Fish meal and dried brewers' yeast as sources of unidentified growth factors in turkey poult nutrition

A series of four feeding tests, involving a total of 610 poults, was conducted to study fish meal and dried brewers' yeast as sources of unidentified factors required by turkey poults for maximum growth. A corn-soybean oil meal ration, supplemented with all known vitamins, was used as a basal ration. Wheat was substituted for corn in two tests. The poults were reared in batteries on wire screen floors for the duration of each test. The addition of 5 per cent fish meal to the all-vegetable ration resulted in an increase in the rate of growth of poults. Since the basal ration contained all the known vitamins, it was apparent that fish meal contained an unidentified factor(s) required by poults for maximum growth. The degree of response to fish meal varied in the different tests. It is suggested that the variation may have been due to a carry-over of the unidentified factor(s) from the parent stock, which varied with the different lots of poults used in the tests. The addition of 5 per cent dried brewers' yeast to the all-vegetable basal ration failed to produce a growth response in poults. This would indicate that the unidentified factor(s), postulated to be present iii dried brewers' yeast, was not required by the poults under the conditions of this experiment, nor was it supplied otherwise by some other ingredient in the ration. The unidentified factor(s) demonstrated to be present in fish meal did not appear to be present in dried brewers' yeast. Supplementation of various rations with an antibiotic preparation containing aureomycin resulted in an increase in the average weights of the male poults, but failed to produce an increase in the average weights of the female poults. The degree of response to aureomycin obtained in the male poults appeared to depend, in part, on the composition of the ration fed. The efficiency of feed utilization was improved slightly when aureomycin was included in the ration. There was no significant difference between the weights of the poults receiving wheat and those fed corn as the cereal part of the diet, although the efficiency of feed utilization was slightly better with the corn rations. The requirement of the poult for an unidentified growth factor present in fish meal has been demonstrated with rations containing either wheat or corn.Land and Food Systems, Faculty ofGraduat