48 EXPERIMENT STATION BULLETIN 354 



approximately 60 per cent of the total nitrogen eliminated is in the form 

 of uric acid nitrogen. Individual birds may vary several per cent from this 

 figure. At present, it is not possible to account for the remainder of the 

 nitrogen present in the feces, although previous work has shown that there 

 is relatively little urea or ammonia nitrogen present. 



A higher percentage of uric acid nitrogen was eliminated by the birds 

 consuming corn gluten meal than by those consuming soybean oil meal. 

 When the data are compared with those obtained for chicks while con- 

 suming animal proteins (Annual Report 1943, Table III) it will be noted 

 that all vegetable protein percentages are higher than those for animal pro- 

 tein. It will also be noted that growth on the animal-protein rations was 

 superior to the vegetable protein rations and that growth on soybean oil 

 meal was superior to corn gluten meal rations. The higher percentage of 

 uric acid eliminated seems to point to the fact that the nitrogen consumed 

 is utilized for energy* rather than for growth. This substantiates the pre- 

 vailing idea that the amino acid content of vegetable proteins is inferior 

 for growth, but that they can and must be utilized for energy when not in- 

 corporated into growing tissues. 



R. C. RiNGROSE, T. B. Charles, S. R. Shimer, H. A. Davis 



A Study of the Cause and Prevention of Gizzard Lesions in Chickens 



It has been postulated that there is a factor in vitamins A and D feed- 

 ing oils whic his active in influencing the incidence of gizzard lesions. This 

 theory has been under study during the year. 



The standard procedure has been to start comparable groups of 20 to 

 25 day-old chicks on various dietary regimes. A standard control diet has 

 been used for all groups, differences in the diets being obtained by direct 

 addition rather than upon a replacement basis. Records of growth, feed 

 consumption, and any abnormalities which develop have been recorded. 

 At four weeks of age all chicks are sacrificed and the gizzards are examined 

 for the presence of lesions. The severity of the lesions is determined by 

 visual scoring of the individual gizzards in each group. A group score is 

 then calculated. 



Using this procedure, the results indicate that high levels of cod liver 

 oil increase the number and severity of the lesions. In addition, there is 

 a further effect on the gizzard lining in that the lining frequently lacks body 

 and tone. One attempt to concentrate the active factor by separation of cod 

 liver oil into its saponifiable and non-saponifiable fractions was without ef- 

 fect. The results obtained by administration of vitamin E indicate incon- 

 clusively, that vitamin E has no effect on the lesions. 



Cholic acid has a marked preventative action. This raises the question 

 as to the feed or body precursors of cholic acid. 



From the results presented it is obvious that one problem concerns the 

 lack of a standard control ration which will produce a uniform severity of 

 gizzard lesions. Work on this problem has been started. 



Another problem concerns the uniformity of visual scoring for the 

 severity of the lesions produced. It is reported that the gizzard lining con- 

 tains cholic acid. Since the feeding of cholic acid has a marked protective 

 action against the occurrence of lesion, it is possible that a cholic acid deter- 

 mination on the gizzard lining will provide an accurate means of measuring 



