HEMATOLOGICAL, PLASMATIC AND URINARY VALUES OF PLATANISTIDAE 247 



measured the cholestérol in cetaceans. Although the methods employed vary 



considerably it can be claimed that, at least in Delphinidae, the blood level of the 



total cholestérol is not far removed from that found in Man. Fewer investigations 



have been performed on the cholestérol fractions (esterified cholestérol and free 



cholestérol) and their ratio to the total cholestérol. 



The convergence of the cholestérol values of cetaceans and Man is particularly 



interesting when considered in the light of the différence in diet, i.e. in the case of 



cetaceans a diet rich in unsaturated fatty acids, and in Man, a diet consisting mainly 



of saturated fatty acids (Ridgway, et al., 1968). In the odontocetes examined by 



ester ified cholestérol 



us to date, the total cholestérol values and the ^ and 



total cholestérol 



free cholestérol 



ratios are not far removed from those found m Man. 



total cholestérol 



Data pertaining to the Inia and Platanîsta spécimens examined by us are set 

 out in Table 3. 



We measured a higher esterified cholestérol fraction in Inia than in Platanîsta. 

 In the latter genus we found that total cholestérol was higher in Platanîsta gangetica 

 than in Platanîsta indi but the ratios between the two fractions and the total 

 cholestérol were practically identical in the two species. 



Thèse results provide further confirmation of the fact that diet has very little 

 influence on the biosynthesis of cholestérol. Nearly ail the Stenella and Delphinus 

 plasma examined by us was so rich in chilomicrons thaï, in the test tube, a "creamy" 

 layer appeared on the surface. This was due to the fact that the diet of the dolphins 

 in question consisted mainly of fish with a high fat content. The plasma of Inia 

 that feeds on freshwater fish and crabs never attained such a high quantity of 

 chilomicrons, yet in spite of the "lean" diet, the mean total cholestérol value was 

 288.75 mg/ 100 ml of plasma. In Delphinus, the mean total cholestérol value is 

 265 mg/100 ml of plasma. 



EXAMINATION OF SOME URINARY CONSTITUENTS 



Table 4 shows the results of studies performed on the urine of one spécimen 

 of Inia, two spécimens of Platanîsta indi and one of P. gangetica. 



The colour of the urine varies from pale to bright yellow or olive. This 

 finding has already been reported by Ridgway (1965) and by ourselves (1970). 

 We have not been able to establish any clearly defined relationship between colour 

 intensity and the presumed concentration of the urine (mOsm). 



The pH value is about 6. 



