Abstract
An experiment was conducted to study the role which protein plays in enabling chicks to utilize “carbohydrate-free” diets in which non-protein calories are supplied by fat. Results showed that neither growth nor nitrogen retention was decreased when fat was substituted isocalorically for glucose in diets containing 13.2, 15.4, 17.6, 19.8 and 22.0 kcal/g of protein. These results show that the requirement of the chick for carbohydrate can be met without diverting amino acids from protein to carbohydrate synthesis, at least when protein is supplied by a mixture of soybean protein, methionine and glycine. Studies to determine the efficiency with which chicks utilized energy when fed high carbohydrate and “carbohydrate-free” diets showed that neither level of protein nor source of non-protein calories affected caloric efficiency or caloric consumption. These results show that lack of carbohydrate in the diet does not affect the ability of the chick to utilize triglyceride and shows that the chick has the ability to utilize large quantities of fat. The results also confirm the concept that chicks eat to meet their energy requirement.