Klasing K C, Knight C D, Forsyth D M
J Nutr. 1980 Sep;110(9):1914-21. doi: 10.1093/jn/110.9.1914.
The effect of iron on the ability of sow's milk to suppress Escherichia coli was examined both in vitro and in ligated intestinal segments of neonatal pigs. Sow's milk from day 7 of lactation was diluted with NaHCO3/KH2PO4 and divided into four treatment groups: (1) diluted milk; (2) diluted milk + ferric citrate; (3) diluted milk heated at 100 degrees for 20 minutes, and (4) treatment 3 + ferric citrate. Treatment groups were tested for antibacterial activity in vitro after inoculation of 10(4) Escherichia coli (strain 263); counts after a 3-hour incubation were: 721, 9,290, 11,400 and 9,680 for treatments 1-4, respectively. The same four treatments were tested in ligated intestinal segments of 9-day-old pigs with or without the addition of 10(4) E. coli. The average total E. coli count (+10(5)) per centimeter of intestine for 16 pigs after 3 hours of incubation were: 11, 50, 84 and 249 for treatments 1-4, respectively, without additional E. coli and 14, 110, 314 and 535 with additional E. coli. The effects of exogenous iron on the in vitro anti-coli capacity of sow's milk were also examined at 3-day intervals throughout the first 21 days of lactation. Iron had a significant detrimental effect on the anti-coli capacity of sow's milk from days 6 to 18 of lactation. Iron did not have an effect on the anti-coli capacity of colostrum, which exhibited bactericidal activity, or on milk from the 21st day of lactation, which allowed good E. coli growth. Results from these studies suggest that iron reduces the capacity of sow's milk to repress E. coli concentrations both in vitro and in vivo.
研究人员在体外以及新生仔猪的结扎肠段中检测了铁对母猪乳汁抑制大肠杆菌能力的影响。将泌乳第7天的母猪乳汁用碳酸氢钠/磷酸二氢钾稀释，并分为四个处理组：（1）稀释乳汁；（2）稀释乳汁+柠檬酸铁；（3）稀释乳汁在100℃加热20分钟，以及（4）处理3+柠檬酸铁。接种10⁴大肠杆菌（菌株263）后，对各处理组进行体外抗菌活性测试；孵育3小时后的菌落计数分别为：处理1至4依次为721、9290、11400和9680。在9日龄仔猪的结扎肠段中对相同的四个处理组进行测试，添加或不添加10⁴大肠杆菌。孵育3小时后，16头仔猪每厘米肠道的大肠杆菌平均总数（+10⁵）分别为：处理1至4依次为11、50、84和249（不添加额外大肠杆菌）以及14、110、314和535（添加额外大肠杆菌）。在泌乳的前21天中，每隔3天还检测了外源铁对母猪乳汁体外抗大肠杆菌能力的影响。在泌乳第6至18天，铁对母猪乳汁的抗大肠杆菌能力有显著的不利影响。铁对具有杀菌活性的初乳或泌乳第21天允许大肠杆菌良好生长的乳汁的抗大肠杆菌能力没有影响。这些研究结果表明，铁会降低母猪乳汁在体外和体内抑制大肠杆菌浓度的能力。
