110 O
. Peulen et al. Livestock Production Science 66 2000 109 –120
significant decrease in the intestinal permeability maturation in suckling rats and, thus, could play a
towards proteins ‘‘gut closure’’ is observed and role in normal intestinal development.
some mucosal enzyme specific activities SAs are In mice, it was also demonstrated that spermine
modified. For example, maltase and sucrase SAs induces the maturation of the small intestine and the
increase in the third postnatal week. Lactase which is associated immune system Ter Steege et al., 1997.
´ essential for lactose hydrolysis during the first two
In the sea bass, data confirm this assertion Peres et postnatal weeks, and lysosomal enzymes, which
al., 1997. A diet enriched in spermine can accelerate intervene in the digestion of chyme molecules, lose a
the appearance of the adult enzymatic profile in the part of their activity and concentration. Some of
intestine and in the pancreas of this fish species. these phenomena are also observed in babies. This
suggests that mice and rats could represent good models to understand biochemical and physio–
2. Polyamines in milk
pathological mechanisms taking place during de- velopment of the human small intestine, and to
Since intestinal maturation occurs in the rat for understand or correct causes and consequences of
doses of spermine equal to or higher than 1 mmol different dysfunctions of the intestine.
day, a likely role of dietary polyamines in normal Luk et al. 1980 and Luk 1990 have shown that
maturation of the intestine was proposed for this ornithine decarboxylase ODC SA and polyamine
animal. concentrations increase in the intestinal mucosa
In order to find out whether ingested polyamines during weaning in rats. They established that a-
can intervene in the normal development of the rat difluoromethylornithine DFMO, an inhibitor of
intestine, the concentration of these substances in rat ODC, delays the intestinal maturation process.
milk and food was estimated. As shown by Pollack Therefore, further research to better evaluate the role
et al. 1992 and Romain et al. 1992, the con- played by polyamines in the intestine maturation was
centration of putrescine and spermine is low less undertaken.
than 2.5 nmol ml and does not vary much during Previous observations, taking into account that
the lactation period, while the spermidine concen- polyamines are substances playing an important role
tration is higher and seems to increase during in tissue proliferation and differentiation, led Dufour
lactation from 9 to . 20 nmol ml. Rat food et al. 1988 to test the effect of dietary polyamines
contains approximately 150-times more putrescine on intestinal maturation. They orally administered
and spermine, and approximately 30-times more spermine and spermidine to rats, which were 7 or 11
spermidine than rat milk. Thus, solid rat food days old, at doses from 3 to 8 mmol twice a day for 3
represents a substantial increase in the exogenous days. They showed that these treatments induce
contribution of polyamines at weaning in the rat. changes in intestinal enzyme activity similar to those
Consequently, the polyamines contained in the occurring during normal maturation. These results
milk at the end of suckling and in the solid-rat food were confirmed by Buts et al. 1993, Wild et al.
could play a role in the postnatal maturation of the 1993, Harada et al. 1994 and Dorhout et al.
rat intestine or in maintaining a functional stage in 1996. Georges et al. 1990 extended these ob-
the bowel. This possibility is reinforced by the fact servations to the ultrastructure of the cell epithelium
that bacterial flora, which constitute another source ´
in rats. Later on, Wery et al. 1992 and Osman et al. of exogenous polyamines, grow with the administra-
1998 proved that these spermine treatments induce tion of solid food Osborne and Seidel, 1990.
‘‘gut closure’’ in these animals. Buts et al. 1993 Therefore, it appears that further investigation on the
demonstrated that the concentration of the secretory intestinal maturation induced by spermine is fun-
component of polymeric immunoglobulins was in- damental.
creased in the villus and crypt cells by spermine Polyamine concentrations of the milk were also
ingestion. All these observations suggest that oral estimated in the cow Sanguansermsri et al., 1974;
ingestion of spermine induces complete intestinal Motyl et al., 1995, sow Kelly et al., 1991; Motyl et
O . Peulen et al. Livestock Production Science 66 2000 109 –120
111
al., 1995, goat Poszaj et al., 1997 and human which was never observed after weaning. Neverthe-
female Sanguansermsri et al., 1974; Pollack et al., less, irreversibility of normal intestinal maturation
1992; Romain et al., 1992; Buts et al., 1995. In has never been proven, maybe because adult rat diets
general, goat’s colostrum and milk are rich in always contain high polyamine levels as compared
polyamines, and concentrations are higher than those with rat milk Pollack et al., 1992; Romain et al.,
in milk of the other mammals. Polyamine concen- 1992 see later and because intestinal microflora
trations vary with the diet, species, time of lactation, synthesise polyamines Osborne and Seidel, 1990.
total litter weight, offspring number and milking Thus, it may be suggested that dietary polyamines
time. Although there are no data demonstrating a are furnished at such an amount after weaning that
role of dietary polyamines in maturation of the postnatal maturation cannot return to its suckling
digestive tract except maybe in babies, there is also state.
no data disproving this possibility. Therefore, experiments were performed in order to
reduce, where possible, all sources providing poly- amines to the intestine of adult rats Deloyer et al.,
3. Role of dietary spermine in intestinal 1996b. By using germ-free animals, the polyamine
