FIELD PEAS AS A MAJOR DIETARY PROTEIN SOURCE FOR THE GROWING CHICK AND LAYING HEN WITH EMPHASIS ON HIGH-TEMPERATURE STEAM PELLETING AS A PRACTICAL MEANS OF IMPROVING NUTRITIONAL VALUE

Abstract

Ontario-grown field peas were fed to chicks (1–3 weeks of age) as the sole source of protein (20%) in semi-purified diets with and without supplemental essential-amino acids calculated to be deficient. Chick growth and feed-efficiency values indicated that methionine was deficient while cystine and tryptophan were adequate. Autoclaving the whole pea (15 min, 121 °C) substantially improved the gain: feed ratio while, in most cases, not affecting growth. Net protein values essentially paralleled the aforementioned parameters except in the case of tryptophan, which would seem to have been marginal in quantity for the chick. Determination of metabolizable energy (ME) with the adult rooster revealed large increases with either autoclaving or high-temperature steam pelleting (90 °C) of the meal. Dry heating of the whole pea in an oven at 121 °C for 45 min caused a reduction in ME.When peas constituted a major source of dietary protein in practical diets calculated to be isocaloric and isonitrogenous, prepelleting of the meal was necessary to achieve broiler chick growth and feed efficiency comparable with those observed with a control corn–soy ration. Contrary to this finding, pelleting of peas was not necessary for optimal performance of laying hens offered diets comprising 15 or 30% pea meal; however, heat-pressure treatment was a prerequisite for optimal feed utilization.