A Bioassay of Certain Protein Supplements When Fed to Baby Chicks. ∗

Abstract

Several investigators have reported the occurrence of a syndrome in chicks which is similar to scurvy in appearance. 1 , 2 , 3 Since several different diets were used in those studies employing different protein sources, it seemed useful to compare the effects produced by various proteins when fed with the same basal ration in order to observe if other proteins allowed the same symptoms to occur as did fish meal, as reported by Holst.

The syndrome has been well described independently by Holst, McFarlane, et al., by Dam, and by Schönheyder. 4 In using a ration similar to the one employed by Holst we were able to produce this syndrome which is characterized by (1) the production of hemorrhages without respect to location, (2) an anemia, and (3) a prolonged blood clotting time.

Feeding experiments. Two groups of experiments were carried on. The diets used and results were as follows :

Diet I—Control. Of 100 parts, corn 55, wheat 20; skim milk 20, NaCl 0.5, cod liver oil (Patch) 1, Ca₃ (PO₄)₄ 1, CaCO₃ 1, dried yeast 1. When 21 chicks were placed upon this ration none died after 10 weeks of feeding. No hemorrhages were observed.

Diet II—Control. Essentially the same as No. I. A commercial casein was used as a protein supplement. Fifteen chicks were placed upon this diet and no hemorrhages were observed at the end of 10 weeks. The mortality was zero.

Diet III—Experimental. Of 100 parts, corn 55.5, wheat 20, fish meal (from 2 samples sold commercially) 20, NaCl 5, cod liver oil 1, Ca₃(PO₄)₂ 1, CaCO₃ 1, and dried yeast 1. When 17 chicks were placed upon this diet, the mortality was 35% in 10 weeks; all of the birds had hemorrhages from time to time which were often fatal. When the fish meal concentration was reduced to 10% the same effect was observed.