UBC Theses and Dissertations

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UBC Theses and Dissertations

The availability of Lysine autoclaved in the presence of carbohydrate [and] The animal protein factor in relation to the nutrition of the chick Stevens, Joan Millicent


(a) The Availability of Lysine Autoclaved in the Presence of a Carbohydrate. Heat treatment has long been known to improve the value of soybean oilmeal for chick growth. However, more recently it has been demonstrated that too much heat or too long a heating period lowers the availability of certain of the amino acids present. This lowered availability was accompanied by a brown coloration. Investigators had shown that such a brown coloration occurs in other materials as a result of a reaction between reducing sugars and amino acids. As a result this study was undertaken to determine whether a similar reaction was responsible for the darkening in colour of the soybean during heating and whether or not such a reaction affected the nutritive value of the meal. The results of the study showed that a decrease in nutritive value did accompany the browning of soybean oilmeal. It was also shown that this decrease was mainly due to a lowering of the available methionine. As the lysine gave the greatest growth response, the study was continued using crystalline lysine and cerelose. It was shown the reaction was affected by the time of heating, the ratio of lysine to carbohydrate present, and the presence of water. Assays were carried out both biologically and micro-biologically. (b) The Animal Protein Factor in Relation to the Nutrition of the Chick. A series of three experiments were carried out to determine, if possible, the value of Animal Protein Factor Concentrates in proactical chick rations when fed to chicks which were not depleted of the factor(s). Experiment I was set up using a basal ration which would correspond to a practical starter ration using wheat and a mixture of coarse grains as the cereals. The ration was fed with and without a source of animal protein and was supplemented at various levels with the A.P.F. produced by-Merck and Company. Experiment II was set up using a high energy type of diet containing corn and soybean such as is used for broiler production. Males and females were fed separately to determine if there was a separate response of cockerels and pullets to the A.P.F. Supplementation. Experiment III was set up again using a corn soybean ration. The purpose of this experiment was to compare the Animal Protein Factor Concentrates produced by Merck and Lederle respectively. From the results it appears that supplementation with A.P.F. concentrates is practical but that the results vary with the level and the type of diet used. Apparently there is an optimum level above which further supplementation exerts a depressing effect upon chick growth. This is also true where fishmeal is included in the diet. Lederle gave a greater response than did the Merck product both in growth and feed efficiency.

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