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 Diet Ⅰ (protein,14.0％;carbohydrate,69.3％;fat,16.7％),Diet Ⅱ (protein,24.0％;carbohydrate,59.3％;fat,16.7％) and Diet Ⅲ (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 Group Ⅰ [(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 Group Ⅰ [(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＜0.001).Male rat offspring's BL of Group Ⅱ were longer than those of Group Ⅰ on the 7th and 14th days after birth[(7.53±0.29) vs (7.53± 0.29) cm,(10.38 ±0.24) vs (9.99± 0.30) em,both P＜0.05].BL of Group Ⅲ was longer than that of Group Ⅰ,but shorter than that of Group Ⅲ on the 14th day after birth[(10.22 ± 0.25) vs (9.99± 0.30) cm,(10.22 ± 0.25) vs (10.38±0.24) cm,both P＜0.05].Male rat offspring's average WG from the 3rd to the 7th and the 7th to the 14th day after birth were higher in Group Ⅱ [(7.70±0.41) and (22.08±1.20) g] and Group Ⅲ [(7.00±0.40) and (20.75± 1.72) g] than in Group Ⅰ [(6.73±0.55) and (19.68± 1.73) g] (F=86.925 and 38.876,both P＜0.001),and the differences between Group Ⅱ and Group Ⅲ were statistically significant (both P＜0.05).(2) No significant differences in WG,FI and FE was observed among the three groups (all P＞0.05).Male rat offspring's BL on the 49th day after birth was longer in Group Ⅱ than in Group Ⅰ and 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 Group Ⅰ 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,Group Ⅱ and Group Ⅲ had a higher level of TG than Group Ⅰ 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.