The rats were housed individually in wire-screen cages 

 fitted on wire-mesh floors. The temperature of the room was maintained 

 at 80° F. The rats were supplied with food and water ad libitum , and 

 weekly records were taken of live weight and food consumption. The 

 feeding study lasted 10 weeks. The apparent digestibilities of the 

 protein consumed by individual rats were determined in aliquots of the 

 ground, debris-free feces, collected during the fourth and fifth week 

 of the feeding test. 



Four adult male albino rats, two each fed PFS and CL protein, 

 were used to determine the biological value for maintenance, according 

 to the method proposed by Mitchell (I92h). The rats were housed in 

 cages on wire screens, over funnels into which a small wire screen 

 was inserted to catch feces and allow urine to pass. Urine was col- 

 lected in 600 ml. beakers under toluene, and a few ml. of a 3-percent 

 solution of HpSC, was used as additional preservative. The feces were 

 collected from trie small screens and separated from food, hair, and 

 other debris, and were ground. Nitrogen was determined in measured 

 aliquots of the urine and feces. 



The non-nitrogenous diet fed to the rats contained: dextrin, 

 60; sucrose, 21; salt mixture U.S. P. XIV, No. 2 for vitamin-A bioassay, 

 h; lard, 13; and cod-liver oil, 2 parts by weight. To each 100 g. of 

 this basal diet vas added 0.072 and 0.2li0 mg. of thiamine and riboflavin, 

 respectively. The test protein was incorporated into a la-percent agar - 

 10-percent sucrose gel mixture. A 3-day precollection and a 2-day 

 collection nonprotein-feeding period; a 3-day precollection and a 3-day 

 collection protein-feeding period; followed by a second 3-day precollection 

 and a 2-day collection nonprotein-feeding period was used. The quantity 

 of test protein fed daily during the protein-feeding period was equivalent 

 to the nitrogen contained in the urine daily during the first collection 

 period. 



RESULTS AND INTERPRETATIONS 



The data in table 1 and figure 1 indicate that the male and 

 female rats fed the diet containing 9 percent protein from PFS alone 

 lost considerable weight and died before the eighth week of the study. 

 The rats fed the basal diet with no added protein lost about the same 

 weight and died at about the same time. Evidently 9 percent PFS protein 

 did not permit growth any better than no protein added to the basal diets. 



The mean gain of 135.9 g. of the group of rats fed the diet 

 containing 9 percent CL protein, indicates that CL was more efficiently 

 utilized than the various other 9 percent protein combinations of PFS-CL 

 contained in the diets (table 1). The mean gain of the group of rats 

 fed this diet at the end of 10 weeks, however, was not statistically 

 significantly different (p=> 0.05) from that of the group fed the diet 

 in -which 2.25 percent PFS protein replaced a like amount of CL protein, 



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