大鼠孕期和哺乳期高蛋白饮食对雄性子代生长的影响

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

目的探讨大鼠孕期和哺乳期高蛋白饮食对雄性子代生长的影响。方法雌性Wistar大鼠受孕后，随机分为Ⅰ组、Ⅱ组和Ⅲ组，每组10只。3组孕期和哺乳期分别以不同蛋白质供能比的等能量纯化饲料喂养，包括饲料Ⅰ（蛋白质14.0%，碳水化合物69.3%，脂肪16.7%）、饲料Ⅱ（蛋白质24.0%，碳水化合物59.3%，脂肪16.7%）和饲料Ⅲ（蛋白质34.0%，碳水化合物49.3%，脂肪16.7%）。子代出生后3 d剔除雌性子代，并小窝喂养，于生后21 d断乳后均以正常标准饲料喂养至生后77 d。测量雄性子代摄食量、空腹体重及身长，同时检测雄性子代内脏脂肪垫比重和血脂水平，并计算体重增长值、喂养效率及内脏脂肪垫比重。采用单因素方差分析、LSD法及Tamhane T2法进行统计学分析。结果（1）生后3 d，Ⅱ组和Ⅲ组雄性子代的空腹体重均高于Ⅰ组[分别为（9.77±0.81）、（9.58±0.54）及（9.17±0.68） g，F=3.222，P=0.026]。生后7、14及21 d时，Ⅱ组雄性子代的空腹体重均高于Ⅰ组和Ⅲ组[7 d：分别为（17.59±1.24）、（15.96±1.17）及（16.52±1.05） g，F=23.684，P〈0.001；14 d：分别为（39.51±2.68）、（35.35±4.11）及（37.06±3.27） g，F=17.070，P〈0.001；21 d：分别为（67.77±4.22）、（63.43±3.98）及（64.43±3.81） g，F=84.195，P〈0.001]。生后7和14 d，Ⅱ组雄性子代的身长均大于Ⅰ组[分别为（7.75±0.32）与（7.53±0.29） cm、（10.38±0.24）与（9.99±0.30） cm，P值均〈0.05]，且生后14 d时Ⅲ组身长大于Ⅰ组，但小于Ⅱ组[分别为（10.22±0.25）与（9.99±0.30） cm、（10.22±0.25）与（10.38±0.24） cm，P值均〈0.05]。生后3~7和7~14 d，Ⅱ组和Ⅲ组雄性子代的平均体重增长均高于Ⅰ组[3~7 d：分别为（7.70±0.41）、（7.00±0.40）及（6.73±0.55） g，F=86.925，P〈0.001；7~14 d：分别为（22.08±1.20）、（20.75±1.72）及（19.68±1.73） g，F=38.876，P〈0.001]，且Ⅱ组雄性子代平均体重增长均大于Ⅲ组（P值均〈0.05）。生后7~14 d，Ⅱ组雄性子代平均身长增长大于Ⅰ组[（2.63±0.19）与（2.48±0.17） cm，P〈0.05]。（2）3组雄性子代生后21~49、49~77及21~77 d的体重增长、摄食量及喂养效率比较，差异均无统计学意义（P值均〉0.05）。生后49 d时，Ⅱ组雄性子代的平均身长均高于Ⅰ组和Ⅲ组[分别为（22.03±0.26）、（21.57±0.43）及（21.77±0.33） cm，F=3.222，P=0.026]。生后49和77 d时，Ⅱ组、Ⅲ组的平均内脏脂肪垫比重均高于Ⅰ组（49 d：分别为3.87±0.32、3.90±0.27及3.50±0.34，F=3.631，P=0.035；77 d：分别为5.13±0.32、5.15±0.33及4.68±0.38，F=3.611，P=0.032）。（3）生后21 d时，Ⅱ组、Ⅲ组雄性子代血清甘油三酯水平均低于Ⅰ组[分别为（0.89±0.10）、（0.97±0.12）及（1.12±0.13） mmol/L，F=7.283，P=0.004]，但生后77 d时，Ⅱ组和Ⅲ组血清甘油三酯水平高于Ⅰ组[分别为（2.64±0.37）、（2.43±0.32）及（1.90±0.21） mmol/L，F=12.321，P〈0.001]。结论大鼠孕期高蛋白饮食可在一定程度上增加雄性子代的出生体重。母体孕期和哺乳期高蛋白饮食可增加雄性子代青春期后内脏脂肪沉积和升高成年早期甘油三酯的水平。

ObjectiveTo investigate the influence of maternal high-protein diet during pregnancy and lactation on the growth of male rat offspring.MethodsFemale 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〈0.001）. Male rat offspring＇s BL of Group Ⅱ were longer than those of Group Ⅰon 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） cm, both P〈0.05 ]. BL of GroupⅢ was longer than that of GroupⅠ, but shorter than that of GroupⅢ 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 GroupⅠ [（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 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].ConclusionMaternal 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.