Effects of Iron on the Anti-Coli Capacity of Sow's Milk in Vitro and in Ligated Intestinal Segments

Abstract

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.

The Potential Impact of Animal Science Research on Global Maternal and Child Nutrition and Health: A Landscape Review

“…Tightly bound iron is believed to make it unavailable to many strains of E. coli and serves to nutritionally deprive them (99). The low content of iron in milk and the withholding of iron by milk-binding proteins may be a physiologic attempt to restrict iron to pathogenic E. coli .…”

Iron Requirements of Baby Pigs Reared in Germ-Free or Conventional Environments on a Condensed Milk Diet

“…By contrast, Geever et al (1968) found greater absorption of Fe from SgFe sulfate by rats raised in a germ-free environment than by conventionally reared rats. Klasing et al (1980) suggest that administration of Fe in amounts exceeding the minimum requirement should be avoided in order to allow maximum enteric bacteriostatic activity. On the other hand, Osborne and Davis (1968) found increased susceptibility to bacterial endotoxin in Fe-deficient pigs.…”

Iron-suppressible production of hydroxamate by Escherichia coli isolates

“…Smith and Huggins (27) (4,30), and, moreover, it is known that the milks from different mammalian species vary in composition. Significantly, an increasing level of unsaturated iron-binding capacity that was associated with the lactoferrin present in the three milks (15,17,24) corresponded with increasing proportions of Hyd' isolates among the fecal E. coli.…”