Discussion 35 



populations might well be applied to some of the animal studies that 

 have been described. Dr. Comfort, in producing some of his Zoo figures, 

 explained to us the difficulties of assessing and interpreting this type of 

 material, but I should imagine that the vast majority of animals that 

 live in Zoos are being badly nourished from a qualitative point of view, 

 at least. Recently, we (The Nutrition Society) have attempted to arrange 

 with the Zoological Society a combined meeting during which we hoped 

 to discuss the nutrition of animals in captivity, but the Zoo people 

 pointed out that they could only say what they gave to animals ; they 

 could, in fact, contribute nothing as to the nutritional requirements of 

 any of them. Taking as an example one particular group of animals, the 

 carnivores, it is almost certain that these animals are grossly deficient, 

 particularly in the vitamin B complex. They have a short digestive 

 tract, the food moves fairly quickly through it, there is probably very 

 little opportunity for bacterial synthesis of B-complex vitamins, and it 

 seems highly probable that all animals in that group are in a subnutri- 

 tional state as far as these vitamins are concerned. This applies probably 

 to domestic dogs also; I have seen some spectacular improvements in 

 health and well-being of dogs after they have been fed their extra sup- 

 plements of dried yeast ; as you know, most carnivores when in the wild 

 eat a whole animal, the liver and kidneys and so on, not just the flesh 

 which is all they are given when they are kept in Zoos or domesticated 

 in the home. I have seen a remarkable improvement in a non-carnivore, 

 namely a race-horse which, at one stage, was about to be condemned to 

 death because of its very poor condition. Within three months of being 

 given regular vitamin B complex in the form of dried brewers' yeast it 

 was winning races without, I might say, my money being on it! The sig- 

 nificance of these comments is that longevity statistics for animals kept 

 in Zoos and kept domestically are affected by the almost certain state 

 of sub-optimal nutrition in which these animals live. 



Olbrich: This is not strange. We have to examine the nutrition but 

 we also have to examine the effect of nutrition on the animal or human 

 being. For example, the specific dynamic action of proteins diminishes 

 the older a person gets, and this is a very important point. Perhaps this 

 applies to animals too; we must not only examine feeding but the 

 response to feeding. 



Landowne: Prof. Bourliere, I think you have outlined the opportunities 

 for experiments of this sort. Tadpoles that appear to have different 

 rates of maturation at different temperatures may do so because of 

 environmental factors other than thermal factors, and the experimental 

 approach could be applied to test such a possibility. For example, their 

 food supply may be quite different too. And in another category, the 

 wild goat story would be even more interesting if one could anticipate 

 the early drop in the slide that you showed, Dr. Comfort. Have we not 

 here the possibility of asking questions which might bear on the mech- 

 anism of these observations? Can you do something in the London Zoo 

 towards modifying the nutritive environment of these animals ? I mean, 

 cannot one suggest that they feed them in two ways rather than in one 

 way over any given period? 



