Smart J L, Stephens D N, Katz H B
Br J Nutr. 1983 May;49(3):497-506. doi: 10.1079/bjn19830058.
In order to exclude the possibility of differences in maternal care which are known to result from typical methods of undernutrition during the suckling period, rat pups were reared artificially on different planes of nutrition away from their mothers. Artificial rearing was accomplished by fitting infant rats with a gastric cannula through which a milk substitute was infused intermittently. Rats were fed thus from 4 to 21 d on a high (ARHI) or a low (ARLO; 44% of ARHI level) plane of nutrition. Underfeeding of the ARLO group was continued till 25 d, after which all rats were given a good-quality pelleted diet qd lib. Compared with mother-reared (MR) litter-mates, ARHI rats showed advanced eye-opening and, at 21 and 25 d, they resisted restraint more strongly. Growth in body-weight of ARHI and MR rats was similar but, when autopsied at 32 weeks, the ARHI rats were shorter (nose-rump length) and had lighter gastrocnemius muscles, adrenals and brains, but heavier epididymal-fat pads. ARLO rats had deficits at 32 weeks compared with ARHI rats in whole body, kidney and epididymal-fat-pad weights, and in tibia length. In a second experiment, ARHI and MR rats were killed at 21 d. All the differences found at 32 weeks were already present at 21 d. In addition, the ARHI pups had enlarged livers and intestines but shorter tibias. The milk substitute, which is one commonly used in such studies, has a low protein and high carbohydrate content compared with rats' milk. This difference probably caused the abnormal organ growth of ARHI rats.
为了排除哺乳期典型营养不良方法导致的母性照料差异的可能性，将幼鼠与母鼠分开，在不同营养水平下进行人工饲养。通过给幼鼠安装胃插管来实现人工饲养，通过该插管间歇性注入代乳品。从4日龄至21日龄，大鼠分别在高营养水平（ARHI）或低营养水平（ARLO，为ARHI水平的44%）下饲养。ARLO组的低喂养持续到25日龄，之后所有大鼠自由采食优质颗粒饲料。与由母鼠抚养（MR）的同窝幼鼠相比，ARHI大鼠睁眼更早，在21日龄和25日龄时，它们对束缚的抵抗力更强。ARHI大鼠和MR大鼠的体重增长相似，但在32周时解剖发现，ARHI大鼠更短（鼻臀长度），腓肠肌、肾上腺和大脑更轻，但附睾脂肪垫更重。与ARHI大鼠相比，ARLO大鼠在32周时全身、肾脏和附睾脂肪垫重量以及胫骨长度方面存在缺陷。在第二个实验中，ARHI大鼠和MR大鼠在21日龄时被处死。在32周时发现的所有差异在21日龄时就已经存在。此外，ARHI幼鼠的肝脏和肠道肿大，但胫骨较短。这种在此类研究中常用的代乳品与大鼠乳汁相比，蛋白质含量低而碳水化合物含量高。这种差异可能导致了ARHI大鼠器官生长异常。
