Identification of Resistant Pea (Pisum sativum L.) Proteins in the Digestive Tract of Chickens

Abstract

This study was undertaken to determine if pea (Pisum sativum L.) protein structure could explain pea protein digestion. A nitrogen-free (NF) diet and two diets containing either whole ground peas or a globulin fraction purified from peas were fed to 3-week-old chickens. Sodium dodecyl sulfate polyacrylamide gel electrophoresis was used to estimate the relative rates of degradation of proteins subfractions in the gastrointestinal contents of chicks. Proteins were quantified by image analysis of Coomassie blue stained bands. Convicilin disappeared already in the gizzard. Legumin α and vicilin were still present in gizzard but disappeared in jejunum. The polypeptides shown to persist until the end of digestive tract were albumin PA2, lectin, and polypeptides of MW in the range 19500−25000 originating presumably from legumin. An endogenous protein of about 57 000 was observed until terminal ileum. Apparent ileal protein digestibility was high and slightly lower for pea diet (89.5%) than for globulin diet (93.3%). Results suggested that, although some pea proteins appeared less susceptible to hydrolysis, they represented only a small amount at the terminal ileum. Keywords: Pea proteins; globulin; chick; digestion; electrophoresis