14 DEPARTMENT OF GAME AND FISHERIES No. 10 



the earlier stages of the disease was also noted. The addition of half an 

 ounce of liver to the daily ration of a mink appears to be well within the 

 necessary requirements. 



In the experiments carried out the symptoms varied in severity accord- 

 ing to the proportion of liver contained in the diet. Consequently, many 

 mink are subjected to a state of nutrition fluctuating between satisfactory 

 and unsatisfactory nutritional requirements. Severe symptoms terminating 

 in death may very seldom be encountered, in some instances the disease 

 going no farther than producing a somewhat dry and lustreless pelt and a 

 slight dribbling of urine in a few young males. Notwithstanding the fact 

 that the quality and denseness of the pelt may be affected to some extent 

 the presence of a tendency to anaemia may not be suspected. 



Once the disease has reached a severe stage treatment is of no avail, 

 as pathological changes have taken place in the liver, lungs and kidneys 

 which are beyond repair. It is only in the early stages that the addition 

 of liver has a curative effect. 



DISCUSSION 



In this paper the underlying cause of the disease and the fact that 

 liver is a preventive and curative in the early stages have been pointed 

 out. There are, however, a number of questions which require further 

 investigation. For example, the proportion of cereal which a young mink 

 can assimilate to advantage may possibly be connected with the proportion 

 of liver in the diet. Young mink are usually fed a ration containing a high 

 percentage of meat and fish and such diets, though not necessarily adequate 

 to offset anaemia, are superior to a high percentage of ceral in the ration. 

 There is a possibility that the addition of liver to a ration containing a 

 high percentage of cereals would supply the deficiencies which exist in these 

 foods. 



Further investigations will no doubt reveal the most satisfactory 

 combinations of cereals, meat, fish, and liver required for the optimum 

 nutrition of mink. 



POST MORTEM FINDINGS 



The carcass is emaciated and upon opening the body cavities the 

 tissues have a decided pallor. The large blood vessels stand out promin- 

 ently. Their walls are thin and flabby and filled with watery, pale blood 

 which does not clot readily. The intestines are thin, white and blanched, 

 containing little or no ingesta. The stomach and intestinal mocosa is 

 usually coated with a rather thick gelatinous exudate. The liver has a 

 mottled appearance varying from a light tawny orange to a dark chocolate 

 brown colour. Small petechial hemorrhages are often present. The lobules 

 may be quite prominent, especially near the borders of the lobes. The 

 spleen is invariably swollen and dark brown to purple in colour. The 

 kidneys are pale and swollen and frequently show light hemorrhagic areas. 

 Th6 heart is dilated and the musculature pale and flabby. The lungs are 

 often edematous and congested. The body lymph glands are enlarged and 

 frequently pale gray in colour. 



MICROSCOPIC PATHOLOGY 



The liver, kidney and lungs show the most pronounced pathological 

 changes. The blood vessels in all organs were only partly filled with blood, 

 which stained poorly and was ill-formed. Many of the cells appeared 

 shrunken and broken. The individual cells in most cases stained a pale 

 pink to a yellow colour and a few stained a dark blue. 



