Farnworth Edward R, Chouinard Yvan P, Jacques Helene, Venkatramanan Sudha, Maf Akier A, Defnoun Sabrina, Jones Peter J H
Food Research and Development Centre, Agriculture Canada, Saint Hyacinthe, Quebec, Canada.
Nutr J. 2007 Jul 9;6:15. doi: 10.1186/1475-2891-6-15.
The primary objective was to determine whether consumption of conjugated linoleic acids (CLAs) affected the fecal microbiota composition, fecal enzyme activity or fecal composition.
Human subjects consumed (1 L/day) cows' milk (4% fat) containing (5 mg/g fat) cis-9, trans-11 CLA (CONT), (32 mg/g fat) cis-9, trans-11 CLA (NAT) and (32 mg/g fat) trans-10, cis-12 CLA and cis-9, trans-11 CLA (SYN) for 8 weeks, in addition to their normal diet. Milk feeding periods were separated by 4 week washout periods. Fecal samples were obtained at the beginning (day 0) and the end (day 56) of each milk feeding period. Fecal samples were analysed for microbiological profile, enzyme activity, pH and short chain fatty acid content.
Samples taken at day 0 and day 56 indicated that the numbers of lactobacilli and bifidobacteria significantly decreased after consumption of all experimental milks; total aerobes, total anaerobes, enterobacteria, and enterococci + streptococci did not change. At day 56, the activities of beta-glucosidase, nitroreductase, and urease enzymes had decreased compared to samples taken on day 0 for all treatments. beta-glucuronidase activity did not change. Fecal pH and ammonia content did not change.
It was concluded that observed changes could have been attributed to increased milk intake; no differences could be attributed to consumption of the different CLAs.
主要目的是确定共轭亚油酸（CLA）的摄入是否会影响粪便微生物群组成、粪便酶活性或粪便成分。
除正常饮食外，人类受试者连续8周每天饮用（1升）含（5毫克/克脂肪）顺式-9，反式-11 CLA的牛奶（4%脂肪）（对照组）、（32毫克/克脂肪）顺式-9，反式-11 CLA的牛奶（天然组）和（32毫克/克脂肪）反式-10，顺式-12 CLA与顺式-9，反式-11 CLA的牛奶（合成组）。每次牛奶喂养期之间间隔4周的洗脱期。在每个牛奶喂养期开始（第0天）和结束（第56天）时采集粪便样本。对粪便样本进行微生物谱、酶活性、pH值和短链脂肪酸含量分析。
第0天和第56天采集的样本表明，饮用所有实验牛奶后，乳酸杆菌和双歧杆菌数量显著减少；需氧菌总数、厌氧菌总数、肠杆菌以及肠球菌+链球菌数量未发生变化。在第56天，与所有处理第0天采集的样本相比，β-葡萄糖苷酶、硝基还原酶和脲酶的活性均有所下降。β-葡萄糖醛酸酶活性未发生变化。粪便pH值和氨含量未发生变化。
得出的结论是，观察到的变化可能归因于牛奶摄入量的增加；不同CLA的摄入未造成差异。
