3). Uric acid concentration (Table 4) was increased (\(p\) < 0.05) in the WD\({}_{\text{ch}}\) group, whereas an increasing tendency was observed in the LCHP\({}_{\text{ch}}\) group (+41% vs. AIN\({}_{\text{ch}}\) group). \begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Parameter [Unit]**} & \multicolumn{4}{c}{**Experimental Groups**} \\ \cline{2-4}  & **AIN\({}_{\text{ch}}\)** & **WD\({}_{\text{ch}}\)** & **LCHP\({}_{\text{ch}}\)** \\ \hline Initial body weight (g) & 175 \({}^{\text{a}}\)\(\pm\) 21.6 & 173 \({}^{\text{a}}\)\(\pm\) 23.6 & 173 \({}^{\text{a}}\)\(\pm\) 26.5 \\ Final body weight (g) & 580 \({}^{\text{a}}\)\(\pm\) 53.7 & 616 \({}^{\text{a}}\)\(\pm\) 90.4 & 544 \({}^{\text{a}}\)\(\pm\) 77.3 \\ Weight gain (g) & 406 \({}^{\text{a}}\)\(\pm\) 40.0 & 443 \({}^{\text{a}}\)\(\pm\) 86.4 & 371 \({}^{\text{a}}\)\(\pm\) 75.7 \\ Liver weight [g/100 g b.w.] & 4.13 \({}^{\text{a}}\)\(\pm\) 0.30 & 4.56 \({}^{\text{a}}\)\(\pm\) 0.62 & 4.66 \({}^{\text{a}}\)\(\pm\) 0.18 \\ Kidney weight [g/100 g b.w.] & 0.64 \({}^{\text{a}}\)\(\pm\) 0.06 & 0.63 \({}^{\text{a}}\)\(\pm\) 0.06 & 0.76 \({}^{\text{b}}\)\(\pm\) 0.05 \\ Heart weight [g/100 g b.w.] & 0.34 \({}^{\text{a}}\)\(\pm\) 0.03 & 0.34 \({}^{\text{ab}}\)\(\pm\) 0.03 & 0.38 \({}^{\text{b}}\)\(\pm\) 0.03 \\ Diet intake [g/day] & 25.10 \({}^{\text{ab}}\)\(\pm\) 8.86 & 28.91 \({}^{\text{b}}\)\(\pm\) 6.27 & 23.01 \({}^{\text{a}}\)\(\pm\) 8.77 \\ Water intake [mL/day] & 45.28 \({}^{\text{a}}\)\(\pm\) 13.90 & 49.48 \({}^{\text{a}}\)\(\pm\) 13.10 & 65.77 \({}^{\text{b}}\)\(\pm\) 15.65 \\ \hline \hline \end{tabular} Data are means \(\pm\) SD. The means marked with letters \({}^{\text{a}}\) and \({}^{\text{b}}\) (in each line) are significantly different (\(p\) < 0.05).  
\end{table} 
Table 2: Body weights, weight gain, diet and water intake as well as the weights of liver, kidney and heart of Wistar rats after 8 weeks of feeding: AIN\({}_{\text{ch}}\); WD\({}_{\text{ch}}\) (Western diet) or LCHP\({}_{\text{ch}}\) (low-carbohydrate–high-protein) diets, enriched with 1% cholesterol.