Protein malnutrition impairs the immune control of Trichinella spiralis infection.

OBJECTIVES

We aimed to analyze the effect of a protein-deficient diet on mucosal and systemic immunity during a Trichinella spiralis infection.

METHODS

Two groups of weaning Wistar rats received a protein-deficient diet (6.5% casein) and the other two groups received a control diet (20% casein). After 10 d, one group of each diet was infected (PDI and CI) with muscle larvae (infecting stage). Food intake and body weight were assessed over time. Blood eosinophils counts, antibodies in serum, and tissue extracts were assessed at different days postinfection. Histologic studies were done in the lungs and intestines, and adult worm (AW) fecundity index score and muscle parasite burden were determined.

RESULTS

Food and protein intake were lower in PDI than in CI. Body weight was lower in PDI than in a non-infected protein-deficient diet. Eosinophils counts were lower in PDI than in CI. Total and specific antibodies were lower in PDI than CI. PDI had a reduced number of mast and goblet cells in the lungs and intestines compared with CI. The persistence of AW in the intestines and migrant larvae at the lungs was longer in PDI than in CI.. The AW fecundity index score was higher in PDI than in CI. Finally, PDI evidenced a higher muscular parasite burden than CI.

CONCLUSIONS

Protein deficiency affects the mucosal and systemic immune response to Trichinella spiralis and delays the expulsion and increases the fecundity index score of AW, which leads to a higher parasite burden in the muscles.