Effects of Copper-bearing Montmorillonite (Cu-MMT) on Escherichia coli and Diarrhea on Weanling Pigs*

Copper-bearing montmorillonite (Cu-MMT) was produced by Cu cation exchange reaction. X-ray diffraction analysis showed that that the (001) basal spacing of the MMT crystal lattice increased from 1.544 to 1.588 nm after Cu exchange. This indicated that Cu entered into interlayer position of MMT as a hydrated cation or composite cation. In vitro results indicated that CuMMT had antibacterial activity on Escherichia coli K88. Cu-MMT had unbalanced positive charge after cation exchange. Its antibacterial activity resulted from two aspects, one was electrostatic attraction which made E. coli K88 being adhered on the montmorillonite surface, the other was the Cu slowly released, which could kill bacteria. In an in vivo study, four replicates of eight weanling pigs were assigned to each of two dietary treatments to study the effects of Cu-MMT on diarrhea, E. coli in the lumen of the jejunum and morphology of jejunal mucosa. As compared to the control, supplementation of the diet with 0.2% Cu-MMT improved average daily gain by 12.50% (p<0.05) and decreased F/G by 9.42% (p<0.05). The mean diarrhrea incidence was decreased by 71.80% (p<0.05). The viable counts of Escherichia coli in jejunal contents were significantly reduced (p<0.05). Villus height and the villus height to crypt depth ratio at the jejunal mucosa were increased by 19.09% (p<0.05) and 37.10% (p<0.05), respectively. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 12 : 1712-1716)