Histology of liver 



Stock, SP 8 HVO, and SPE diets.— Micro- 

 scopic examination of the livers from 115 rats fed 

 the stock diet showed very little pathology. Peri- 

 ductal infiltration and edema were noted occa- 

 sionally in the older animals. Only one of the 

 livers examined showed the presence of fat 

 vacuoles. 



The results from examination of 98 livers from 

 rats fed the SP 8 HVO diet in general were similar 

 to those for rats fed the stock diet except for the 

 occasional appearance of small amounts of fat. 

 Of these livers, 14 showed microscopic evidence 

 of fat, and 10 of the 14 were from moribund rats 

 that were more than 600 days old. In no case 

 were the livers excessively fatty. 



In contrast to the results with rats fed stock 

 or SP 8 HVO diet, microscopic examination indi- 

 cated that most of the livers from rats fed SPE 

 diet were fatty. In table 19 are summarized the 

 results from the histological ratings for fat of 202 

 livers from rats fed SPE diet. Relatively high 

 ratings for fat were obtained for livers from rats, 

 regardless of age, that were maintaining their 

 weight at the time of sacrifice. In rats over 500 

 days of age, the score for large vacuoles as well as 

 for small vacuoles was high. Only 7 of the 58 

 rats over 200 days of age had livers showing no 

 evidence of fat. Fat was also seen in two of the 

 five livers from young nonfasted rats approxi- 

 mately 150 days old. The presence of glycogen 

 in livers from nonfasted rats as well as protein 

 that may be lost during fasting was responsible 



for the somewhat lower rating for fat in the livers 

 of nonfasted rats 200 to 400 days old. There was 

 a tendency for the scores for liver fat to be lower 

 for moribund rats, particularly for animals losing 

 more than 100 grams in weight. No evidence of 

 fat was observed in livers from 27 of the 78 rats in 

 this latter group. 



SPM, SPB, and SPPB diets.— The results 

 from microscopic examination of the livers for fat 

 in rats fed SPM, SPB, and SPPB diets are sum- 

 marized in table 20. Excessively fatty livers were 

 rarely seen with any of these three diets. On 

 SPM diet, fat was observed most frequently in the 

 older rats; the larger amounts were seen in the 

 livers of moribund rats over 700 days old and 

 losing more than 100 grams. On SPB diet, rela- 

 tively little fat was apparent regardless of the age 

 or general health of the rat. On SPPB diet, 

 small amounts of fat were generally observed in 

 rats over 400 days of age that were maintaining 

 weight but, in contrast to the results with SPM 

 diet, fat was not detected in the livers of the older 

 moribund rats that were losing over 100 grams. 



All other diets. — In table 21 are summarized 

 the results of microscopic examination of the livers 

 from rats, chiefly sick or moribund, fed all of the 

 other experimental diets. None of the supple- 

 ments added to SPE diet were able to prevent the 

 tendency to fatty livers with this diet. Although 

 interpretation of data on liver fats in moribund 

 rats is complicated by variable weight losses, there 

 appears to be evidence for exceedingly fatty livers 

 in rats fed SPE diet to which cholesterol was 



Table 19. — Liver fat determined ■microscopically for fasted and nonfasted rats maintaining or losing weight 



at different ages on SPE diet 





Fasted 



Nonfasted 



Weight status and age 

 of rats (days) 



Rats 



Histological 

 rating 



Livers with — 



Rats 



Histological 

 rating 



Livers with — 





Small 

 vacuoles 



Large 

 vacuoles 



Small 

 vacuoles 



Large 

 vacuoles 



Small 

 vacuoles 



Large 

 vacuoles 



Small 

 vacuoles 



Large 

 vacuoles 



Rats maintaining 

 weight : 

 Less than 200 _. 



Number 



/Score 



Score 



Percent 



Percent 



Number 



5 



16 



4 



Score 



0. 6 



1. 8 

 1. 2 



Score 

 0.2 



. 4 

 .8 



Percent 



40 



88 



100 



Percent 

 20 



200 to 299 



300 to 399 



7 



8 



14 



9 



4 

 12 

 13 

 14 



2.3 

 3.0 



2. 1 



2.4 



1.0 

 1. 4 

 1. 4 

 1. 5 



0.3 



. 9 



. 9 



2. 1 







. 8 

 1. 5 

 1. 6 



86 



100 

 79 

 89 



50 

 58 

 62 



71 



29 



87 



57 



100 





 58 

 92 

 93 



44 

 75 



400 to 499. ... 





500 and over. . 













Rats losing less than 

 100 grams: 

 200 to 299.. 



2 

 8 

 5 

 3 



1 

 12 

 15 

 14 



1. 5 



2. 4 

 2.0 

 1.3 





 . 3 

 . 9 

 . 6 







1. 

 1. 

 1. 



__ 



. t 



. 8 

 1.0 



50 

 88 

 80 

 67 





 17 

 40 

 36 



o 



300 to 399 . . 



75 



400 to 499. . 



80 



500 and over 

 Rats losing more than 

 100 grams: 

 200 to 299. ... 



100 

 



300 to 399. 



7 

 10 

 19 



1. 3 

 . 9 

 . 9 



. 9 

 1. 4 

 1. 1 



71 

 50 



47 



57 

 90 

 63 



67 



400 to 499 



60 



500 and over 



57 



33 



