Factors influencing haemoglobin synthesis byDaphnia

Abstract

It is known thatDaphniaincreases the haemoglobin content of its blood in water that has a low content of dissolved oxygen. It has now been found that a high temperature results in the synthesis of more haemoglobin than a low temperature, in waters of the same low oxygen content. The increased haemoglobin synthesis is probably due to the greater rate of metabolism of the animal at a high temperature and consequent lower oxygen concentration within the body, and to the lower oxygen affinity of haemoglobin at a high temperature resulting in a poorer oxygen supply to the tissues. It must also be due in part to the lower egg production at a high temperature and consequent lesser drain of haemoglobin from the blood into the eggs. Carbon dioxide is without influence on haemoglobin production. Duck faeces increase the haemoglobin synthesis in water of low oxygen content. This effect is not due to better nutrition. Vitamin B12causes a small increase in the amount of haemoglobin synthesized in response to oxygen deficiency. Iron salts added to water of low oxygen content can greatly increase the amount of haemoglobin synthesized. Ferrous salts are more effective than ferric salts. This is probably due to the ferrous ion producing ferric hydroxide in a more finely divided state than that produced by the ferric ion, so that the ferric hydroxide remains suspended in the water and available to be swallowed for a longer time. The rate of loss of haemoglobin by red animals transferred to aerated water has been studied.