Zhao X, Jørgensen H, Eggum B O
National Institute of Animal Science, Department of Animal Physiology and Biochemistry, Research Centre Foulum, Tjele, Denmark.
Br J Nutr. 1995 May;73(5):687-99. doi: 10.1079/bjn19950073.
The present study was undertaken to provide detailed information on the effect of dietary fibre (DF) level on body composition, visceral organ weight, nutrient digestibility and on energy and protein metabolism of rats housed in cold (16 degrees), warm (24 degrees) or hot (32 degrees) thermal environments. High- or low-fibre diets (257 v. 56 g DF/kg dry matter (DM)) were studied in a 6-week balance experiment (initial body weight about 100 g). Heat production was measured using open-air circuit respiration chambers. Pea fibre and pectin were used to adjust the DF level in the high-fibre diet. The ranking order of daily gain of rats kept in different environments was: 24 degrees > 16 degrees > 32 degrees, while the ranking order for carcass protein was: 16 degrees > 24 degrees > 32 degrees. Rats on the high-DF diet had a lower daily gain than those on the low DF diet, and more protein in DM of empty body weight (EBW) and less fat. The relative weights (g/kg EBW) of liver, heart and kidney decreased when increasing the environmental temperature. The relative weight of the heart was highest in rats on the high DF level, while liver and kidney weights were unaffected by DF. Per kg EBW, the stomach, small intestine, caecum and colon and the length of colon were significantly greater in rats consuming the high-fibre diet compared with those on the low-fibre diet. Rats kept at low temperature had a significantly heavier gastrointestinal (GI) tract than those kept at the highest temperature. Digestibility of protein, DM and energy was lowest for rats fed on the high-fibre diet. Heat production (HP) of fed rats as well as fasting HP decreased significantly as environmental temperature increased. HP as a proportion of metabolizable energy (ME) was significantly lower for rats at 24 degrees compared with the other environmental temperatures. The proportion of energy retained as protein was slightly higher in rats fed on the high-fibre than on the low-fibre diet. Based on the results of the present study the authors measured a net energy value of 5.4 kJ/g DF fermented; approximately 50% of the DF came from peas. Possible implications of the present findings are discussed.
本研究旨在提供详细信息，以阐明膳食纤维（DF）水平对处于寒冷（16摄氏度）、温暖（24摄氏度）或炎热（32摄氏度）热环境中的大鼠的身体组成、内脏器官重量、养分消化率以及能量和蛋白质代谢的影响。在一项为期6周的平衡实验（初始体重约100克）中，研究了高纤维或低纤维日粮（257对56克DF/千克干物质（DM））。使用开放式呼吸室测量产热。在高纤维日粮中，使用豌豆纤维和果胶来调节DF水平。处于不同环境中的大鼠的日增重排序为：24摄氏度＞16摄氏度＞32摄氏度，而胴体蛋白质的排序为：16摄氏度＞24摄氏度＞32摄氏度。高DF日粮组大鼠的日增重低于低DF日粮组大鼠，空体重（EBW）的DM中蛋白质含量更高，脂肪含量更低。随着环境温度升高，肝脏、心脏和肾脏的相对重量（克/千克EBW）下降。高DF水平组大鼠的心脏相对重量最高，而肝脏和肾脏重量不受DF影响。每千克EBW，与低纤维日粮组大鼠相比，高纤维日粮组大鼠的胃、小肠、盲肠和结肠以及结肠长度显著更长。低温饲养的大鼠的胃肠道（GI）比高温饲养的大鼠明显更重。高纤维日粮组大鼠的蛋白质、DM和能量消化率最低。随着环境温度升高，采食大鼠的产热（HP）以及空腹HP显著降低。与其他环境温度相比，24摄氏度环境下大鼠的HP占可代谢能量（ME）的比例显著更低。高纤维日粮组大鼠保留为蛋白质的能量比例略高于低纤维日粮组大鼠。基于本研究结果，作者测得发酵DF的净能量值为5.4千焦/克；约50%的DF来自豌豆。讨论了本研究结果可能的意义。
