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In piglet rearing a probiotic preparation of Bacillus cereus showed positive effects on daily weight gain and feed conversion (1). Very little is known about the underlying mechanisms of action of probiotics. Baum et al. (2) observed an increase in villus length in the small intestine in piglets, which were fed a diet supplemented with Bacillus cereus. Furthermore, Breves et al. (3) showed positive effects on the glucose transport rates. Bacillus cereus also seems to have a growth-retarding effect on enterobacteria in the digesta of the small intestine in piglets.
Sows were assigned randomly to a control group and a probiotic group which was fed with a diet supplemented with 4,4-8,8 x 108 CFU/kg of Bacillus cereus var. toyoi from the 91st day before birth. The supplemented diet was fed to the piglets from the 15th day after birth. Tissue samples (epithelia) were taken from the mid jejunum of the piglets at day 14, 28, 35 and 56. The mucosa was stripped and mounted into conventional Ussing chambers.
Glucose transport was stimulated by 0.5, 1, 4 and 10 mmol/l of glucose and secretion was stimulated by different concentrations of PGE2 (0.05, 0.1, 0.5 and 1 µmol/l). The tissues were incubated under short circuit conditions and the changes in short circuit current (DIsc) were recorded.
The response of Isc on addition of increasing concentrations of glucose showed saturation kinetics. The mean of DIsc was lower in the probiotic group compared to the control group on day 14 and 56. The DIsc was inconsistent on day 28 and 35. The variation between the animals was high.
Serosal PGE2 caused a dose-dependent change in Isc. On the 14th day the response to PGE2 was reduced in the probiotic group at higher PGE2 concentrations. The effect of PGE2 on Isc significantly varied with age.
The working hypothesis of this study is the assumption that the positive effect of Bacillus cereus on daily weight gain and feed conversion can be explained by altered transport properties of the intestine. The obtained data of the present study partly support this hypothesis (reduced DIsc after treatment with PGE2). However, the reduced response of Isc after mucosal addition of glucose is in contrast to previous findings (3) and obviously age dependent.
1) ALEXOPOULOS, C., KARAGIANNIDIS, A., KRITAS, S.K., BOSCOS, C., GEORGOULAKIS,
I.E., KYRIAKIS, S.C. (2001): J. Vet. Med. A. Physiol. Pathol. Clin. Med. 48, 137-45
2) BAUM, B., LIEBLER-TENORIO, E.M., ENSS, M.L., POHLENZ, J.F., BREVES, G. (2002): Z.
Gastroenterol. 40, 277-84.
3) BREVES, G., WALTER, C., BURMESTER, M., SCHRÖDER, B., (2000): J. Anim. Physiol. a.
Anim. Nutr. 84:9-20
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