On the Protein Allowance to the Young Angora-rabbit

Abstract

Feeding experiments on the young Angora-rabbit were performed to obtain the influence of tne protein allowance upon body growth and hair production. Diets used contained mulberry leaves, wheat bran, alkali treated wood powder, & c. and different amounts of casein and starch, ranging 8-15% total protein contents. When the diets contained more than 12% proteine or animals were fed more than 4.5g digestible protein per kg. body weight, the amounts of fed protein did not affect the rate of both growth and hair production at equi-caloric intakes.
On the lower protein diets, 8% protein contents or ca. 3g. per kg. digestible protein, the rate of these two decreased followed by the reduction of n. f. e. digestibility, suggesting the increase of available energy losses. The decrease of hair production on these diets was almost parallel to the rate of body growth and due mainly to the decrease of hair growth velocity and new fiber formation, and the body side half of old hair staples contained slightly less cystine than that of animals on the higher protein diets.
However, the thickness of old and new fibers, total N, S contents of hair did not differ greatly among the respective protein level under these experimental conditions, and the rate of apparent N, S transformation from intake to hair ranged 6-8% of N, 25-45% of S, and greater in the lower protein diets.
The diet proteins used were assumed to have their biological value of ca. 70 and limiting amino acid of sulfur containing one, indicating a sulfur deficiency in the low protein animals.