Effects of maternal high-protein diet during pregnancy and lactation on growth of male rat offspring

Abstract

Objective To investigate the influence of maternal high-protein diet during pregnancy and lactation on the growth of male rat offspring. Methods Female Wistar rats were mated with male rats and the pregnant ones were randomly assigned into three groups (n=10): Group Ⅰ, Group Ⅱ and Group Ⅲ. Three isocaloric purified diets, which were DietⅠ (protein, 14.0%; carbohydrate, 69.3%; fat, 16.7%), Diet Ⅱ (protein, 24.0%; carbohydrate, 59.3%; fat, 16.7%) and DietⅢ (protein, 34.0%; carbohydrate, 49.3%; fat, 16.7%), were offered ad libitum to the rats in the three groups, respectively. On the 3rd day after birth, only three male rat offspring of each litter were kept. All male rat offspring at the age of 21 days were weaned onto the same normal diets until 77-day-old. Food intake (FI), body weight (BW), body length (BL) and visceral fat mass (VFM) of them were recorded. Blood lipids levels on the 21st, 49th and 77th days after birth were detected. Weight gain (WG), food efficiency (FE) and percentage of VFM (VFM %) were calculated to assess the growth of male rat offspring. One-way ANOVA, LSD or Tamhane T2 test was used for statistical analysis. Results (1) On the 3rd day after birth, male rat offspring in Group Ⅱ and Group Ⅲ had higher fast BW than those in GroupⅠ[(9.77±0.81), (9.58±0.54) and (9.17±0.68) g; F=3.222, P=0.026]. On the 7th, 14th and 21st days after birth, male rat offspring in Group Ⅱ [(17.59±1.24), (39.51±2.68) and (67.77±4.22) g] had higher BW than those in GroupⅠ [(15.96±1.17), (35.35±4.11) and (63.43±3.98) g] and Group Ⅲ [(16.52±1.05), (37.06±3.27) and (64.43±3.81) g] (F=23.684, 17.070 and 84.195, all P 0.05). Male rat offspring's BL on the 49th day after birth was longer in Group Ⅱthan in Group Ⅰand Group Ⅲ [(22.03±0.26), (21.57±0.43) and (21.77±0.33) cm, F=3.222, P=0.026). VFM % of Group Ⅱ (3.87±0.32 and 5.13±0.32) and Group Ⅲ (3.90±0.27 and 5.15±0.33) on the 49th and 77th days after birth were higher than those of Group Ⅰ (3.50±0.34 and 4.68±0.38) (F=3.631 and 3.611, both P<0.05). (3) Triglyceride (TG) level was higher in GroupⅠ than in Group Ⅱ and Group Ⅲ on the 21st day after birth [(1.12±0.13), (0.89±0.10) and (0.97±0.12) mmol/L, F=7.283, P=0.004]. However, GroupⅡ and GroupⅢ had a higher level of TG than GroupⅠ on the 77th day after birth[(2.64±0.37), (2.43±0.32) and (1.90±0.21) mmol/L, F=12.321, P<0.001]. Conclusion Maternal high-protein diet can increase the birth weight of male rat offspring to a certain extent, which is influenced by carbohydrate content. Moreover, male rat offspring of dams fed with high-protein diet during pregnancy and lactation will have increased visceral fat accumulation and serum TG level during adulthood. Key words: Pregnancy, animals; Lactation; Dietary pretiens; Animals, newborn; Rats