Immunological changes in growing mice fed on diets containing casein or peas (Pisum sativum var. Belinda) as the source of protein

Abstract

The effects of two different sources of protein: peas (Pisum sativum var. Belinda) and casein on immunocompetence, nutritional utilization and growth performance have been investigated in recently weaned mice. Feeding these animals on a pea diet resulted in an impairment in growth and significant decreases in the weights of liver, muscle, kidneys and femur, while intestine weights increased. No differences in food consumption were observed, but food conversion efficiency (food intake: weight gain) was increased in pea-fed animals compared with those offered the casein diet. Packed cell volume and serum Fe and Zn levels fell significantly after legume-protein intake, and, by contrast, Cu values increased slightly. Serum albumin levels showed a statistically significant reduction in mice fed on the diet containing peas. However, y-globulins and immunoglobulin G titres were markedly increased. The characterization of spleen-cell subsets using monoclonal antibodies revealed a significantly higher percentage of T-lymphocytes in the pea group compared with casein-fed animals, while no changes were observed in the proportions of B-lymphocytes and macrophages. In vitro mitogenic responses to phytohaemagglutinin, concanavalin A and Escherichia coli lipopolysaccharide S were slightly, but not significantly, lower in the pea-fed animals. Our results describe, apparently for the first time in mice, some immunological disturbances after peak intake. These results may lead to a better understanding of the possible role of antigenic proteins in gastrointestinal disorders and the poor individual performance after legume intake.