Cestode nutrition /
Tarr, John J
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The literature pertaining to the nutrition of cestodes, including attempts to cultivate the organisms in vitro, is reviewed. On the basis of findings to date few definite conclusions can be made concerning either the specific food requirements of tapeworms or the functions the host's tissues play in fulfilling these needs. Because of the worms' largely anaerobic environment, glucose is considered to be the most probable energy source for cestodes because its lower respiratory quotient makes possible a more efficient utilization of oxygen than would be the case for either proteins or fats. All workers are of the opinion that fats and fatty substances present within cestodes are waste products of the organisms' metabolism rather than evidence of assimilated food materials. Protein in some form is undoubtedly necessary for cestode growth and reproduction. While the source from which tapeworms absorb these nitrogenous compounds has not been established, the host's tissues rather than the host's diet would seem to supply the necessary factors. Vitamin G, when absent from the diet of the female host, exerts an inhibitory effect on the establishment, growth, and reproductive capacity of Hymenolepis diminuta, but otherwise cestodes are apparently not dependent on the host's ration for their vitamin needs. It has been proven that Hymenolepis diminuta can absorb vitamin B1 from the host's tissues. The fat soluble vitamins A, D, and E might possibly by synthesized by the worms themselves. Noting that other workers had found milk to affect adversely cestode egg production, the author attempted to learn the effect of an all-milk diet on the establishment of Hymenolepis fraterna in the golden hamster, when the experimental diet and the attempt at infection were imposed concurrently. A control group on a well-balanced diet was also maintained. While none of the experimental animals showed signs of infection, six of the eight control hamsters became parasitized. It is suggested that milk may have in some way interfered with protein metabolism, since milk has been demonstrated by other workers to inhibit reproduction, and since in this case, it was assumed to have prevented established and growth.
Thesis (M.A.)--Boston University Includes bibliographical references (leaves 41-46).
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