- Five separate trials were conducted to test the feeding value
of Pacific Northwest grown soybeans for chickens and turkeys. Soybeans
were obtained from farms near Walla Walla, Washington and
incorporated into rations which were fed to replacement pullets,
laying pullets, broiler chickens, turkey poults and market turkeys.
These rations were either solvent soybean meal, extruded or raw
soybean based and balanced isocalorically and isonitrogenously.
Extruded and raw soybean rations fed laying pullets were supplemented
with and without added methionine. Similarly, rations fed
turkey poults were supplemented with and without added zinc
bacitracin and procaine penicillin, and broiler rations with and
without zinc bacitracin.
In the first experiment, extruded soybeans were found to have
essentially the same feeding value as solvent soybean meal for
replacement pullets. The observed effects of feeding raw soybeans
were delayed sexual maturity, reduced body weight, poor feed
conversion, pancreatic hypertrophy and liver atrophy.
In the second experiment, laying pullets which were fed
either of three soybean rations in the grower phase, were again
either fed or switched to solvent soybean meal, extruded or raw
soybeans in the layer phase. Again, extruded soybeans were
found to be equal in feeding value to solvent soybean meal in terms
of supporting good egg production. The observed effects of feeding
raw soybeans to laying pullets were poor egg production, poor feed
conversion, decreased feed consumption, pancreatic hypertrophy,
and liver atrophy. Pullets fed raw soybean in the grower phase
produced significantly fewer (P < . 05) eggs in the layer phase even
when they were fed solvent soybean meal. Birds fed raw soybean
supplemented with methionine produced significantly more (P < . 05)
eggs than birds fed raw soybean without supplemental methionine.
In the remaining three experiments, the three soybean rations
were fed to broiler chickens and growing turkeys. Extruded soybeans
were found to be similar in feeding value to solvent soybean
meal. Those birds fed extruded soybean and solvent soybean meal
rations gained significantly more (P < . 05) and converted feed to
body weight significantly better (P < . 05) than those fed raw soybean
rations. With turkey poults, the supplementation of zinc
bacitracin was found to significantly increase (P < .05) body weights of birds fed extruded soybeans over those fed solvent soybean meal.
With broilers, added zinc bacitracin and procaine penicillin
did not prove to be beneficial. The observed effects of feeding raw
soybeans were reduced body weight, poor feed conversion, wet litter
and pancreatic hypertrophy in both species. Additionally, kidney
hypertrophy was noted in broilers. Using up to 25 and 33 percent
raw soybeans in broiler and market turkey rations, respectively,
did not cause any significant growth depression.
Under the conditions of this experiment, Pacific Northwest
grown soybeans treated by an extrusion process were equal in
feeding value, for all ages of poultry, to solvent extracted soybeans.
The raw soybeans were found to be inferior to solvent extracted
soybeans for feeding poultry.