Selective decontamination, induced colonization resistance and connected immunological changes in piglets.

Area of Science:

• Microbiology
• Immunology
• Animal Science

Background:

• Gut microbiota plays a crucial role in host immunity and colonization resistance.
• Understanding the impact of specific bacterial groups, like Enterobacteriaceae, on the host immune system is vital.

Purpose of the Study:

• To investigate the effects of selective decontamination of Enterobacteriaceae on the immune system of piglets.
• To assess the impact of Enterobacteriaceae absence on colonization resistance.

Main Methods:

• 14-day-old piglets underwent selective decontamination using antibiotics (nalidixic acid, kanamycin, nystatin).
• Fecal samples were analyzed for Enterobacteriaceae absence, confirmed by germfree piglet inoculation.
• Hematological parameters (white blood cell count, granulocytes) and splenic immune cell populations (IgG, IgA) were monitored.
• Colonization resistance was tested by introducing various E. coli strains.

Main Results:

• Selective decontamination successfully eliminated Enterobacteriaceae from piglet feces.
• A significant decrease in white blood cell count, primarily due to reduced granulocytes, was observed.
• Spleen analysis revealed a decrease in IgG-positive cells and an increase in IgA-positive cells.
• Piglets deprived of Enterobacteriaceae exhibited reduced colonization resistance to introduced E. coli strains.

Conclusions:

• Selective decontamination of Enterobacteriaceae profoundly impacts piglet hematology and splenic immune cell composition.
• The absence of Enterobacteriaceae compromises colonization resistance, making piglets more susceptible to E. coli colonization.
• These findings highlight the critical role of Enterobacteriaceae in maintaining gut homeostasis and immune function in young pigs.