20 



one microgram of thiamine per gram of diet. In this series, the poor growth was 

 apparently not due primarily to a thiamine deficiency. 



The carbohydrate contents of the diets containing starfish meal were lower 

 than that of the control diet but hardly to an extent which would account for the 

 extremely large differences observed. In fact, the only explanation for the poor 

 results of feeding starfish meal to rats appears to be that the rat will not tolerate 

 the serious imbalance of the calcium: phosphorus ratio which resulted from the 

 large excess of acid-soluble calcium contained in the starfish meal. 



STARFISH MEAL FOR GROWTH OF CHICKS 



It was evident from the tests with rats that this animal is not satisfactory 

 for assaying diets containing high levels of calcium. Results obtained from a 

 series of feeding tests with chicks were much more satisfactory and have the fur- 

 ther advantage of being, directly applicable to commercial practice. The poultry 

 feed industry is probably the largest single user of high protein meals . Chicks 

 and hens were therefore used in all subsequent feeding tests. 



All chicks were a Rhode Island Red-New Hampshire cross, purchased from a 

 nearby hatchery. Chicks were housed by groups in batteries in a room in which 

 the temperature was maintained at 78°-82° F. Birds were distributed between the 

 groups at random, although an effort was made to have initial weights of the 

 groups about equal. Size of groups was limited to 10 chicks each by the small 

 size and limited number of batteries available. Birds were weighed individually 

 at weekly intervals and group feed-consumption records were kept. These data are 

 not highly significant, since there was some wastage in scattered feed. 



The same starfish meal was used for the first series of rat and chick tests 

 and similar levels were fed. Bran, soybean oilmeal, and dried skim milk supplied 

 additional phosphorus to reduce the calcium: phosphorus ratios materially below 

 those of the diets containing comparable levels of starfish meal which were fed 

 to the rats. The composition of the mashes is presented in Table 1. The crude 

 protein was maintained at a 23.5 percent level, primarily by the adjustment in the 

 amount of pilchard meal. Starfish meal was fed at 8, 16, and 32 percent levels. 

 These are really abnormally high levels and were fed with the sole intention of 

 determining the tolerance of the chick for excessive calcium content with no com- 

 pensating sources of phosphorus. The amounts of calcium and phosphorus, calculated 

 from tables of feed analyses and the calcium: phosphorus ratios are presented in 

 this table also. 



A second series of chicks was fed in the same manner as the first, with diets 

 modified on the basis of the results obtained in the first test. In this second 

 series, starfish meal was fed at 3 t 6, and 9 percent levels in order to determine 

 the level which permitted optimum growth. The composition of these diets is given 

 in Table 2 (see page 12). 



In the first series with chicks, the control group made rather poor growth, 

 for reasons to be explained later. The group fed the lowest level of starfish 

 meal is used as a basis of comparison in this case. It was difficult also to 

 find a basis of comparison by which the two groups fed the highest levels could 

 be included, because only one-half of these groups survived, and these would have 

 died except for supplementary thiamine supplied after 3 weeks. These chicks made 

 small gains in weight during the first 3 weeks, but in the third week, half of the 

 group died. Thiamine deficiency was considered to be the probable cause of death, 



