COMPARATIVE STUDIES ON THE SENSE OF TASTE 



289 



dietary deficiency. It seems reasonable that differences in adequacy of 

 diets could explain discrepancies in the reports on preference behavior of 

 chicks for sucrose. 



While cats have been frequently described as being indifferent to sucrose, 

 Frings (1951) reported contrary results. He found that cats do distinguish 

 between diluted milk with sucrose and that without, when starved 24 hr. 







Fig. 4. The influence of nutri 



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tional state on preference and intake of sucrose 

 in solution 

 *Periods represent successive 18 day trials. 



Although this study with chicks was designed to measure the influence 

 of caloric deficiency on preference behavior, other nutritional deficiencies or 

 imbalances (e.g., LeMagnen, 1956) could modify preference behavior. 

 Bernard et al. (1961) reported that vitamin A depleted rats show abnormal 

 taste behavior. An inherent " nutritional wisdom " of domestic animals 

 cannot be relied on in preference trials. In recent studies in our laboratory 

 with protein deficient chicks they failed to prefer a casein solution in a two- 

 choice situation. 



The differences in response to sugars by the chick, the rat and the calf 

 might also be considered with relation to their circulating blood glucose 

 level and their physiological regulating mechanisms. The chicken nor- 

 mally has a blood glucose level that would be described as diabetic for the 

 rat, while the cow normally has a low blood sugar level that would be in a 

 pathological category for the rat. Further, both the chicken and the cow are 

 refractory to insulin, the blood sugar regulating hormone. 



Expressing preference as per cent of fluid intake gives only part of the 

 picture for sugars. Xylose is preferred by the rat to about the same degree 

 as glucose, maltose and sucrose (i.e., 97 per cent or over. Fig. 5). How- 

 ever, while the common sugar solutions cause a doubling of fluid intake, 

 the volume of xvlose solution consumed remains close to the control. It 



