The Utilization of Raw Soybean Meal Protein for Egg Production in the Chicken

Abstract

The utilization of raw soybean meal as the only source of dietary protein was studied in laying hens in experiments of three- and 4-weeks duration. It was shown that raw meal when fed at the 15% protein level and properly supplemented with methionine and vitamin B₁₂ would support equally good egg production as properly heated meal under the same conditions. When the effects of protein level, vitamin B₁₂, and methionine and crude soybean inhibitor were studied in separate trials it was shown that: (1) the raw meal was poorly utilized at the 12.21% protein level; this level supported good production with the heated meal; (2) supplementary vitamin B₁₂ was essential for proper utilization of raw soybean meal irrespective of protein level but was not essential with properly heated meal; (3) the utilization of sulfur amino acids from the raw meal was inferior to that from heated meal; (4) hens were insensitive to the growth-inhibiting properties of crude soybean inhibitors. It is concluded that the major difference in the utilization of raw soybean meal between laying hens and growing chicks lies in the insensitivity of the former to soybean inhibitors. Thus, when raw meal was fed at a sufficiently high protein level and properly supplemented with methionine and vitamin B₁₂, it was effectively utilized as a good protein source for egg production purposes under the conditions of these experiments.