Protein malnutrition impairs the immune control of Trichinella spiralis infection

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