Yajima T, Kanno T, Katoku Y, Kuwata T
Department of Nutritional Research, Nutrition Science Institute, Meiji Milk Products Co., Ltd., Kanagawa, Japan.
Biol Neonate. 1998 Oct;74(4):314-22. doi: 10.1159/000014039.
To elucidate the mechanism of gut hypertrophy observed in rats artificially reared (AR) on milk formulas, the effects of four refined formulas with different ratios of casein (C) and whey protein (W), CW 2:8, CW 4:6, CW 6:4 and CW 8:2, on the gut growth of AR rats were examined. Four groups of pups were infused with each formula through an intragastric cannula from age 5 to 15 days. Each of the four milk formulas showed a different character in the stomach, such as no curd, very soft curd, soft curd and hard curd, in response to an increasing ratio of C:W. There were no significant differences in body weight gain among the AR groups and mother-reared (MR) controls. The stomach growth, in weight, of AR rats increased in response to the increasing ratios of C:W. In comparison with MR controls, hypertrophy of the stomach of AR rats appeared within the formulas with higher proportions of casein than whey protein (CW 6:4 and CW 8:2), but not those with lower proportions (CW 2:8 and CW 4:6). The growth of the small intestine was also related to the increasing ratio of C:W in the formulas. A similar pattern of hypertrophy in the hindgut was seen in AR rats. There was no association between hypertrophy of the gut in AR rats and plasma triiodothyronine. The present results clearly demonstrated that the gut growth of AR rat pups was directly influenced by the diet but not by AR per se, and that hard casein-curd in the stomach might be one cause of gut hypertrophy.
为阐明人工饲养（AR）于奶粉的大鼠肠道肥大的机制，研究了酪蛋白（C）与乳清蛋白（W）比例不同的四种精制配方奶粉（CW 2:8、CW 4:6、CW 6:4和CW 8:2）对AR大鼠肠道生长的影响。四组幼崽从5日龄至15日龄通过胃内插管灌注每种配方奶粉。随着C:W比例的增加，四种奶粉在胃内呈现出不同特性，如无凝乳、凝乳非常软、凝乳软和凝乳硬。AR组与母鼠饲养（MR）对照组之间的体重增加无显著差异。AR大鼠胃的生长重量随C:W比例增加而增加。与MR对照组相比，酪蛋白比例高于乳清蛋白的配方奶粉（CW 6:4和CW 8:2）会使AR大鼠出现胃肥大，而酪蛋白比例较低的配方奶粉（CW 2:8和CW 4:6）则不会。小肠的生长也与配方奶粉中C:W比例增加有关。AR大鼠后肠也出现了类似的肥大模式。AR大鼠肠道肥大与血浆三碘甲状腺原氨酸之间无关联。目前的结果清楚地表明，AR幼鼠的肠道生长直接受饮食影响，而非AR本身，胃内硬酪蛋白凝乳可能是肠道肥大的原因之一。
